WO2020059866A1 - Liquid detection system - Google Patents

Liquid detection system Download PDF

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Publication number
WO2020059866A1
WO2020059866A1 PCT/JP2019/037066 JP2019037066W WO2020059866A1 WO 2020059866 A1 WO2020059866 A1 WO 2020059866A1 JP 2019037066 W JP2019037066 W JP 2019037066W WO 2020059866 A1 WO2020059866 A1 WO 2020059866A1
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WIPO (PCT)
Prior art keywords
unit
cable
detection
liquid
voltage
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PCT/JP2019/037066
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French (fr)
Japanese (ja)
Inventor
輔 上坂
正美 荻野
Original Assignee
株式会社 潤工社
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Application filed by 株式会社 潤工社 filed Critical 株式会社 潤工社
Priority to JP2020549152A priority Critical patent/JPWO2020059866A1/en
Publication of WO2020059866A1 publication Critical patent/WO2020059866A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/16—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using electric detection means

Definitions

  • the present invention relates to a liquid detection system.
  • the present invention relates to a liquid detection system that detects a contact of a liquid to be detected by detecting a change in capacitance of a sensor having a cable structure.
  • a liquid detecting means an optical type, a resistance value between electrodes, a capacitance change type, and the like are known.
  • the capacitance change type which detects liquid contact by changing the capacitance, is not only excellent in detection speed and detection sensitivity, but also can detect liquids with high electrical resistance such as oil and organic solvents. Excellent in Due to the recent increase in safety requirements and environmental awareness, these liquids are not only stored around the storage tank and used equipment (for example, fuel tanks and generators), but also in the piping from the storage tank to the used equipment. Is required to be able to detect leaks at an early stage. However, pipes are often laid three-dimensionally in a building over long distances, bending many times, and liquid detection sensors for leak monitoring require a short time in such a complicated layout. In addition, detection with high sensitivity is required.
  • Patent Document 1 discloses an oscillation unit that has a capacitance type moisture detection element connected to a pulse signal generation circuit and outputs a pulse signal according to a change in capacitance, and an output unit that outputs the pulse signal.
  • a digital arithmetic processing unit for measuring the number of pulses of the pulse signal in a certain period of time and obtaining a water content based on the counting result; and a DC component removing device for removing a DC component applied to the water content detection element.
  • a quantity detection device is disclosed.
  • Patent Document 1 does not disclose details other than the fact that the moisture detection element is a capacitance type element made of aluminum hydroxide or the like, and performs detection over a certain distance or detection under a complicated layout. There is no disclosure of the enabling technology.
  • FIGS. 1 and 3 of Patent Document 2 are shown in FIGS. 7 and 8 of the present specification, respectively.
  • Patent Literature 2 discloses a moisture sensor 1 whose capacitance changes based on the relative dielectric constant of moisture detected, and an oscillator 2 including a CMOS timer that converts a change in capacitance of the moisture sensor into a change in frequency.
  • a moisture detecting device provided with a capacitor between a moisture sensor and an oscillator.
  • the moisture sensor 1 is provided on one surface of a flexible substrate 5 in parallel with two conductive detection lines 6 and 7 at an interval, and the detection protrusions 8 and 9 are alternately provided inside from both the detection lines 6 and 7.
  • Patent Document 2 does not disclose a detailed structure of a structure for supplying power to an element that performs arithmetic and communication.
  • the layout of the sensor is greatly restricted, and it is not practical to increase the length of the sensor beyond a certain length due to accuracy and cost.
  • Patent Literature 3 discloses a leak detection device using a leak detection cable whose characteristic impedance changes due to penetration of a liquid. Since a terminator having an impedance equivalent to the characteristic impedance of the detection cable is connected to the other end of the detection cable whose one end is connected to the detector, if there is no leakage, a pulse signal incident on the detection cable Does not produce reflected waves. When leakage occurs and the liquid permeates, the characteristic impedance of the permeated portion changes and a reflected wave is generated. By detecting the reflected wave, the detector can detect the leak and specify the leak location.
  • this detection cable Since this detection cable has a cable structure, it can be manufactured efficiently by using a general-purpose technology having a sufficient track record, even if it exceeds 1 m or several hundred m. In addition, since the cable structure is used, it is easily bent in any direction, and there is no directivity of detection sensitivity. Therefore, the degree of freedom in layout of sensor arrangement can be greatly increased.
  • the detection circuit using the characteristic impedance change disclosed in Patent Document 3 is designed so that the circuit tends to be complicated and the detection cable does not include a change point of the characteristic impedance due to factors other than liquid penetration. There was room for improvement in layability, such as the need to lay.
  • An object of the present invention is to provide a liquid detection system capable of performing high-sensitivity and high-precision detection even under conditions where the layout of the sensor is small and the detection is disadvantageous.
  • a liquid detection system includes a first conductor, a second conductor electrically insulated from the first conductor, and the first conductor and the second conductor.
  • a calculating unit that obtains a pulse corresponding to a frequency generated by the oscillation circuit from the timer IC, and calculates the capacitance of the detection cable by counting the number of pulses per unit time; and
  • a first voltage generation unit that generates a first voltage that is a voltage applied to the unit, and a second voltage generation unit that generates a second voltage that is a voltage applied to the timer IC.
  • a liquid detection system includes a first conductor, a second conductor electrically insulated from the first conductor, and the first conductor and the second conductor.
  • a detection cable that has a dielectric layer formed between the first and second conductors and has a capacitance that changes by contact with a liquid; a measurement unit that includes a calculation unit that calculates the capacitance of the detection cable; When the change in the capacitance calculated in the unit satisfies a predetermined condition, a control unit including a notification unit that notifies that a contact between the detection cable and the liquid has been detected, the detection cable and the measurement unit And a second cable connecting the measuring unit and the control unit, wherein the first cable is shorter than the second cable.
  • a liquid detection system includes a plurality of measurement units, and a control unit that receives a signal from the plurality of measurement units.
  • a second measurement unit having a second communication unit for transmitting to the outside, a third detection cable, a third calculation unit for determining contact of the liquid with the third detection cable, Third, the contact determination information of the third arithmetic unit is transmitted to the outside as a signal.
  • a third measuring unit having a communication unit, and, the ⁇ ⁇ the first measuring unit and the second measuring unit, each without contact determination information through the communication unit of the other measuring unit, Transmitting to the control unit, the third measuring unit transmits the contact determination information of the third measuring unit to the control unit via the first communication unit of the first measuring unit.
  • liquid detection system capable of performing high-sensitivity and high-precision detection even under conditions that are less restrictive in sensor layout and are disadvantageous for detection.
  • FIG. 1 is a block diagram showing an example of the liquid detection system according to the present invention.
  • the liquid detection device LDS includes a measurement unit MU and a sensor unit SU.
  • the measurement unit MU includes a wiring board, and a plurality of electronic components described below are formed on the wiring board.
  • the wiring board includes a connector MC1, and the measuring unit MU and the sensor unit SU are electrically connected to each other via a connector MC1 formed substantially on the wiring board.
  • the sensor unit SU includes a detection cable having a cable-like structure provided with a region where the capacitance at the position where the sensor unit SU comes into contact with the liquid changes. The detection cable is directly connected to the connector MC1.
  • the detection cable may be connected to the connector MC1 via a sensor-side connector (not shown) provided at one end of the detection cable and connectable to the connector MC1.
  • the sensor unit SU may be further provided with a lead cable formed between one end of the detection cable and the connector MC1, and electrically connecting these.
  • the sensing cable includes two conductors and a dielectric layer formed therebetween.
  • the two conductors each have faces facing each other and are electrically insulated.
  • the detection cable has a function as a capacitor.
  • the detection cable is a string-like elongated body having flexibility, and each of the two conductors and the dielectric formed therebetween extends in the longitudinal direction of the elongated body.
  • the dielectric layer includes an air layer, and is configured so that a liquid to be detected can enter the dielectric layer. With this configuration, the capacitance of the detection cable changes due to penetration of the liquid to be detected into the dielectric layer of the detection cable.
  • FIG. 2 is a cross-sectional view illustrating an example of the detection cable.
  • the detection cable SDC of the first example shown in FIG. 2A has a center conductor SCC and an outer conductor SOC.
  • the center conductor SCC can be formed of a soft copper wire or the like.
  • the outer conductor SOC can be formed as a braid made of a tin-plated soft copper wire.
  • the outer conductor SOC can also be formed as a braid in which a tin-plated soft copper wire and a porous PTFE (polytetrafluoroethylene) tape are mixed.
  • the center conductor SCC is configured by twisting seven strands made of copper.
  • the center conductor SCC is electrically connected to the connector MC1 of the measurement unit MU shown in FIG. 1 at one end of the detection cable SDC, and is connected to another current path or transmission path at the other end of the detection cable SDC.
  • the termination may be configured without any need.
  • the outer conductor SOC is electrically connected to the connector MC1 of the measuring unit MU shown in FIG. 1 at one end of the detection cable SDC, and is connected to another current path or transmission path at the other end of the detection cable SDC.
  • the termination may be configured without any need.
  • the external conductor SOC is preferably grounded, and is electrically connected to, for example, a terminal having a ground potential of the measuring unit MU shown in FIG.
  • a dielectric layer SPL is formed between the center conductor SCC of the detection cable SDC and the outer conductor SOC.
  • the dielectric layer SPL is formed, for example, by winding a tape of porous PTFE around the center conductor SCC.
  • the detection cable SDC of the first example constitutes a capacitive element using the center conductor SCC and the outer conductor SOC as first and second electrodes and using the dielectric layer SPL as a dielectric. This capacitance element can function as a detection cable because the capacitance to be detected changes when the liquid to be detected penetrates into the dielectric layer SPL via the external conductor SOC.
  • the detection cable SDC may further include an internal protection layer SIPL between the center conductor SCC and the dielectric layer SPL.
  • the internal protective layer SIPL is formed by extrusion using a resin such as PFA (perfluoroalkoxy alkane), and can prevent oils from penetrating into the central conductor SCC.
  • An outer protective layer SOPL and / or a protective braid SBL may be further formed on the outer periphery of the outer conductor SOC.
  • the outer protective layer SOPL is formed of, for example, a porous PTFE tape. Porous PTFE has good water repellency, but has the property of easily penetrating oils.
  • the outer protective layer SOPL including the porous PTFE tape as a material can transmit oils to the dielectric layer SPL without permeating moisture such as rainwater.
  • the protective braid SBL is formed by braiding, for example, aramid fiber or flame-retardant polyester yarn, and protects the detection cable SDC from physical external effects such as rubbing.
  • the air content of the protective braid SBL is preferably larger than the air content of the outer protective layer SOPL.
  • the air content of the outer protective layer SOPL is higher than the dielectric layer SPL.
  • the air content of the dielectric layer SPL is higher than the air content of the internal protective layer SIPL.
  • the air content is defined as SMat, which is the area occupied by one or more materials constituting the layer, and SAir, which is the area occupied by air without those materials.
  • FIG. 2B is a side view of the detection cable SDC of the second example
  • FIG. 2C is a cross-sectional view of the detection cable SDC at a position indicated by XX ′ in FIG. 2B
  • FIG. The detection cable SDC of the second example has a core material SCT which has flexibility and gives mechanical strength to the detection cable SDC.
  • Two conductor wires SUC1 and SUC2 are spirally wound around the outer periphery of the core material SCT at an equal pitch, respectively.
  • An external protective layer may be further provided to cover these core materials and conductor wires from outside (not shown).
  • a capacitance element is formed between the conductor line SUC1 and the conductor line SUC2.
  • the core material SCT may be composed of, for example, a resin alone, or a cord-like material in which a metal is coated with a resin, or may be a hollow tube made of a resin or a multilayer structure of these. It is preferable that the whole or a part is porous, and it is particularly preferable that the surface of the core material is constituted by a wound porous PTFE tape.
  • the conductor wires SUC1 and SUC2 are made of, for example, metal wires or stranded metal wires, and may have an insulating film formed on the surface.
  • the outer protective layer is made of resin and / or metal, and may be a solid layer or a porous layer.
  • both the conductor lines SUC1 and SUC2 serving as two electrodes constituting the capacitance are the same as those of the detection cable SDC of the second example. Since it is arranged on the surface of the core material SCT, compared with the detection cable SDC of the above-described first example, the liquid to be detected permeates directly from the outside into the core material SDC serving as the dielectric layer. Detection becomes possible. In addition, since a change in capacity occurs even if there is no permeation into the porous layer, it is possible to detect a liquid that does not permeate or hardly permeates into the porous layer.
  • All of the detection cables shown in FIG. 2 can be manufactured with a stable quality up to several hundred meters, as well as several meters, by using the wire manufacturing technology. Further, since these detection cables have a concentric cross section or a spiral structure, they are easily bent in any direction. Further, unlike other capacitance detecting elements, since a metal element wire is used as a conductor forming an electrode, deterioration due to bending or sliding hardly occurs. Although there are restrictions, attachment to the movable part is possible depending on the conditions. Furthermore, detection can be performed with the same sensitivity regardless of the direction in which the detection cable comes into contact with the liquid.
  • the linear length of the detection cable SDC was L SDC
  • L SDC linear length of the detection cable
  • the detection cable preferably has a circular cross section, and the maximum diameter thereof is preferably 10 mm or less, more preferably 5 mm or less.
  • the detection cable has such a flexibility that the function as a capacitance element is not destroyed even if the detection cable is bent and extended ten times with a bending radius corresponding to 30 times the diameter of the detection cable.
  • the capacity of the detection cable depends on its length, but is preferably 50 pF / m or more, and particularly preferably 100 pF / m or more from the viewpoint of sensitivity.
  • the upper limit is not particularly limited as long as the function of the oscillation circuit described below is not impaired, but is preferably 500 pF / m or less, particularly preferably 200 pF / m or less.
  • the lead cable for electrically connecting the detection cable SDC and the measurement unit MU is a long string having flexibility like the detection cable.
  • the lead cable includes at least two conductor wires, each of which is connected to two conductors of the sensing cable.
  • the lead cable may have a two-core parallel line or a twisted pair structure, but preferably has a coaxial structure.
  • the lead cable may include a plurality of components in common with the detection cable, but it is preferable that the lead cable has an external appearance that allows the difference from the detection cable with the naked eye.
  • the lead cable is covered with, for example, a lead cable protection layer composed of a solid layer, so that a change in capacitance due to contact with the liquid to be detected can be prevented.
  • Lead cable also has capacitance due to its structure.
  • the capacity per unit length of the lead cable is smaller than the capacity per unit length of the detection cable. More preferably, the capacity of the lead cable is smaller than the capacity of the detection cable SDC.
  • the length of the lead cable is longer than the length of the detection cable, and particularly preferable when the length of the lead cable is longer than three times the length of the detection cable.
  • a liquid having a large difference in relative permittivity from air is preferable.
  • it is suitable for detecting a liquid having a relative dielectric constant of 1.8 or more.
  • the detection can be performed at a relatively low voltage, it is particularly suitable for detecting the leakage of a flammable liquid such as oil or an organic solvent.
  • measurement unit MU includes operation unit MP, timer IC unit MT, and connector MC1.
  • the timer IC unit MT functions as an oscillator, and forms a CR oscillation circuit together with a capacitance element C (not shown) and a resistance element R (not shown) each having at least a capacitance including the capacitance of the sensor unit SU. Since the oscillation frequency of this oscillation circuit is determined by the combined capacitance of the connected capacitance elements and the combined resistance of the connected resistance elements, the capacitance of the detection cable is used as part or all of the capacitance of the oscillation circuit. Thus, the change in the capacitance of the detection cable can be detected from the change in the oscillation frequency.
  • a circuit that realizes a desired function may be configured using individual elements, but it is preferable to use a commercially available timer IC as the timer IC unit MT.
  • the timer IC has a plurality of transistors, diodes, resistors, and the like mounted on one silicon die and packaged.
  • the timer IC is not only inexpensive and small, but also has high reliability because it is a mature technology.
  • LMC555CM or NE555 from Texas Instruments, or 556 in which 555 is dualized can be used.
  • timer ICs output a pulse signal equal to the oscillation frequency from the output pin.
  • the arithmetic unit MP receives this pulse signal and counts the number of pulses per unit time, so that the capacitance value of the detection cable and its change during that period can be calculated. Then, the arithmetic unit MP can determine the contact of the liquid to the detection cable by a known method based on the capacitance value of the detection cable and its change.
  • the measurement unit MU may further include a display unit MD.
  • the display unit MD includes a display unit such as a liquid crystal display or an LED.
  • the display unit MD can display a measurement state, a measurement value, the presence or absence of an abnormality, and the like in an externally visible manner based on, for example, a command from the calculation unit MP.
  • the measurement unit MU may further include a storage unit MM.
  • the storage unit MM includes storage means such as an EEPROM, a RAM, and a dip switch, and holds data necessary for the operation in the operation unit MP, a log of measurement, and the like. Data can be stored or provided to the arithmetic unit MP.
  • the measurement unit MU includes a first voltage generation unit ME1 that generates a voltage applied to the operation unit MP, and a second voltage generation unit ME2 that generates a voltage applied to the timer IC unit MT.
  • the liquid detection system of the present embodiment stably provides high-sensitivity and high-precision detection even when combined with a detection cable.
  • the detection cable has excellent detection characteristics.
  • the inventors of the present application have found that there is a measurement problem due to the length, and that a problem may become apparent due to a change in an external factor, thereby lowering measurement accuracy.
  • the longer the detection cable is the smaller the change in measured capacitance tends to be.
  • the sensor is a capacitance change type sensor, if a conventional point sensor or a sensor to which flexible substrate technology is applied, the detection range is small, so that a large area in the dielectric layer due to liquid contact or all areas Changes in capacitance.
  • the detection range extends over a long distance of 1 m or more, 2.5 m or more, or 10 m or more. For this reason, depending on the type of leakage, and at least at the beginning of the leakage, only a part of the detection range of the detection cable often comes into contact with the liquid. In such a case, only a part of the capacitance in the dielectric layer changes. Therefore, it is required to determine the detection of the liquid based on a change in capacitance smaller than that in the related art.
  • the second is that the longer the detection cable becomes, the more susceptible to external noise.
  • Setting a long detection area by utilizing the length of the detection cable means that the detection cable passes through various electromagnetic wave environments.
  • a long detection cable can also act as an antenna to pick up external noise. As a result, noise flows from the sensor unit to the measurement unit, which may adversely affect the detection accuracy.
  • the amount of change in the capacitance is relatively increased to increase the signal required for determination, or the area through which the detection cable passes is limited (for example, It is conceivable that the influence of noise can be reduced by arranging the detection cables around the area so as to be densely arranged. However, such a restriction impairs the degree of freedom of the layout of the detection cables. I will.
  • liquid detection which is provided with a detection cable longer than a certain length and which is determined by using a change in the capacitance, considered that, in principle, there are factors that make the sensitivity and accuracy unstable. Even in this state, although sufficient sensitivity and accuracy are provided for practical use, the problem may become apparent when more disadvantageous conditions overlap. For example, there is a deterioration in measurement accuracy due to an increase in the calculation scale, such as processing more information in a shorter time.
  • the arithmetic unit MP mounted on the measuring unit MU together with the timer IC is, for example, a microcomputer, and the power consumption of the arithmetic unit MP greatly fluctuates due to the operation.
  • the timer IC unit shares the power supply system with the operation unit MP the voltage applied to the timer IC may decrease depending on the operation state of the operation unit MP, which is a cause of deterioration of the measured value.
  • the measuring unit MU includes a second voltage that generates a voltage applied to the timer IC unit MT separately from the first voltage generating unit ME1 that generates a voltage applied to the arithmetic unit MP.
  • a generation unit ME2 is provided. This enables stable measurement regardless of the operation state of the operation unit MP.
  • the decrease in the supply voltage due to the operation state of the calculation unit MP is superimposed on the fact that the detection cable having a large total length has a large capacitance and also acts on the error factor due to the above-described problem inherent to the detection cable, and becomes apparent in the detection cable. It is presumed that it became easier.
  • An external voltage is applied to the first voltage generation unit ME1 of the measurement unit MU from outside the measurement unit MU (a supply line of the external voltage is indicated by a double line).
  • the external voltage is, for example, DC24V.
  • the first voltage generation unit is, for example, a DC-DC converter that generates DC5V (first voltage), and applies this voltage to the calculation unit MP (a supply line of the first voltage is indicated by a solid line).
  • the accuracy of the output voltage of the first voltage generator may be, for example, a magnitude exceeding ⁇ 2%.
  • the first voltage may be applied to the display unit MD, the storage unit MM, and the second voltage generation unit ME2 in addition to the operation unit MP.
  • the second voltage generation unit ME2 includes, for example, a voltage reference IC that generates DC5V (second voltage), and applies this voltage to the timer IC unit (the supply line of the second voltage is indicated by a dashed line). It is preferable that the accuracy of the output voltage of the second voltage generator is, for example, ⁇ 1% or less.
  • the second voltage generator ME2 is, for example, a linear regulator.
  • the first voltage generation unit that dares to apply the voltage to the arithmetic unit MP and the voltage is applied to the timer IC unit
  • the first voltage and the second voltage are substantially equal means that the ratio V1 of the value V1 of the first voltage generated from the first voltage generator to the value of the second voltage V2 generated from the second voltage generator. / V2 is 0.7 or more and 1.3 or less.
  • the second voltage generator ME2 may further include a charge pump.
  • the charge pump boosts the applied voltage (for example, the first voltage of 5 V) to, for example, about 7 V, and applies the boosted voltage to the voltage reference IC. As described above, by applying a voltage including a margin to the voltage reference IC, the accuracy of the output voltage of the voltage reference IC can be further improved.
  • the charge pump is, for example, a switching regulator.
  • the measuring unit MU Since the measuring unit MU has the above configuration, it is possible to supply a highly controlled voltage to the timer IC unit regardless of fluctuations in the power consumption of the arithmetic unit MP. Thus, liquid detection can be performed with high accuracy without restricting the layout of the detection cable.
  • the form in which the voltage generated by the first voltage generation unit ME1 is applied to the second voltage generation unit ME2 has been described.
  • the voltage may be directly applied to the second voltage generator ME2, or a voltage generated by another DC-DC converter may be applied.
  • the second voltage generated by the second voltage generation unit ME2 is preferably in a form not applied to the display unit, and more preferably in a form not applied to the storage unit. It is particularly preferable that the second voltage generated by the second voltage generation unit ME2 is applied only to the timer IC unit.
  • the measurement unit MU may further include a communication unit MRT.
  • the communication unit MRT transmits a measurement status of the measurement unit MU, an abnormality detection, and the like to another device such as a control panel based on a command from the calculation unit. Such communication often occurs with a command from the control panel as a trigger, and the power consumption of the arithmetic unit MP may vary greatly during the measurement of the capacitance. Therefore, when the measurement unit MU includes the communication unit MRT, the second voltage that generates the voltage applied to the timer IC unit MT is separate from the first voltage generation unit ME1 that generates the voltage applied to the arithmetic unit MP. Providing the generation unit ME2 is particularly effective in obtaining highly accurate detection.
  • the measurement unit MU includes a low-pass filter MF between the timer IC unit and the connector MC1.
  • the low-pass filter is formed of, for example, a ⁇ -type filter, and prevents a high-frequency component of the external noise picked up by the sensor unit SU from being transmitted to the timer IC.
  • the oscillation circuit of the measurement unit MU may be operated at several kHz. On the other hand, for example, it was found that the detection cable picked up noise exceeding 40 kHz generated by a noise generation source disposed near the liquid leakage monitoring target, thereby deteriorating the detection accuracy.
  • the low-pass filter can effectively remove unnecessary noise while leaving necessary pulse signals.
  • the second voltage generator ME2 that generates the voltage applied to the timer IC unit MT.
  • the second voltage generating unit ME2 that generates the voltage applied to the timer IC unit MT in addition to the low-pass filter, two variation factors applied to the timer IC unit, namely, fluctuation of the power supply voltage and And noise from the sensor unit can be suppressed, which is particularly effective in obtaining highly accurate detection.
  • the liquid detection system LDS further includes a control unit CU having a notification unit CA.
  • the control unit CU is connected to the measurement unit MU by a control unit communication cable CCC, and is configured to perform transmission and reception of signals in any one or two directions with the measurement unit MU.
  • the measuring unit MU and the detection cable SDC are connected by the same lead cable SLC as in the above-described embodiment.
  • the liquid detection system When the size of the monitoring target increases, the distance between the measurement unit and the detection cable may increase.
  • the laying position of the detection cable is fixed at a position where there is a risk of leakage or where leakage should be monitored, while the position of the measurement unit is not necessarily related to the position of the leakage and is not This is because it must be placed in a place that is easy to monitor. Even in such a case, monitoring can be performed by increasing the length of the detection cable itself or the length of the lead cable.
  • the lead cable also has capacitance, and the capacitance of the lead cable, which increases in proportion to the length of the lead cable, is added to the combined capacitance of the oscillation circuit. Worsens.
  • the liquid detection system according to the present embodiment has the following configuration.
  • a control unit including a notification unit that notifies that the contact between the detection cable and the liquid is detected, a first cable that connects the detection cable and the measurement unit, the measurement unit and the control unit And a second cable for connecting Further, the first cable is shorter than the second cable.
  • the liquid detection system is configured such that a distance between a detection unit and a detection cable for notifying a user or an administrator of the detection system that contact with the liquid has been detected or that an abnormality has occurred is determined. Even if it is necessary to increase the size, the measurement unit including the timer IC and the calculation unit and the control unit including the notification unit are configured separately, and the measurement unit is arranged at a position close to the detection cable. Accordingly, it is possible to prevent the lead cable from becoming excessively long, and to suppress deterioration in detection accuracy.
  • the control unit CU includes a notification unit CA.
  • the notification unit CA may be a display unit such as a liquid crystal display or an LED, or may be a sound generation unit that notifies by sound such as a buzzer or a speaker. Alternatively, a signal transmission unit for generating a notification by a display unit or a sound generation unit in another device may be used.
  • the notification unit CA can notify the operation state of the control unit CU to the outside, for example.
  • the notification unit CA can further externally notify information acquired from the measurement unit MU via the control unit communication cable CCC, a determination result based on the information, and the like.
  • the control unit CU may further include an operation unit CO.
  • the operation unit CO includes, for example, an input interface such as a keyboard, a touch panel, or a push button.
  • the operation of the operation unit CO not only controls the operation of each function of the control unit CU but also controls the measurement unit MU via the control unit communication cable. Can be controlled remotely.
  • the control unit CU may include a storage unit CM including a storage element and the like, an operation unit CP that executes a program stored in the storage unit CM, and a communication unit CC1 that controls communication with the measurement unit.
  • control unit CU includes a timer IC unit MT, a calculation unit MP, a first voltage generation unit ME1, a second voltage generation unit ME2, a low-pass filter MF, and a part or all of the connector MC1, similarly to the measurement unit MU.
  • An internal measurement unit CIM that monitors a change in the capacitance of the detection cable connected to the connector MC1 may be provided.
  • the measurement unit MU may have the same configuration as that of FIG. 1, but it is sufficient that at least the timer IC unit MT, the operation unit MP, and the communication unit MRT are provided, and for example, the display unit MD can be omitted. .
  • the measuring unit MU only needs to be able to monitor the change in the capacitance of the connected detection cable SDC and transmit the monitoring result to the outside.
  • the second voltage generator may be omitted and the voltage generated by the first voltage generator may be applied to the timer IC as long as the measurement accuracy can be maintained.
  • the effect of suppressing the instability of the oscillation circuit including the timer IC due to the power consumption of the communication via the control unit communication cable CCC is obtained. It is particularly preferable to include a voltage generator.
  • the control unit communication cable CCC is composed of only conductor wires for signal transmission using, for example, differential transmission.
  • the control unit communication cable CCC may further include a power supply line for supplying power from the control unit CU to the measurement unit MU. In such a configuration, the restriction on the arrangement of the measurement unit MU can be reduced, and as a result, the lead cable can be further shortened.
  • the measurement unit MU monitors a change in the capacitance of the detection cable SDC. This monitoring result is transmitted to the control unit CU periodically or in response to a request from the control unit CU.
  • the control unit CU communicates with the detection cable via the notification unit CU. That the liquid has been contacted.
  • the notification that it is determined that the detection cable has come into contact with the liquid to be detected includes a notification that the contact means. For example, it may be a notification that an abnormality such as leakage has occurred.
  • the administrator who has received the notification can perform necessary measures such as displaying necessary information or stopping an alarm by operating the operation unit CO.
  • the determination as to whether the change in the capacitance satisfies the predetermined condition may be made by the control unit or by the measurement unit.
  • the first measuring unit and the second measuring unit are configured to be able to communicate with each other via a first cable, and the change in capacitance observed in the first measuring unit or the second measuring unit is And a control unit for notifying the contact between the sensor cable and the liquid when a predetermined condition is satisfied.
  • the liquid detection system in the present embodiment may have, for example, the following configuration.
  • a plurality of measurement units, and a control unit that receives a signal from the plurality of measurement units, the plurality of measurement units, the first detection cable, the contact of the liquid to the first detection cable
  • a first measurement unit having a first calculation unit to be determined, a first communication unit that transmits the contact determination information of the first calculation unit to the outside as a signal, a second detection cable,
  • a second measurement unit including a second calculation unit that determines the contact of the liquid with the second detection cable, and a second communication unit that transmits the contact determination information of the second calculation unit to the outside as a signal.
  • a third measurement unit comprising: a communication unit; and a first measurement unit and the third measurement unit. The second measurement unit transmits the contact determination information to the control unit without passing through the communication unit of the other measurement unit, and the third measurement unit transmits the contact determination information of the third measurement unit to the control unit. And transmitting to the control unit via the first communication unit of the first measurement unit.
  • the monitoring target area is divided into two or more sections, dedicated detection cables are laid on each section, dedicated detection sections are connected to each detection cable, and the plurality of measurement sections are connected to one control section. It has a configuration to be managed by. This makes it possible to suppress the deterioration of the detection accuracy even though the monitoring cable appears to be one continuous monitoring cable for long-distance monitoring. For example, when the same treatment is required irrespective of the detection section, simple measures can be taken, which is preferable. Alternatively, a configuration may be adopted in which the control unit notifies which of the measurement sections has been detected so as to be identifiable. Knowing the approximate position enables the operator to quickly confirm the site. In the present embodiment, the configuration and operation of the control unit CU and the measurement unit MU may be the same as the configuration and operation of the control unit CU and the measurement unit MU in the third embodiment.
  • FIG. 4A is a diagram showing an example in which the measuring units MU10 to MU12 are connected in series to the control unit CU.
  • the measuring unit MU10, the measuring unit MU11, and the measuring unit MU12 are connected to the sensor unit SU10, the sensor unit SU11, and the sensor unit SU12, respectively.
  • the measurement unit MU10 is directly connected to the control unit CU.
  • the measurement unit MU11 and the measurement unit MU12 are connected to the control unit CU via another measurement unit.
  • the measurement unit MU10 acquires the capacitance value measured by the measurement unit MU11 or the measurement unit MU12, and transmits the capacitance value to the control unit CU.
  • FIG. 4B is a diagram showing an example in which the measuring units MU10 to MU30 are connected in parallel to the control unit CU.
  • Each of the measurement units MU10 to MU30 communicates directly with the control unit without passing through another measurement unit.
  • the measuring units are connected in series as shown in FIG. 4A, a large difference occurs in the communication load between the measuring units.
  • the measurement unit MU12 only communicates with the measurement unit MU11, but the measurement unit MU10 can generate communication with the control unit CU, the measurement unit MU11, and further with the measurement unit MU12.
  • FIG. 4C shows an example of a configuration in which measuring units MU10 to MU30 are connected in parallel to the control unit CU, and a plurality of measuring units are connected in series to each of the measuring units MU10 to MU30. It is. As described above, each of the series and the parallel has advantages and disadvantages. When the number of the measurement units MU connected to the control unit CU increases, one of the problems is inevitably manifested. On the other hand, by configuring a block in which a plurality of measurement units are connected in series, and connecting one measurement unit MU in each block to the control unit CU in parallel, a high value utilizing each characteristic is obtained. A monitoring network with high sensitivity and accuracy can be constructed. For example, it is suitable for constructing a large-scale monitoring system including a measuring unit of 100 ch or more, and further, 300 ch or more.
  • FIG. 5 is a diagram for explaining the operation in the multipoint monitoring according to the present invention.
  • the liquid detection system LDS includes a control unit CU and a plurality of measurement units MU connected to the control unit CU via a control unit communication cable. Although illustration is omitted, a sensor unit SU is connected to each of the plurality of measurement units MU. A unique identification number is set for each of the plurality of measurement units MU. These identification numbers are held in a memory or a dip switch of each measurement unit MU, and the measurement unit MU can read its own identification number.
  • each measurement unit MU in FIG. 5 includes 1-1, 1-2, 2-1, 2-2a, 2-3a, and 2-2b at positions behind the MU.
  • Each identification number is displayed.
  • the control unit CU and the measurement unit MU include a communication port.
  • a communication port of the control unit CU is connected to a communication unit CC1 (not shown) in the control unit CU, and a signal sent from the communication unit is sent out of the control unit CU via this port.
  • a signal transmitted from outside the control unit CU is received by the communication unit of the control unit CU via the port.
  • the communication port of the measurement unit MU transmits and receives signals transmitted and received by the communication unit MRT (not shown) of the measurement unit MU via the communication port of the measurement unit MU.
  • These communication ports are connected to communication ports of another measurement unit MU or control unit CU via a control unit communication cable.
  • the control unit CU has a downstream port CDP.
  • Each of the plurality of measurement units MU includes an upstream port MUP and a downstream port MDP.
  • the upstream port MUP is a port for transmitting and receiving data toward the control unit CU
  • the downstream port MDP is a port for transmitting and receiving data in the opposite direction to the control unit CU.
  • the upstream port MUP of the measurement unit MU1-1 is connected to the downstream port of the control unit CU
  • the downstream port MDP of the measurement unit MU1-1 is connected to the upstream port of the measurement unit MU1-2.
  • the plurality of measurement units MU monitor changes in the capacitance of the detection cables connected to the respective measurement units, and hold the results.
  • the control unit CU can acquire information held by any control unit. A method in which the control unit CU acquires a monitoring result held by the control unit MU2-3a will be described as an example. First, the control unit CU transmits a signal requesting a monitoring result of the control units MU2-3a to all the measurement units MU. The approximate signal is directly transmitted from the control unit CU in a connection such as the measurement units MU1-1 and MU2-1. On the other hand, for example, in a connection such as the measurement unit MU1-2, the information may be delivered via the measurement unit MU1-1.
  • the designated measuring unit MU2-3a changes the electrical state of the upstream port MUP. For example, a potential that was at a high level is switched to a low level.
  • the measurement unit MU2-2a is connected to a position adjacent to the upstream of the measurement unit MU1-2.
  • the downstream port MDP of the measurement unit MU2-2a acquires the change in the electrical state of the upstream port of the measurement MU2-3a
  • the information received at the downstream port MDP of the measurement unit MU2-2a is measured. Transmission is possible from the upstream port MUP of 2a to the upstream.
  • the measurement unit MU2-1 transmits information received at the downstream port MDP to the upstream port MDP. From the side port MUP, it is possible to transmit upstream to the control unit DU in this example.
  • the measurement unit MU2-3a transmits the requested information, that is, the monitoring result, to the control unit CU after the transmission path of the information from the measurement unit MU2-3a to the control unit CU is formed.
  • the liquid detection system LDS has the above configuration, so that it is possible to monitor a monitoring area over a long distance exceeding, for example, 100 km. Further, even when a plurality of pipes are complicated and complicated like a plant, a monitoring network can be set with a high degree of freedom. In addition, since individual communication with the control unit is possible regardless of the connection position as long as there is a unique identification number, even after the monitoring network has been constructed, addition and deletion of measurement units, generation of branches, etc. Easy to do. It is particularly preferable that the measurement unit MU can support two types of power reception.
  • a measurement unit that is not restricted by power supply is provided.
  • the arrangement becomes possible.
  • the second power receiving unit that is supplied with power from an external power supply when a specific measuring unit MU is arranged at a position separated by a large distance, or when a specific measuring unit MU on the power supply side receives power, Even when many other measuring units MU on the side are connected, a stable operation can be obtained.
  • FIG. 6 is a diagram showing an example of laying of detection cables in multipoint monitoring according to the present invention.
  • the configuration of the liquid utilization system to be monitored will be described with reference to FIG.
  • the general liquid use system includes a transport path LPL, one end of the transport path LPL is connected to a liquid storage tank LUT1, and the other end of the transport path LPL is connected to a liquid storage tank LUT2.
  • the liquid storage tank LUT1 is, for example, a main tank and holds more than 1000 L of fuel, for example, heavy oil.
  • the liquid storage tank LUT2 is, for example, a fuel tank in an emergency generator, and has a storage amount of 100 L or less, which is smaller than the liquid storage tank LUT1.
  • the liquid storage tank LUT2 is a final storage position of fuel supplied to the engine during power generation, and has a buffer-like function of absorbing fluctuations in fuel consumption.
  • the transport path LPL is a pipeline and may include a pump and a valve (not shown).
  • the generator consumes fuel
  • the fuel is supplied from the storage tank LUT1 to the storage tank LUT2, that is, the fuel tank in the generator, via the transport path LPL.
  • the liquid storage tank LUT1 is disposed on the basement floor
  • the liquid storage tank LUT2 is disposed on the ground floor. Accordingly, the transport path LPL and its monitoring area have a section extending in the horizontal direction indicated by LDR2 and LDR4 in the figure and a section including an area extending in the vertical direction indicated by LDR3.
  • the monitoring area further has two compartments, indicated by LDR1 and LDR5 in the figure, respectively including an area below the reservoir LUT1 and an area below the reservoir LUT2.
  • “downward” means the same direction as the direction of gravity
  • “horizontal direction” means a direction perpendicular to the downward direction.
  • the liquid storage tank LUT1 is mounted on a pit LUP consisting of a concave portion formed on the floor in order to prevent fuel leaked due to emergency damage or the like from spreading on the floor or penetrating into the soil. ing.
  • the liquid detection system according to the fourth embodiment of the present invention includes one or more of the following configurations shown in FIG. Thereby, in liquid detection using a detection cable whose capacitance changes due to contact with liquid, detection with high sensitivity and high accuracy is realized.
  • the detection system LDS includes a plurality of measurement units MU, and the plurality of measurement units MU are connected to one control unit CU via a control unit communication cable CCC.
  • Each measurement unit MU is connected to a detection cable SDC laid in each section to be monitored.
  • the measurement unit MU and the detection cable SDC may be directly connected, but are preferably connected via a lead cable SLC. Describing the detection of liquid leakage from the monitoring section LDR1, that is, the liquid storage tank LUT1, for example, a detection cable SDC1 is laid on the bottom surface of the pit LUP, and the detection cable SDC1 is connected to the measurement unit MU1 via a lead cable SLC1. Is done.
  • the detection cable SDC2 is laid in the monitoring section LDR2, the detection cable SDC3 in the monitoring section LDR3, the detection cable SDC4 in the monitoring section LDR4, and the detection cable SDC5 in the monitoring section LDR5.
  • the number of detection cables per monitoring section may be one or more.
  • FIG. 3 shows an example in which three detection cables SDC2 are laid in the section LDR2. Although illustration is omitted, more detection cables SDC2 may be laid in an area of the section LDR2 where the detection cable SDC2 is not laid.
  • a detection cable may be laid on the floor immediately below the storage region.
  • a detection cable may be laid along the lowermost region of the outer peripheral surface.
  • the liquid detection system LDS of the present embodiment includes detection cables having different lengths.
  • the detection cable SDC4 laid above the upper section that is, the section (LDR4 in the figure) at a higher position, is connected to the section (LDR2 in the figure) at a lower position.
  • the detection cable SDC2 laid in a section (LDR2 in the figure) of the transportation route LPL having a small height difference is a detection cable laid in a section (LDR3 in the figure) with a larger height difference. It is shorter than cable SDC3.
  • the detection cable SDC5 laid in the section (LDR5 in the figure) where the liquid storage volume of the liquid storage tank is small is smaller than the storage cable in the liquid storage tank LUT. It is shorter than the detection cable SDC1 laid in the large capacity section (LDR1 in the figure).
  • the detection cable SDC5 laid in a section (LDR5 in the figure) that is not a recess for storing leaked liquid is laid in a section (LDR1 in the figure) in the recess for storing leaked liquid. It is shorter than the detection cable SDC1.
  • the detection cable is made to have an appropriate length, thereby achieving high detection sensitivity as a whole system. And detection accuracy can be realized.
  • the value of D SDC / L SDC when the linear distance was D SDC between the one end and the other end of the detection cable after laying a subject to monitor the presence of the liquid was laid while bending the detection cable
  • it is an index of the size of the monitoring area per unit length of the detection cable.
  • D SDC / L SDC when the value of D SDC / L SDC is 1, it means k that the detection cable is laid linearly, and when it is less than 1, it means that the curved portion is included.
  • efficient laying such that the value of D SDC / L SDC becomes 0.3 or more is possible. More efficient laying as described above is also possible.
  • D SDC / L value of the SDC may be calculated in a single detection cable, among the plurality of sensing cable connected to the same control unit CU, for each five sensing cable that randomly D SDC / It may be calculated as an average of the values of LSDC .

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  • General Physics & Mathematics (AREA)
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  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
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Abstract

A liquid detection system characterized by comprising: a detection cable that changes in capacitance due to contact with a liquid, and that is provided with a first conductor, a second conductor electrically insulated from the first conductor, and a dielectric layer formed between the first conductor and the second conductor; a timer IC that constitutes an oscillation circuit; a computation unit that acquires, from the timer IC, a pulse corresponding to the frequency generated by the oscillation circuit, and that calculates the capacitance of the detection cable by counting the number of pulses per unit time; a first voltage generation unit that generates a first voltage, which is a voltage to be applied to the computation unit; and a second voltage generation unit that generates a second voltage, which is a voltage to be applied to the timer IC.

Description

液体検知システムLiquid detection system
　本発明は液体検知システムに関する。特に、ケーブル構造を有するセンサの、静電容量の変化を検出することにより、被検知液体が接触したことを検知する液体検知システムに関する。 The present invention relates to a liquid detection system. In particular, the present invention relates to a liquid detection system that detects a contact of a liquid to be detected by detecting a change in capacitance of a sensor having a cable structure.
　液体の検知手段としては、光学型、電極間抵抗値型、静電容量変化型などが知られている。なかでも、静電容量の変化により液体の接触を検知する静電容量変化型は、検出速度や検出感度に優れるだけでなく、油や有機溶剤のような高い電気抵抗を有する液体も検知できる点において優れている。近年の安全要求や環境意識の高まりにより、その液体の貯槽および使用機器（例えば燃料タンクおよび発電機）の周辺だけでなく、貯槽から使用機器までの輸送経路となる配管を含めて、これらの液体の漏洩を早い段階で検知できることが求められる。しかし配管は建屋内を、長距離にわたり、何度も屈曲しながら３次元的に敷設されることが多く、漏洩監視のための液体検知センサでは、このような複雑なレイアウト下における短時間での、かつ、高感度での検知が求められる。 光学 As a liquid detecting means, an optical type, a resistance value between electrodes, a capacitance change type, and the like are known. Above all, the capacitance change type, which detects liquid contact by changing the capacitance, is not only excellent in detection speed and detection sensitivity, but also can detect liquids with high electrical resistance such as oil and organic solvents. Excellent in Due to the recent increase in safety requirements and environmental awareness, these liquids are not only stored around the storage tank and used equipment (for example, fuel tanks and generators), but also in the piping from the storage tank to the used equipment. Is required to be able to detect leaks at an early stage. However, pipes are often laid three-dimensionally in a building over long distances, bending many times, and liquid detection sensors for leak monitoring require a short time in such a complicated layout. In addition, detection with high sensitivity is required.
　特許文献１には、パルス信号発生回路に接続された静電容量型の水分量検知素子を有し、静電容量の変化に応じたパルス信号を出力する発振手段と、該発振手段から出力されたパルス信号の一定時間におけるパルス数を計測し、その計数結果に基づいて水分量を求めるディジタル演算処理手段と、前記水分量検知素子にかかる直流成分を除去する直流成分除去手段とを具備する水分量検出装置が開示されている。特許文献１には、水分量検知素子が水酸化アルミニウム等からなる静電容量型のものであることの他に詳細の開示は無く、一定以上の距離にわたる検知、あるいは複雑なレイアウト下における検知を可能とする技術に関する開示も無い。 Patent Document 1 discloses an oscillation unit that has a capacitance type moisture detection element connected to a pulse signal generation circuit and outputs a pulse signal according to a change in capacitance, and an output unit that outputs the pulse signal. A digital arithmetic processing unit for measuring the number of pulses of the pulse signal in a certain period of time and obtaining a water content based on the counting result; and a DC component removing device for removing a DC component applied to the water content detection element. A quantity detection device is disclosed. Patent Document 1 does not disclose details other than the fact that the moisture detection element is a capacitance type element made of aluminum hydroxide or the like, and performs detection over a certain distance or detection under a complicated layout. There is no disclosure of the enabling technology.
　特許文献２の図１及び図３を、本願明細書の図７及び図８にそれぞれ示す。特許文献２は、検知される水分の比誘電率に基づいて静電容量が変化する水分センサ１と、水分センサの静電容量の変化を周波数の変化に変換するＣＭＯＳタイマからなる発振器２とを備え、水分センサと発振器との間にコンデンサを入れたことを特徴とする水分検知装置を開示する。概水分センサ１は、フレキシブル基板５の片面に二本の導電性の検知ライン６、７と間隔をあけて平行に設け、両検知ライン６、７から内側に検知突子８、９を交互に突出させてくし形にし、隣り合う検知突子８、９間に水分が接触すると両検知ライン６、７間の浮遊容量が変化するようにしてある。
　特許文献２には、演算や通信を担う要素への給電構造に関する詳細な開示は無い。また、フレキシブル基板技術を用いるものであるため、センサのレイアウト上の制約が大きい上に、一定以上の長尺化は精度上、コスト上現実的ではない。 FIGS. 1 and 3 of Patent Document 2 are shown in FIGS. 7 and 8 of the present specification, respectively. Patent Literature 2 discloses a moisture sensor 1 whose capacitance changes based on the relative dielectric constant of moisture detected, and an oscillator 2 including a CMOS timer that converts a change in capacitance of the moisture sensor into a change in frequency. Disclosed is a moisture detecting device provided with a capacitor between a moisture sensor and an oscillator. The moisture sensor 1 is provided on one surface of a flexible substrate 5 in parallel with two conductive detection lines 6 and 7 at an interval, and the detection protrusions 8 and 9 are alternately provided inside from both the detection lines 6 and 7. The detection projections 8 and 9 are made to protrude to form a comb so that when moisture comes into contact between the detection projections 8 and 9 adjacent to each other, the floating capacitance between the detection lines 6 and 7 changes.
Patent Document 2 does not disclose a detailed structure of a structure for supplying power to an element that performs arithmetic and communication. In addition, since the flexible substrate technology is used, the layout of the sensor is greatly restricted, and it is not practical to increase the length of the sensor beyond a certain length due to accuracy and cost.
　特許文献３には、液体が浸透することにより特性インピーダンスが変化する漏洩検出ケーブルを用いた漏洩検出装置が開示されている。一端が検出器に接続された検出ケーブルの他端には検出ケーブルの特性インピーダンスと等価のインピーダンスを有する終端器が接続されているため、漏洩がない場合には、検出ケーブルに入射されるパルス信号は、反射波を生じない。漏洩が生じて液体が浸透すると、浸透した部分の特性インピーダンスが変化し反射波を生じる。検出器は、この反射波を検出することにより、漏洩を検出するとともに、漏洩箇所を特定することができる。この検出ケーブルはケーブルの構造を有しているため、十分な実績のある汎用技術を用いることにより、１ｍ以上はもちろん、数百ｍを超える場合であっても効率よく製造することができる。また、ケーブル構造のため、いずれの方向にも容易に曲がり、また、検出感度の指向性なども無いことからセンサ配置のレイアウト上の自由度を大きく高めることができる。
　しかしながら、特許文献３に示された特性インピーダンス変化を用いた検知回路は、回路が複雑になりがちであること、検出ケーブル内に液体の浸透以外の要因による特性インピーダンスの変化点を含まないように敷設する必要があるなど、敷設性に改善の余地があった。 Patent Literature 3 discloses a leak detection device using a leak detection cable whose characteristic impedance changes due to penetration of a liquid. Since a terminator having an impedance equivalent to the characteristic impedance of the detection cable is connected to the other end of the detection cable whose one end is connected to the detector, if there is no leakage, a pulse signal incident on the detection cable Does not produce reflected waves. When leakage occurs and the liquid permeates, the characteristic impedance of the permeated portion changes and a reflected wave is generated. By detecting the reflected wave, the detector can detect the leak and specify the leak location. Since this detection cable has a cable structure, it can be manufactured efficiently by using a general-purpose technology having a sufficient track record, even if it exceeds 1 m or several hundred m. In addition, since the cable structure is used, it is easily bent in any direction, and there is no directivity of detection sensitivity. Therefore, the degree of freedom in layout of sensor arrangement can be greatly increased.
However, the detection circuit using the characteristic impedance change disclosed in Patent Document 3 is designed so that the circuit tends to be complicated and the detection cable does not include a change point of the characteristic impedance due to factors other than liquid penetration. There was room for improvement in layability, such as the need to lay.
　これに対して、静電容量変化を検知可能な検知システムに、特許文献３の検出ケーブルを応用したケーブル構造の静電容量センサを適用することにより、シンプルな構成でありながら、レイアウトの自由度が極めて高く、かつ、敷設性に優れた液体検知システムを構成することが考えられる。しかしながら、単にこれらを組み合わせただけでは、所望の検知感度や判定精度を得られないことが懸念された。 On the other hand, by applying a capacitance sensor having a cable structure to which a detection cable of Patent Document 3 is applied to a detection system capable of detecting a change in capacitance, the degree of freedom in layout can be improved with a simple configuration. It is conceivable to configure a liquid detection system that is extremely high and has excellent layability. However, there was a concern that simply combining these would not provide the desired detection sensitivity or determination accuracy.
特公平７－９５０５５Tokuhei 7-95055 特開２００２－３５７５８２JP-A-2002-357852 特開２０１２－５２８３６JP 2012-52836A
　本発明の目的は、センサのレイアウト上の制約が小さく、かつ、検知には不利な条件下にあっても、高感度かつ高精度での検知が可能な液体検知システムを提供することである。 目的 An object of the present invention is to provide a liquid detection system capable of performing high-sensitivity and high-precision detection even under conditions where the layout of the sensor is small and the detection is disadvantageous.
上記目的達成のため、本発明にかかる液体検知システムは、第一の導体、前記第一の導体と電気的に絶縁された第二の導体、および、前記第一の導体と前記第二の導体との間に形成された誘電体層を備え、液体との接触により静電容量が変化する検知ケーブルと、前記検知ケーブルとともに、前記検知ケーブルの前記静電容量を含む発振回路を構成するタイマＩＣと、前記タイマＩＣから前記発振回路の生成される周波数に対応するパルスを取得し、単位時間あたりの前記パルス数をカウントすることで前記検知ケーブルの静電容量を算出する演算部と、前記演算部に印加される電圧である第一電圧を発生する第一電圧発生部と、前記タイマＩＣに印加される電圧である第二電圧を発生する第二電圧発生部と、を備えることを特徴とする。 To achieve the above object, a liquid detection system according to the present invention includes a first conductor, a second conductor electrically insulated from the first conductor, and the first conductor and the second conductor. A detection cable having a dielectric layer formed between the detection cable and the capacitance, and a timer IC forming an oscillation circuit including the capacitance of the detection cable together with the detection cable A calculating unit that obtains a pulse corresponding to a frequency generated by the oscillation circuit from the timer IC, and calculates the capacitance of the detection cable by counting the number of pulses per unit time; and A first voltage generation unit that generates a first voltage that is a voltage applied to the unit, and a second voltage generation unit that generates a second voltage that is a voltage applied to the timer IC. I do.
　また、上記目的達成のため、本発明にかかる液体検知システムは、第一の導体、前記第一の導体と電気的に絶縁された第二の導体、および、前記第一の導体と前記第二の導体との間に形成された誘電体層を備え、液体との接触により静電容量が変化する検知ケーブルと、前記検知ケーブルの静電容量を算出する演算部を備える計測部と、前記計測部において算出された静電容量の変化が予め定めた条件を満たすときに、検知ケーブルと液体との接触を検知したことを通知する通知部を備える制御部と、前記検知ケーブルと前記計測部とを接続する第一のケーブルと、前記計測部と前記制御部とを接続する第二のケーブルとを備え、前記第一のケーブルは、前記第二のケーブルより短いことを特徴とする。 In order to achieve the above object, a liquid detection system according to the present invention includes a first conductor, a second conductor electrically insulated from the first conductor, and the first conductor and the second conductor. A detection cable that has a dielectric layer formed between the first and second conductors and has a capacitance that changes by contact with a liquid; a measurement unit that includes a calculation unit that calculates the capacitance of the detection cable; When the change in the capacitance calculated in the unit satisfies a predetermined condition, a control unit including a notification unit that notifies that a contact between the detection cable and the liquid has been detected, the detection cable and the measurement unit And a second cable connecting the measuring unit and the control unit, wherein the first cable is shorter than the second cable.
　また、上記目的達成のため、本発明にかかる液体検知システムは、複数の計測部と、当該複数の計測部からの信号を受信する制御部と、を備え、　前記複数の計測部は、　第一の検知ケーブルと、当該第一の検知ケーブルへの液体の接触を判定する第一の演算部と、当該第一の演算部の接触判定情報を信号として外部に送信する第一の通信部と、を有する第一の計測部と、　第二の検知ケーブルと、当該第二の検知ケーブルへの液体の接触を判定する第二の演算部と、当該第二の演算部の接触判定情報を信号として外部に送信する第二の通信部と、を有する第二の計測部と、　第三の検知ケーブルと、前記第三の検知ケーブルへの液体の接触を判定する第三の演算部と、当該第三の演算部の接触判定情報を信号として外部に送信する第三の通信部、を備えた第三の計測部と、　を有し、　前記第一の計測部および前記第二の計測部は、それぞれ接触判定情報を他の計測部の通信部を経由せずに前記制御部に送信し、　前記第三の計測部は、前記第三の計測部の接触判定情報を前記第一の計測部の前記第一の通信部を経由して前記制御部に送信することを特徴とする。 In order to achieve the above object, a liquid detection system according to the present invention includes a plurality of measurement units, and a control unit that receives a signal from the plurality of measurement units. A detection cable, a first calculation unit that determines contact of the liquid to the first detection cable, and a first communication unit that transmits the contact determination information of the first calculation unit as a signal to the outside, A first measurement unit having a second detection cable, a second calculation unit that determines contact of the liquid to the second detection cable, and contact determination information of the second calculation unit as a signal. A second measurement unit having a second communication unit for transmitting to the outside, a third detection cable, a third calculation unit for determining contact of the liquid with the third detection cable, Third, the contact determination information of the third arithmetic unit is transmitted to the outside as a signal. A third measuring unit having a communication unit, and, the 計 測 the first measuring unit and the second measuring unit, each without contact determination information through the communication unit of the other measuring unit, Transmitting to the control unit, the third measuring unit transmits the contact determination information of the third measuring unit to the control unit via the first communication unit of the first measuring unit. Features.
　本発明によれば、センサのレイアウト上の制約が小さく、かつ、検知には不利な条件下にあっても、高感度かつ高精度での検知が可能な液体検知システムが提供される。 According to the present invention, there is provided a liquid detection system capable of performing high-sensitivity and high-precision detection even under conditions that are less restrictive in sensor layout and are disadvantageous for detection.
本発明に係る液体検知システムの一例を示すブロック図である。It is a block diagram showing an example of the liquid detection system concerning the present invention. 本発明に係る検知ケーブルの一例を示す断面図である。It is sectional drawing which shows an example of the detection cable which concerns on this invention. 本発明に係る制御部および制御部を有する液体検知システムの一例を示す図である。It is a figure showing an example of a control part and a liquid detection system which has a control part concerning the present invention. 本発明に係る多点監視における通信の接続を説明する図である。It is a figure explaining the connection of the communication in the multipoint monitoring concerning the present invention. 本発明に係る多点監視における動作を説明する図である。It is a figure explaining operation in multipoint monitoring concerning the present invention. 本発明に係る多点監視における検知ケーブルの敷設の一例を示す図である。It is a figure showing an example of laying of a detection cable in multipoint monitoring concerning the present invention. 従来の水分検知装置を示す図である。It is a figure showing the conventional moisture detector. 従来の水分検知装置における水分センサを示す平面図である。It is a top view showing the moisture sensor in the conventional moisture detector.
　以下、添付図面を参照して、本発明に係る漏洩検出装置について詳細に説明する。それぞれの図面において、同一、又は類似する機能を有する構成素子には、同一、又は類似する符号が付される。したがって、先に説明した構成要素と同一、又は類似する機能を有する構成素子に関しては、改めて説明をしないことがある。
　また、以下に説明する実施形態は請求の範囲にかかる発明を限定するものではなく、また実施形態の中で説明されている特徴の組み合わせの全てが発明の解決手段に必須であるとは限らない。また、それぞれの実施例における各々の実施形態は、本発明の技術的な意義を失わない範囲で自由に組み合わせてもよい。 Hereinafter, a leakage detection device according to the present invention will be described in detail with reference to the accompanying drawings. In the respective drawings, components having the same or similar functions are denoted by the same or similar reference numerals. Therefore, components having the same or similar functions as the components described above may not be described again.
Further, the embodiments described below do not limit the invention according to the claims, and all combinations of the features described in the embodiments are not necessarily essential to the solution of the invention. . In addition, each embodiment in each example may be freely combined without departing from the technical significance of the present invention.
（第一の実施形態）
　図１は、本発明に係る液体検知システムの一例を示すブロック図である。本実施形態において液体検知装置ＬＤＳは、計測部ＭＵとセンサ部ＳＵとを含む。計測部ＭＵは配線基板を含んでおり、該配線基板上には、後述する複数の電子部品が形成されている。該配線基板はコネクタＭＣ１を含み、計測部ＭＵとセンサ部ＳＵとは、概配線基板上に形成されたコネクタＭＣ１を介して電気的に接続される。センサ部ＳＵは液体と接触することにより、接触した位置の静電容量が変化する領域を備えたケーブル状の構造を有する検知ケーブルを含む。
　検知ケーブルは、コネクタＭＣ１に直接接続される。あるいは、検知ケーブルの一端に設けられ、コネクタＭＣ１と接続可能なセンサ側コネクタ（不図示）を介して検知ケーブルとコネクタＭＣ１とが接続されてもよい。センサ部ＳＵは、検知ケーブルの一端とコネクタＭＣ１との間に形成され、これらを電気的に接続するリードケーブルをさらに備えていてもよい。 (First embodiment)
FIG. 1 is a block diagram showing an example of the liquid detection system according to the present invention. In the present embodiment, the liquid detection device LDS includes a measurement unit MU and a sensor unit SU. The measurement unit MU includes a wiring board, and a plurality of electronic components described below are formed on the wiring board. The wiring board includes a connector MC1, and the measuring unit MU and the sensor unit SU are electrically connected to each other via a connector MC1 formed substantially on the wiring board. The sensor unit SU includes a detection cable having a cable-like structure provided with a region where the capacitance at the position where the sensor unit SU comes into contact with the liquid changes.
The detection cable is directly connected to the connector MC1. Alternatively, the detection cable may be connected to the connector MC1 via a sensor-side connector (not shown) provided at one end of the detection cable and connectable to the connector MC1. The sensor unit SU may be further provided with a lead cable formed between one end of the detection cable and the connector MC1, and electrically connecting these.
　検知ケーブルは２つの導体及びその間に形成された誘電体層を含む。２つの導体は互いに向かい合う面をそれぞれ有し、かつ、電気的に絶縁されている。このような構成により、検知ケーブルは容量素子としての機能を有する。検知ケーブルは可とう性を備えた紐状の長尺体であり、上記の２つ導体及びその間に形成された誘電体のそれぞれは、長尺体の長手方向に沿って延伸する。誘電体層は空気層を含み、検知対象となる液体が誘電体層に浸入可能に構成されている。この構成により、検知ケーブルの静電容量は、検知対象液体の検知ケーブルの誘電体層への浸入により、変化する。 The sensing cable includes two conductors and a dielectric layer formed therebetween. The two conductors each have faces facing each other and are electrically insulated. With such a configuration, the detection cable has a function as a capacitor. The detection cable is a string-like elongated body having flexibility, and each of the two conductors and the dielectric formed therebetween extends in the longitudinal direction of the elongated body. The dielectric layer includes an air layer, and is configured so that a liquid to be detected can enter the dielectric layer. With this configuration, the capacitance of the detection cable changes due to penetration of the liquid to be detected into the dielectric layer of the detection cable.
　図２は、検知ケーブルの例を示す断面図である。図２（ａ）に示す第１の例の検知ケーブルＳＤＣは、中心導体ＳＣＣと、外部導体ＳＯＣとを有する。中心導体ＳＣＣは、軟銅線などで形成できる。外部導体ＳＯＣは、錫めっき軟銅線からなる編組として形成できる。外部導体ＳＯＣは、錫めっき軟銅線及び多孔質ＰＴＦＥ（ｐｏｌｙｔｅｔｒａｆｌｕｏｒｏｅｔｈｙｌｅｎｅ、ポリテトラフルオロエチレン）テープを混合した編組としても形成できる。本実施形態において中心導体ＳＣＣは、７本の銅からなる素線を撚り合わせて構成される。中心導体ＳＣＣは、検知ケーブルＳＤＣの一端の側において図１に示す計測部ＭＵのコネクタＭＣ１に電気的に接続され、検知ケーブルＳＤＣの他端の側においては他の電流経路や伝送経路と接続されることなく終端を構成して良い。外部導体ＳＯＣは、検知ケーブルＳＤＣの一端の側において図１に示す計測部ＭＵのコネクタＭＣ１に電気的に接続され、検知ケーブルＳＤＣの他端の側においては他の電流経路や伝送経路と接続されることなく終端を構成して良い。また、外部導体ＳＯＣは、接地されていることが好ましく、例えば図１に示す計測部ＭＵの接地電位を有する端子と電気的に接続される。
　検知ケーブルＳＤＣの中心導体ＳＣＣと外部導体ＳＯＣとの間には誘電体層ＳＰＬが形成される。誘電体層ＳＰＬは、例えば多孔質ＰＴＦＥのテープを中心導体ＳＣＣの周囲に巻回させることにより形成される。第１の例の検知ケーブルＳＤＣは、中心導体ＳＣＣと外部導体ＳＯＣとを第一、第二の電極とし、誘電体層ＳＰＬを誘電体とする容量素子を構成している。この容量素子は、検知対象とする液体が外部導体ＳＯＣを介して誘電体層ＳＰＬに浸透することにより静電容量が変化するため、検知ケーブルとして機能させることが出来る。 FIG. 2 is a cross-sectional view illustrating an example of the detection cable. The detection cable SDC of the first example shown in FIG. 2A has a center conductor SCC and an outer conductor SOC. The center conductor SCC can be formed of a soft copper wire or the like. The outer conductor SOC can be formed as a braid made of a tin-plated soft copper wire. The outer conductor SOC can also be formed as a braid in which a tin-plated soft copper wire and a porous PTFE (polytetrafluoroethylene) tape are mixed. In the present embodiment, the center conductor SCC is configured by twisting seven strands made of copper. The center conductor SCC is electrically connected to the connector MC1 of the measurement unit MU shown in FIG. 1 at one end of the detection cable SDC, and is connected to another current path or transmission path at the other end of the detection cable SDC. The termination may be configured without any need. The outer conductor SOC is electrically connected to the connector MC1 of the measuring unit MU shown in FIG. 1 at one end of the detection cable SDC, and is connected to another current path or transmission path at the other end of the detection cable SDC. The termination may be configured without any need. The external conductor SOC is preferably grounded, and is electrically connected to, for example, a terminal having a ground potential of the measuring unit MU shown in FIG.
A dielectric layer SPL is formed between the center conductor SCC of the detection cable SDC and the outer conductor SOC. The dielectric layer SPL is formed, for example, by winding a tape of porous PTFE around the center conductor SCC. The detection cable SDC of the first example constitutes a capacitive element using the center conductor SCC and the outer conductor SOC as first and second electrodes and using the dielectric layer SPL as a dielectric. This capacitance element can function as a detection cable because the capacitance to be detected changes when the liquid to be detected penetrates into the dielectric layer SPL via the external conductor SOC.
　検知ケーブルＳＤＣは、図２（ａ）に示すように、中心導体ＳＣＣと誘電体層ＳＰＬとの間に、内部保護層ＳＩＰＬをさらに有していても良い。内部保護層ＳＩＰＬは、例えばＰＦＡ（パーフルオロアルコキシアルカン）などの樹脂を用いた押出しにより形成され、中心導体ＳＣＣに油類が浸透することを防止できる。外部導体ＳＯＣの外周には、さらに外部保護層ＳＯＰＬおよび／または保護編組ＳＢＬが形成されていても良い。外部保護層ＳＯＰＬは、例えば多孔質ＰＴＦＥのテープで形成される。多孔質ＰＴＦＥは、良好な撥水性を有する一方、油類を容易に浸透させる特性を有する。このため、多孔質ＰＴＦＥのテープを材料として含む外部保護層ＳＯＰＬは雨水などの水分を浸透させずに、油類を誘電体層ＳＰＬに透過させることが可能である。保護編組ＳＢＬは例えばアラミド繊維や難燃ポリエステル糸を編組することにより構成され、こすれ等の物理的な外部作用から検知ケーブルＳＤＣを保護する。 (2) As shown in FIG. 2A, the detection cable SDC may further include an internal protection layer SIPL between the center conductor SCC and the dielectric layer SPL. The internal protective layer SIPL is formed by extrusion using a resin such as PFA (perfluoroalkoxy alkane), and can prevent oils from penetrating into the central conductor SCC. An outer protective layer SOPL and / or a protective braid SBL may be further formed on the outer periphery of the outer conductor SOC. The outer protective layer SOPL is formed of, for example, a porous PTFE tape. Porous PTFE has good water repellency, but has the property of easily penetrating oils. For this reason, the outer protective layer SOPL including the porous PTFE tape as a material can transmit oils to the dielectric layer SPL without permeating moisture such as rainwater. The protective braid SBL is formed by braiding, for example, aramid fiber or flame-retardant polyester yarn, and protects the detection cable SDC from physical external effects such as rubbing.
　同図の断面視において、保護編組ＳＢＬの空気含有率は外部保護層ＳＯＰＬの空気含有率より大きいことが好ましい。また、外部保護層ＳＯＰＬの空気含有率は誘電体層ＳＰＬより大きいことが好ましい。また、誘電体層ＳＰＬの空気含有率は内部保護層ＳＩＰＬの空気含有率より大きいことが好ましい。ここで空気含有率は、各層の断面観察において、その層を構成する１つまたは複数の材料が占める面積をＳＭａｔとし、それらの材料が存在せず空気が占める面積ＳＡｉｒとしたとき、
　ＳＡｉｒ／（ＳＡｉｒ＋ＳＭａｔ）　（％）　
として、計算される。このように、一つの層より外側にある層の空気含有率を相対的に大きくすることにより、検知対象となる液体の浸透を促進し、検出速度、検出感度に優れた検知ケーブルを得ることが出来る。 In the cross-sectional view of the figure, the air content of the protective braid SBL is preferably larger than the air content of the outer protective layer SOPL. Preferably, the air content of the outer protective layer SOPL is higher than the dielectric layer SPL. Preferably, the air content of the dielectric layer SPL is higher than the air content of the internal protective layer SIPL. Here, in the cross-section observation of each layer, the air content is defined as SMat, which is the area occupied by one or more materials constituting the layer, and SAir, which is the area occupied by air without those materials.
SAir / (SAir + SMat) (%)
Is calculated as As described above, by relatively increasing the air content of the layer outside one layer, the penetration of the liquid to be detected is promoted, and a detection cable having excellent detection speed and detection sensitivity can be obtained. I can do it.
　図２（ｂ）は第２の例の検知ケーブルＳＤＣを側面から見た図であり、図２（ｃ）は図２（ｂ）のＸ－Ｘ‘で示した位置における検知ケーブルＳＤＣの断面を示す図である。この第２の例の検知ケーブルＳＤＣは、可とう性を有し、検知ケーブルＳＤＣに機械的な強度を与える芯材ＳＣＴを備える。芯材ＳＣＴの外周には、２本の導体線ＳＵＣ１とＳＵＣ２とが、それぞれ等ピッチで、らせん状に巻きつけられている。これらの芯材、導体線の外側から、これらを覆う外部保護層をさらに有していても良い（不図示）。この検知ケーブルは、導体線ＳＵＣ１と導体線ＳＵＣ２との間で容量素子を構成する。 FIG. 2B is a side view of the detection cable SDC of the second example, and FIG. 2C is a cross-sectional view of the detection cable SDC at a position indicated by XX ′ in FIG. 2B. FIG. The detection cable SDC of the second example has a core material SCT which has flexibility and gives mechanical strength to the detection cable SDC. Two conductor wires SUC1 and SUC2 are spirally wound around the outer periphery of the core material SCT at an equal pitch, respectively. An external protective layer may be further provided to cover these core materials and conductor wires from outside (not shown). In this detection cable, a capacitance element is formed between the conductor line SUC1 and the conductor line SUC2.
　芯材ＳＣＴは、例えば、樹脂のみで構成され、また金属に樹脂が被覆された紐状のもので構成されてもよく、樹脂製の中空のチューブ状でも、これらの多層構造でも構わない。全体または一部が多孔質であることが好ましく、芯材の表面が巻回された多孔質ＰＴＦＥのテープにより構成されていることが特に好ましい。導体線ＳＵＣ１およびＳＵＣ２は、例えば金属素線または金属素線の撚り線からなり、表面に絶縁膜が形成されていても良い。外部保護層は樹脂および／または金属からなり、充実層でもよく、多孔質層でも良い。検知感度、検知速度の観点からはメッシュや編組のように接触した液体が速やかに透過、浸透する構成であることが好ましい。
図２（ｂ）および図２（ｃ）に示す第２の例の検知ケーブルＳＤＣは、容量を構成する２つの電極となる導体線ＳＵＣ１およびＳＵＣ２がいずれも、第２の例の検知ケーブルＳＤＣの芯材ＳＣＴの表面に配置されるため、上述した第１の例の検知ケーブルＳＤＣと比較して、検知する液体が直接外部から誘電体層となる芯材ＳＤＣに浸透するため、短時間での検出が可能となる。また、多孔質層への浸透がなくても容量変化が生じるため、多孔質層に浸透しない、または、浸透しにくい液体の検知も可能となる。 The core material SCT may be composed of, for example, a resin alone, or a cord-like material in which a metal is coated with a resin, or may be a hollow tube made of a resin or a multilayer structure of these. It is preferable that the whole or a part is porous, and it is particularly preferable that the surface of the core material is constituted by a wound porous PTFE tape. The conductor wires SUC1 and SUC2 are made of, for example, metal wires or stranded metal wires, and may have an insulating film formed on the surface. The outer protective layer is made of resin and / or metal, and may be a solid layer or a porous layer. From the viewpoint of the detection sensitivity and the detection speed, it is preferable that the liquid which has contacted like a mesh or a braid penetrates and permeates quickly.
In the detection cable SDC of the second example shown in FIG. 2B and FIG. 2C, both the conductor lines SUC1 and SUC2 serving as two electrodes constituting the capacitance are the same as those of the detection cable SDC of the second example. Since it is arranged on the surface of the core material SCT, compared with the detection cable SDC of the above-described first example, the liquid to be detected permeates directly from the outside into the core material SDC serving as the dielectric layer. Detection becomes possible. In addition, since a change in capacity occurs even if there is no permeation into the porous layer, it is possible to detect a liquid that does not permeate or hardly permeates into the porous layer.
　図２に示した検知ケーブルは、いずれも、電線の製造技術を利用することにより、数ｍはもちろん、数百ｍに及ぶものまで安定した品質で製造できる。また、これらの検知ケーブルは、同心円構造の断面を有する、または、螺旋構造を有するため、いずれの方向にも容易に湾曲する。
　さらに、他の容量検知素子と異なり、電極を構成する導体として金属素線を用いるため、湾曲や摺動による劣化なども発生しにくい。制約はあるが、条件によっては可動部への取り付けも可能である。
　さらに、検知ケーブルのいずれの方向において液体と接触した場合であっても、同様の感度での検知が可能である。 All of the detection cables shown in FIG. 2 can be manufactured with a stable quality up to several hundred meters, as well as several meters, by using the wire manufacturing technology. Further, since these detection cables have a concentric cross section or a spiral structure, they are easily bent in any direction.
Further, unlike other capacitance detecting elements, since a metal element wire is used as a conductor forming an electrode, deterioration due to bending or sliding hardly occurs. Although there are restrictions, attachment to the movable part is possible depending on the conditions.
Furthermore, detection can be performed with the same sensitivity regardless of the direction in which the detection cable comes into contact with the liquid.
　検知ケーブルＳＤＣの直線長をＬＳＤＣとしたとき、レイアウトの自由度の観点からは、ＬＳＤＣが１ｍ以上であれば好ましく、２．５ｍ以上であればさらに好ましく、１０ｍ以上であれば特に好ましい。また、検知ケーブルは断面が円形であることが好ましく、その最大径は１０ｍｍ以下が好ましく、５ｍｍ以下がさらに好ましい。
　また、検知ケーブルは、検知ケーブルの直径の３０倍に相当する曲げ半径で１０回曲げ伸ばししても容量素子としての機能が破壊されない程度の可とう性を備えるとよい。　
　また、検知ケーブルの容量は、その長さにもよるが、感度の観点からは５０ｐＦ／ｍ以上が好ましく、１００ｐＦ／ｍ以上が特に好ましい。後述する発振回路の機能さえ損なわない範囲であれば、その上限は特に限定されないが、５００ｐＦ／ｍ以下が好ましく、２００ｐＦ／ｍ以下が特に好ましい。 When the linear length of the detection cable SDC was L SDC, in terms of freedom of layout, preferably if L SDC is more than 1 m, more preferably equal to or greater than 2.5 m, particularly preferably equal to or greater than 10 m. Further, the detection cable preferably has a circular cross section, and the maximum diameter thereof is preferably 10 mm or less, more preferably 5 mm or less.
Further, it is preferable that the detection cable has such a flexibility that the function as a capacitance element is not destroyed even if the detection cable is bent and extended ten times with a bending radius corresponding to 30 times the diameter of the detection cable.
Further, the capacity of the detection cable depends on its length, but is preferably 50 pF / m or more, and particularly preferably 100 pF / m or more from the viewpoint of sensitivity. The upper limit is not particularly limited as long as the function of the oscillation circuit described below is not impaired, but is preferably 500 pF / m or less, particularly preferably 200 pF / m or less.
　検知ケーブルＳＤＣと計測部ＭＵとを電気的に接続するリードケーブルは、検知ケーブルと同様に可とう性を備えた紐状の長尺体である。リードケーブルは、少なくとも２つの導体線を含み、これらの２つの導体線は、検知ケーブルの２つの導体にそれぞれ接続される。リードケーブルは、２心平行線や、ツイストペア構造でもよいが、好ましくは同軸構造で構成される。このようにリードケーブルは検知ケーブルと共通の構成を複数備えることがあるが、肉眼で検知ケーブルとの違いを識別可能な外観を備えるとよい。リードケーブルは、例えば充実層からなるリードケーブル保護層により被覆されることにより被検知液体との接触による静電容量の変化を防止できる。 (4) The lead cable for electrically connecting the detection cable SDC and the measurement unit MU is a long string having flexibility like the detection cable. The lead cable includes at least two conductor wires, each of which is connected to two conductors of the sensing cable. The lead cable may have a two-core parallel line or a twisted pair structure, but preferably has a coaxial structure. As described above, the lead cable may include a plurality of components in common with the detection cable, but it is preferable that the lead cable has an external appearance that allows the difference from the detection cable with the naked eye. The lead cable is covered with, for example, a lead cable protection layer composed of a solid layer, so that a change in capacitance due to contact with the liquid to be detected can be prevented.
　リードケーブルもその構造から静電容量を有する。ある検知ケーブルと、その検知ケーブルに接続されたリードケーブルにおいて、リードケーブルの単位長さあたりの容量は、検知ケーブルの単位長さあたりの容量よりも小さいことが好ましい。リードケーブルの容量は、検知ケーブルＳＤＣの容量より小さいことがさらに好ましい。これにより、リードケーブルの長さが検知ケーブルに対して大きな場合であっても、リードケーブルの容量により検知精度が低下することを抑制することができる。このような構成は、リードケーブルの長さが検知ケーブルの長さより大きな場合に好ましく、リードケーブルの長さが検知ケーブルの長さの３倍より大きな場合に特に好ましい。 Lead cable also has capacitance due to its structure. In a certain detection cable and a lead cable connected to the detection cable, it is preferable that the capacity per unit length of the lead cable is smaller than the capacity per unit length of the detection cable. More preferably, the capacity of the lead cable is smaller than the capacity of the detection cable SDC. Thus, even when the length of the lead cable is longer than the length of the detection cable, it is possible to suppress a decrease in detection accuracy due to the capacity of the lead cable. Such a configuration is preferable when the length of the lead cable is longer than the length of the detection cable, and particularly preferable when the length of the lead cable is longer than three times the length of the detection cable.
　　本発明に係る液体検知システムの検知対象となる液体としては、空気との比誘電率の差が大きな液体が好ましい。例えば比誘電率が１．８以上の液体の検出に好適である。また、比較的低い電圧で検知が可能であるため、油、有機溶媒のような可燃性の液体の漏洩検知に特に好適である。 液体 As a liquid to be detected by the liquid detection system according to the present invention, a liquid having a large difference in relative permittivity from air is preferable. For example, it is suitable for detecting a liquid having a relative dielectric constant of 1.8 or more. Further, since the detection can be performed at a relatively low voltage, it is particularly suitable for detecting the leakage of a flammable liquid such as oil or an organic solvent.
　再び図１を参照して、計測部ＭＵは、演算部ＭＰ、タイマＩＣ部ＭＴ、および、コネクタＭＣ１を含んでいる。タイマＩＣ部ＭＴは、発振器として機能し、少なくともセンサ部ＳＵの静電容量を含む容量からなる容量素子Ｃ（不図示）、抵抗素子Ｒ（不図示）とともにＣＲ発振回路を構成する。この発振回路の発振周波数は接続された容量素子の合成静電容量と、接続された抵抗素子の合成抵抗により定まるため、発振回路の容量の一部または全部として検知ケーブルの静電容量を利用することにより、発振周波数の変化から検知ケーブルの静電容量の変化を検知することができる。ここで、容量素子Ｃおよび抵抗素子Ｒと周波数との関係は、周波数Ｆ＝１．４４／（Ｃ×Ｒ）で表される。
　発振器としては、個別の素子を用いて、所望の機能を実現する回路を構成しても良いが、タイマＩＣ部ＭＴとしては市販のタイマＩＣを適用することが好ましい。タイマＩＣは複数のトランジスタ、ダイオードおよび抵抗等を１つのシリコンダイに搭載、パッケージ化したものである。タイマＩＣは、安価で小型なだけでなく、成熟技術であるため高い信頼性を備えている。タイマＩＣとしては、例えばＴｅｘａｓ　Ｉｎｓｔｒｕｍｅｎｔｓ社のＬＭＣ５５５ＣＭやＮＥ５５５、あるいは５５５をデュアル化した５５６等を適用することが出来る。これらのタイマＩＣは、その出力ピンより、発振周波数に等しいパルス信号を出力する。演算部ＭＰは、このパルス信号を受信し、単位時間当たりのパルス数をカウントすることにより、その期間における、検知ケーブルの静電容量値やその変化を算出することができる。そして、演算部ＭＰは、検知ケーブルの静電容量値やその変化に基づき、検知ケーブルへの液体の接触を公知の手法により判定することができる。 Referring to FIG. 1 again, measurement unit MU includes operation unit MP, timer IC unit MT, and connector MC1. The timer IC unit MT functions as an oscillator, and forms a CR oscillation circuit together with a capacitance element C (not shown) and a resistance element R (not shown) each having at least a capacitance including the capacitance of the sensor unit SU. Since the oscillation frequency of this oscillation circuit is determined by the combined capacitance of the connected capacitance elements and the combined resistance of the connected resistance elements, the capacitance of the detection cable is used as part or all of the capacitance of the oscillation circuit. Thus, the change in the capacitance of the detection cable can be detected from the change in the oscillation frequency. Here, the relationship between the capacitance element C and the resistance element R and the frequency is represented by a frequency F = 1.44 / (C × R).
As the oscillator, a circuit that realizes a desired function may be configured using individual elements, but it is preferable to use a commercially available timer IC as the timer IC unit MT. The timer IC has a plurality of transistors, diodes, resistors, and the like mounted on one silicon die and packaged. The timer IC is not only inexpensive and small, but also has high reliability because it is a mature technology. As the timer IC, for example, LMC555CM or NE555 from Texas Instruments, or 556 in which 555 is dualized can be used. These timer ICs output a pulse signal equal to the oscillation frequency from the output pin. The arithmetic unit MP receives this pulse signal and counts the number of pulses per unit time, so that the capacitance value of the detection cable and its change during that period can be calculated. Then, the arithmetic unit MP can determine the contact of the liquid to the detection cable by a known method based on the capacitance value of the detection cable and its change.
　計測部ＭＵは、さらに表示部ＭＤを備えていても良い。なお、図１において、白抜きの両矢印は信号伝送経路を示している。表示部ＭＤは例えば液晶またはＬＥＤによる表示手段を含んでおり、例えば演算部ＭＰの命令に基づき、計測状況、計測値、異常の有無などを外部より視認可能に表示することが出来る。計測部ＭＵはさらに記憶部ＭＭを有していても良い。記憶部ＭＭはＥＥＰＲＯＭ、ＲＡＭ、ディップスイッチなどの記憶手段を含んでおり、演算部ＭＰにおける演算に必要なデータや、計測のログなどを保持しており、演算部ＭＰの命令に応じてこれらのデータを格納したり、演算部ＭＰに提供することが出来る。 (4) The measurement unit MU may further include a display unit MD. Note that, in FIG. 1, white double arrows indicate signal transmission paths. The display unit MD includes a display unit such as a liquid crystal display or an LED. The display unit MD can display a measurement state, a measurement value, the presence or absence of an abnormality, and the like in an externally visible manner based on, for example, a command from the calculation unit MP. The measurement unit MU may further include a storage unit MM. The storage unit MM includes storage means such as an EEPROM, a RAM, and a dip switch, and holds data necessary for the operation in the operation unit MP, a log of measurement, and the like. Data can be stored or provided to the arithmetic unit MP.
　本実施形態において、計測部ＭＵは、演算部ＭＰに印加される電圧を生成する第一電圧生成部ＭＥ１と、タイマＩＣ部ＭＴに印加される電圧を生成する第二電圧生成部ＭＥ２とを備える。これにより、本実施形態の液体検知システムは検知ケーブルと組み合わせた場合であっても、高感度かつ高精度での検知を安定して提供される。 In the present embodiment, the measurement unit MU includes a first voltage generation unit ME1 that generates a voltage applied to the operation unit MP, and a second voltage generation unit ME2 that generates a voltage applied to the timer IC unit MT. . Thus, the liquid detection system of the present embodiment stably provides high-sensitivity and high-precision detection even when combined with a detection cable.
　本実施形態において、高感度かつ高精度での検知が得られる理由を以下に具体的に説明する。
　上述のように検知ケーブルは優れた検知特性を有する。しかし、その長さに起因する計測上の課題があり、外的要因の変動により、課題が顕在化して測定精度が低下し得ることを本願発明者らは見出した。
　１つ目は検知ケーブルを長くするほど、計測される静電容量の変化が相対的に小さくなる傾向を有する点である。静電容量変化型のセンサであっても、従来のポイントセンサやフレキシブル基板技術を適用したセンサであれば、検知範囲が小さいため、液体の接触により誘電体層中の大きな領域か、全ての領域の静電容量が変化する。このため、検知される静電容量の変化量も大きく、液体の検知判定が比較的容易であった。これに対して検知ケーブルを用いた液体検知では検知範囲が１ｍ以上、２．５ｍ以上、あるいは１０ｍ以上と長距離にわたる。このため、漏洩の形態によっては、また、少なくとも漏洩の初期においては、検知ケーブルの検知範囲中の一部しか液体と接触しないことも多い。このような場合においては、誘電体層中のごく一部のみの静電容量しか変化しない。従って、従来より小さな静電容量の変化をもって液体の検知を判定することが求められることになる。 The reason why high-sensitivity and high-accuracy detection can be obtained in the present embodiment will be specifically described below.
As described above, the detection cable has excellent detection characteristics. However, the inventors of the present application have found that there is a measurement problem due to the length, and that a problem may become apparent due to a change in an external factor, thereby lowering measurement accuracy.
First, the longer the detection cable is, the smaller the change in measured capacitance tends to be. Even if the sensor is a capacitance change type sensor, if a conventional point sensor or a sensor to which flexible substrate technology is applied, the detection range is small, so that a large area in the dielectric layer due to liquid contact or all areas Changes in capacitance. For this reason, the amount of change in the detected capacitance is large, and the detection determination of the liquid is relatively easy. On the other hand, in liquid detection using a detection cable, the detection range extends over a long distance of 1 m or more, 2.5 m or more, or 10 m or more. For this reason, depending on the type of leakage, and at least at the beginning of the leakage, only a part of the detection range of the detection cable often comes into contact with the liquid. In such a case, only a part of the capacitance in the dielectric layer changes. Therefore, it is required to determine the detection of the liquid based on a change in capacitance smaller than that in the related art.
　２つ目は検知ケーブルが長くなるに従い、外部ノイズの影響を受けやすくなる点である。検知ケーブルの長さを活かして、長距離の検知領域を設定することは、検知ケーブルがさまざまな電磁波環境を通過する形になることを意味する。また、長い検知ケーブルは外部ノイズを拾うアンテナとしても作用し得る。これらにより、センサ部から計測部にノイズが流入し、これが検出精度に悪い影響を与えることがある。 The second is that the longer the detection cable becomes, the more susceptible to external noise. Setting a long detection area by utilizing the length of the detection cable means that the detection cable passes through various electromagnetic wave environments. A long detection cable can also act as an antenna to pick up external noise. As a result, noise flows from the sensor unit to the measurement unit, which may adversely affect the detection accuracy.
　つまり、静電容量変化型の検知ケーブルを用いた液体検知では、判定に必要な静電容量変化は小さくなる一方で、判定の障害となるノイズの影響は大きくなってしまうことがある。これが、タイマＩＣ部を含む発振回路と検知ケーブルとを単純に組み合わせただけでは、所望の精度を得られないとの課題を発生させていると考えた。 In other words, in the liquid detection using the capacitance change type detection cable, the change in capacitance required for the determination is small, but the influence of noise that is an obstacle to the determination may be large. It is considered that this has caused a problem that a desired accuracy cannot be obtained by simply combining the oscillation circuit including the timer IC unit and the detection cable.
　上記の課題に対して、発振回路の駆動電圧を高くすることで、外部ノイズの影響を相対的に小さくすることが考えられる。しかし電圧を高くすることは発振回路の温度上昇だけでなく、仮に検知ケーブルに絶縁破壊が生じた場合に、過熱リスクを増大させることとなり、一定以上の高電圧化は好ましくない。また、逆に、長い検知ケーブルがノイズの発信源となってしまう虞もある。こうなると、他の機器への影響との観点から、レイアウト上の制約となってしまう。
　あるいは、検知ケーブルの長さを制限することにより、静電容量の変化量を相対的に大きくして判定に必要な信号を大きくする、あるいは、検知ケーブルが通過する領域を制限する（例えば、小さな領域内で検知ケーブルを周回させるなどで密集配置させる）ことによりノイズの影響を小さくすることも考えられるが、このような制限を設けることは、検知ケーブルのレイアウトの自由度の高さを損なってしまう。 To solve the above problem, it is conceivable that the influence of external noise is relatively reduced by increasing the drive voltage of the oscillation circuit. However, increasing the voltage not only raises the temperature of the oscillation circuit, but also increases the risk of overheating in the event that a dielectric breakdown occurs in the detection cable. It is not preferable to increase the voltage beyond a certain level. Conversely, a long detection cable may be a source of noise. In this case, the layout is restricted in view of the influence on other devices.
Alternatively, by restricting the length of the detection cable, the amount of change in the capacitance is relatively increased to increase the signal required for determination, or the area through which the detection cable passes is limited (for example, It is conceivable that the influence of noise can be reduced by arranging the detection cables around the area so as to be densely arranged. However, such a restriction impairs the degree of freedom of the layout of the detection cables. I will.
　このように、一定以上の長さの検知ケーブルを備え、その静電容量の変化を用いて判定する液体検知は、その原理上、感度や精度が不安定になる要素が内在すると考えた。この状態であっても、実用に十分な感度、精度は備えているが、より不利な条件が重なったときに課題が顕在化する虞がある。例えば、より多くの情報をより短時間で処理するような、演算規模の増大による測定精度の悪化である。 液体 Thus, liquid detection, which is provided with a detection cable longer than a certain length and which is determined by using a change in the capacitance, considered that, in principle, there are factors that make the sensitivity and accuracy unstable. Even in this state, although sufficient sensitivity and accuracy are provided for practical use, the problem may become apparent when more disadvantageous conditions overlap. For example, there is a deterioration in measurement accuracy due to an increase in the calculation scale, such as processing more information in a shorter time.
　鋭意研究した結果、本願発明者らは、タイマＩＣに、高精度に制御された安定した電圧を印加することで、計測値が安定することを見出した。しかも、この方法はレイアウトの自由度を損なうとの課題を生じない。
　計測部ＭＵ上にタイマＩＣと共に搭載される演算部ＭＰは、例えばマイコンであり、動作による消費電力の変動が大きい。タイマＩＣ部が電源系統を演算部ＭＰと共有している場合、演算部ＭＰの動作状況次第では、タイマＩＣに印加される電圧の低下が発生してしまい、これが計測値の悪化要因となっていた。これに対して本実施形態において、計測部ＭＵは、演算部ＭＰに印加される電圧を生成する第一電圧生成部ＭＥ１とは別に、タイマＩＣ部ＭＴに印加される電圧を生成する第二電圧生成部ＭＥ２を備える。これにより、演算部ＭＰの動作状況によらず、安定した計測が可能となる。 As a result of earnest study, the inventors of the present application have found that a measured value is stabilized by applying a stable voltage controlled with high precision to the timer IC. Moreover, this method does not cause a problem that the degree of freedom of layout is impaired.
The arithmetic unit MP mounted on the measuring unit MU together with the timer IC is, for example, a microcomputer, and the power consumption of the arithmetic unit MP greatly fluctuates due to the operation. When the timer IC unit shares the power supply system with the operation unit MP, the voltage applied to the timer IC may decrease depending on the operation state of the operation unit MP, which is a cause of deterioration of the measured value. Was. On the other hand, in the present embodiment, the measuring unit MU includes a second voltage that generates a voltage applied to the timer IC unit MT separately from the first voltage generating unit ME1 that generates a voltage applied to the arithmetic unit MP. A generation unit ME2 is provided. This enables stable measurement regardless of the operation state of the operation unit MP.
　演算部ＭＰの動作状況による供給電圧の低下は、全長が大きな検知ケーブルでは静電容量が大きいこと、また、上述の検知ケーブル固有の課題による誤差要因と重畳して作用し、検知ケーブルにおいて顕在化しやすくなったものと推測される。 The decrease in the supply voltage due to the operation state of the calculation unit MP is superimposed on the fact that the detection cable having a large total length has a large capacitance and also acts on the error factor due to the above-described problem inherent to the detection cable, and becomes apparent in the detection cable. It is presumed that it became easier.
　図１を参照して、計測部ＭＵにおける各ブロック間の電力供給の接続を説明する。計測部ＭＵの第一電圧生成部ＭＥ１には、計測部ＭＵの外部より、外部電圧が印加される（外部電圧の供給ラインを二重線で示す）。外部電圧は例えばＤＣ２４Ｖである。第一電圧生成部は、例えばＤＣ５Ｖ（第一電圧）を生成するＤＣ－ＤＣコンバータであり、演算部ＭＰにこの電圧を印加する（第一電圧の供給ラインを実線で示す）。第一電圧生成部の出力電圧の精度は例えば±２％を超える大きさであっても良い。第一電圧は、演算部ＭＰの他に、表示部ＭＤ、記憶部ＭＭ、第二電圧生成部ＭＥ２にも印加されていて良い。
　第二電圧生成部ＭＥ２は、例えばＤＣ５Ｖ（第二電圧）を生成する電圧リファレンスＩＣを含み、タイマＩＣ部にこの電圧を印加する（第二電圧の供給ラインを一点鎖線で示す）。第二電圧生成部の出力電圧の精度は例えば±１％以下であることが好ましい。第二電圧生成部ＭＥ２は例えばリニア型のレギュレータである。 With reference to FIG. 1, connection of power supply between each block in the measurement unit MU will be described. An external voltage is applied to the first voltage generation unit ME1 of the measurement unit MU from outside the measurement unit MU (a supply line of the external voltage is indicated by a double line). The external voltage is, for example, DC24V. The first voltage generation unit is, for example, a DC-DC converter that generates DC5V (first voltage), and applies this voltage to the calculation unit MP (a supply line of the first voltage is indicated by a solid line). The accuracy of the output voltage of the first voltage generator may be, for example, a magnitude exceeding ± 2%. The first voltage may be applied to the display unit MD, the storage unit MM, and the second voltage generation unit ME2 in addition to the operation unit MP.
The second voltage generation unit ME2 includes, for example, a voltage reference IC that generates DC5V (second voltage), and applies this voltage to the timer IC unit (the supply line of the second voltage is indicated by a dashed line). It is preferable that the accuracy of the output voltage of the second voltage generator is, for example, ± 1% or less. The second voltage generator ME2 is, for example, a linear regulator.
　上述のように、本実施形態において、第一電圧と第二電圧はほぼ等しい場合であっても、あえて、演算部ＭＰに電圧を印加する第一電圧生成部と、タイマＩＣ部に電圧を印加する第二電圧生成部とを分離することにより、高い感度を高い精度を得ることができる。ここで、第一電圧と第二電圧はほぼ等しいとは、第一電圧発生部から発生する第一電圧の値Ｖ１と前記第二電圧発生部から発生する第二電圧Ｖ２の値との比Ｖ１／Ｖ２が、０．７以上１．３以下であることを意味する。 As described above, in the present embodiment, even when the first voltage and the second voltage are substantially equal, the first voltage generation unit that dares to apply the voltage to the arithmetic unit MP and the voltage is applied to the timer IC unit By separating the second voltage generator from the second voltage generator, high sensitivity and high accuracy can be obtained. Here, that the first voltage and the second voltage are substantially equal means that the ratio V1 of the value V1 of the first voltage generated from the first voltage generator to the value of the second voltage V2 generated from the second voltage generator. / V2 is 0.7 or more and 1.3 or less.
　第二電圧生成部ＭＥ２は、さらにチャージポンプを備えていても良い。このチャージポンプは印加された電圧（例えば前記第一電圧の５Ｖ）を、例えば約７Ｖに昇圧して、昇圧した電圧を前記の電圧リファレンスＩＣに印加する。このように、電圧リファレンスＩＣにマージンを含めた電圧を印加することで、電圧リファレンスＩＣの出力電圧の精度をさらに向上することができる。概チャージポンプは、例えばスイッチング型のレギュレータである。 The second voltage generator ME2 may further include a charge pump. The charge pump boosts the applied voltage (for example, the first voltage of 5 V) to, for example, about 7 V, and applies the boosted voltage to the voltage reference IC. As described above, by applying a voltage including a margin to the voltage reference IC, the accuracy of the output voltage of the voltage reference IC can be further improved. The charge pump is, for example, a switching regulator.
　計測部ＭＵが上記の構成を有することにより、演算部ＭＰの消費電力の変動によらず、タイマＩＣ部に高精度に制御された電圧を供給できるため、演算規模を拡大した場合であっても、検知ケーブルのレイアウトに制約を与えることなく、高精度での液体検知が可能となる。
　本実施例において、第二電圧生成部ＭＥ２には、第一電圧生成部ＭＥ１が生成した電圧が印加される形を説明したが、これに限定されず、例えば、定格の範囲内で外部からの電圧が第二電圧生成部ＭＥ２に直接印加されてもよく、あるいは、他のＤＣ－ＤＣコンバータで生成された電圧が印加される形としても良い。また、第二電圧生成部ＭＥ２が生成する第二電圧は、表示部に印加されない形が好ましく、さらに記憶部にも印加されない形とすることがより好ましい。第二電圧生成部ＭＥ２が生成する第二電圧はタイマＩＣ部のみに印加される形が、特に好ましい。 Since the measuring unit MU has the above configuration, it is possible to supply a highly controlled voltage to the timer IC unit regardless of fluctuations in the power consumption of the arithmetic unit MP. Thus, liquid detection can be performed with high accuracy without restricting the layout of the detection cable.
In the present embodiment, the form in which the voltage generated by the first voltage generation unit ME1 is applied to the second voltage generation unit ME2 has been described. However, the present invention is not limited to this. The voltage may be directly applied to the second voltage generator ME2, or a voltage generated by another DC-DC converter may be applied. Further, the second voltage generated by the second voltage generation unit ME2 is preferably in a form not applied to the display unit, and more preferably in a form not applied to the storage unit. It is particularly preferable that the second voltage generated by the second voltage generation unit ME2 is applied only to the timer IC unit.
（第一の実施形態の変形例）
　計測部ＭＵはさらに通信部ＭＲＴを含んでいても良い。通信部ＭＲＴは、演算部の指令に基づき、計測部ＭＵの計測状況や、異常検知などを制御盤等の他の機器に送信する。このような通信は制御盤からの指令をトリガとして発生することも多く、静電容量の計測中に演算部ＭＰの消費電力を大きく変動させることがある。このため、計測部ＭＵが通信部ＭＲＴを含む場合、演算部ＭＰに印加される電圧を生成する第一電圧生成部ＭＥ１とは別に、タイマＩＣ部ＭＴに印加される電圧を生成する第二電圧生成部ＭＥ２を備えることは、高精度の検知を得るうえで特に有効である。 (Modification of First Embodiment)
The measurement unit MU may further include a communication unit MRT. The communication unit MRT transmits a measurement status of the measurement unit MU, an abnormality detection, and the like to another device such as a control panel based on a command from the calculation unit. Such communication often occurs with a command from the control panel as a trigger, and the power consumption of the arithmetic unit MP may vary greatly during the measurement of the capacitance. Therefore, when the measurement unit MU includes the communication unit MRT, the second voltage that generates the voltage applied to the timer IC unit MT is separate from the first voltage generation unit ME1 that generates the voltage applied to the arithmetic unit MP. Providing the generation unit ME2 is particularly effective in obtaining highly accurate detection.
（第二の実施形態）　
　本実施形態において、計測部ＭＵは、タイマＩＣ部とコネクタＭＣ１との間にローパスフィルタＭＦを備える。ローパスフィルタは例えばπ形フィルタで構成され、センサ部ＳＵが拾った外部ノイズのうち、高周波成分がタイマＩＣに伝わることを防止する。計測部ＭＵの発振回路は数ｋＨｚで動作させて良い。これに対して、例えば漏液監視対象の近傍に配置されたノイズ発生源が発する４０ｋＨｚを超えるノイズを検知ケーブルが拾ってしまい、検知精度を悪化させることがわかった。これに対して、ローパスフィルタにより、必要なパルス信号は残しつつ、不要なノイズを効果的に除去することができる。 (Second embodiment)
In the present embodiment, the measurement unit MU includes a low-pass filter MF between the timer IC unit and the connector MC1. The low-pass filter is formed of, for example, a π-type filter, and prevents a high-frequency component of the external noise picked up by the sensor unit SU from being transmitted to the timer IC. The oscillation circuit of the measurement unit MU may be operated at several kHz. On the other hand, for example, it was found that the detection cable picked up noise exceeding 40 kHz generated by a noise generation source disposed near the liquid leakage monitoring target, thereby deteriorating the detection accuracy. On the other hand, the low-pass filter can effectively remove unnecessary noise while leaving necessary pulse signals.
　本実施形態において、タイマＩＣ部ＭＴに印加される電圧を生成する第二電圧生成部ＭＥ２を備えることは必須ではない。ただし、上記のローパスフィルタに加え、タイマＩＣ部ＭＴに印加される電圧を生成する第二電圧生成部ＭＥ２を備えることで、タイマＩＣ部に印加される２つのばらつき要因、つまり電源電圧の揺らぎと、センサ部からのノイズ、を共に抑制することができるため、高精度の検知を得るうえで特に有効である。 In the present embodiment, it is not essential to include the second voltage generator ME2 that generates the voltage applied to the timer IC unit MT. However, by providing the second voltage generating unit ME2 that generates the voltage applied to the timer IC unit MT in addition to the low-pass filter, two variation factors applied to the timer IC unit, namely, fluctuation of the power supply voltage and And noise from the sensor unit can be suppressed, which is particularly effective in obtaining highly accurate detection.
（第三の実施形態）
　図３（ａ）および図３（ｂ）を用いて、第三の実施形態を説明する。本実施形態において液体検知システムＬＤＳは、通知部ＣＡを有する制御部ＣＵをさらに含む。制御部ＣＵは、計測部ＭＵと制御部通信ケーブルＣＣＣにより接続されており、計測部ＭＵとの間で、いずれか１方向または双方向の信号の送受信を行うように構成されている。計測部ＭＵと検知ケーブルＳＤＣとは、上述の実施例と同様のリードケーブルＳＬＣにて接続されている。 (Third embodiment)
The third embodiment will be described with reference to FIGS. 3A and 3B. In the present embodiment, the liquid detection system LDS further includes a control unit CU having a notification unit CA. The control unit CU is connected to the measurement unit MU by a control unit communication cable CCC, and is configured to perform transmission and reception of signals in any one or two directions with the measurement unit MU. The measuring unit MU and the detection cable SDC are connected by the same lead cable SLC as in the above-described embodiment.
　監視対象が大規模化したとき、計測部と検知ケーブルとの間の距離が大きくなる場合がある。検知ケーブルの敷設位置は漏洩が発生する懸念がある位置、あるいは、漏洩を監視すべき位置に固定される一方で、計測部の位置は必ずしも漏洩の位置とは関係なく、管理者や管理機器にとって監視しやすい場所に配置しなくてはならないためである。このような場合であっても、検知ケーブル自体を長くしたり、リードケーブルを長くすることにより、監視は可能である。しかし、前述のようにリードケーブルも静電容量を有しており、リードケーブルの長さに比例して大きくなるリードケーブルの静電容量が発振回路の合成容量に上乗せされてしまうため、検知精度を悪化させてしまう。
　これに対して、本実施形態における液体検知システムは以下の構成を有する。 When the size of the monitoring target increases, the distance between the measurement unit and the detection cable may increase. The laying position of the detection cable is fixed at a position where there is a risk of leakage or where leakage should be monitored, while the position of the measurement unit is not necessarily related to the position of the leakage and is not This is because it must be placed in a place that is easy to monitor. Even in such a case, monitoring can be performed by increasing the length of the detection cable itself or the length of the lead cable. However, as described above, the lead cable also has capacitance, and the capacitance of the lead cable, which increases in proportion to the length of the lead cable, is added to the combined capacitance of the oscillation circuit. Worsens.
In contrast, the liquid detection system according to the present embodiment has the following configuration.
　第一の導体、前記第一の導体と電気的に絶縁された第二の導体、および、前記第一の導体と前記第二の導体との間に形成された誘電体層を備え、液体との接触により静電容量が変化する検知ケーブルと、前記検知ケーブルの静電容量を算出する演算部を備える計測部と、前記計測部において算出された静電容量の変化が予め定めた条件を満たすときに、検知ケーブルと液体との接触を検知したことを通知する通知部を備える制御部と、前記検知ケーブルと前記計測部とを接続する第一のケーブルと、前記計測部と前記制御部とを接続する第二のケーブルとを備える。
　さらに、前記第一のケーブルは、前記第二のケーブルより短い。 A first conductor, a second conductor electrically insulated from the first conductor, and a dielectric layer formed between the first conductor and the second conductor, and a liquid A detection cable having a capacitance that changes due to contact with the sensor, a measurement unit including a calculation unit that calculates the capacitance of the detection cable, and a change in the capacitance calculated by the measurement unit that satisfies a predetermined condition. When, a control unit including a notification unit that notifies that the contact between the detection cable and the liquid is detected, a first cable that connects the detection cable and the measurement unit, the measurement unit and the control unit And a second cable for connecting
Further, the first cable is shorter than the second cable.
　本実施形態における液体検知システムは、該検知システムの利用者や管理者に対して、液体との接触を検知したことや異常が発生したことを通知する通知部と検知ケーブルとの間の距離を大きくせざるを得ない場合であっても、タイマＩＣ及び演算部を含む計測部と通知部を含む制御部とを別体として構成し、かつ、計測部を検知ケーブルに近い位置に配置することにより、リードケーブルが過度に長くなることを防止でき、検知精度の悪化を抑制することが出来る。 The liquid detection system according to the present embodiment is configured such that a distance between a detection unit and a detection cable for notifying a user or an administrator of the detection system that contact with the liquid has been detected or that an abnormality has occurred is determined. Even if it is necessary to increase the size, the measurement unit including the timer IC and the calculation unit and the control unit including the notification unit are configured separately, and the measurement unit is arranged at a position close to the detection cable. Accordingly, it is possible to prevent the lead cable from becoming excessively long, and to suppress deterioration in detection accuracy.
　図３（ａ）に示すように、制御部ＣＵは通知部ＣＡを備える。通知部ＣＡは、液晶ディスプレイやＬＥＤのような表示手段でも良く、あるいは、ブザー、スピーカのように音声により通知する音声発生手段でも良い。あるいは他の機器にある表示手段、音声発生手段による通知を発生させるための信号送信手段であっても良い。通知部ＣＡは、例えば制御部ＣＵの動作状態を外部に通知できる。通知部ＣＡは、さらに、計測部ＭＵから制御部通信ケーブルＣＣＣを介して取得した情報や、該情報に基づいた判定結果などを外部に通知できる。
　制御部ＣＵはさらに操作部ＣＯを有していても良い。操作部ＣＯは例えばキーボード、タッチパネル、またはプッシュボタンなどの入力インターフェースを含み、操作部ＣＯの操作により、制御部ＣＵの各機能の動作の制御だけでなく、制御部通信ケーブルを介して計測部ＭＵの動作を遠隔で制御することができる。
　制御部ＣＵは、記憶素子などを含む記憶部ＣＭ、記憶部ＣＭに格納されたプログラムを実行する演算部ＣＰ，計測部との通信を制御する通信部ＣＣ１を備えていても良い。さらに制御部ＣＵは、計測部ＭＵ同様にタイマＩＣ部ＭＴ、演算部ＭＰ、第一電圧生成部ＭＥ１、第二電圧生成部ＭＥ２、ローパスフィルタＭＦ、及び、コネクタＭＣ１の一部又は全部を含み、該コネクタＭＣ１に接続された検知ケーブルの静電容量の変化を監視する内部計測部ＣＩＭを備えていても良い。 As shown in FIG. 3A, the control unit CU includes a notification unit CA. The notification unit CA may be a display unit such as a liquid crystal display or an LED, or may be a sound generation unit that notifies by sound such as a buzzer or a speaker. Alternatively, a signal transmission unit for generating a notification by a display unit or a sound generation unit in another device may be used. The notification unit CA can notify the operation state of the control unit CU to the outside, for example. The notification unit CA can further externally notify information acquired from the measurement unit MU via the control unit communication cable CCC, a determination result based on the information, and the like.
The control unit CU may further include an operation unit CO. The operation unit CO includes, for example, an input interface such as a keyboard, a touch panel, or a push button. The operation of the operation unit CO not only controls the operation of each function of the control unit CU but also controls the measurement unit MU via the control unit communication cable. Can be controlled remotely.
The control unit CU may include a storage unit CM including a storage element and the like, an operation unit CP that executes a program stored in the storage unit CM, and a communication unit CC1 that controls communication with the measurement unit. Further, the control unit CU includes a timer IC unit MT, a calculation unit MP, a first voltage generation unit ME1, a second voltage generation unit ME2, a low-pass filter MF, and a part or all of the connector MC1, similarly to the measurement unit MU. An internal measurement unit CIM that monitors a change in the capacitance of the detection cable connected to the connector MC1 may be provided.
　本実施形態において計測部ＭＵは、図１と同様の構成であってもよいが、少なくともタイマＩＣ部ＭＴと演算部ＭＰと通信部ＭＲＴがあれば良く、例えば表示部ＭＤを省略することができる。換言すれば、計測部ＭＵは接続された検知ケーブルＳＤＣの静電容量の変化を監視でき、かつ、その監視結果を外部に送信できればよい。また、本実施形態において、測定精度を維持できる範囲内であれば、第二電圧生成部を省略し、第一電圧生成部が生成した電圧をタイマＩＣ部に印加することもできる。しかし、本実施形態においては、制御部通信ケーブルＣＣＣを介した通信の消費電力によるタイマＩＣを含む発振回路の不安定化を抑制するとの効果が得られるため、第一の実施形態同様に第二電圧生成部を備えることが特に好ましい。 In the present embodiment, the measurement unit MU may have the same configuration as that of FIG. 1, but it is sufficient that at least the timer IC unit MT, the operation unit MP, and the communication unit MRT are provided, and for example, the display unit MD can be omitted. . In other words, the measuring unit MU only needs to be able to monitor the change in the capacitance of the connected detection cable SDC and transmit the monitoring result to the outside. In the present embodiment, the second voltage generator may be omitted and the voltage generated by the first voltage generator may be applied to the timer IC as long as the measurement accuracy can be maintained. However, in the present embodiment, the effect of suppressing the instability of the oscillation circuit including the timer IC due to the power consumption of the communication via the control unit communication cable CCC is obtained. It is particularly preferable to include a voltage generator.
　制御部通信ケーブルＣＣＣは、例えば差動伝送を用いた信号伝送用の導体線だけで構成される。制御部通信ケーブルＣＣＣは、さらに、制御部ＣＵから計測部ＭＵに電源を供給する電源線を含めて構成してもよい。このような構成においては、計測部ＭＵの配置上の制約を小さくでき、結果的にリードケーブルをさらに短くすることが可能となる。 (4) The control unit communication cable CCC is composed of only conductor wires for signal transmission using, for example, differential transmission. The control unit communication cable CCC may further include a power supply line for supplying power from the control unit CU to the measurement unit MU. In such a configuration, the restriction on the arrangement of the measurement unit MU can be reduced, and as a result, the lead cable can be further shortened.
　本実施形態において、計測部ＭＵは検知ケーブルＳＤＣの静電容量の変化を監視する。この監視結果は、定期的に、あるいは制御部ＣＵの要求に応じる形で、制御部ＣＵに送信される。静電容量の変化が所定の条件を満たすとき、例えば、静電容量の変化量あるいは変化率が予め定めた所定の値より大きなとき、制御部ＣＵは通知部ＣＵを介して検知ケーブルと検知対象の液体の接触があったと判定したことを通知する。ここで検知ケーブルと検知対象の液体の接触があったと判定したことの通知は、接触が意味することの通知を含む。例えば、漏洩等の異常が発生したことの通知であってもよい。通知を受けた管理者は、操作部ＣＯの操作により必要な情報を表示させたり、警報を止めるなどの処置を行うことができる。なお、静電容量の変化が所定の条件を満たすかの判定は制御部で行ってもよく、計測部で行ってもよい。 In this embodiment, the measurement unit MU monitors a change in the capacitance of the detection cable SDC. This monitoring result is transmitted to the control unit CU periodically or in response to a request from the control unit CU. When the change in the capacitance satisfies a predetermined condition, for example, when the change amount or the change rate of the capacitance is larger than a predetermined value, the control unit CU communicates with the detection cable via the notification unit CU. That the liquid has been contacted. Here, the notification that it is determined that the detection cable has come into contact with the liquid to be detected includes a notification that the contact means. For example, it may be a notification that an abnormality such as leakage has occurred. The administrator who has received the notification can perform necessary measures such as displaying necessary information or stopping an alarm by operating the operation unit CO. The determination as to whether the change in the capacitance satisfies the predetermined condition may be made by the control unit or by the measurement unit.
（第四の実施形態）
　監視対象領域がとくに広い場合など、検知ケーブル長を極端に長くしないと対象領域をカバーできないことがある。しかし単純に長くすることは上述の検知ケーブルの長さに起因する課題を顕在化させる虞がある。図４を用いて、第四の実施形態を説明する。本実施形態における液体検知システムは例えば、以下の構成を有する。 (Fourth embodiment)
For example, when the monitoring target area is particularly large, the target area may not be covered unless the detection cable length is extremely long. However, simply increasing the length may cause the above-described problem due to the length of the detection cable to become apparent. The fourth embodiment will be described with reference to FIG. The liquid detection system according to the present embodiment has, for example, the following configuration.
　第一の導体、前記第一の導体と電気的に絶縁された第二の導体、および、前記第一の導体と前記第二の導体との間に形成された誘電体層を備え、液体との接触により静電容量が変化する第一の検知ケーブルと、
　第一の導体、前記第一の導体と電気的に絶縁された第二の導体、および、前記第一の導体と前記第二の導体との間に形成された誘電体層を備え、液体との接触により静電容量が変化する第二の検知ケーブルと、
　前記第一の検知ケーブルに接続され、前記第一の検知ケーブルの静電容量の変化を監視する第一の計測部と、
　前記第二の検知ケーブルに接続され、前記第二の検知ケーブルの静電容量の変化を監視する第二の計測部と、
　前記第一の計測部及び前記第二の計測部と第一のケーブルを介して通信可能に構成され、前記第一の計測部または前記第二の計測部において観測された静電容量の変化が、予め定めた条件を満たすときにセンサケーブルと液体との接触を通知する制御部とをそなえることを特徴とする。 A first conductor, a second conductor electrically insulated from the first conductor, and a dielectric layer formed between the first conductor and the second conductor, and a liquid A first detection cable whose capacitance changes due to the contact of
A first conductor, a second conductor electrically insulated from the first conductor, and a dielectric layer formed between the first conductor and the second conductor, and a liquid A second detection cable whose capacitance changes due to the contact of
A first measurement unit that is connected to the first detection cable and monitors a change in capacitance of the first detection cable,
A second measurement unit that is connected to the second detection cable and monitors a change in capacitance of the second detection cable,
The first measuring unit and the second measuring unit are configured to be able to communicate with each other via a first cable, and the change in capacitance observed in the first measuring unit or the second measuring unit is And a control unit for notifying the contact between the sensor cable and the liquid when a predetermined condition is satisfied.
　また、本実施形態における、液体検知システムは、例えば以下の構成を有していてもよい。
　複数の計測部と、当該複数の計測部からの信号を受信する制御部と、を備え、　前記複数の計測部は、　第一の検知ケーブルと、当該第一の検知ケーブルへの液体の接触を判定する第一の演算部と、当該第一の演算部の接触判定情報を信号として外部に送信する第一の通信部と、を有する第一の計測部と、　第二の検知ケーブルと、当該第二の検知ケーブルへの液体の接触を判定する第二の演算部と、当該第二の演算部の接触判定情報を信号として外部に送信する第二の通信部と、を有する第二の計測部と、　第三の検知ケーブルと、前記第三の検知ケーブルへの液体の接触を判定する第三の演算部と、当該第三の演算部の接触判定情報を信号として外部に送信する第三の通信部、を備えた第三の計測部と、　を有し、　前記第一の計測部および前記第二の計測部は、それぞれ接触判定情報を他の計測部の通信部を経由せずに前記制御部に送信し、前記第三の計測部は、前記第三の計測部の接触判定情報を前記第一の計測部の前記第一の通信部を経由して前記制御部に送信することを特徴とする Further, the liquid detection system in the present embodiment may have, for example, the following configuration.
A plurality of measurement units, and a control unit that receives a signal from the plurality of measurement units, the plurality of measurement units, the first detection cable, the contact of the liquid to the first detection cable A first measurement unit having a first calculation unit to be determined, a first communication unit that transmits the contact determination information of the first calculation unit to the outside as a signal, a second detection cable, A second measurement unit including a second calculation unit that determines the contact of the liquid with the second detection cable, and a second communication unit that transmits the contact determination information of the second calculation unit to the outside as a signal. A third detection cable, a third calculation unit that determines contact of the liquid with the third detection cable, and a third unit that transmits contact determination information of the third calculation unit to the outside as a signal. A third measurement unit comprising: a communication unit; and a first measurement unit and the third measurement unit. The second measurement unit transmits the contact determination information to the control unit without passing through the communication unit of the other measurement unit, and the third measurement unit transmits the contact determination information of the third measurement unit to the control unit. And transmitting to the control unit via the first communication unit of the first measurement unit.
　つまり、監視対象領域を２つ以上の区画に分割し、それぞれに専用の検知ケーブルの敷設し、かつ各検知ケーブルに専用の計測部を接続した上で、これら複数の計測部を１つの制御部で管理する構成を備える。これにより、監視者からの見かけ上は１つの連続した長距離監視を行う検知ケーブルでありながら、検知精度の悪化を抑制することが出来る。例えば、検知区画によらず、同一の処置が求められる場合などには、単純な対応が可能となり好適である。あるいは、制御部においていずれの計測区画による検知かを識別可能に通知する構成としても良い。およその位置が分かることにより、作業者の現場確認を迅速に行うことができる。本実施形態において、制御部ＣＵ、計測部ＭＵの構成や動作は、第三の実施形態における制御部ＣＵ、計測部ＭＵの構成や動作と同様であってもよい。 In other words, the monitoring target area is divided into two or more sections, dedicated detection cables are laid on each section, dedicated detection sections are connected to each detection cable, and the plurality of measurement sections are connected to one control section. It has a configuration to be managed by. This makes it possible to suppress the deterioration of the detection accuracy even though the monitoring cable appears to be one continuous monitoring cable for long-distance monitoring. For example, when the same treatment is required irrespective of the detection section, simple measures can be taken, which is preferable. Alternatively, a configuration may be adopted in which the control unit notifies which of the measurement sections has been detected so as to be identifiable. Knowing the approximate position enables the operator to quickly confirm the site. In the present embodiment, the configuration and operation of the control unit CU and the measurement unit MU may be the same as the configuration and operation of the control unit CU and the measurement unit MU in the third embodiment.
　図４（ａ）は、制御部ＣＵに対して、各計測部ＭＵ１０～ＭＵ１２を直列に接続した例を示す図である。計測部ＭＵ１０、計測部ＭＵ１１、計測部ＭＵ１２はそれぞれセンサ部ＳＵ１０、センサ部ＳＵ１１、センサ部ＳＵ１２が接続される。計測部ＭＵ１０は制御部ＣＵと直接接続される。計測部ＭＵ１１および計測部ＭＵ１２は、他の計測部を経由して制御部ＣＵに接続される。例えば、計測部ＭＵ１０は、計測部ＭＵ１１や計測部ＭＵ１２の計測した静電容量値を取得し、制御部ＣＵに送信する。このようにすることで、接続される計測部の数が大きくなった場合であっても、制御部ＣＵの負荷が極端に大きくなることを防止できる。また、長距離の監視が必要な場合においても、通信の中継の過程で信号の品質を復元することが可能であるため、敷地内で距離の離れた２点間を結ぶ液体輸送路の漏洩監視などに好適である。 FIG. 4A is a diagram showing an example in which the measuring units MU10 to MU12 are connected in series to the control unit CU. The measuring unit MU10, the measuring unit MU11, and the measuring unit MU12 are connected to the sensor unit SU10, the sensor unit SU11, and the sensor unit SU12, respectively. The measurement unit MU10 is directly connected to the control unit CU. The measurement unit MU11 and the measurement unit MU12 are connected to the control unit CU via another measurement unit. For example, the measurement unit MU10 acquires the capacitance value measured by the measurement unit MU11 or the measurement unit MU12, and transmits the capacitance value to the control unit CU. By doing so, it is possible to prevent the load on the control unit CU from becoming extremely large even when the number of connected measurement units increases. Even when long-distance monitoring is required, it is possible to restore signal quality in the process of relaying communications, so it is necessary to monitor leakage on a liquid transport path between two distant points on the premises. It is suitable for, for example.
　図４（ｂ）は、制御部ＣＵに対して、各計測部ＭＵ１０～ＭＵ３０を並列に接続した例を示す図である。それぞれの計測部ＭＵ１０～ＭＵ３０は、他の計測部を介することなく、直接制御部との通信を行う。図４（ａ）のように計測部を直列に接続した場合、各計測部で通信負荷に大きな違いが生じることとなる。たとえば計測部ＭＵ１２は計測部ＭＵ１１と通信するだけだが、計測部ＭＵ１０は、制御部ＣＵ、計測部ＭＵ１１、さらには計測部ＭＵ１２との通信が発生しうる。これにより、通信に伴う演算部による消費電力の変動も計測部ＭＵ１０と、計測部ＭＵ１２とで大きな差が生じる可能性がある。これに対して、図４（ｂ）のように、各計測部ＭＵ１０～ＭＵ３０を並列に接続することで、各計測部毎の通信による電圧変動の影響を小さくすることができる。このような接続においては、通信ラインを一筆書きのように形成する必要がなく、制御部ＣＵから放射状に監視領域を展開できるため、液体輸送路が３次元で複雑に交差するようなプラントや、分岐や合流を含む液体輸送路における漏洩の監視などに好適である。 FIG. 4B is a diagram showing an example in which the measuring units MU10 to MU30 are connected in parallel to the control unit CU. Each of the measurement units MU10 to MU30 communicates directly with the control unit without passing through another measurement unit. When the measuring units are connected in series as shown in FIG. 4A, a large difference occurs in the communication load between the measuring units. For example, the measurement unit MU12 only communicates with the measurement unit MU11, but the measurement unit MU10 can generate communication with the control unit CU, the measurement unit MU11, and further with the measurement unit MU12. As a result, there is a possibility that a large difference between the measurement unit MU10 and the measurement unit MU12 also occurs in the fluctuation of the power consumption due to the arithmetic unit due to the communication. On the other hand, as shown in FIG. 4B, by connecting the measuring units MU10 to MU30 in parallel, it is possible to reduce the influence of voltage fluctuation due to communication of each measuring unit. In such a connection, it is not necessary to form a communication line like a single stroke, and the monitoring area can be developed radially from the control unit CU. It is suitable for monitoring leakage in a liquid transport path including branching and merging.
　図４（ｃ）は、制御部ＣＵに対して、計測部ＭＵ１０～ＭＵ３０を並列に接続し、さらに計測部ＭＵ１０～ＭＵ３０のそれぞれに、複数の計測部を直列に接続した構成の例を示す図である。上記のように直列、並列それぞれには長短所があり、制御部ＣＵに接続される計測部ＭＵの数が多くなると、どうしても何れかの課題が顕在化してしまう。これに対して、複数の計測部が直列に接続されたブロックを構成し、さらに各ブロックの中の１つの計測部ＭＵを並列に制御部ＣＵに接続することにより、それぞれの特徴を活かした高感度高精度の監視ネットワークを構築することができる。例えば、１００ｃｈ以上、さらには３００ｃｈ以上の計測部を含む大規模な監視体制を構築する場合に好適である。 FIG. 4C shows an example of a configuration in which measuring units MU10 to MU30 are connected in parallel to the control unit CU, and a plurality of measuring units are connected in series to each of the measuring units MU10 to MU30. It is. As described above, each of the series and the parallel has advantages and disadvantages. When the number of the measurement units MU connected to the control unit CU increases, one of the problems is inevitably manifested. On the other hand, by configuring a block in which a plurality of measurement units are connected in series, and connecting one measurement unit MU in each block to the control unit CU in parallel, a high value utilizing each characteristic is obtained. A monitoring network with high sensitivity and accuracy can be constructed. For example, it is suitable for constructing a large-scale monitoring system including a measuring unit of 100 ch or more, and further, 300 ch or more.
　本発明によれば、図４に示されるように、制御部ＣＵに対して、複数の計測部ＭＵが、直列及び／又は並列に接続された場合であっても、任意の計測部との個別の通信制御が可能である。図５は、本発明に係る多点監視における動作を説明する図である。液体検知システムＬＤＳは制御部ＣＵと、この制御部ＣＵに制御部通信ケーブルを介して接続された複数の計測部ＭＵを含む。図示は省略するが、複数の計測部ＭＵにはそれぞれセンサ部ＳＵが接続されている。複数の計測部ＭＵには、それぞれに固有の識別番号が設定されている。これら識別番号は、各計測部ＭＵのメモリやディップスイッチなどに保持され、計測部ＭＵは自身の識別番号を読み出すことができる。説明のため、図５におけるそれぞれの計測部ＭＵには、ＭＵの後ろの位置に、１－１、１－２、２－１、２－２ａ、２－３ａ、及び、２－２ｂからなる、それぞれの識別番号を表示している。以下において、特定の計測部ＭＵを指すときはＭＵ１－１のようにＭＵに続けて識別番号を併記する形で表記する。
　制御部ＣＵおよび計測部ＭＵは、通信用のポートを備える。制御部ＣＵの通信用のポートは制御部ＣＵ内の通信部ＣＣ１（不図示）に接続され、通信部から送出された信号はこのポートを介して、制御部ＣＵの外部に送出される。あるいは、制御部ＣＵの外部から送られてきた信号は、該ポートを介して、制御部ＣＵの通信部にて受信される。計測部ＭＵの通信ポートも同様に、計測部ＭＵの通信部ＭＲＴ（不図示）で送受信される信号は、計測部ＭＵの通信ポートを介して、計測部の内外を行き来する。
　これらの通信ポートは、制御部通信ケーブルを介して他の計測部ＭＵ又は制御部ＣＵの通信ポートと接続される。 According to the present invention, as shown in FIG. 4, even when a plurality of measurement units MU are connected in series and / or parallel to the control unit CU, individual Communication control is possible. FIG. 5 is a diagram for explaining the operation in the multipoint monitoring according to the present invention. The liquid detection system LDS includes a control unit CU and a plurality of measurement units MU connected to the control unit CU via a control unit communication cable. Although illustration is omitted, a sensor unit SU is connected to each of the plurality of measurement units MU. A unique identification number is set for each of the plurality of measurement units MU. These identification numbers are held in a memory or a dip switch of each measurement unit MU, and the measurement unit MU can read its own identification number. For explanation, each measurement unit MU in FIG. 5 includes 1-1, 1-2, 2-1, 2-2a, 2-3a, and 2-2b at positions behind the MU. Each identification number is displayed. In the following, when a specific measurement unit MU is indicated, it is described in a form in which an identification number is added following the MU, such as MU1-1.
The control unit CU and the measurement unit MU include a communication port. A communication port of the control unit CU is connected to a communication unit CC1 (not shown) in the control unit CU, and a signal sent from the communication unit is sent out of the control unit CU via this port. Alternatively, a signal transmitted from outside the control unit CU is received by the communication unit of the control unit CU via the port. Similarly, the communication port of the measurement unit MU transmits and receives signals transmitted and received by the communication unit MRT (not shown) of the measurement unit MU via the communication port of the measurement unit MU.
These communication ports are connected to communication ports of another measurement unit MU or control unit CU via a control unit communication cable.
　制御部ＣＵは下流側ポートＣＤＰを備える。複数の計測部ＭＵは、それぞれ、上流側ポートＭＵＰと、下流側ポートＭＤＰとを備える。それぞれの計測部ＭＵにおいて、上流側ポートＭＵＰは、制御部ＣＵに向かってデータを送受信するポートであり、下流側ポートＭＤＰは制御部ＣＵと逆の向きにデータを送受信するポートである。例えば、図５において、計測部ＭＵ１－１の上流側ポートＭＵＰは、制御部ＣＵの下流側ポートと接続され、計測部ＭＵ１－１の下流側ポートＭＤＰは、計測部ＭＵ１－２の上流側ポートと接続される。 The control unit CU has a downstream port CDP. Each of the plurality of measurement units MU includes an upstream port MUP and a downstream port MDP. In each measurement unit MU, the upstream port MUP is a port for transmitting and receiving data toward the control unit CU, and the downstream port MDP is a port for transmitting and receiving data in the opposite direction to the control unit CU. For example, in FIG. 5, the upstream port MUP of the measurement unit MU1-1 is connected to the downstream port of the control unit CU, and the downstream port MDP of the measurement unit MU1-1 is connected to the upstream port of the measurement unit MU1-2. Connected to
　複数の計測部ＭＵは、それぞれに接続された検知ケーブルの静電容量の変化を監視し、その結果を保持している。制御部ＣＵは任意の制御部の保持する情報を取得することができる。制御部ＣＵが制御部ＭＵ２－３ａの保持している監視結果を取得する方法を例として説明する。まず、制御部ＣＵは、全ての計測部ＭＵに対して、制御部ＭＵ２－３ａの監視結果を要求する信号を送信する。概信号は、計測部ＭＵ１－１及びＭＵ２－１のような接続においては、制御部ＣＵから直接届けられる。一方、例えば計測部ＭＵ１－２のような接続においては計測部ＭＵ１－１を介して届けられてもよい。本例において、指定された計測部ＭＵ２－３ａは、上流側ポートＭＵＰの電気的な状態を変化させる。例えばＨｉｇｈレベルにあった電位をＬｏｗレベルに切り替える。計測部ＭＵ１－２の上流側に隣接する位置には計測部ＭＵ２－２ａが接続されている。計測部ＭＵ２－２ａの下流側ポートＭＤＰは、計測ＭＵ２－３ａの上流側ポートの電気的な状態の変化を取得すると、計測部ＭＵ２－２ａの下流側ポートＭＤＰで受信した情報を計測部ＭＵ２－２ａの上流側ポートＭＵＰから上流にむけて送信可能な状態になる。また、計測部ＭＵ２－３ａと同様に、計測部ＭＵ２－２ａの上流側ポートＭＵＰの電気的な状態を変化させることで、計測部ＭＵ２－１が、その下流側ポートＭＤＰで受信した情報を上流側ポートＭＵＰから上流に向けて、本例においては制御部ＤＵに向けて、送信可能な状態になる。
　計測部ＭＵ２－３ａは、計測部ＭＵ２－３ａから制御部ＣＵに至る情報の伝送通路が形成されたのちに、要求された情報、すなわち監視結果を制御部ＣＵに対して送信する。 The plurality of measurement units MU monitor changes in the capacitance of the detection cables connected to the respective measurement units, and hold the results. The control unit CU can acquire information held by any control unit. A method in which the control unit CU acquires a monitoring result held by the control unit MU2-3a will be described as an example. First, the control unit CU transmits a signal requesting a monitoring result of the control units MU2-3a to all the measurement units MU. The approximate signal is directly transmitted from the control unit CU in a connection such as the measurement units MU1-1 and MU2-1. On the other hand, for example, in a connection such as the measurement unit MU1-2, the information may be delivered via the measurement unit MU1-1. In this example, the designated measuring unit MU2-3a changes the electrical state of the upstream port MUP. For example, a potential that was at a high level is switched to a low level. The measurement unit MU2-2a is connected to a position adjacent to the upstream of the measurement unit MU1-2. When the downstream port MDP of the measurement unit MU2-2a acquires the change in the electrical state of the upstream port of the measurement MU2-3a, the information received at the downstream port MDP of the measurement unit MU2-2a is measured. Transmission is possible from the upstream port MUP of 2a to the upstream. Further, similarly to the measurement unit MU2-3a, by changing the electrical state of the upstream port MUP of the measurement unit MU2-2a, the measurement unit MU2-1 transmits information received at the downstream port MDP to the upstream port MDP. From the side port MUP, it is possible to transmit upstream to the control unit DU in this example.
The measurement unit MU2-3a transmits the requested information, that is, the monitoring result, to the control unit CU after the transmission path of the information from the measurement unit MU2-3a to the control unit CU is formed.
　本実施形態に係る液体検知システムＬＤＳは上記の構成を有することにより、例えば１００ｋｍを超えるような長距離に至る監視領域の監視が可能となる。また、プラントのように複数の配管が複雑に入り組んだ状態にあっても、高い自由度で監視網を設定することが可能となる。また、固有の識別番号さえあれば接続位置を問わず制御部との個別の通信が可能となるため、監視網を構築したあとであっても、計測部の追加や削除、分岐の生成などを容易に行える。
　なお、計測部ＭＵは、２種類の受電に対応できることが特に好ましい。制御部通信ケーブルと同梱された電源ケーブルを介して、上流又は下流に位置する他の計測部ＭＵから給電される第一の受電手段をそなえることで、電源供給の制約を受けない計測部の配置が可能となる。これに加え、外部電源から給電される第二の受電手段備えることで、特定の計測部ＭＵが大きな距離だけ離れた位置に配置された場合や、給電側となる特定の計測部ＭＵに、受電側となる他の計測部ＭＵが多く接続された場合においても、安定した動作を得ることができる。 The liquid detection system LDS according to the present embodiment has the above configuration, so that it is possible to monitor a monitoring area over a long distance exceeding, for example, 100 km. Further, even when a plurality of pipes are complicated and complicated like a plant, a monitoring network can be set with a high degree of freedom. In addition, since individual communication with the control unit is possible regardless of the connection position as long as there is a unique identification number, even after the monitoring network has been constructed, addition and deletion of measurement units, generation of branches, etc. Easy to do.
It is particularly preferable that the measurement unit MU can support two types of power reception. By providing a first power receiving unit that is supplied with power from another measurement unit MU located upstream or downstream via a power cable bundled with the control unit communication cable, a measurement unit that is not restricted by power supply is provided. The arrangement becomes possible. In addition, by providing the second power receiving unit that is supplied with power from an external power supply, when a specific measuring unit MU is arranged at a position separated by a large distance, or when a specific measuring unit MU on the power supply side receives power, Even when many other measuring units MU on the side are connected, a stable operation can be obtained.
　図６は、本発明に係る多点監視における検知ケーブルの敷設の一例を示す図である。図６（ａ）を用いて監視対象となる液体利用系の構成を説明する。概液体利用系は輸送路ＬＰＬを含み、該輸送路ＬＰＬの一端には貯液槽ＬＵＴ１が接続され、輸送路ＬＰＬの他端には貯液槽ＬＵＴ２が接続される。貯液槽ＬＵＴ１は例えばメインタンクであり、１０００Ｌを超える燃料、例えば重油を保持する。貯液槽ＬＵＴ２は例えば非常用発電機内の燃料タンクであり貯液量は１００Ｌ以下と貯液槽ＬＵＴ１より小さい。貯液槽ＬＵＴ２は発電時にエンジンに供給される燃料の最終貯留位置であり、燃料の消費変動を吸収するバッファ的な機能を有する。輸送路ＬＰＬはパイプラインであり、図示されないポンプやバルブを含んでいてよい。発電機が燃料を消費すると、貯液槽ＬＵＴ１から、輸送路ＬＰＬを介して、貯液槽ＬＵＴ２、つまり発電機内の燃料タンクに燃料が補給される。本例においては、貯液槽ＬＵＴ１が地下階に配置され、貯液槽ＬＵＴ２が地上階に設置されている。従って輸送路ＬＰＬ及びその監視領域は図においてＬＤＲ２及びＬＤＲ４で示された水平方向に延伸する区画と、ＬＤＲ３で示された垂直方向に延伸する領域を含む区画とを有する。監視領域はさらに、図においてＬＤＲ１及びＬＤＲ５で示された、貯液槽ＬＵＴ１の下の領域と貯液槽ＬＵＴ２の下の領域とをそれぞれ含む２つの区画を有する。なお、図６及びその説明において下方とは重力の向きと同じ向きを意味し、水平方向は前記下方に対して垂直な方向を意味する。本液体利用系において、貯液槽ＬＵＴ１は万が一の破損などにより漏洩した燃料がフロア上に広がったり土壌に浸透することを防止するため、フロアに形成された凹部からなるピットＬＵＰ上に載置されている。 FIG. 6 is a diagram showing an example of laying of detection cables in multipoint monitoring according to the present invention. The configuration of the liquid utilization system to be monitored will be described with reference to FIG. The general liquid use system includes a transport path LPL, one end of the transport path LPL is connected to a liquid storage tank LUT1, and the other end of the transport path LPL is connected to a liquid storage tank LUT2. The liquid storage tank LUT1 is, for example, a main tank and holds more than 1000 L of fuel, for example, heavy oil. The liquid storage tank LUT2 is, for example, a fuel tank in an emergency generator, and has a storage amount of 100 L or less, which is smaller than the liquid storage tank LUT1. The liquid storage tank LUT2 is a final storage position of fuel supplied to the engine during power generation, and has a buffer-like function of absorbing fluctuations in fuel consumption. The transport path LPL is a pipeline and may include a pump and a valve (not shown). When the generator consumes fuel, the fuel is supplied from the storage tank LUT1 to the storage tank LUT2, that is, the fuel tank in the generator, via the transport path LPL. In this example, the liquid storage tank LUT1 is disposed on the basement floor, and the liquid storage tank LUT2 is disposed on the ground floor. Accordingly, the transport path LPL and its monitoring area have a section extending in the horizontal direction indicated by LDR2 and LDR4 in the figure and a section including an area extending in the vertical direction indicated by LDR3. The monitoring area further has two compartments, indicated by LDR1 and LDR5 in the figure, respectively including an area below the reservoir LUT1 and an area below the reservoir LUT2. In FIG. 6 and its description, “downward” means the same direction as the direction of gravity, and “horizontal direction” means a direction perpendicular to the downward direction. In this liquid utilization system, the liquid storage tank LUT1 is mounted on a pit LUP consisting of a concave portion formed on the floor in order to prevent fuel leaked due to emergency damage or the like from spreading on the floor or penetrating into the soil. ing.
　このような１つの経路からなる監視対象に検知ケーブルＳＤＣを敷設する場合は、１本の検知ケーブルを用い、区画ＬＤＲ１、ＬＤＲ２，ＬＤＲ３，ＬＤＲ４，及びＬＤＲ５をこの順に通過させることでも監視は可能である。しかし、漏液量が少ない場合や、監視対象が大きく検知ケーブルＳＤＣが長い場合には上述したような理由から十分な感度が得られなかったり、判定の精度が悪化する虞があった。
　これに対して、本発明の第四の実施形態にかかる液体検知システムは、図６（ｂ）に示される、以下の構成のいずれか１つ以上を含む。これにより、液体との接触により静電容量が変化する検知ケーブルを用いた液体検知において、高い感度と高い精度を有する検知が実現される。
　検知システムＬＤＳは、複数の計測部ＭＵを含み、複数の計測部ＭＵは制御部通信ケーブルＣＣＣを介して１つの制御部ＣＵに接続される。それぞれの計測部ＭＵは、監視対象のそれぞれの区画に敷設された検知ケーブルＳＤＣと接続されている。計測部ＭＵと検知ケーブルＳＤＣとは直接接続されていてもよいが、好ましくはリードケーブルＳＬＣを介して接続される。監視区画ＬＤＲ１、つまり、貯液槽ＬＵＴ１の漏液検知を例に説明すると、ピットＬＵＰの底面上に検知ケーブルＳＤＣ１が敷設されており、検知ケーブルＳＤＣ１はリードケーブルＳＬＣ１を介して計測部ＭＵ１に接続される。他の区画も同様に、監視区画ＬＤＲ２には検知ケーブルＳＤＣ２が、監視区画ＬＤＲ３には検知ケーブルＳＤＣ３が、監視区画ＬＤＲ４には検知ケーブルＳＤＣ４が、監視区画ＬＤＲ５には検知ケーブルＳＤＣ５が、それぞれ敷設される。監視区画あたりの検知ケーブルは１つでも複数でもよく、本図において区画ＬＤＲ２には３本の検知ケーブルＳＤＣ２が敷設された例を示している。図示は省力しているが区画ＬＤＲ２のうち検知ケーブルＳＤＣ２が敷設されていない領域に更に多くの検知ケーブルＳＤＣ２を敷設してもよい。なお、区画ＬＤＲ１および区画ＬＤＲ５のように底面が平坦な貯液領域の場合には、その直下の床上に検知ケーブルを敷設してよい。一方で区画ＬＤＲ２及び区画ＬＤＲ４のように水平方向に延伸するパイプラインのように底面が円形の漏液検知では、その外周面のうち最も下方の領域にそって検知ケーブルを敷設してよい。 When laying the detection cable SDC on such a monitoring target composed of one path, monitoring can be performed by using one detection cable and passing the sections LDR1, LDR2, LDR3, LDR4, and LDR5 in this order. is there. However, when the amount of liquid leakage is small, or when the monitoring target is large and the detection cable SDC is long, sufficient sensitivity may not be obtained or the accuracy of the determination may be deteriorated for the reasons described above.
On the other hand, the liquid detection system according to the fourth embodiment of the present invention includes one or more of the following configurations shown in FIG. Thereby, in liquid detection using a detection cable whose capacitance changes due to contact with liquid, detection with high sensitivity and high accuracy is realized.
The detection system LDS includes a plurality of measurement units MU, and the plurality of measurement units MU are connected to one control unit CU via a control unit communication cable CCC. Each measurement unit MU is connected to a detection cable SDC laid in each section to be monitored. The measurement unit MU and the detection cable SDC may be directly connected, but are preferably connected via a lead cable SLC. Describing the detection of liquid leakage from the monitoring section LDR1, that is, the liquid storage tank LUT1, for example, a detection cable SDC1 is laid on the bottom surface of the pit LUP, and the detection cable SDC1 is connected to the measurement unit MU1 via a lead cable SLC1. Is done. Similarly, in the other sections, the detection cable SDC2 is laid in the monitoring section LDR2, the detection cable SDC3 in the monitoring section LDR3, the detection cable SDC4 in the monitoring section LDR4, and the detection cable SDC5 in the monitoring section LDR5. You. The number of detection cables per monitoring section may be one or more. FIG. 3 shows an example in which three detection cables SDC2 are laid in the section LDR2. Although illustration is omitted, more detection cables SDC2 may be laid in an area of the section LDR2 where the detection cable SDC2 is not laid. In the case of a liquid storage region having a flat bottom surface, such as the partition LDR1 and the partition LDR5, a detection cable may be laid on the floor immediately below the storage region. On the other hand, in the case of detecting a liquid leak having a circular bottom surface such as a pipeline extending in the horizontal direction as in the sections LDR2 and LDR4, a detection cable may be laid along the lowermost region of the outer peripheral surface.
　本実施形態の液体検知システムＬＤＳは、長さの異なる検知ケーブルを含む。例えば、輸送路ＬＰＬのうち、水平方向に延伸する領域において、より上方、すなわち高い位置にある区画（図のＬＤＲ４）に敷設された検出ケーブルＳＤＣ４は、それより低い位置にある区画（図のＬＤＲ２）に敷設された検出ケーブルＳＤＣ２より短い。液体の自重による圧力が小さく、漏液量が小さい場合であっても高感度高精度での検知が可能となる。他の例としては、輸送経路ＬＰＬのうち、経路の高低差が小さい区画（図のＬＤＲ２）に敷設された検出ケーブルＳＤＣ２は、それより高低差が大きな区画（図のＬＤＲ３）に敷設された検出ケーブルＳＤＣ３より短い。さらに他の例としては、貯液槽ＬＵＴの下方の監視領域において、貯液槽の貯液量が小さな区画（図のＬＤＲ５）に敷設された検出ケーブルＳＤＣ５は、それより貯液槽の貯液容量が大きな区画（図のＬＤＲ１）に敷設された検出ケーブルＳＤＣ１より短い。さらに他の例としては、漏洩した液体をためる凹部になっていない区画（図のＬＤＲ５）に敷設された検出ケーブルＳＤＣ５は、漏洩した液体をためる凹部内の区画（図のＬＤＲ１）に敷設された検出ケーブルＳＤＣ１より短い。
　このように、それぞれの監視対象位置において、想定される漏液量に基づいて検知ケーブルの静電容量の変化を考慮して、検知ケーブルを適切な長さとすることで、系全体として高い検知感度と検知精度を実現できる。 The liquid detection system LDS of the present embodiment includes detection cables having different lengths. For example, in the area extending in the horizontal direction of the transport path LPL, the detection cable SDC4 laid above the upper section, that is, the section (LDR4 in the figure) at a higher position, is connected to the section (LDR2 in the figure) at a lower position. ) Is shorter than the detection cable SDC2 laid. Even when the pressure due to the weight of the liquid is small and the amount of liquid leakage is small, detection with high sensitivity and high accuracy is possible. As another example, the detection cable SDC2 laid in a section (LDR2 in the figure) of the transportation route LPL having a small height difference is a detection cable laid in a section (LDR3 in the figure) with a larger height difference. It is shorter than cable SDC3. As still another example, in the monitoring area below the liquid storage tank LUT, the detection cable SDC5 laid in the section (LDR5 in the figure) where the liquid storage volume of the liquid storage tank is small is smaller than the storage cable in the liquid storage tank LUT. It is shorter than the detection cable SDC1 laid in the large capacity section (LDR1 in the figure). As still another example, the detection cable SDC5 laid in a section (LDR5 in the figure) that is not a recess for storing leaked liquid is laid in a section (LDR1 in the figure) in the recess for storing leaked liquid. It is shorter than the detection cable SDC1.
As described above, at each monitoring target position, by taking into account the change in the capacitance of the detection cable based on the expected amount of liquid leakage, the detection cable is made to have an appropriate length, thereby achieving high detection sensitivity as a whole system. And detection accuracy can be realized.
　また、液体の存在を監視する対象に敷設後の検知ケーブルの一端と他端との間の直線距離をＤＳＤＣとしたときのＤＳＤＣ／ＬＳＤＣの値は、検知ケーブルを屈曲させながら敷設した場合における、検知ケーブルの単位長さあたりの監視領域の大きさの指標となる。例えば、ＤＳＤＣ／ＬＳＤＣの値が１の場合は、検知ケーブルが直線的に敷設されているｋとを意味し、１より小さいと湾曲部を含むことを意味する。
　一筆書きなどの制約が小さく、レイアウトの自由度が極めて大きな本実施形態においては、このＤＳＤＣ／ＬＳＤＣの値が０．３以上となるような効率的な敷設が可能であり、０．５以上となるようなさらに効率的な敷設も可能となる。ＤＳＤＣ／ＬＳＤＣの値は単独の検知ケーブルにおいて算出してもよく、同一の制御部ＣＵに接続された複数の検知ケーブルのうち、無作為に抽出した５本の検知ケーブルそれぞれのＤＳＤＣ／ＬＳＤＣの値の平均値として算出してもよい。
  The value of D SDC / L SDC when the linear distance was D SDC between the one end and the other end of the detection cable after laying a subject to monitor the presence of the liquid was laid while bending the detection cable In this case, it is an index of the size of the monitoring area per unit length of the detection cable. For example, when the value of D SDC / L SDC is 1, it means k that the detection cable is laid linearly, and when it is less than 1, it means that the curved portion is included.
In the present embodiment, in which restrictions such as one-stroke writing are small and the degree of freedom in layout is extremely large, efficient laying such that the value of D SDC / L SDC becomes 0.3 or more is possible. More efficient laying as described above is also possible. D SDC / L value of the SDC may be calculated in a single detection cable, among the plurality of sensing cable connected to the same control unit CU, for each five sensing cable that randomly D SDC / It may be calculated as an average of the values of LSDC .

Claims (10)

  1. 　第一の導体、前記第一の導体と電気的に絶縁された第二の導体、および、前記第一の導体と前記第二の導体との間に形成された誘電体層を備え、液体との接触により静電容量が変化する検知ケーブルと、
    　前記検知ケーブルとともに、前記検知ケーブルの前記静電容量を含む発振回路を構成するタイマＩＣと、
    　前記タイマＩＣから前記発振回路の生成される周波数に対応するパルスを取得し、単位時間あたりの前記パルス数をカウントすることで前記検知ケーブルの静電容量を算出する演算部と、
    　前記演算部に印加される電圧である第一電圧を発生する第一電圧発生部と、
    　前記タイマＩＣに印加される電圧である第二電圧を発生する第二電圧発生部と、を備えることを特徴とする液体検知システム。     A first conductor, a second conductor electrically insulated from the first conductor, and a dielectric layer formed between the first conductor and the second conductor, and a liquid A detection cable whose capacitance changes due to contact with
    Together with the detection cable, a timer IC that constitutes an oscillation circuit including the capacitance of the detection cable;
    A calculation unit that obtains a pulse corresponding to the frequency generated by the oscillation circuit from the timer IC, and calculates the capacitance of the detection cable by counting the number of pulses per unit time;
    A first voltage generator that generates a first voltage that is a voltage applied to the arithmetic unit,
    A liquid detection system, comprising: a second voltage generator that generates a second voltage that is a voltage applied to the timer IC.
  2. 　前記液体検知システムの前記発振回路が、ＣＲ発振回路であることを特徴とする、請求項１に記載の液体検知システム。 The liquid detection system according to claim 1, wherein the oscillation circuit of the liquid detection system is a CR oscillation circuit.
  3. 　前記第二電圧発生部は電源リファレンスＩＣを含むことを特徴とする、請求項１または２に記載の液体検知システム。 The liquid detection system according to claim 1, wherein the second voltage generator includes a power supply reference IC.
  4. 　前記第二電圧発生部はさらに、電源リファレンスＩＣに印加される第三電圧を生成するチャージポンプを含むことを特徴とする、請求項１ないし３のいずれかに記載の液体検知システム。 4. The liquid detection system according to claim 1, wherein the second voltage generator further includes a charge pump that generates a third voltage applied to a power supply reference IC.
  5. 　前記第三電圧は前記第一電圧より高く、かつ、前記第三電圧は、前記第二電圧より高いことを特徴とする、請求項４に記載の液体検知システム。 The liquid detection system according to claim 4, wherein the third voltage is higher than the first voltage, and the third voltage is higher than the second voltage.
  6. 　前記演算部の指令に基づき、少なくとも計測状況を制御部に送信する通信部をさらに備えることを特徴とする、請求項１ないし５のいずれかに記載の液体検知システム。 6. The liquid detection system according to claim 1, further comprising a communication unit that transmits at least a measurement status to a control unit based on a command from the arithmetic unit.
  7. 　前記演算部にデータを提供する記憶部をさらに備え、
    　前記第二電圧は、当該記憶部、前記演算部、前記通信部、または前記タイマＩＣのうち、前記タイマＩＣのみに印加されることを特徴とする、請求項１ないし６のいずれかに記載の液体検知システム。     A storage unit that provides data to the arithmetic unit;
    The method according to claim 1, wherein the second voltage is applied only to the timer IC among the storage unit, the arithmetic unit, the communication unit, and the timer IC. Liquid detection system.
  8. 　前記第一電圧発生部から発生する第一電圧の値Ｖ１と前記第二電圧発生部から発生する第二電圧Ｖ２の値との比Ｖ１／Ｖ２は、０．７以上１．３以下であることを特徴とする、請求項１ないし７のいずれかに記載の液体検知システム。 The ratio V1 / V2 of the value V1 of the first voltage generated from the first voltage generator to the value of the second voltage V2 generated from the second voltage generator is 0.7 or more and 1.3 or less. The liquid detection system according to any one of claims 1 to 7, wherein:
  9. 　第一の導体、前記第一の導体と電気的に絶縁された第二の導体、および、前記第一の導体と前記第二の導体との間に形成された誘電体層を備え、液体との接触により静電容量が変化する検知ケーブルと、
    　前記検知ケーブルの静電容量を算出する演算部を備える計測部と、
    　前記計測部において算出された静電容量の変化が予め定めた条件を満たすときに、検知ケーブルと液体との接触を検知したことを通知する通知部を備える制御部と、
    　前記検知ケーブルと前記計測部とを接続する第一のケーブルと、
    　前記計測部と前記制御部とを接続する第二のケーブルとを備え、
    　前記第一のケーブルは、前記第二のケーブルより短いことを特徴とする液体検知システム。     A first conductor, a second conductor electrically insulated from the first conductor, and a dielectric layer formed between the first conductor and the second conductor, and a liquid A detection cable whose capacitance changes due to contact with
    A measurement unit including a calculation unit that calculates the capacitance of the detection cable;
    When the change in the capacitance calculated by the measurement unit satisfies a predetermined condition, a control unit including a notification unit that notifies that a contact between the detection cable and the liquid has been detected,
    A first cable connecting the detection cable and the measurement unit,
    A second cable that connects the measurement unit and the control unit,
    The liquid detection system according to claim 1, wherein the first cable is shorter than the second cable.
  10. 　複数の計測部と、
    　当該複数の計測部からの信号を受信する制御部と、を備え、
    　前記複数の計測部は、
    　第一の検知ケーブルと、当該第一の検知ケーブルへの液体の接触を判定する第一の演算部と、当該第一の演算部の接触判定情報を信号として外部に送信する第一の通信部と、を有する第一の計測部と、
    　第二の検知ケーブルと、当該第二の検知ケーブルへの液体の接触を判定する第二の演算部と、当該第二の演算部の接触判定情報を信号として外部に送信する第二の通信部と、を有する第二の計測部と、
    　第三の検知ケーブルと、前記第三の検知ケーブルへの液体の接触を判定する第三の演算部と、当該第三の演算部の接触判定情報を信号として外部に送信する第三の通信部、を備えた第三の計測部と、　を有し、
    　前記第一の計測部および前記第二の計測部は、それぞれ接触判定情報を他の計測部の通信部を経由せずに前記制御部に送信し、
    　前記第三の計測部は、前記第三の計測部の接触判定情報を前記第一の計測部の前記第一の通信部を経由して前記制御部に送信することを特徴とする液体検知システム。
          A plurality of measuring units,
    A control unit that receives signals from the plurality of measurement units,
    The plurality of measurement units,
    A first detection cable, a first calculation unit that determines contact of the liquid with the first detection cable, and a first communication unit that transmits contact determination information of the first calculation unit to the outside as a signal. And a first measurement unit having
    A second detection cable, a second calculation unit that determines contact of the liquid with the second detection cable, and a second communication unit that transmits the contact determination information of the second calculation unit to the outside as a signal And a second measurement unit having:
    A third detection cable, a third calculation unit that determines contact of the liquid with the third detection cable, and a third communication unit that transmits the contact determination information of the third calculation unit as a signal to the outside And a third measuring unit having:
    The first measurement unit and the second measurement unit each transmits the contact determination information to the control unit without passing through the communication unit of another measurement unit,
    The liquid detection system, wherein the third measurement unit transmits the contact determination information of the third measurement unit to the control unit via the first communication unit of the first measurement unit. .
PCT/JP2019/037066 2018-09-20 2019-09-20 Liquid detection system WO2020059866A1 (en)

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