WO2019167660A1 - Liquid level position detection device - Google Patents
Liquid level position detection device Download PDFInfo
- Publication number
- WO2019167660A1 WO2019167660A1 PCT/JP2019/005488 JP2019005488W WO2019167660A1 WO 2019167660 A1 WO2019167660 A1 WO 2019167660A1 JP 2019005488 W JP2019005488 W JP 2019005488W WO 2019167660 A1 WO2019167660 A1 WO 2019167660A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- wave
- transmission
- surface portion
- main surface
- reception unit
- Prior art date
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/296—Acoustic waves
Definitions
- the present invention relates to a liquid level position detection device.
- the speed of sound of a surface wave propagating through a portion of a propagating body in a liquid is slower than the speed of sound of a surface wave propagating through a portion exposed from the liquid.
- the thing which detects the liquid level position of a liquid using this is disclosed.
- the surface wave propagating through the propagating body is attenuated and the S / N ratio (Signal-Noise ratio) is deteriorated.
- the detection accuracy may deteriorate.
- the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid surface position detection device with high liquid surface position detection accuracy.
- a liquid surface position detection device is A propagating body in which a ratio of a portion immersed in the liquid changes according to a liquid surface position; A first transmission / reception unit for generating a first surface wave in the propagation body and receiving a second surface wave; A second transmission / reception unit for generating the second surface wave in the propagating body and receiving the first surface wave; The liquid level position is detected based on at least one of the propagation time of the first surface wave received by the second wave transmitting / receiving unit and the propagation time of the second surface wave received by the first wave transmitting / receiving unit.
- the propagator is A first main surface portion and a second main surface portion, which are in reverse relation to each other; And connecting the first main surface portion and the second main surface portion, and a bottom surface portion having a curved shape in a side view,
- the first transmitting / receiving unit generates the first surface wave propagating through the first main surface unit
- the second transmission / reception unit receives the first surface wave that has propagated through the first main surface portion and the bottom surface portion and the second main surface portion
- the second wave transmitting / receiving unit generates the second surface wave propagating through the second main surface part
- the first wave transmitting / receiving unit receives the second surface wave that has propagated through the second main surface portion and the bottom surface portion and the first main surface portion.
- FIG. 1 It is a schematic block diagram of the liquid level position detection apparatus which concerns on 1st Embodiment of this invention.
- (A) is a front view of the propagating body and vibrator according to the first embodiment, and (b) is a side view of the propagating body and vibrator according to the first embodiment. It is a schematic diagram for demonstrating a 1st surface wave and a 2nd surface wave. It is a flowchart which shows an example of a liquid level position detection process.
- (A) is a front view of the propagating body and vibrator according to the second embodiment,
- (b) is a side view of the propagating body and vibrator according to the second embodiment, and (c) It is a top view at the vibrator side of the propagating body according to the second embodiment.
- FIG. 1 It is a schematic diagram for demonstrating a 3rd surface wave and a 4th surface wave.
- A is a schematic diagram of the waveform for mainly explaining an internal propagation wave
- (b) is a schematic diagram of the waveform by the propagation body which concerns on 2nd Embodiment. It is a flowchart which shows an example of a liquid level position detection process.
- the liquid surface position detection device 100 is a device that detects the position of the liquid surface 91 of the liquid 90 put in the container 80. As the amount of the liquid 90 increases or decreases, the liquid level 91 also moves up and down.
- the liquid level position detection apparatus 100 includes a propagation body 10, a vibrator 20, a transmission / reception circuit 30, and a control unit 40.
- the propagating body 10 propagates a surface wave and is made of a synthetic resin such as PPS (polyphenylene sulfide).
- the propagating body 10 has a strip shape that is long in the vertical direction.
- the outer surface of the propagating body 10 includes an upper surface facing the vibrator 20, a bottom surface opposite to the upper surface, two main surfaces that connect the upper surface and the bottom surface, and have a reverse relationship with each other, and an upper surface and a bottom surface that are connected to each other. It is mainly composed of six sides, which are the two side surfaces that are in the relationship.
- the propagating body 10 includes a main surface portion 11 (an example of a first main surface portion) including one of two main surfaces, and a main surface portion 12 (second main surface) including the other.
- An example of the surface portion a side surface portion 13 including one of the two side surfaces, a side surface portion 14 including the other, a contact portion 15 including the upper surface and contacting the vibrator 20, and a bottom surface portion 16 including the bottom surface.
- the surface wave propagates through the propagating body 10, but reaches the same depth as the wavelength of the surface wave from the surface of the propagating body 10 during propagation.
- the main surface portion 11 and the main surface portion 12 are portions including not only the main surface of the propagation body 10 but also the depth. The same applies to the contact portion 15 and the bottom surface portion 16.
- the main surface portion 11 hangs from one end of the contact portion 15 in a side view.
- the main surface portion 12 hangs from the other end of the contact portion 15.
- the bottom surface portion 16 connects the main surface portion 11 and the main surface portion 12 on the side opposite to the contact portion 15 and has a U-shaped smooth curved surface that protrudes downward.
- the bottom surface portion 16 formed in this way reduces loss due to leakage when a first surface wave W1 and a second surface wave W2 described later propagate to the bottom surface portion 16.
- the propagating body 10 is fixed by being sandwiched between fixing members 81 and 82 provided on the container 80 by the side surface portion 13 and the side surface portion 14.
- the fixing method is arbitrary.
- the propagating body 10 is arranged such that the lower end of the bottom surface portion 16 is separated from the bottom surface of the container 80 by a length d.
- the length along the vertical direction from the upper end of the contact portion 15 to the liquid surface 91 in the propagation body 10 (the length of the first portion 10a where the propagation body 10 is not immersed in the liquid 90) L1 and the bottom surface
- the length along the vertical direction from the lower end of the portion 16 to the liquid level 91 (the length of the second portion 10b where the propagation body 10 is immersed in the liquid 90) L2 varies depending on the increase or decrease of the liquid 90. .
- the vibrator 20 is, for example, a transverse wave transducer and includes a piezoelectric element mounted on a circuit board. The vibrator 20 is pressed against the contact portion 15 of the propagating body 10 to generate surface waves on the main surface portion 11 and the main surface portion 12 of the propagating body 10.
- first surface wave W1 the surface wave generated by the vibrator 20 on the main surface portion 11
- second surface wave W2 the surface wave generated on the main surface portion 12
- first surface wave W1 and the second surface wave W2 may be simply referred to as surface waves without being distinguished.
- the vibrator 20 generates the first surface wave W1 in the propagating body 10 and generates the first surface wave receiving and receiving unit 21 that receives the second surface wave W2, and the propagating body 10 generates the second surface wave W2 and And a second transmission / reception unit 22 that receives the surface wave W1.
- the first transmission / reception unit 21 vibrates by an electrical signal supplied from the transmission / reception circuit 30.
- the vibration of the first transmitting / receiving unit 21 is transmitted to the propagation body 10, and the first surface wave W ⁇ b> 1 is generated at the upper end of the main surface part 11.
- the generated first surface wave W ⁇ b> 1 propagates toward the lower end of the main surface portion 11, propagates along the bottom surface portion 16 having a smooth curved surface as described above, and then Propagate towards the top.
- the first surface wave W1 that has reached the upper end of the main surface portion 12 causes the second wave transmitting / receiving portion 22 to vibrate.
- the second transmission / reception unit 22 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
- the second transmission / reception unit 22 vibrates by the electric signal supplied from the transmission / reception circuit 30.
- the vibration of the second transmission / reception unit 22 is transmitted to the propagation body 10, and the second surface wave W ⁇ b> 2 is generated at the upper end of the main surface portion 12.
- the generated second surface wave W2 propagates toward the lower end of the main surface portion 12, propagates along the bottom surface portion 16 having a smooth curved surface as described above, and then Propagate towards the top.
- the second surface wave W2 that has reached the upper end of the main surface part 11 vibrates the first wave transmitting / receiving part 21.
- the first transmission / reception unit 21 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
- the generation of the first surface wave W1 in the propagation body 10 by the first transmitting / receiving unit 21 is also expressed as transmitting the first surface wave W1.
- the generation of the second surface wave W2 in the propagation body 10 by the second transmitting / receiving unit 22 is also expressed as transmitting the second surface wave W2.
- the first surface wave W1 and the second surface wave W2 are pulses (ultrasonic pulses) of ultrasonic waves (for example, a sound wave of 20 KHz or higher).
- the first surface wave W1 and the second surface wave W2 are Rayleigh waves.
- the vibrator 20 may include an ultrasonic contact medium that is interposed between the piezoelectric element and the propagating body 10 and that efficiently transmits vibration.
- the transmission / reception circuit 30 is connected to the vibrator 20.
- the transmission / reception circuit 30 supplies an electric signal for generating an ultrasonic pulse as a surface wave to the vibrator 20 to vibrate the vibrator 20.
- the transmission / reception circuit 30 receives an electrical signal supplied from the transducer 20 as an ultrasonic reception circuit, and amplifies and converts the received electrical signal.
- the transmission / reception circuit 30 supplies an electric signal for transmission of the first surface wave W1 to the first transmission / reception unit 21 to vibrate the first transmission / reception unit 21. Further, it receives an electrical signal supplied from the second transmitting / receiving unit 22 that has received the first surface wave W1, and amplifies and converts the received electrical signal. In addition, the transmission / reception circuit 30 supplies an electric signal for transmission of the second surface wave W ⁇ b> 2 to the second transmission / reception unit 22 to vibrate the second transmission / reception unit 22. Further, it receives an electrical signal supplied from the first transmitting / receiving unit 21 that has received the second surface wave W2, and amplifies and converts the received electrical signal.
- the control unit 40 includes a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a timer, a D / A (digital / analog) converter, an A / D ( An analog / digital converter is included.
- the control unit 40 is connected to the transmission / reception circuit 30.
- the control unit 40 controls the transmission / reception circuit 30 to supply an electrical signal from the transmission / reception circuit 30 to each of the first transmission / reception unit 21 and the second transmission / reception unit 22 of the vibrator 20.
- the first surface wave W1 is generated on the main surface portion 11 and the second surface wave W2 is generated on the main surface portion 12.
- control unit 40 receives electrical signals from each of the first transmission / reception unit 21 and the second transmission / reception unit 22 of the vibrator 20 that are amplified and converted by the transmission / reception circuit 30, and based on the received electrical signals.
- the liquid level position is detected as will be described later.
- control unit 40 can exchange data with an external device 60 outside the liquid level position detection device 100. The configuration of the liquid surface position detection device 100 has been described above.
- the operation of the liquid level position detection apparatus 100 will be described focusing on the liquid level position detection process (see FIG. 4) executed by the control unit 40.
- the CPU of the control unit 40 executes the liquid surface position detection process using the RAM as a main memory, according to a program stored in the ROM, and using various data stored in the ROM.
- the control unit 40 starts the liquid surface position detection process based on a command from the external device 60.
- the generated first surface wave W ⁇ b> 1 propagates toward the lower end of the main surface portion 11, propagates along the bottom surface portion 16 having a smooth curved surface, and then toward the upper end of the main surface portion 12.
- the first surface wave W1 that has reached the upper end of the main surface portion 12 causes the second wave transmitting / receiving portion 22 to vibrate.
- the second transmission / reception unit 22 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
- the transmission / reception circuit 30 amplifies and converts the supplied electric signal and supplies it to the control unit 40.
- this amplified and converted electrical signal (that is, the first surface wave W1 that reaches the second transmitting / receiving unit 22 through propagation to the bottom surface part 16 shows vibrations generated by the second transmitting / receiving unit 22).
- the electric signal is referred to as a first propagation wave signal.
- the first surface wave W1 transmitted from the first wave transmitting / receiving unit 21 reaches the second wave transmitting / receiving unit 22 while the first portion 10a in contact with the gas and the second portion in contact with the liquid 90. It propagates across the boundary with 10b twice.
- the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S1 is performed until the first propagation wave signal is received (step S2).
- the period is a period from the timing at which the first transmitting / receiving unit 21 generates the first surface wave W1 to the timing at which the second transmitting / receiving unit 22 receives the first surface wave W1, and in short, the first transmitting / receiving wave. It is the propagation time of the first surface wave W1 from the unit 21 to the second transmission / reception unit 22 (hereinafter referred to as the first propagation time).
- the control unit 40 determines whether or not the first propagation wave signal is received from the transmission / reception circuit 30 (step S3). This determination can be performed by an appropriate method. For example, the control unit 40 acquires the electric signal supplied from the second transmission / reception unit 22 and amplified and converted by the transmission / reception circuit 30. A value based on the voltage (for example, the voltage value, the average value of the square of the voltage value in a predetermined period, the change of the voltage value or the average value, the amplitude of the electrical signal, etc.) is equal to or greater than a threshold value stored in the ROM in advance. It is determined whether or not.
- the control unit 40 acquires the electric signal supplied from the second transmission / reception unit 22 and amplified and converted by the transmission / reception circuit 30.
- a value based on the voltage for example, the voltage value, the average value of the square of the voltage value in a predetermined period, the change of the voltage value or the average value, the amplitude of the electrical signal, etc.
- the first propagation wave signal may be measured in advance by an experiment, and the threshold value may be determined based on the measurement result.
- step S3 When the first propagation wave signal has not been received yet (step S3; No), the control unit 40 updates the timer value of the timer by +1 (step S4), and executes the process of step S3 again. As a result, the control unit 40 keeps timing until the first propagation wave signal is received.
- the control unit 40 stores the current timer value as the first propagation time, for example, in the RAM (step S5).
- control unit 40 vibrates the second transmission / reception unit 22 via the transmission / reception circuit 30 to generate the second surface wave W2 at the upper end of the main surface unit 12 (step S6).
- the generated second surface wave W ⁇ b> 2 propagates toward the lower end of the main surface portion 12, propagates along the bottom surface portion 16 having a smooth curved surface, and then toward the upper end of the main surface portion 11. Propagate.
- the second surface wave W2 that has reached the upper end of the main surface part 11 vibrates the first wave transmitting / receiving part 21.
- the first transmission / reception unit 21 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
- the transmission / reception circuit 30 amplifies and converts the supplied electric signal and supplies it to the control unit 40.
- this amplified and converted electrical signal (that is, the second surface wave W2 that reaches the first transmission / reception unit 21 through propagation to the bottom surface part 16 shows vibration generated in the first transmission / reception unit 21).
- Electrical signal is referred to as a second propagation wave signal.
- the second surface wave W2 transmitted from the second transmitting / receiving unit 22 reaches the first transmitting / receiving unit 21 while the first portion 10a contacting the gas and the second portion contacting the liquid 90. It propagates across the boundary with 10b twice.
- the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S6 is performed until the second propagation wave signal is received (step S7).
- the period is a period from the timing at which the second transmitting / receiving unit 22 generates the second surface wave W2 to the timing at which the first transmitting / receiving unit 21 receives the second surface wave W2, in short, the second transmitting / receiving wave.
- This is the propagation time of the second surface wave W2 from the unit 22 to the first transmission / reception unit 21 (hereinafter referred to as the second propagation time).
- the first propagation time and the second propagation time may be simply referred to as propagation time without being distinguished.
- control unit 40 determines whether or not the second propagation wave signal is received from the transmission / reception circuit 30 (step S8). This determination is performed in the same manner as in step S3, and when the second propagation wave signal has not been received yet (step S8; No), the control unit 40 updates the timer value of the timer to +1 or the like ( Step S9), the process of step S8 is executed again. Thereby, the control unit 40 performs time measurement until the second propagation wave signal is received.
- control unit 40 stores the current timer value as the second propagation time, for example, in the RAM (step S10).
- control unit 40 specifies the position of the liquid surface 91 (liquid surface position) based on the first propagation time stored in step S5 and the second propagation time stored in step S10 (step S11). .
- the relationship between the first propagation time, the second propagation time, and the position of the liquid level 91 is specified in advance by experiments or the like, and the specified relationship is stored in the ROM as a table or an arithmetic expression.
- the control unit 40 specifies the liquid level position based on the table or arithmetic expression stored in the ROM, and the first propagation time and the second propagation time.
- control part 40 uses the table for calculating a liquid level position based on 1st propagation time, or a computing equation, and says the liquid level position (henceforth a 1st liquid level position) based on 1st propagation time. ) And a liquid surface position based on the second propagation time (hereinafter referred to as the second liquid surface position) using a table or an arithmetic expression for identifying the liquid surface position based on the second propagation time. You may specify. That is, the control unit 40 may specify each of the first liquid level position and the second liquid level position. The average of the first liquid level position and the second liquid level position (simple average or weighted average) may be used as the liquid level position to be detected this time.
- control unit 40 outputs the position of the liquid level 91 specified in step S11 to the external device 60 (step S12).
- the external device 60 includes, for example, an image display such as an LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Diode), and displays the position of the liquid level 91 on the image display. This is the end of the description of the liquid surface position detection process.
- the propagation speed of the surface wave propagating through the second portion 10b that contacts the liquid 90 (hereinafter referred to as the second sound velocity) is the first portion 10a that contacts the air. It is known that the velocity is slower than the propagation speed of the surface wave propagating through (hereinafter referred to as the first sound velocity). For this reason, the propagation time (first propagation time, second propagation time) measured by the timer becomes longer as the length L2 of the second portion 10b is longer. That is, the longer the liquid 90 is in the container 80 and the higher the position of the liquid level 91 from the bottom surface of the container 80, the longer the propagation time.
- composition of the synthetic resin forming the propagating body 10 is not limited as long as the propagation time of the surface wave can be detected, but polyethylene, polystyrene, etc. are adopted in addition to PPS (polyphenylene sulfide). be able to. In addition, it is thought that PPS which can observe the propagation wave of a surface wave is suitable as the said synthetic resin.
- the control unit 40 detects a propagation time in which the period becomes longer as the liquid contact portion (second portion 10b) becomes longer according to the position of the liquid surface 91 of the liquid 90, and the position of the liquid surface 91 is based on the detected propagation time. Is detected.
- the position of the liquid level 91 is, for example, the length L2 of the second portion 10b where the propagating body 10 is immersed in the liquid 90, the height of the liquid level 91 from the bottom surface of the container 80, the length L2 or the height of the liquid level 91. What is necessary is just to represent with the value etc. according to.
- the height of the liquid surface 91 from the bottom surface of the container 80 is the depth of the liquid 90, and is obtained by length L2 + length d (see FIG. 1).
- the first surface wave W1 and the second surface wave W2 are reflected by the bottom surface portion 16. This causes leakage and loss.
- the first surface wave W1 and the second surface wave W2 are not reflected by the bottom surface portion 16 and leakage does not occur. Since the attenuation of the surface wave Wr received by the child 20 is small, the S / N ratio can be improved. However, an unnecessary propagation wave U may be generated near the surface wave.
- FIG. 7 (a) schematically shows an unnecessary propagation wave U.
- FIG. Wd represents a surface wave sent from the vibrator 20 to the propagating body 10, and Wr represents a surface wave received by the vibrator 20.
- control unit 40 may execute a liquid surface position detection process for simultaneously generating the first surface wave W1 and the second surface wave W2. At this time, the first and second propagation wave signals are superimposed and observed (received) as propagation wave signals.
- the liquid surface position detection process will be described with reference to FIG.
- control unit 40 vibrates the first transmission / reception unit 21 via the transmission / reception circuit 30 to generate the first surface wave W ⁇ b> 1 at the upper end of the main surface part 11.
- the second transmission / reception unit 22 is vibrated to generate the second surface wave W2 at the upper end of the main surface part 12 (step S101).
- the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S101 is performed until the propagation wave signal is received (step S102).
- the first and second transmitting / receiving units 21, 22 is a period until the timing of receiving a propagation wave signal, that is, a propagation time.
- the control unit 40 determines whether or not a propagation wave signal has been received from the transmission / reception circuit 30 (step S103). This determination is performed by the same method as in step S3 described above, and when the propagation wave signal has not been received yet (step S103; No), the control unit 40 updates the timer value of the timer by +1 or the like ( Step S104), the process of step S103 is executed again. Thereby, the control part 40 performs time measurement until a propagation wave signal is received.
- control unit 40 When receiving the propagation wave signal (step S103; Yes), the control unit 40 stores the current timer value as the propagation time, for example, in the RAM (step S105).
- control unit 40 specifies the position of the liquid level 91 (liquid level position) based on the propagation time stored in step S105 (step S106).
- the relationship between the propagation time and the position of the liquid surface 91 is specified in advance by experiments or the like, and the specified relationship is stored in the ROM as a table or an arithmetic expression.
- the control unit 40 specifies the liquid level position based on the table or arithmetic expression stored in the ROM and the propagation time.
- control unit 40 outputs the position of the liquid level 91 specified in step S106 to the external device 60 (step S107).
- the external device 60 displays the position of the liquid level 91 on the image display.
- the amplitude of the surface wave Wr received by the vibrator 20 is increased. Therefore, the S / N ratio can be further improved.
- the propagating body 210 according to the second embodiment includes the main surface portion 11 and the main surface portion 12, the side surface portion 13 and the side surface portion 14, the contact portion 15, and the bottom surface portion 16. .
- the vibrator 220 according to the second embodiment includes the same as the first transmission / reception unit 21 and the second transmission / reception unit 22 as in the first embodiment.
- a third transmission / reception unit 23 and a fourth transmission / reception unit 24 are provided.
- the propagating body 210 has a concave portion 17 that is recessed from the contact portion 15 toward the bottom surface portion 16. As shown in FIG. 5B, the recess 17 is located between the main surface portion 11 and the second main surface portion 12 in a side view.
- the concave portion 17 is a portion that is hollowed out in, for example, a rectangular parallelepiped shape from the contact portion 15 toward the bottom surface portion 16, and includes first to fourth inner side surface portions 17a to 17d and an inner bottom surface portion 17e.
- the first inner side surface portion 17 a is located on the back side of the main surface portion 11.
- the second inner side surface portion 17 b is located on the back side of the main surface portion 12.
- the first inner side surface portion 17a and the second inner side surface portion 17b face each other.
- the third inner side surface portion 17 c is located on the back side of the side surface portion 13.
- the fourth inner side surface portion 17 d is located on the back side of the side surface portion 14.
- the third inner side surface portion 17c and the fourth inner side surface portion 17d face each other.
- the inner bottom surface portion 17e is located at the bottom of the concave portion 17, and has a rectangular shape in plan view as shown in FIG.
- FIG. 7B schematically shows a state in which the detection wave D is generated by providing the propagation body 210 with the concave portion 17.
- the detection wave D indicates a first detection wave D1 or a second detection wave D2 described later.
- the third wave transmitting / receiving unit 23 generates a first detection wave D1 made of a surface wave or a plate wave in the propagation body 210 and receives the first detection wave D1 reflected by the inner bottom surface part 17e of the recess 17.
- the fourth transmission / reception unit 24 generates a second detection wave D ⁇ b> 2 composed of a surface wave or a plate wave in the propagation body 210 and receives the second detection wave D ⁇ b> 2 reflected by the inner bottom surface part 17 e of the recess 17.
- the third transmission / reception unit 23 vibrates by the electric signal supplied from the transmission / reception circuit 30.
- the vibration of the third transmission / reception unit 23 is transmitted to the propagation body 210, and the first detection wave D1 is generated at the upper end of the first inner side surface portion 17a.
- the generated first detection wave D1 propagates toward the lower end of the first inner side surface portion 17a, reflects off the inner bottom surface portion 17e, and then propagates toward the upper end of the first inner side surface portion 17a. .
- the first detection wave D1 that has reached the upper end of the first inner side surface portion 17a vibrates the third transmission / reception unit 23.
- the third transmission / reception unit 23 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
- the fourth transmission / reception unit 24 vibrates by the electric signal supplied from the transmission / reception circuit 30.
- the vibration of the fourth transmission / reception unit 24 is transmitted to the propagation body 210, and the second detection wave D2 is generated at the upper end of the second inner side surface portion 17b.
- the generated second detection wave D2 propagates toward the lower end of the second inner side surface portion 17b, reflects off the inner bottom surface portion 17e, and then propagates toward the upper end of the second inner side surface portion 17b. .
- the second detection wave D2 that has reached the upper end of the second inner side surface portion 17b vibrates the fourth transmission / reception unit 24.
- the fourth transmission / reception unit 24 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
- the first detection wave D1 received by the third transmission / reception unit 23 and the second detection wave D2 received by the fourth transmission / reception unit 24 depend on the temperature of the propagating body 210 regardless of the position of the liquid surface 91. Changes.
- the temperature of the propagating body 210 is detected using at least one of the first detection wave D1 and the second detection wave D2, and the detected temperature is converted into a surface wave (the first surface wave W1 and the first detection wave D1). This is used for temperature correction when detecting the two surface waves W2). For this reason, it is not necessary to provide the temperature sensor which consists of the thermistor chip etc. which were provided in the conventional liquid level position detection apparatus.
- the transmission / reception circuit 30 supplies the third transmission / reception unit 23 with the electrical signal for transmission of the first detection wave D1 to vibrate the third transmission / reception unit 23. Further, it receives an electrical signal supplied from the third transmitting / receiving unit 23 that has received the first detection wave D1, and amplifies and converts the received electrical signal. In addition, the transmission / reception circuit 30 supplies an electric signal for transmission of the second detection wave D2 to the fourth transmission / reception unit 24, and vibrates the fourth transmission / reception unit 24. Also, the electric signal supplied from the fourth transmitting / receiving unit 24 that has received the second detection wave D2 is received, and the received electric signal is amplified and converted.
- the control unit 40 drives and controls each of the third transmission / reception unit 23 and the fourth transmission / reception unit 24 via the transmission / reception circuit 30.
- the control unit 40 receives electrical signals from each of the third transmission / reception unit 23 and the fourth transmission / reception unit 24 that are amplified and converted by the transmission / reception circuit 30, and based on the received electrical signals, Detect temperature.
- the control unit 40 detects the propagation time of each of the first detection wave D1 and the second detection wave D2 by a method similar to the method described in the liquid level position detection process described above.
- the propagation time of the first detection wave D1 is referred to as a first detection time
- the propagation time of the second detection wave D2 is referred to as a second detection time.
- the control unit 40 generates the first detection wave D1 by the third transmission / reception unit 23, and then the third transmission / reception unit 23 receives the first detection wave D1 after being reflected by the inner bottom surface part 17e. Is determined based on the timer value. Then, the specified time is stored in the RAM as the first detection time. Further, based on the timer value, the time from when the fourth transmission / reception unit 24 generates the second detection wave D2 to when the fourth transmission / reception unit 24 receives the second detection wave D2 after being reflected by the inner bottom surface portion 17e. To identify. Then, the specified time is stored in the RAM as the second detection time. The control unit 40 specifies (detects) the temperature of the propagating body 210 based on at least one of the first detection time and the second detection time obtained as described above.
- the sound velocity of the first detection wave D1 and the second detection wave D2 changes depending on the temperature of the propagating body 210 regardless of the position of the liquid surface 91.
- the first detection time and the second detection time also change depending on the temperature of the propagating body 210 regardless of the position of the liquid surface 91.
- the relationship between the first detection time, the second detection time, and the temperature of the propagation body 210 is specified in advance by experiments, and the specified relationship is stored in the ROM as a table or an arithmetic expression.
- the control unit 40 specifies the temperature of the propagating body 210 based on the table or arithmetic expression stored in the ROM and the first detection time and the second detection time.
- the control unit 40 uses a table or an arithmetic expression for specifying the temperature of the propagating body 210 based on the first detection time, and uses the temperature of the propagating body 210 based on the first detection time (hereinafter referred to as the first temperature).
- the temperature of the propagating body 210 based on the second detection time (hereinafter referred to as the second temperature) using a table or an arithmetic expression for identifying the temperature of the propagating body 210 based on the second detection time.
- the control unit 40 may specify each of the first temperature and the second temperature.
- the average of the first temperature and the second temperature (simple average or weighted average) may be used as the temperature to be detected this time.
- the temperature that does not indicate the error value may be set as the temperature to be detected this time.
- control part 40 performs temperature correction of 1st propagation time and 2nd propagation time based on the temperature of the propagation body 210 specified (detected) as mentioned above.
- the speed of sound is temperature dependent and changes according to the temperature of the propagating body 210. That is, the first propagation time and the second propagation time also change according to the temperature of the propagation body 210. For this reason, in order to maintain the detection accuracy of the liquid surface position, the temperature correction is necessary.
- a table configured by associating the temperature of the propagating body 210 with the correction amount and correction coefficient of the propagation time is stored in the ROM in advance, and the control unit 40 refers to the table and determines the specified propagation.
- a correction amount or correction coefficient corresponding to the temperature of the body 210 may be acquired. And the control part 40 performs the calculation which adds / subtracts the acquired correction amount to each of 1st propagation time and 2nd propagation time, and the calculation which multiplies a correction coefficient, and is 1st propagation time and 2nd propagation time. Time temperature correction may be performed.
- a table configured by associating the temperature of the propagating body 210 with the correction amount and correction coefficient of the liquid surface position is stored in advance in the ROM and specified based on the first propagation time and the second propagation time.
- the liquid surface position may be corrected.
- the control unit 40 is not limited to the table, and stores an expression (may be an approximate expression) representing the temperature dependence of the sound speed in the ROM, and the propagation time or the liquid surface position is stored using the expression.
- the correction amount and the correction coefficient may be obtained.
- the temperature correction method for the propagation time and the liquid surface position can be arbitrarily selected from known table construction methods and calculation methods.
- the above temperature correction process includes the above-described liquid surface position detection process as long as the first detection wave D1 and the second detection wave D2 do not interfere with the first surface wave W1 and the second surface wave W2.
- the generation timing of the first detection wave D1 and the second detection wave D2 may be made simultaneously with the generation timing of the first surface wave W1 and the second surface wave W2.
- the temperature correction process may be executed as a process independent of the liquid surface position detection process.
- the concave portion 17 is cut out in a rectangular parallelepiped shape and the inner bottom surface portion 17e is flat has been described, but the present invention is not limited to this.
- the inner bottom surface portion 17e of the concave portion 17 may be formed in a U-shaped smooth curved surface that protrudes downward like the bottom surface portion 16 according to the first embodiment.
- the fourth transmission / reception unit 24 receives the first detection wave D1 transmitted from the third transmission / reception unit 23 to the propagating body 210, and the fourth transmission / reception unit.
- the liquid level position detection in addition to detecting the detailed position of the liquid level 91 (detecting the height of the liquid level 91 from the bottom surface of the container 80 as described above), what is the position of the liquid level 91. It also includes detecting to which stage the current position of the liquid level 91 belongs, divided into stages. Further, the image displayed on the external device 60 after the liquid level position is detected by the control unit 40 may not indicate the liquid level position itself, but may indicate the amount of the liquid 90 corresponding to the liquid level position.
- the propagation bodies 10 and 210 are made of synthetic resin, and it is preferable that the propagation time becomes longer as the second portion 10b (liquid contact portion) becomes longer according to the liquid surface position of the liquid 90, and propagates through the second portion 10b. It is preferable that the difference between the speed of the surface wave that travels and the speed of the surface wave that propagates through the first portion 10a (the portion exposed from the liquid 90) becomes more significant.
- the propagating bodies 10 and 210 may be made of a metal such as aluminum, stainless steel, or steel as long as the liquid level position can be detected by the method described above.
- the propagating bodies 10 and 210 may be arranged such that the longitudinal direction thereof is parallel to the normal direction of the liquid surface 91 and the longitudinal direction is inclined with respect to the normal direction of the liquid surface 91. Good. Further, a plurality of concave portions or convex portions extending along the traveling direction of the surface wave may be formed on the surface of the propagating bodies 10 and 210 where the surface wave propagates, and the concave and convex portions may be formed on this surface.
- the type of the liquid 90 whose liquid level position is to be detected is not limited, and water, gasoline, cleaning liquid and the like are arbitrary. Further, the liquid surface 91 may be a gas other than air or a vacuum.
- the container 80 may be a fuel tank mounted on a vehicle.
- the liquid 90 becomes a fuel such as gasoline.
- the propagating bodies 10 and 210 may be attached to, for example, a fuel pumping unit that is attached to the fuel tank and includes a fuel pump that extracts fuel from the fuel tank.
- PPS polyphenylene sulfide
- POM polyacetal
- PBT polybutylene terephthalate
- PPS examples include linear type, cross-linked type, and anti-cross-linked type. Further, there are those added with fillers (additive materials) such as glass fibers and inorganic fillers. PPS can be used. Surface wave or plate wave propagation state (for example, good S / N ratio, surface due to differences in linear type, cross-linked type, anti-cross-linked type, presence / absence of filler addition, type of filler, etc. The effect on the sound speed of waves or plate waves is considered to be small.
- Surface waves may be other than Rayleigh waves.
- the surface wave may be a sound wave having a lower frequency than the ultrasonic wave. Further, the surface wave may not be a pulse wave, and may be a burst wave, for example.
- the plate wave may be a pulse wave or a burst wave.
- the liquid surface position detection device 100 described above includes the propagation bodies 10 and 210 in which the ratio of the portion immersed in the liquid 90 changes according to the liquid surface position of the liquid 90 (the position of the liquid surface 91).
- the first transmitting / receiving unit 21 that generates the first surface wave W1 in the bodies 10 and 210 and receives the second surface wave W2, and the second surface wave W2 in the propagation bodies 10 and 210 and the first surface wave W1
- the second transmission / reception unit 22 to receive, the propagation time of the first surface wave W1 received by the second transmission / reception unit 22, and the propagation time of the second surface wave W2 received by the first transmission / reception unit 21 And a detection part (for example, control part 40) which detects a liquid level position based on.
- the propagating bodies 10 and 210 connect the main surface portion 11 (first main surface portion) and the main surface portion 12 (second main surface portion), and the main surface portion 11 and the main surface portion 12, which are in reverse relation to each other, and are curved in a side view. And a bottom surface portion 16 having a shape.
- the first transmission / reception unit 21 generates a first surface wave W1 propagating through the main surface part 11, and the second transmission / reception unit 22 is transmitted through the main surface part 11 through the bottom surface part 16 and the main surface part 12.
- the second transmission / reception unit 22 generates a second surface wave W2 that propagates through the main surface portion 12, and the first transmission / reception unit 21 propagates through the main surface portion 12 through the bottom surface portion 16 and the main surface portion 11.
- the bottom surface portion 16 having a curved shape in the side view is provided, loss due to leakage when the first surface wave W1 and the second surface wave W2 propagate to the bottom surface portion 16 can be reduced. The deterioration of the N ratio can be reduced. As a result, the detection accuracy of the liquid surface position can be improved. Further, since the liquid surface position is detected based on at least one of the propagation time of the first surface wave W1 and the propagation time of the second surface wave W2 received by the first transmission / reception unit 21, it is possible to superimpose noise. Even when the detection accuracy of one propagation time is inferior, the detection accuracy of the liquid level can be improved.
- the propagation bodies 10 and 210 have the contact part 15 which contacts the 1st transmission / reception part 21 and the 2nd transmission / reception part 22, and the main surface part 11 is a contact part in side view.
- the main surface portion 12 hangs down from the other end of the contact portion 15 in a side view.
- the first wave transmitting / receiving unit 21 generates the first surface wave W1 propagating through the main surface part 11 via the contact part 15, and the second wave transmitting / receiving part 22 is transmitted through the contact part 15 to the main surface part 12. 2nd surface wave W2 which propagates is generated.
- the first transmission / reception unit 21 is provided in contact with the first main surface portion 11, and the second transmission / reception unit 22 is provided in contact with the second main surface portion 12. May be adopted.
- the first transmission / reception unit 21 and the second transmission / reception unit 22 may simultaneously generate the first surface wave W1 and the second surface wave W2 (the first surface wave W1 by the first transmission / reception unit 21). And the generation of the second surface wave W2 by the second transmission / reception unit 22 may be simultaneous).
- the propagating body 210 according to the second embodiment is recessed from the contact portion 15 toward the bottom surface portion 16, and has a recess 17 located between the main surface portion 11 and the main surface portion 12 in a side view. With this recess 17, the internal propagation wave U generated from the vibrator 220 to the propagation body 210 can be reduced or eliminated. Thereby, the detection error of liquid level position detection can be reduced.
- the liquid level position detection apparatus applies a detection wave (at least one of the first detection wave D1 and the second detection wave D2) that is a surface wave or a plate wave to the propagating body 210.
- a specific transmitting / receiving unit (at least one of the third transmitting / receiving unit 23 and the fourth transmitting / receiving unit 24) to be generated is further provided.
- the specific transmission / reception unit generates a detection wave propagating through the inner side surface portion of the concave portion 17 via the contact portion 15 and receives the detection wave reflected by the inner bottom surface portion 17e of the concave portion 17 through the inner side surface portion.
- the detection unit detects the temperature of the propagation body 210 based on the propagation time of the detection wave received by the specific transmission / reception unit. Since it did in this way, it is not necessary to provide the temperature sensor which consists of thermistor chips etc. which were provided in the conventional liquid level position detection apparatus, and reduction of a number of parts is possible.
- the 1st transmission / reception part 21, the 2nd transmission / reception part 22, and the specific transmission / reception part may generate
- the generation of the first surface wave W1 by the first transmission / reception unit 21, the generation of the second surface wave W2 by the second transmission / reception unit 22, and the generation of the detection wave by the specific transmission / reception unit may be simultaneous).
- SYMBOLS 100 Liquid level position detection apparatus 10, 210 ... Propagation body 10a ... 1st part, 10b ... 2nd part 11 ... Main surface part (an example of 1st main surface part) 12 ... Main surface portion (an example of a second main surface portion) DESCRIPTION OF SYMBOLS 13, 14 ... Side surface part 15 ... Contact part 16 ... Bottom part 20, 220 ... Vibrator 21 ... 1st transmission / reception part, 22 ... 2nd transmission / reception part W1 ... 1st surface wave, W2 ... 2nd surface wave 23 ... 3rd transmission / reception part, 24 ... 4th transmission / reception part D1 ... 1st detection wave, D2 ... 2nd detection wave 30 ... Transmission / reception circuit 40 ... Control part
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Electromagnetism (AREA)
- Thermal Sciences (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
Provided is a liquid level position detection device having good precision of liquid level position detection. A liquid level position detection device is provided with a propagation body 10 in which the ratio of a portion thereof that is immersed in a liquid varies according to the liquid level position, a first transmitting/receiving part 21, a second transmitting/receiving part 22, and a detection part for detecting the liquid level position on the basis of the propagation time of a first surface wave W1 and/or a second surface wave W2. The propagation body 10 has a bottom surface part 16 which connects a main surface part 11 and a main surface part 12 and forms a curved surface shape in side view. The first transmitting/receiving part 21 generates a first surface wave W1 propagated through the main surface part 11, and the second transmitting/receiving part 22 receives the first surface wave W1 propagated through the bottom surface part 16 and the main surface part 12 via the main surface part 11. The second transmitting/receiving part 22 generates a second surface wave W2 propagated through the main surface part 12, and the first transmitting/receiving part 21 receives the second surface wave W2 propagated through the bottom surface part 16 and the main surface part 11 via the main surface part 12.
Description
本発明は、液面位置検出装置に関する。
The present invention relates to a liquid level position detection device.
液面位置検出装置として、例えば、特許文献1には、伝搬体のうち液体中の部分を伝搬する表面波の音速が、液体から露出している部分を伝搬する表面波の音速よりも遅くなることを利用して液体の液面位置を検出するものが開示されている。
As a liquid surface position detection device, for example, in Patent Document 1, the speed of sound of a surface wave propagating through a portion of a propagating body in a liquid is slower than the speed of sound of a surface wave propagating through a portion exposed from the liquid. The thing which detects the liquid level position of a liquid using this is disclosed.
特許文献1に開示された液面位置検出装置では、液面位置によっては伝搬体を伝搬する表面波が減衰してS/N比(Signal-Noise ratio)が悪化してしまい、液面位置の検出精度が悪くなる場合がある。
In the liquid level position detection device disclosed in Patent Document 1, depending on the liquid level position, the surface wave propagating through the propagating body is attenuated and the S / N ratio (Signal-Noise ratio) is deteriorated. The detection accuracy may deteriorate.
本発明は、上記実情に鑑みてなされたものであり、液面位置の検出精度が良い液面位置検出装置を提供することを目的とする。
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid surface position detection device with high liquid surface position detection accuracy.
上記目的を達成するため、本発明に係る液面位置検出装置は、
液体の液面位置に応じて、前記液体に浸る部分の割合が変化する伝搬体と、
前記伝搬体に第1表面波を発生させるとともに第2表面波を受ける第1送受波部と、
前記伝搬体に前記第2表面波を発生させるとともに前記第1表面波を受ける第2送受波部と、
前記第2送受波部が受けた前記第1表面波の伝搬時間と、前記第1送受波部が受けた前記第2表面波の伝搬時間との少なくともいずれかに基づいて前記液面位置を検出する検出部と、を備え、
前記伝搬体は、
互いに裏表の関係にある第1主面部及び第2主面部と、
前記第1主面部と前記第2主面部とを繋ぐとともに、側面視において曲面状をなす底面部と、を有し、
前記第1送受波部は、前記第1主面部を伝搬する前記第1表面波を発生させ、
前記第2送受波部は、前記第1主面部を経て前記底面部と前記第2主面部とを伝搬した前記第1表面波を受け、
前記第2送受波部は、前記第2主面部を伝搬する前記第2表面波を発生させ、
前記第1送受波部は、前記第2主面部を経て前記底面部と前記第1主面部とを伝搬した前記第2表面波を受ける。 In order to achieve the above object, a liquid surface position detection device according to the present invention is
A propagating body in which a ratio of a portion immersed in the liquid changes according to a liquid surface position;
A first transmission / reception unit for generating a first surface wave in the propagation body and receiving a second surface wave;
A second transmission / reception unit for generating the second surface wave in the propagating body and receiving the first surface wave;
The liquid level position is detected based on at least one of the propagation time of the first surface wave received by the second wave transmitting / receiving unit and the propagation time of the second surface wave received by the first wave transmitting / receiving unit. And a detecting unit
The propagator is
A first main surface portion and a second main surface portion, which are in reverse relation to each other;
And connecting the first main surface portion and the second main surface portion, and a bottom surface portion having a curved shape in a side view,
The first transmitting / receiving unit generates the first surface wave propagating through the first main surface unit,
The second transmission / reception unit receives the first surface wave that has propagated through the first main surface portion and the bottom surface portion and the second main surface portion,
The second wave transmitting / receiving unit generates the second surface wave propagating through the second main surface part,
The first wave transmitting / receiving unit receives the second surface wave that has propagated through the second main surface portion and the bottom surface portion and the first main surface portion.
液体の液面位置に応じて、前記液体に浸る部分の割合が変化する伝搬体と、
前記伝搬体に第1表面波を発生させるとともに第2表面波を受ける第1送受波部と、
前記伝搬体に前記第2表面波を発生させるとともに前記第1表面波を受ける第2送受波部と、
前記第2送受波部が受けた前記第1表面波の伝搬時間と、前記第1送受波部が受けた前記第2表面波の伝搬時間との少なくともいずれかに基づいて前記液面位置を検出する検出部と、を備え、
前記伝搬体は、
互いに裏表の関係にある第1主面部及び第2主面部と、
前記第1主面部と前記第2主面部とを繋ぐとともに、側面視において曲面状をなす底面部と、を有し、
前記第1送受波部は、前記第1主面部を伝搬する前記第1表面波を発生させ、
前記第2送受波部は、前記第1主面部を経て前記底面部と前記第2主面部とを伝搬した前記第1表面波を受け、
前記第2送受波部は、前記第2主面部を伝搬する前記第2表面波を発生させ、
前記第1送受波部は、前記第2主面部を経て前記底面部と前記第1主面部とを伝搬した前記第2表面波を受ける。 In order to achieve the above object, a liquid surface position detection device according to the present invention is
A propagating body in which a ratio of a portion immersed in the liquid changes according to a liquid surface position;
A first transmission / reception unit for generating a first surface wave in the propagation body and receiving a second surface wave;
A second transmission / reception unit for generating the second surface wave in the propagating body and receiving the first surface wave;
The liquid level position is detected based on at least one of the propagation time of the first surface wave received by the second wave transmitting / receiving unit and the propagation time of the second surface wave received by the first wave transmitting / receiving unit. And a detecting unit
The propagator is
A first main surface portion and a second main surface portion, which are in reverse relation to each other;
And connecting the first main surface portion and the second main surface portion, and a bottom surface portion having a curved shape in a side view,
The first transmitting / receiving unit generates the first surface wave propagating through the first main surface unit,
The second transmission / reception unit receives the first surface wave that has propagated through the first main surface portion and the bottom surface portion and the second main surface portion,
The second wave transmitting / receiving unit generates the second surface wave propagating through the second main surface part,
The first wave transmitting / receiving unit receives the second surface wave that has propagated through the second main surface portion and the bottom surface portion and the first main surface portion.
本発明によれば、液面位置の検出精度が良い液面位置検出装置を提供することができる。
According to the present invention, it is possible to provide a liquid surface position detection device with good liquid surface position detection accuracy.
本発明の一実施形態に係る液面位置検出装置について図面を参照して説明する。
DETAILED DESCRIPTION A liquid level position detection apparatus according to an embodiment of the present invention will be described with reference to the drawings.
(第1実施形態)
第1実施形態に係る液面位置検出装置100は、図1に示すように、容器80内に入れられた液体90の液面91の位置を検出する装置である。液体90の量の増減に伴い、液面91も上下する。 (First embodiment)
As shown in FIG. 1, the liquid surfaceposition detection device 100 according to the first embodiment is a device that detects the position of the liquid surface 91 of the liquid 90 put in the container 80. As the amount of the liquid 90 increases or decreases, the liquid level 91 also moves up and down.
第1実施形態に係る液面位置検出装置100は、図1に示すように、容器80内に入れられた液体90の液面91の位置を検出する装置である。液体90の量の増減に伴い、液面91も上下する。 (First embodiment)
As shown in FIG. 1, the liquid surface
液面位置検出装置100は、伝搬体10と、振動子20と、送受信回路30と、制御部40と、を備える。
The liquid level position detection apparatus 100 includes a propagation body 10, a vibrator 20, a transmission / reception circuit 30, and a control unit 40.
伝搬体10は、表面波が伝搬するものであり、例えば、PPS(ポリフェニレンサルファイド)などの合成樹脂から形成されている。伝搬体10は、上下方向に長尺な帯板形状である。伝搬体10の外面は、振動子20に向く上面と、上面とは反対側の底面と、上面と底面を繋ぐとともに互いに裏表の関係となる2つの主面と、上面と底面を繋ぐとともに互いに裏表の関係となる2つの側面と、の6面から主に構成される。
The propagating body 10 propagates a surface wave and is made of a synthetic resin such as PPS (polyphenylene sulfide). The propagating body 10 has a strip shape that is long in the vertical direction. The outer surface of the propagating body 10 includes an upper surface facing the vibrator 20, a bottom surface opposite to the upper surface, two main surfaces that connect the upper surface and the bottom surface, and have a reverse relationship with each other, and an upper surface and a bottom surface that are connected to each other. It is mainly composed of six sides, which are the two side surfaces that are in the relationship.
伝搬体10は、図2(a)、(b)に示すように、2つの主面のうち一方を含む主面部11(第1主面部の一例)、他方を含む主面部12(第2主面部の一例)と、2つの側面のうち一方を含む側面部13、他方を含む側面部14と、上面を含み振動子20と当接する当接部15と、底面を含む底面部16と、を有する。後述のように、表面波は、伝搬体10を伝搬するが、伝搬の際には伝搬体10の表面から表面波の波長とほぼ同じ深さまで達する。主面部11や主面部12は、伝搬体10の主面だけでなく当該深さをも含む部分である。当接部15や底面部16なども同様である。
2A and 2B, the propagating body 10 includes a main surface portion 11 (an example of a first main surface portion) including one of two main surfaces, and a main surface portion 12 (second main surface) including the other. An example of the surface portion), a side surface portion 13 including one of the two side surfaces, a side surface portion 14 including the other, a contact portion 15 including the upper surface and contacting the vibrator 20, and a bottom surface portion 16 including the bottom surface. Have. As will be described later, the surface wave propagates through the propagating body 10, but reaches the same depth as the wavelength of the surface wave from the surface of the propagating body 10 during propagation. The main surface portion 11 and the main surface portion 12 are portions including not only the main surface of the propagation body 10 but also the depth. The same applies to the contact portion 15 and the bottom surface portion 16.
図2(b)に示すように、側面視では、主面部11は、当接部15の一端から垂下する。また、主面部12は、当接部15の他端から垂下する。また、底面部16は、当接部15とは反対側において主面部11と主面部12とを繋ぐとともに、下方に凸となるU字状の滑らかな曲面状をなしている。このように形成された底面部16は、後述の第1表面波W1及び第2表面波W2が底面部16に伝搬する際の漏洩による損失を低減する。
2B, the main surface portion 11 hangs from one end of the contact portion 15 in a side view. The main surface portion 12 hangs from the other end of the contact portion 15. Further, the bottom surface portion 16 connects the main surface portion 11 and the main surface portion 12 on the side opposite to the contact portion 15 and has a U-shaped smooth curved surface that protrudes downward. The bottom surface portion 16 formed in this way reduces loss due to leakage when a first surface wave W1 and a second surface wave W2 described later propagate to the bottom surface portion 16.
伝搬体10は、図1に示すように、側面部13及び側面部14で容器80に設けられた固定部材81、82に挟まれることによって固定されている。なお、伝搬体10は、表面波の伝搬を阻害しないように、表面波が伝搬する主面部11及び主面部12以外の部分で固定されれば、その固定方法は任意である。
As shown in FIG. 1, the propagating body 10 is fixed by being sandwiched between fixing members 81 and 82 provided on the container 80 by the side surface portion 13 and the side surface portion 14. In addition, if the propagation body 10 is fixed in parts other than the main surface part 11 and the main surface part 12 which a surface wave propagates so that propagation of a surface wave may not be inhibited, the fixing method is arbitrary.
伝搬体10は、底面部16の下端が容器80の底面と長さdだけ離間して配置される。伝搬体10における、当接部15の上端から液面91までの上下方向に沿った長さ(伝搬体10が液体90に浸っていない部分である第1部分10aの長さ)L1と、底面部16の下端から液面91までの上下方向に沿った長さ(伝搬体10が液体90に浸っている部分である第2部分10bの長さ)L2とは、液体90の増減によって変化する。
The propagating body 10 is arranged such that the lower end of the bottom surface portion 16 is separated from the bottom surface of the container 80 by a length d. The length along the vertical direction from the upper end of the contact portion 15 to the liquid surface 91 in the propagation body 10 (the length of the first portion 10a where the propagation body 10 is not immersed in the liquid 90) L1 and the bottom surface The length along the vertical direction from the lower end of the portion 16 to the liquid level 91 (the length of the second portion 10b where the propagation body 10 is immersed in the liquid 90) L2 varies depending on the increase or decrease of the liquid 90. .
振動子20は、例えば、横波トランスデューサであり、回路基板に実装された圧電素子などを含んで構成される。振動子20は、伝搬体10の当接部15に押しつけられ、伝搬体10の主面部11及び主面部12に表面波を発生させる。
The vibrator 20 is, for example, a transverse wave transducer and includes a piezoelectric element mounted on a circuit board. The vibrator 20 is pressed against the contact portion 15 of the propagating body 10 to generate surface waves on the main surface portion 11 and the main surface portion 12 of the propagating body 10.
以下では、振動子20が主面部11に発生させる表面波を第1表面波W1と呼び、主面部12に発生させる表面波を第2表面波W2と呼ぶ。また、第1表面波W1と第2表面波W2とを区別なく、単に表面波と呼ぶこともある。
Hereinafter, the surface wave generated by the vibrator 20 on the main surface portion 11 is referred to as a first surface wave W1, and the surface wave generated on the main surface portion 12 is referred to as a second surface wave W2. Further, the first surface wave W1 and the second surface wave W2 may be simply referred to as surface waves without being distinguished.
振動子20は、伝搬体10に第1表面波W1を発生させるとともに、第2表面波W2を受ける第1送受波部21と、伝搬体10に第2表面波W2を発生させるとともに、第1表面波W1を受ける第2送受波部22と、を有する。
The vibrator 20 generates the first surface wave W1 in the propagating body 10 and generates the first surface wave receiving and receiving unit 21 that receives the second surface wave W2, and the propagating body 10 generates the second surface wave W2 and And a second transmission / reception unit 22 that receives the surface wave W1.
第1送受波部21は、送受信回路30から供給される電気信号によって振動する。第1送受波部21の振動は伝搬体10に伝達され、主面部11の上端に第1表面波W1が発生する。発生した第1表面波W1は、図3に示すように、主面部11の下端へ向かって伝搬し、前記のように滑らかな曲面を有する底面部16に沿って伝搬した後、主面部12の上端へ向かって伝搬する。主面部12の上端へ到達した第1表面波W1は、第2送受波部22を振動させる。第2送受波部22は、この振動を電気信号に変換して送受信回路30に供給する。
The first transmission / reception unit 21 vibrates by an electrical signal supplied from the transmission / reception circuit 30. The vibration of the first transmitting / receiving unit 21 is transmitted to the propagation body 10, and the first surface wave W <b> 1 is generated at the upper end of the main surface part 11. As shown in FIG. 3, the generated first surface wave W <b> 1 propagates toward the lower end of the main surface portion 11, propagates along the bottom surface portion 16 having a smooth curved surface as described above, and then Propagate towards the top. The first surface wave W1 that has reached the upper end of the main surface portion 12 causes the second wave transmitting / receiving portion 22 to vibrate. The second transmission / reception unit 22 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
第2送受波部22は、送受信回路30から供給される電気信号によって振動する。第2送受波部22の振動は伝搬体10に伝達され、主面部12の上端に第2表面波W2が発生する。発生した第2表面波W2は、図3に示すように、主面部12の下端へ向かって伝搬し、前記のように滑らかな曲面を有する底面部16に沿って伝搬した後、主面部11の上端へ向かって伝搬する。主面部11の上端へ到達した第2表面波W2は、第1送受波部21を振動させる。第1送受波部21は、この振動を電気信号に変換して送受信回路30に供給する。
The second transmission / reception unit 22 vibrates by the electric signal supplied from the transmission / reception circuit 30. The vibration of the second transmission / reception unit 22 is transmitted to the propagation body 10, and the second surface wave W <b> 2 is generated at the upper end of the main surface portion 12. As shown in FIG. 3, the generated second surface wave W2 propagates toward the lower end of the main surface portion 12, propagates along the bottom surface portion 16 having a smooth curved surface as described above, and then Propagate towards the top. The second surface wave W2 that has reached the upper end of the main surface part 11 vibrates the first wave transmitting / receiving part 21. The first transmission / reception unit 21 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
なお、以上のように第1送受波部21が伝搬体10に第1表面波W1を発生させることを、第1表面波W1を送る、とも表現する。同様に、第2送受波部22が伝搬体10に第2表面波W2を発生させることを、第2表面波W2を送る、とも表現する。
Note that, as described above, the generation of the first surface wave W1 in the propagation body 10 by the first transmitting / receiving unit 21 is also expressed as transmitting the first surface wave W1. Similarly, the generation of the second surface wave W2 in the propagation body 10 by the second transmitting / receiving unit 22 is also expressed as transmitting the second surface wave W2.
この実施形態では、第1表面波W1及び第2表面波W2は、超音波(例えば、20KHz以上の音波であればよい。)のパルス(超音波パルス)となっている。また、第1表面波W1及び第2表面波W2は、レイリー波である。なお、振動子20は、圧電素子と伝搬体10との間に介在され、振動の伝わりを効率良くするための超音波用接触媒質を含んでいてもよい。
In this embodiment, the first surface wave W1 and the second surface wave W2 are pulses (ultrasonic pulses) of ultrasonic waves (for example, a sound wave of 20 KHz or higher). The first surface wave W1 and the second surface wave W2 are Rayleigh waves. Note that the vibrator 20 may include an ultrasonic contact medium that is interposed between the piezoelectric element and the propagating body 10 and that efficiently transmits vibration.
送受信回路30は、振動子20に接続される。送受信回路30は、超音波発生回路として、表面波として超音波パルスを発生させる電気信号を振動子20に供給し、振動子20を振動させる。送受信回路30は、超音波受信回路として、振動子20から供給される電気信号を受け取り、受け取った電気信号を増幅、変換する。
The transmission / reception circuit 30 is connected to the vibrator 20. As the ultrasonic wave generation circuit, the transmission / reception circuit 30 supplies an electric signal for generating an ultrasonic pulse as a surface wave to the vibrator 20 to vibrate the vibrator 20. The transmission / reception circuit 30 receives an electrical signal supplied from the transducer 20 as an ultrasonic reception circuit, and amplifies and converts the received electrical signal.
具体的には、送受信回路30は、第1表面波W1の送波用の電気信号を第1送受波部21に供給し、第1送受波部21を振動させる。また、第1表面波W1を受けた第2送受波部22から供給される電気信号を受け取り、受け取った電気信号を増幅、変換する。また、送受信回路30は、第2表面波W2の送波用の電気信号を第2送受波部22に供給し、第2送受波部22を振動させる。また、第2表面波W2を受けた第1送受波部21から供給される電気信号を受け取り、受け取った電気信号を増幅、変換する。
Specifically, the transmission / reception circuit 30 supplies an electric signal for transmission of the first surface wave W1 to the first transmission / reception unit 21 to vibrate the first transmission / reception unit 21. Further, it receives an electrical signal supplied from the second transmitting / receiving unit 22 that has received the first surface wave W1, and amplifies and converts the received electrical signal. In addition, the transmission / reception circuit 30 supplies an electric signal for transmission of the second surface wave W <b> 2 to the second transmission / reception unit 22 to vibrate the second transmission / reception unit 22. Further, it receives an electrical signal supplied from the first transmitting / receiving unit 21 that has received the second surface wave W2, and amplifies and converts the received electrical signal.
制御部40は、CPU(Central Processing Unit)、ROM(Read Only Memory)、RAM(Random Access Memory)、タイマなどから構成されるマイクロコンピュータ、D/A(デジタル/アナログ)変換器、A/D(アナログ/デジタル)変換器などを含んで構成される。制御部40は、送受信回路30に接続される。制御部40は、送受信回路30を制御し、送受信回路30から電気信号を振動子20の第1送受波部21と第2送受波部22の各々に供給させる。これにより、第1表面波W1を主面部11に発生させ、第2表面波W2を主面部12に発生させる。また、制御部40は、送受信回路30で増幅、変換された、振動子20の第1送受波部21と第2送受波部22の各々からの電気信号を受け取り、受け取った電気信号に基づいて後述のように液面位置を検出する。また、制御部40は、液面位置検出装置100の外部の外部装置60とデータのやり取りが可能になっている。液面位置検出装置100の構成の説明は以上である。
The control unit 40 includes a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a timer, a D / A (digital / analog) converter, an A / D ( An analog / digital converter is included. The control unit 40 is connected to the transmission / reception circuit 30. The control unit 40 controls the transmission / reception circuit 30 to supply an electrical signal from the transmission / reception circuit 30 to each of the first transmission / reception unit 21 and the second transmission / reception unit 22 of the vibrator 20. Thus, the first surface wave W1 is generated on the main surface portion 11 and the second surface wave W2 is generated on the main surface portion 12. Further, the control unit 40 receives electrical signals from each of the first transmission / reception unit 21 and the second transmission / reception unit 22 of the vibrator 20 that are amplified and converted by the transmission / reception circuit 30, and based on the received electrical signals. The liquid level position is detected as will be described later. In addition, the control unit 40 can exchange data with an external device 60 outside the liquid level position detection device 100. The configuration of the liquid surface position detection device 100 has been described above.
次に、液面位置検出装置100の動作を、制御部40が実行する液面位置検出処理(図4参照)を中心に説明する。例えば、制御部40のCPUが、RAMをメインメモリとして、ROMに格納されているプログラムに従って、及びROMに格納されている各種データを用いて、液面位置検出処理を実行する。制御部40は、例えば、外部装置60からの指令に基づいて、液面位置検出処理を開始する。
Next, the operation of the liquid level position detection apparatus 100 will be described focusing on the liquid level position detection process (see FIG. 4) executed by the control unit 40. For example, the CPU of the control unit 40 executes the liquid surface position detection process using the RAM as a main memory, according to a program stored in the ROM, and using various data stored in the ROM. For example, the control unit 40 starts the liquid surface position detection process based on a command from the external device 60.
(液面位置検出処理)
液面位置検出処理を開始すると、図4に示すように、制御部40は、送受信回路30を介して第1送受波部21を振動させ、主面部11の上端に第1表面波W1を発生させる(ステップS1)。 (Liquid surface position detection process)
When the liquid level position detection process is started, as shown in FIG. 4, thecontrol unit 40 vibrates the first transmission / reception unit 21 via the transmission / reception circuit 30 and generates the first surface wave W <b> 1 at the upper end of the main surface unit 11. (Step S1).
液面位置検出処理を開始すると、図4に示すように、制御部40は、送受信回路30を介して第1送受波部21を振動させ、主面部11の上端に第1表面波W1を発生させる(ステップS1)。 (Liquid surface position detection process)
When the liquid level position detection process is started, as shown in FIG. 4, the
発生した第1表面波W1は、図3に示すように、主面部11の下端へ向かって伝搬し、滑らかな曲面を有する底面部16に沿って伝搬した後、主面部12の上端へ向かって伝搬する。主面部12の上端へ到達した第1表面波W1は、第2送受波部22を振動させる。第2送受波部22は、この振動を電気信号に変換して送受信回路30に供給する。送受信回路30は、供給された電気信号を増幅、変換して制御部40に供給する。以下では、この増幅、変換された電気信号(つまり、底面部16への伝搬を経て第2送受波部22に到達する第1表面波W1が、第2送受波部22に発生させる振動を示す電気信号)を、第1伝搬波信号と言う。このように、第1送受波部21から送られた第1表面波W1は、第2送受波部22に到達する間に、気体に接触する第1部分10aと液体90に接触する第2部分10bとの境界を二回跨いで伝搬する。
As shown in FIG. 3, the generated first surface wave W <b> 1 propagates toward the lower end of the main surface portion 11, propagates along the bottom surface portion 16 having a smooth curved surface, and then toward the upper end of the main surface portion 12. Propagate. The first surface wave W1 that has reached the upper end of the main surface portion 12 causes the second wave transmitting / receiving portion 22 to vibrate. The second transmission / reception unit 22 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30. The transmission / reception circuit 30 amplifies and converts the supplied electric signal and supplies it to the control unit 40. In the following, this amplified and converted electrical signal (that is, the first surface wave W1 that reaches the second transmitting / receiving unit 22 through propagation to the bottom surface part 16 shows vibrations generated by the second transmitting / receiving unit 22). The electric signal) is referred to as a first propagation wave signal. As described above, the first surface wave W1 transmitted from the first wave transmitting / receiving unit 21 reaches the second wave transmitting / receiving unit 22 while the first portion 10a in contact with the gas and the second portion in contact with the liquid 90. It propagates across the boundary with 10b twice.
続いて、制御部40は、ステップS1の処理を行ってから第1伝搬波信号を受信するまでの期間を計測するために、タイマを初期値の0に設定する(ステップS2)。当該期間は、第1送受波部21が第1表面波W1を発生させたタイミングから、第2送受波部22が第1表面波W1を受けるタイミングまでの期間であり、要するに、第1送受波部21から第2送受波部22までの第1表面波W1の伝搬時間(以下、第1伝搬時間と言う。)である。
Subsequently, the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S1 is performed until the first propagation wave signal is received (step S2). The period is a period from the timing at which the first transmitting / receiving unit 21 generates the first surface wave W1 to the timing at which the second transmitting / receiving unit 22 receives the first surface wave W1, and in short, the first transmitting / receiving wave. It is the propagation time of the first surface wave W1 from the unit 21 to the second transmission / reception unit 22 (hereinafter referred to as the first propagation time).
続いて、制御部40は、送受信回路30から第1伝搬波信号を受信したか否かを判別する(ステップS3)。この判別は、適宜の方法で行うことができるが、例えば、制御部40は、第2送受波部22から供給されて送受信回路30で増幅、変換された電気信号を取得し、取得した電気信号の電圧に基づく値(例えば、電圧値、電圧値の2乗の所定期間における平均値、前記電圧値又は前記平均値の変化度、電気信号の振幅など)が予めROM内に格納された閾値以上となったか否かを判別する。例えば、予め実験によって第1伝搬波信号を測定しておき、測定結果に基づいて閾値を定めておけばよい。そして、制御部40は、電気信号の電圧に基づく値が閾値以上となった場合に、第1伝搬波信号を受信した(ステップS3;Yes)と判別する。一方、制御部40は、電気信号の電圧に基づく値が閾値未満である場合は、第1伝搬波信号を受信していない(ステップS3;No)と判別する。
Subsequently, the control unit 40 determines whether or not the first propagation wave signal is received from the transmission / reception circuit 30 (step S3). This determination can be performed by an appropriate method. For example, the control unit 40 acquires the electric signal supplied from the second transmission / reception unit 22 and amplified and converted by the transmission / reception circuit 30. A value based on the voltage (for example, the voltage value, the average value of the square of the voltage value in a predetermined period, the change of the voltage value or the average value, the amplitude of the electrical signal, etc.) is equal to or greater than a threshold value stored in the ROM in advance. It is determined whether or not. For example, the first propagation wave signal may be measured in advance by an experiment, and the threshold value may be determined based on the measurement result. And the control part 40 discriminate | determines that the 1st propagation wave signal was received when the value based on the voltage of an electrical signal becomes more than a threshold value (step S3; Yes). On the other hand, the control part 40 discriminate | determines that the 1st propagation wave signal is not received when the value based on the voltage of an electrical signal is less than a threshold value (step S3; No).
第1伝搬波信号を未だ受信していない場合(ステップS3;No)、制御部40は、タイマのタイマ値を+1などして更新し(ステップS4)、再度ステップS3の処理を実行する。これにより、制御部40は、第1伝搬波信号を受信するまで計時を行う。
When the first propagation wave signal has not been received yet (step S3; No), the control unit 40 updates the timer value of the timer by +1 (step S4), and executes the process of step S3 again. As a result, the control unit 40 keeps timing until the first propagation wave signal is received.
第1伝搬波信号を受信した場合(ステップS3;Yes)、制御部40は、現在のタイマ値を第1伝搬時間として、例えばRAMに記憶する(ステップS5)。
When the first propagation wave signal is received (step S3; Yes), the control unit 40 stores the current timer value as the first propagation time, for example, in the RAM (step S5).
続いて、制御部40は、送受信回路30を介して第2送受波部22を振動させ、主面部12の上端に第2表面波W2を発生させる(ステップS6)。
Subsequently, the control unit 40 vibrates the second transmission / reception unit 22 via the transmission / reception circuit 30 to generate the second surface wave W2 at the upper end of the main surface unit 12 (step S6).
発生した第2表面波W2は、図3に示すように、主面部12の下端へ向かって伝搬し、滑らかな曲面を有する底面部16に沿って伝搬した後、主面部11の上端へ向かって伝搬する。主面部11の上端へ到達した第2表面波W2は、第1送受波部21を振動させる。第1送受波部21は、この振動を電気信号に変換して送受信回路30に供給する。送受信回路30は、供給された電気信号を増幅、変換して制御部40に供給する。以下では、この増幅、変換された電気信号(つまり、底面部16への伝搬を経て第1送受波部21に到達する第2表面波W2が、第1送受波部21に発生させる振動を示す電気信号)を、第2伝搬波信号と言う。このように、第2送受波部22から送られた第2表面波W2は、第1送受波部21に到達する間に、気体に接触する第1部分10aと液体90に接触する第2部分10bとの境界を二回跨いで伝搬する。
As shown in FIG. 3, the generated second surface wave W <b> 2 propagates toward the lower end of the main surface portion 12, propagates along the bottom surface portion 16 having a smooth curved surface, and then toward the upper end of the main surface portion 11. Propagate. The second surface wave W2 that has reached the upper end of the main surface part 11 vibrates the first wave transmitting / receiving part 21. The first transmission / reception unit 21 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30. The transmission / reception circuit 30 amplifies and converts the supplied electric signal and supplies it to the control unit 40. In the following, this amplified and converted electrical signal (that is, the second surface wave W2 that reaches the first transmission / reception unit 21 through propagation to the bottom surface part 16 shows vibration generated in the first transmission / reception unit 21). Electrical signal) is referred to as a second propagation wave signal. As described above, the second surface wave W2 transmitted from the second transmitting / receiving unit 22 reaches the first transmitting / receiving unit 21 while the first portion 10a contacting the gas and the second portion contacting the liquid 90. It propagates across the boundary with 10b twice.
続いて、制御部40は、ステップS6の処理を行ってから第2伝搬波信号を受信するまでの期間を計測するために、タイマを初期値の0に設定する(ステップS7)。当該期間は、第2送受波部22が第2表面波W2を発生させたタイミングから、第1送受波部21が第2表面波W2を受けるタイミングまでの期間であり、要するに、第2送受波部22から第1送受波部21までの第2表面波W2の伝搬時間(以下、第2伝搬時間と言う。)である。なお、以下では、第1伝搬時間と第2伝搬時間とを区別なく、単に伝搬時間と呼ぶこともある。
Subsequently, the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S6 is performed until the second propagation wave signal is received (step S7). The period is a period from the timing at which the second transmitting / receiving unit 22 generates the second surface wave W2 to the timing at which the first transmitting / receiving unit 21 receives the second surface wave W2, in short, the second transmitting / receiving wave. This is the propagation time of the second surface wave W2 from the unit 22 to the first transmission / reception unit 21 (hereinafter referred to as the second propagation time). Hereinafter, the first propagation time and the second propagation time may be simply referred to as propagation time without being distinguished.
続いて、制御部40は、送受信回路30から第2伝搬波信号を受信したか否かを判別する(ステップS8)。この判別は、ステップS3と同様な手法で行われ、第2伝搬波信号を未だ受信していない場合(ステップS8;No)、制御部40は、タイマのタイマ値を+1などして更新し(ステップS9)、再度ステップS8の処理を実行する。これにより、制御部40は、第2伝搬波信号を受信するまで計時を行う。
Subsequently, the control unit 40 determines whether or not the second propagation wave signal is received from the transmission / reception circuit 30 (step S8). This determination is performed in the same manner as in step S3, and when the second propagation wave signal has not been received yet (step S8; No), the control unit 40 updates the timer value of the timer to +1 or the like ( Step S9), the process of step S8 is executed again. Thereby, the control unit 40 performs time measurement until the second propagation wave signal is received.
第2伝搬波信号を受信した場合(ステップS8;Yes)、制御部40は、現在のタイマ値を第2伝搬時間として、例えばRAMに記憶する(ステップS10)。
When the second propagation wave signal is received (step S8; Yes), the control unit 40 stores the current timer value as the second propagation time, for example, in the RAM (step S10).
続いて、制御部40は、ステップS5で記憶した第1伝搬時間と、ステップS10で記憶した第2伝搬時間とに基づいて、液面91の位置(液面位置)を特定する(ステップS11)。
Subsequently, the control unit 40 specifies the position of the liquid surface 91 (liquid surface position) based on the first propagation time stored in step S5 and the second propagation time stored in step S10 (step S11). .
例えば、第1伝搬時間と第2伝搬時間と液面91の位置との関係を予め実験などで特定し、特定した関係をテーブル又は演算式としてROMに格納しておく。制御部40は、ROMに格納されたテーブル又は演算式と、第1伝搬時間及び第2伝搬時間に基づいて液面位置を特定する。
For example, the relationship between the first propagation time, the second propagation time, and the position of the liquid level 91 is specified in advance by experiments or the like, and the specified relationship is stored in the ROM as a table or an arithmetic expression. The control unit 40 specifies the liquid level position based on the table or arithmetic expression stored in the ROM, and the first propagation time and the second propagation time.
なお、制御部40は、第1伝搬時間に基づいて液面位置を特定するためのテーブル又は演算式を用いて、第1伝搬時間に基づく液面位置(以下、第1液面位置と言う。)を特定し、第2伝搬時間に基づいて液面位置を特定するためのテーブル又は演算式を用いて、第2伝搬時間に基づく液面位置(以下、第2液面位置と言う。)を特定してもよい。つまり、制御部40は、第1液面位置と第2液面位置の各々を特定してもよい。そして、第1液面位置と第2液面位置の平均(単純平均でも加重平均でもよい)を、今回検出すべき液面位置としてもよい。なお、加重平均を求める場合は、予め実験などにより、第1液面位置と第2液面位置との各々の重み付け定数を求めておけばよい。また、第1液面位置と第2液面位置のいずれかが、エラー値を示している場合は、エラー値を示していない方を、今回検出すべき液面位置としてもよい。
In addition, the control part 40 uses the table for calculating a liquid level position based on 1st propagation time, or a computing equation, and says the liquid level position (henceforth a 1st liquid level position) based on 1st propagation time. ) And a liquid surface position based on the second propagation time (hereinafter referred to as the second liquid surface position) using a table or an arithmetic expression for identifying the liquid surface position based on the second propagation time. You may specify. That is, the control unit 40 may specify each of the first liquid level position and the second liquid level position. The average of the first liquid level position and the second liquid level position (simple average or weighted average) may be used as the liquid level position to be detected this time. In addition, when calculating | requiring a weighted average, what is necessary is just to obtain | require each weighting constant of a 1st liquid level position and a 2nd liquid level position by experiment etc. previously. Further, when either the first liquid level position or the second liquid level position indicates an error value, the liquid level position to be detected this time may be determined as the one not indicating the error value.
続いて、制御部40は、ステップS11で特定した液面91の位置を外部装置60に出力する(ステップS12)。外部装置60は、例えば、LCD(Liquid Crystal Display)、OLED(Organic Light Emitting Diode)などの画像表示ディスプレイを含み、当該画像表示ディスプレイに、液面91の位置を表示する。液面位置検出処理の説明は以上である。
Subsequently, the control unit 40 outputs the position of the liquid level 91 specified in step S11 to the external device 60 (step S12). The external device 60 includes, for example, an image display such as an LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Diode), and displays the position of the liquid level 91 on the image display. This is the end of the description of the liquid surface position detection process.
なお、伝搬体10を合成樹脂で形成した場合は、液体90に接触する第2部分10bを伝搬する表面波の伝搬速度(以下、第2音速という。)が、空気に接触する第1部分10aを伝搬する表面波の伝搬速度(以下、第1音速という。)よりも遅くなることが知られている。このため、タイマで計測される伝搬時間(第1伝搬時間、第2伝搬時間)は、第2部分10bの長さL2が長いほど、長くなる。つまり、容器80に多く液体90が入っており容器80の底面からの液面91の位置が高いほど、伝搬時間も長くなる。伝搬体10を形成する合成樹脂としては、表面波の伝搬時間を検出することができれば、その組成は限定されるものではないが、PPS(ポリフェニレンサルファイド)の他に、ポリエチレン、ポリスチレンなどを採用することができる。なお、当該合成樹脂としては、表面波の伝搬波を観測しやすいPPSが好適であると考えられる。
When the propagating body 10 is formed of synthetic resin, the propagation speed of the surface wave propagating through the second portion 10b that contacts the liquid 90 (hereinafter referred to as the second sound velocity) is the first portion 10a that contacts the air. It is known that the velocity is slower than the propagation speed of the surface wave propagating through (hereinafter referred to as the first sound velocity). For this reason, the propagation time (first propagation time, second propagation time) measured by the timer becomes longer as the length L2 of the second portion 10b is longer. That is, the longer the liquid 90 is in the container 80 and the higher the position of the liquid level 91 from the bottom surface of the container 80, the longer the propagation time. The composition of the synthetic resin forming the propagating body 10 is not limited as long as the propagation time of the surface wave can be detected, but polyethylene, polystyrene, etc. are adopted in addition to PPS (polyphenylene sulfide). be able to. In addition, it is thought that PPS which can observe the propagation wave of a surface wave is suitable as the said synthetic resin.
制御部40は、液体90の液面91の位置に応じて液体接触部分(第2部分10b)が長くなるほど期間が長くなる伝搬時間を検出し、検出した伝搬時間に基づいて液面91の位置を検出する。液面91の位置は、例えば、伝搬体10が液体90に浸る第2部分10bの長さL2や、容器80の底面から液面91の高さや、長さL2や液面91の高さに応じた値などで表されればよい。容器80の底面から液面91の高さは、液体90の深さであり、長さL2+長さd(図1参照)で求められる。
The control unit 40 detects a propagation time in which the period becomes longer as the liquid contact portion (second portion 10b) becomes longer according to the position of the liquid surface 91 of the liquid 90, and the position of the liquid surface 91 is based on the detected propagation time. Is detected. The position of the liquid level 91 is, for example, the length L2 of the second portion 10b where the propagating body 10 is immersed in the liquid 90, the height of the liquid level 91 from the bottom surface of the container 80, the length L2 or the height of the liquid level 91. What is necessary is just to represent with the value etc. according to. The height of the liquid surface 91 from the bottom surface of the container 80 is the depth of the liquid 90, and is obtained by length L2 + length d (see FIG. 1).
ここで、底面部16が滑らかな曲面でなく、四角柱などで構成される伝搬体10では、第1表面波W1及び第2表面波W2が底面部16で反射する。このため漏洩が生じ、損失となる。一方、底面部16を滑らかな曲線にすることで、第1表面波W1、第2表面波W2は底面部16で反射せず、漏洩が生じないため、底面部16での損失がなく、振動子20が受ける表面波Wrの減衰が少ないため、S/N比を改善することができる。但し、不要な伝搬波Uが表面波の近くに発生することがある。
Here, in the propagation body 10 in which the bottom surface portion 16 is not a smooth curved surface but is formed of a quadrangular column or the like, the first surface wave W1 and the second surface wave W2 are reflected by the bottom surface portion 16. This causes leakage and loss. On the other hand, by making the bottom surface portion 16 into a smooth curve, the first surface wave W1 and the second surface wave W2 are not reflected by the bottom surface portion 16 and leakage does not occur. Since the attenuation of the surface wave Wr received by the child 20 is small, the S / N ratio can be improved. However, an unnecessary propagation wave U may be generated near the surface wave.
図7(a)は、不要な伝搬波Uを模式的に示したものである。Wdは、振動子20から伝搬体10に送られる表面波を示し、Wrは、振動子20が受ける表面波を示している。
FIG. 7 (a) schematically shows an unnecessary propagation wave U. FIG. Wd represents a surface wave sent from the vibrator 20 to the propagating body 10, and Wr represents a surface wave received by the vibrator 20.
また、制御部40は、第1表面波W1と第2表面波W2を同時に発生させる液面位置検出処理を実行してもよい。このとき、第1、第2伝搬波信号は重畳されて伝搬波信号として観測(受信)される。当該液面位置検出処理について図8を参照して説明する。
Further, the control unit 40 may execute a liquid surface position detection process for simultaneously generating the first surface wave W1 and the second surface wave W2. At this time, the first and second propagation wave signals are superimposed and observed (received) as propagation wave signals. The liquid surface position detection process will be described with reference to FIG.
図8に示すように、制御部40は、送受信回路30を介して第1送受波部21を振動させ、主面部11の上端に第1表面波W1を発生させる。また、同時に第2送受波部22を振動させ、主面部12の上端に第2表面波W2を発生させる(ステップS101)。
As shown in FIG. 8, the control unit 40 vibrates the first transmission / reception unit 21 via the transmission / reception circuit 30 to generate the first surface wave W <b> 1 at the upper end of the main surface part 11. At the same time, the second transmission / reception unit 22 is vibrated to generate the second surface wave W2 at the upper end of the main surface part 12 (step S101).
続いて、制御部40は、ステップS101の処理を行ってから伝搬波信号を受信するまでの期間を計測するために、タイマを初期値の0に設定する(ステップS102)。当該期間は、第1送受波部21が第1表面波W1を発生させ、同時に第2送受波部22が第2表面波W2を発生させたタイミングから、第1,第2送受波部21,22が伝搬波信号を受けるタイミングまでの期間、つまり伝搬時間である。
Subsequently, the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S101 is performed until the propagation wave signal is received (step S102). During the period, from the timing when the first transmitting / receiving unit 21 generates the first surface wave W1 and the second transmitting / receiving unit 22 generates the second surface wave W2, the first and second transmitting / receiving units 21, 22 is a period until the timing of receiving a propagation wave signal, that is, a propagation time.
続いて、制御部40は、送受信回路30から伝搬波信号を受信したか否かを判別する(ステップS103)。この判別は、前述のステップS3と同様な手法で行われ、伝搬波信号を未だ受信していない場合(ステップS103;No)、制御部40は、タイマのタイマ値を+1などして更新し(ステップS104)、再度ステップS103の処理を実行する。これにより、制御部40は、伝搬波信号を受信するまで計時を行う。
Subsequently, the control unit 40 determines whether or not a propagation wave signal has been received from the transmission / reception circuit 30 (step S103). This determination is performed by the same method as in step S3 described above, and when the propagation wave signal has not been received yet (step S103; No), the control unit 40 updates the timer value of the timer by +1 or the like ( Step S104), the process of step S103 is executed again. Thereby, the control part 40 performs time measurement until a propagation wave signal is received.
制御部40は、伝搬波信号を受信した場合(ステップS103;Yes)、現在のタイマ値を伝搬時間として、例えばRAMに記憶する(ステップS105)。
When receiving the propagation wave signal (step S103; Yes), the control unit 40 stores the current timer value as the propagation time, for example, in the RAM (step S105).
続いて、制御部40は、ステップS105で記憶した伝搬時間に基づいて、液面91の位置(液面位置)を特定する(ステップS106)。
Subsequently, the control unit 40 specifies the position of the liquid level 91 (liquid level position) based on the propagation time stored in step S105 (step S106).
例えば、伝搬時間と液面91の位置との関係を予め実験などで特定し、特定した関係をテーブル又は演算式としてROMに格納しておく。制御部40は、ROMに格納されたテーブル又は演算式と、伝搬時間に基づいて液面位置を特定する。
For example, the relationship between the propagation time and the position of the liquid surface 91 is specified in advance by experiments or the like, and the specified relationship is stored in the ROM as a table or an arithmetic expression. The control unit 40 specifies the liquid level position based on the table or arithmetic expression stored in the ROM and the propagation time.
続いて、制御部40は、ステップS106で特定した液面91の位置を外部装置60に出力する(ステップS107)。外部装置60は、画像表示ディスプレイに液面91の位置を表示する。
Subsequently, the control unit 40 outputs the position of the liquid level 91 specified in step S106 to the external device 60 (step S107). The external device 60 displays the position of the liquid level 91 on the image display.
このように、第1表面波W1と、第2表面波W2を同時に発生させることによって、振動子20が受ける表面波Wrの振幅が大きくなる。従って、S/N比を更に改善することができる。
Thus, by simultaneously generating the first surface wave W1 and the second surface wave W2, the amplitude of the surface wave Wr received by the vibrator 20 is increased. Therefore, the S / N ratio can be further improved.
(第2実施形態)
ここからは、第2実施形態に係る液面位置検出装置について、主に図5~図7を参照して説明する。なお、第1実施形態と同様な構成及び機能を有する各部については、第1実施形態と同一又は対応する符号を付すとともに、適宜説明を省略する。また、第2実施形態では、第1実施形態と異なる点を中心に説明する。 (Second Embodiment)
From here, the liquid level position detection apparatus according to the second embodiment will be described mainly with reference to FIGS. In addition, about each part which has the structure and function similar to 1st Embodiment, while attaching | subjecting the code | symbol same or corresponding to 1st Embodiment, description is abbreviate | omitted suitably. Further, in the second embodiment, a description will be given focusing on differences from the first embodiment.
ここからは、第2実施形態に係る液面位置検出装置について、主に図5~図7を参照して説明する。なお、第1実施形態と同様な構成及び機能を有する各部については、第1実施形態と同一又は対応する符号を付すとともに、適宜説明を省略する。また、第2実施形態では、第1実施形態と異なる点を中心に説明する。 (Second Embodiment)
From here, the liquid level position detection apparatus according to the second embodiment will be described mainly with reference to FIGS. In addition, about each part which has the structure and function similar to 1st Embodiment, while attaching | subjecting the code | symbol same or corresponding to 1st Embodiment, description is abbreviate | omitted suitably. Further, in the second embodiment, a description will be given focusing on differences from the first embodiment.
第2実施形態に係る伝搬体210は、第1実施形態と同様に、主面部11及び主面部12と、側面部13及び側面部14と、当接部15と、底面部16と、を有する。また、第2実施形態に係る振動子220は、図5(b)、図6に示すように、第1実施形態と同様の第1送受波部21及び第2送受波部22の他に、第3送受波部23と、第4送受波部24と、を備える。
Similar to the first embodiment, the propagating body 210 according to the second embodiment includes the main surface portion 11 and the main surface portion 12, the side surface portion 13 and the side surface portion 14, the contact portion 15, and the bottom surface portion 16. . Further, as shown in FIG. 5B and FIG. 6, the vibrator 220 according to the second embodiment includes the same as the first transmission / reception unit 21 and the second transmission / reception unit 22 as in the first embodiment. A third transmission / reception unit 23 and a fourth transmission / reception unit 24 are provided.
伝搬体210は、図5(a)~(c)に示すように、当接部15から底面部16に向かって凹む凹部17を有する。凹部17は、図5(b)に示すように、側面視では主面部11と第2主面部12との間に位置する。
As shown in FIGS. 5A to 5C, the propagating body 210 has a concave portion 17 that is recessed from the contact portion 15 toward the bottom surface portion 16. As shown in FIG. 5B, the recess 17 is located between the main surface portion 11 and the second main surface portion 12 in a side view.
凹部17は、当接部15から底面部16に向かって、例えば直方体状にくり抜かれた部分であり、第1~第4内側面部17a~17dと、内底面部17eとを有する。
The concave portion 17 is a portion that is hollowed out in, for example, a rectangular parallelepiped shape from the contact portion 15 toward the bottom surface portion 16, and includes first to fourth inner side surface portions 17a to 17d and an inner bottom surface portion 17e.
第1内側面部17aは、主面部11の裏側に位置する。第2内側面部17bは、主面部12の裏側に位置する。第1内側面部17aと第2内側面部17bとは互いに対向している。第3内側面部17cは、側面部13の裏側に位置する。第4内側面部17dは、側面部14の裏側に位置する。第3内側面部17cと第4内側面部17dとは互いに対向している。内底面部17eは、凹部17の底に位置し、図5(c)に示すように、平面視で矩形状をなす。
The first inner side surface portion 17 a is located on the back side of the main surface portion 11. The second inner side surface portion 17 b is located on the back side of the main surface portion 12. The first inner side surface portion 17a and the second inner side surface portion 17b face each other. The third inner side surface portion 17 c is located on the back side of the side surface portion 13. The fourth inner side surface portion 17 d is located on the back side of the side surface portion 14. The third inner side surface portion 17c and the fourth inner side surface portion 17d face each other. The inner bottom surface portion 17e is located at the bottom of the concave portion 17, and has a rectangular shape in plan view as shown in FIG.
図7(b)は、伝搬体210に凹部17を設けることにより、検出波Dが生じる様子を模式的に示したものである。検出波Dは、後述の第1検出波D1又は第2検出波D2を示す。
FIG. 7B schematically shows a state in which the detection wave D is generated by providing the propagation body 210 with the concave portion 17. The detection wave D indicates a first detection wave D1 or a second detection wave D2 described later.
第3送受波部23は、伝搬体210に表面波又は板波からなる第1検出波D1を発生させるとともに、凹部17の内底面部17eで反射した第1検出波D1を受ける。第4送受波部24は、伝搬体210に表面波又は板波からなる第2検出波D2を発生させるとともに、凹部17の内底面部17eで反射した第2検出波D2を受ける。
The third wave transmitting / receiving unit 23 generates a first detection wave D1 made of a surface wave or a plate wave in the propagation body 210 and receives the first detection wave D1 reflected by the inner bottom surface part 17e of the recess 17. The fourth transmission / reception unit 24 generates a second detection wave D <b> 2 composed of a surface wave or a plate wave in the propagation body 210 and receives the second detection wave D <b> 2 reflected by the inner bottom surface part 17 e of the recess 17.
第3送受波部23は、送受信回路30から供給される電気信号によって振動する。第3送受波部23の振動は伝搬体210に伝達され、第1内側面部17aの上端に第1検出波D1が発生する。発生した第1検出波D1は、図6に示すように、第1内側面部17aの下端へ向かって伝搬し、内底面部17eで反射した後、第1内側面部17aの上端へ向かって伝搬する。第1内側面部17aの上端へ到達した第1検出波D1は、第3送受波部23を振動させる。第3送受波部23は、この振動を電気信号に変換して送受信回路30に供給する。
The third transmission / reception unit 23 vibrates by the electric signal supplied from the transmission / reception circuit 30. The vibration of the third transmission / reception unit 23 is transmitted to the propagation body 210, and the first detection wave D1 is generated at the upper end of the first inner side surface portion 17a. As shown in FIG. 6, the generated first detection wave D1 propagates toward the lower end of the first inner side surface portion 17a, reflects off the inner bottom surface portion 17e, and then propagates toward the upper end of the first inner side surface portion 17a. . The first detection wave D1 that has reached the upper end of the first inner side surface portion 17a vibrates the third transmission / reception unit 23. The third transmission / reception unit 23 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
第4送受波部24は、送受信回路30から供給される電気信号によって振動する。第4送受波部24の振動は伝搬体210に伝達され、第2内側面部17bの上端に第2検出波D2が発生する。発生した第2検出波D2は、図6に示すように、第2内側面部17bの下端へ向かって伝搬し、内底面部17eで反射した後、第2内側面部17bの上端へ向かって伝搬する。第2内側面部17bの上端へ到達した第2検出波D2は、第4送受波部24を振動させる。第4送受波部24は、この振動を電気信号に変換して送受信回路30に供給する。
The fourth transmission / reception unit 24 vibrates by the electric signal supplied from the transmission / reception circuit 30. The vibration of the fourth transmission / reception unit 24 is transmitted to the propagation body 210, and the second detection wave D2 is generated at the upper end of the second inner side surface portion 17b. As shown in FIG. 6, the generated second detection wave D2 propagates toward the lower end of the second inner side surface portion 17b, reflects off the inner bottom surface portion 17e, and then propagates toward the upper end of the second inner side surface portion 17b. . The second detection wave D2 that has reached the upper end of the second inner side surface portion 17b vibrates the fourth transmission / reception unit 24. The fourth transmission / reception unit 24 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
第3送受波部23が受ける第1検出波D1と、第4送受波部24が受ける第2検出波D2とは、液面91の位置に関係なく、伝搬体210の温度に依存して音速が変化する。第2実施形態では、第1検出波D1と第2検出波D2との少なくともいずれかを用いて、伝搬体210の温度を検出し、検出した温度を、表面波(第1表面波W1及び第2表面波W2)を検出する際の温度補正に利用する。このため、従来の液面位置検出装置に設けていたサーミスタチップなどからなる温度センサを設けずに済む。
The first detection wave D1 received by the third transmission / reception unit 23 and the second detection wave D2 received by the fourth transmission / reception unit 24 depend on the temperature of the propagating body 210 regardless of the position of the liquid surface 91. Changes. In the second embodiment, the temperature of the propagating body 210 is detected using at least one of the first detection wave D1 and the second detection wave D2, and the detected temperature is converted into a surface wave (the first surface wave W1 and the first detection wave D1). This is used for temperature correction when detecting the two surface waves W2). For this reason, it is not necessary to provide the temperature sensor which consists of the thermistor chip etc. which were provided in the conventional liquid level position detection apparatus.
送受信回路30は、第1検出波D1の送波用の電気信号を第3送受波部23に供給し、第3送受波部23を振動させる。また、第1検出波D1を受けた第3送受波部23から供給される電気信号を受け取り、受け取った電気信号を増幅、変換する。また、送受信回路30は、第2検出波D2の送波用の電気信号を第4送受波部24に供給し、第4送受波部24を振動させる。また、第2検出波D2を受けた第4送受波部24から供給される電気信号を受け取り、受け取った電気信号を増幅、変換する。
The transmission / reception circuit 30 supplies the third transmission / reception unit 23 with the electrical signal for transmission of the first detection wave D1 to vibrate the third transmission / reception unit 23. Further, it receives an electrical signal supplied from the third transmitting / receiving unit 23 that has received the first detection wave D1, and amplifies and converts the received electrical signal. In addition, the transmission / reception circuit 30 supplies an electric signal for transmission of the second detection wave D2 to the fourth transmission / reception unit 24, and vibrates the fourth transmission / reception unit 24. Also, the electric signal supplied from the fourth transmitting / receiving unit 24 that has received the second detection wave D2 is received, and the received electric signal is amplified and converted.
制御部40は、送受信回路30を介して、第3送受波部23及び第4送受波部24の各々を駆動制御する。また、制御部40は、送受信回路30で増幅、変換された、第3送受波部23と第4送受波部24の各々からの電気信号を受け取り、受け取った電気信号に基づいて伝搬体210の温度を検出する。
The control unit 40 drives and controls each of the third transmission / reception unit 23 and the fourth transmission / reception unit 24 via the transmission / reception circuit 30. In addition, the control unit 40 receives electrical signals from each of the third transmission / reception unit 23 and the fourth transmission / reception unit 24 that are amplified and converted by the transmission / reception circuit 30, and based on the received electrical signals, Detect temperature.
制御部40は、前述の液面位置検出処理で説明した手法と同様な手法で、第1検出波D1と第2検出波D2の各々の伝搬時間を検出する。以下では、第1検出波D1の伝搬時間を第1検出時間、第2検出波D2の伝搬時間を第2検出時間と言う。
The control unit 40 detects the propagation time of each of the first detection wave D1 and the second detection wave D2 by a method similar to the method described in the liquid level position detection process described above. Hereinafter, the propagation time of the first detection wave D1 is referred to as a first detection time, and the propagation time of the second detection wave D2 is referred to as a second detection time.
具体的には、制御部40は、第3送受波部23で第1検出波D1を発生させてから、内底面部17eで反射後に、第3送受波部23が第1検出波D1を受けるまでの時間をタイマ値に基づいて特定する。そして、特定した時間を第1検出時間としてRAMに記憶する。また、第4送受波部24で第2検出波D2を発生させてから、内底面部17eで反射後に、第4送受波部24が第2検出波D2を受けるまでの時間をタイマ値に基づいて特定する。そして、特定した時間を第2検出時間としてRAMに記憶する。制御部40は、このようにして得た、第1検出時間と第2検出時間の少なくともいずれかに基づいて、伝搬体210の温度を特定(検出)する。
Specifically, the control unit 40 generates the first detection wave D1 by the third transmission / reception unit 23, and then the third transmission / reception unit 23 receives the first detection wave D1 after being reflected by the inner bottom surface part 17e. Is determined based on the timer value. Then, the specified time is stored in the RAM as the first detection time. Further, based on the timer value, the time from when the fourth transmission / reception unit 24 generates the second detection wave D2 to when the fourth transmission / reception unit 24 receives the second detection wave D2 after being reflected by the inner bottom surface portion 17e. To identify. Then, the specified time is stored in the RAM as the second detection time. The control unit 40 specifies (detects) the temperature of the propagating body 210 based on at least one of the first detection time and the second detection time obtained as described above.
前記のように、第1検出波D1と第2検出波D2は、液面91の位置に関係なく、伝搬体210の温度に依存して音速が変化する。このため、第1検出時間と第2検出時間も、液面91の位置に関係なく、伝搬体210の温度に依存して変化する。この特性を利用して、例えば、第1検出時間と第2検出時間と伝搬体210の温度との関係を予め実験などで特定し、特定した関係をテーブル又は演算式としてROMに格納しておく。制御部40は、ROMに格納されたテーブル又は演算式と、第1検出時間及び第2検出時間とに基づいて伝搬体210の温度を特定する。
As described above, the sound velocity of the first detection wave D1 and the second detection wave D2 changes depending on the temperature of the propagating body 210 regardless of the position of the liquid surface 91. For this reason, the first detection time and the second detection time also change depending on the temperature of the propagating body 210 regardless of the position of the liquid surface 91. Using this characteristic, for example, the relationship between the first detection time, the second detection time, and the temperature of the propagation body 210 is specified in advance by experiments, and the specified relationship is stored in the ROM as a table or an arithmetic expression. . The control unit 40 specifies the temperature of the propagating body 210 based on the table or arithmetic expression stored in the ROM and the first detection time and the second detection time.
なお、制御部40は、第1検出時間に基づいて伝搬体210の温度を特定するためのテーブル又は演算式を用いて、第1検出時間に基づく伝搬体210の温度(以下、第1温度と言う。)を特定し、第2検出時間に基づいて伝搬体210の温度を特定するためのテーブル又は演算式を用いて、第2検出時間に基づく伝搬体210の温度(以下、第2温度と言う。)を特定してもよい。つまり、制御部40は、第1温度と第2温度の各々を特定してもよい。そして、第1温度と第2温度の平均(単純平均でも加重平均でもよい)を、今回検出すべき温度としてもよい。なお、加重平均を求める場合は、予め実験などにより、第1温度と第2温度との各々の重み付け定数を求めておけばよい。また、第1温度と第2温度のいずれかが、エラー値を示している場合は、エラー値を示していない方を、今回検出すべき温度としてもよい。
The control unit 40 uses a table or an arithmetic expression for specifying the temperature of the propagating body 210 based on the first detection time, and uses the temperature of the propagating body 210 based on the first detection time (hereinafter referred to as the first temperature). The temperature of the propagating body 210 based on the second detection time (hereinafter referred to as the second temperature) using a table or an arithmetic expression for identifying the temperature of the propagating body 210 based on the second detection time. Say). That is, the control unit 40 may specify each of the first temperature and the second temperature. The average of the first temperature and the second temperature (simple average or weighted average) may be used as the temperature to be detected this time. In addition, when calculating | requiring a weighted average, what is necessary is just to obtain | require each weighting constant of 1st temperature and 2nd temperature by experiment etc. previously. In addition, when one of the first temperature and the second temperature indicates an error value, the temperature that does not indicate the error value may be set as the temperature to be detected this time.
そして、制御部40は、以上のように特定(検出)した伝搬体210の温度に基づいて、第1伝搬時間と第2伝搬時間の温度補正を行う。音速は、温度依存性があり、伝搬体210の温度に応じて変化する。つまり、第1伝搬時間と第2伝搬時間も伝搬体210の温度に応じて変化する。このため、液面位置の検出精度を保つには、当該温度補正が必要となる。例えば、伝搬体210の温度と、伝搬時間の補正量や補正係数とを対応付けて構成されるテーブルを予めROM内に格納しておき、制御部40は、テーブルを参照して、特定した伝搬体210の温度に応じた補正量や補正係数を取得すればよい。そして、制御部40は、第1伝搬時間と第2伝搬時間との各々に、取得した補正量を加減する演算や、補正係数を乗算する演算を行うことで、第1伝搬時間と第2伝搬時間の温度補正を行えばよい。
And the control part 40 performs temperature correction of 1st propagation time and 2nd propagation time based on the temperature of the propagation body 210 specified (detected) as mentioned above. The speed of sound is temperature dependent and changes according to the temperature of the propagating body 210. That is, the first propagation time and the second propagation time also change according to the temperature of the propagation body 210. For this reason, in order to maintain the detection accuracy of the liquid surface position, the temperature correction is necessary. For example, a table configured by associating the temperature of the propagating body 210 with the correction amount and correction coefficient of the propagation time is stored in the ROM in advance, and the control unit 40 refers to the table and determines the specified propagation. A correction amount or correction coefficient corresponding to the temperature of the body 210 may be acquired. And the control part 40 performs the calculation which adds / subtracts the acquired correction amount to each of 1st propagation time and 2nd propagation time, and the calculation which multiplies a correction coefficient, and is 1st propagation time and 2nd propagation time. Time temperature correction may be performed.
なお、伝搬体210の温度と、液面位置の補正量や補正係数とを対応付けて構成されるテーブルを予めROM内に格納しておき、第1伝搬時間や第2伝搬時間に基づいて特定した液面位置を補正してもよい。また、制御部40は、テーブルに限らず、音速の温度依存性を表す式(近似式であってもよい)をROM内に格納しておき、当該式を用いて、伝搬時間または液面位置の補正量や補正係数を求めてもよい。伝搬時間や液面位置の温度補正手法は、公知のテーブル構成法や演算法を適宜用いることができ、任意である。
A table configured by associating the temperature of the propagating body 210 with the correction amount and correction coefficient of the liquid surface position is stored in advance in the ROM and specified based on the first propagation time and the second propagation time. The liquid surface position may be corrected. The control unit 40 is not limited to the table, and stores an expression (may be an approximate expression) representing the temperature dependence of the sound speed in the ROM, and the propagation time or the liquid surface position is stored using the expression. The correction amount and the correction coefficient may be obtained. The temperature correction method for the propagation time and the liquid surface position can be arbitrarily selected from known table construction methods and calculation methods.
また、以上の温度補正処理は、第1検出波D1や第2検出波D2が、第1表面波W1や第2表面波W2と干渉しない限りにおいては、前述の液面位置検出処理の中に組み込み、第1検出波D1及び第2検出波D2の発生タイミングを、第1表面波W1及び第2表面波W2の発生タイミングと同時にしてもよい。また、温度補正処理は、液面位置検出処理とは独立した処理として実行されてもよい。
In addition, the above temperature correction process includes the above-described liquid surface position detection process as long as the first detection wave D1 and the second detection wave D2 do not interfere with the first surface wave W1 and the second surface wave W2. The generation timing of the first detection wave D1 and the second detection wave D2 may be made simultaneously with the generation timing of the first surface wave W1 and the second surface wave W2. Further, the temperature correction process may be executed as a process independent of the liquid surface position detection process.
本発明は以上の実施形態及び図面によって限定されるものではない。本発明の要旨を変更しない範囲で、適宜、変更(構成要素の削除も含む)を加えることが可能である。
The present invention is not limited to the above embodiments and drawings. Changes (including deletion of components) can be made as appropriate without departing from the scope of the present invention.
(変形例)
以上では、第1送受波部21と第2送受波部22とが当接部15に当接する構成例を説明したが、第1送受波部21を、第1主面部11と当接して設け、第2送受波部22を、第2主面部12と当接して設ける構成を採用してもよい。 (Modification)
The configuration example in which the first transmission /reception unit 21 and the second transmission / reception unit 22 are in contact with the contact unit 15 has been described above. However, the first transmission / reception unit 21 is provided in contact with the first main surface unit 11. In addition, a configuration in which the second transmission / reception unit 22 is provided in contact with the second main surface portion 12 may be employed.
以上では、第1送受波部21と第2送受波部22とが当接部15に当接する構成例を説明したが、第1送受波部21を、第1主面部11と当接して設け、第2送受波部22を、第2主面部12と当接して設ける構成を採用してもよい。 (Modification)
The configuration example in which the first transmission /
第2実施形態では、凹部17が直方体状にくり抜かれ、内底面部17eが平坦な例を説明したが、これに限られない。凹部17の内底面部17eを、第1実施形態に係る底面部16のように、下方に凸となるU字状の滑らかな曲面状に形成してもよい。また、このように内底面部17eを曲面状に形成した場合、第3送受波部23が伝搬体210に送った第1検出波D1を第4送受波部24で受け、第4送受波部24が伝搬体210に送った第2検出波D2を第3送受波部23で受けるように構成してもよい。また、第3送受波部23と第4送受波部24のいずれか一方を省いてもよい。
In the second embodiment, the example in which the concave portion 17 is cut out in a rectangular parallelepiped shape and the inner bottom surface portion 17e is flat has been described, but the present invention is not limited to this. The inner bottom surface portion 17e of the concave portion 17 may be formed in a U-shaped smooth curved surface that protrudes downward like the bottom surface portion 16 according to the first embodiment. Further, when the inner bottom surface portion 17e is formed in a curved surface as described above, the fourth transmission / reception unit 24 receives the first detection wave D1 transmitted from the third transmission / reception unit 23 to the propagating body 210, and the fourth transmission / reception unit. You may comprise so that the 2nd detection wave D2 which 24 sent to the propagation body 210 may be received in the 3rd transmission / reception part 23. FIG. Further, either one of the third transmission / reception unit 23 and the fourth transmission / reception unit 24 may be omitted.
液面位置検出は、液面91の詳細な位置を検出すること(上記のように、容器80の底面からの液面91の高さを検出すること)の他、液面91の位置を何段階かに分けて現在の液面91の位置がどの段階に属するかを検出することなども含む。また、制御部40が液面位置検出後に外部装置60に表示させる画像は、液面位置そのものを示していなくともよく、液面位置に応じた液体90の量を示していてもよい。
In the liquid level position detection, in addition to detecting the detailed position of the liquid level 91 (detecting the height of the liquid level 91 from the bottom surface of the container 80 as described above), what is the position of the liquid level 91. It also includes detecting to which stage the current position of the liquid level 91 belongs, divided into stages. Further, the image displayed on the external device 60 after the liquid level position is detected by the control unit 40 may not indicate the liquid level position itself, but may indicate the amount of the liquid 90 corresponding to the liquid level position.
また、伝搬体10、210は合成樹脂製であり、液体90の液面位置に応じて第2部分10b(液体接触部分)が長くなるほど伝搬時間が長くなることが好ましく、第2部分10bを伝搬する表面波の速さと、第1部分10a(液体90から露出する部分)を伝搬する表面波の速さとの差がより顕著となる方が好ましい。しかしながら、以上に説明した手法で液面位置を検出することができれば、伝搬体10、210を、アルミ、ステンレス、鋼などの金属で構成してもよい。
Further, the propagation bodies 10 and 210 are made of synthetic resin, and it is preferable that the propagation time becomes longer as the second portion 10b (liquid contact portion) becomes longer according to the liquid surface position of the liquid 90, and propagates through the second portion 10b. It is preferable that the difference between the speed of the surface wave that travels and the speed of the surface wave that propagates through the first portion 10a (the portion exposed from the liquid 90) becomes more significant. However, the propagating bodies 10 and 210 may be made of a metal such as aluminum, stainless steel, or steel as long as the liquid level position can be detected by the method described above.
また、伝搬体10、210は、その長尺方向を液面91の法線方向と平行として配置するほか、その長尺方向を液面91の法線方向に対して傾けるように配置してもよい。また、伝搬体10、210のうち表面波が伝搬する面に、表面波の進行方向の沿って延びる凹部又は凸部を複数形成し、この面に凹凸を形成してもよい。
Further, the propagating bodies 10 and 210 may be arranged such that the longitudinal direction thereof is parallel to the normal direction of the liquid surface 91 and the longitudinal direction is inclined with respect to the normal direction of the liquid surface 91. Good. Further, a plurality of concave portions or convex portions extending along the traveling direction of the surface wave may be formed on the surface of the propagating bodies 10 and 210 where the surface wave propagates, and the concave and convex portions may be formed on this surface.
液面位置検出対象の液体90の種類は限られず、水、ガソリン、洗浄液など任意である。また、液面91の上は空気以外の他の気体であってもよく、真空であってもよい。
The type of the liquid 90 whose liquid level position is to be detected is not limited, and water, gasoline, cleaning liquid and the like are arbitrary. Further, the liquid surface 91 may be a gas other than air or a vacuum.
例えば、容器80は、車両に搭載される燃料タンクであってもよい。この場合、液体90は、ガソリンなどの燃料になる。このような場合、伝搬体10、210は、例えば、燃料タンクに取り付けられる、燃料タンクから燃料を取り出す燃料ポンプを備える燃料圧送ユニットなどに取り付けられてもよい。なお、このような燃料タンクの場合、耐薬品性などの観点から伝搬体10、210として使用される樹脂は、PPS(ポリフェニレンサルファイド)、POM(ポリアセタール)、PBT(ポリブチレンテレフタレート)が用いられることが多いが、これらの中では、検出信号のS/N比が良いPPSを用いることが好ましい。
For example, the container 80 may be a fuel tank mounted on a vehicle. In this case, the liquid 90 becomes a fuel such as gasoline. In such a case, the propagating bodies 10 and 210 may be attached to, for example, a fuel pumping unit that is attached to the fuel tank and includes a fuel pump that extracts fuel from the fuel tank. In the case of such a fuel tank, PPS (polyphenylene sulfide), POM (polyacetal), and PBT (polybutylene terephthalate) are used as the resins used as the propagation bodies 10 and 210 from the viewpoint of chemical resistance. However, among these, it is preferable to use PPS with a good S / N ratio of the detection signal.
PPSとしては、直鎖型、架橋型、反架橋型などがあり、さらに、ガラス繊維や無機フィラーなどのフィラー(添加材料)を添加したものなどがあるが、伝搬体10に用いるPPSとしては各種のPPSを用いることができる。直鎖型、架橋型、反架橋型などの違い、フィラーの添加の有無やフィラーの種類の違いなどによる、表面波や板波の伝搬の状態(例えば、S/N比が良好なこと、表面波又は板波の音速など)への影響は小さいものと考えられる。
Examples of PPS include linear type, cross-linked type, and anti-cross-linked type. Further, there are those added with fillers (additive materials) such as glass fibers and inorganic fillers. PPS can be used. Surface wave or plate wave propagation state (for example, good S / N ratio, surface due to differences in linear type, cross-linked type, anti-cross-linked type, presence / absence of filler addition, type of filler, etc. The effect on the sound speed of waves or plate waves is considered to be small.
表面波は、レイリー波以外のものであってもよい。表面波は、超音波よりも低い周波数の音波であってもよい。また、表面波は、パルス波でなくてもよく、例えば、バースト波などであってもよい。また、板波もパルス波やバースト波などであればよい。
Surface waves may be other than Rayleigh waves. The surface wave may be a sound wave having a lower frequency than the ultrasonic wave. Further, the surface wave may not be a pulse wave, and may be a burst wave, for example. The plate wave may be a pulse wave or a burst wave.
(1)以上に説明した液面位置検出装置100は、液体90の液面位置(液面91の位置)に応じて、液体90に浸る部分の割合が変化する伝搬体10、210と、伝搬体10、210に第1表面波W1を発生させるとともに第2表面波W2を受ける第1送受波部21と、伝搬体10、210に第2表面波W2を発生させるとともに第1表面波W1を受ける第2送受波部22と、第2送受波部22が受けた第1表面波W1の伝搬時間と、第1送受波部21が受けた第2表面波W2の伝搬時間との少なくともいずれかに基づいて液面位置を検出する検出部(例えば、制御部40)と、を備える。伝搬体10、210は、互いに裏表の関係にある主面部11(第1主面部)及び主面部12(第2主面部)と、主面部11と主面部12とを繋ぐとともに、側面視において曲面状をなす底面部16と、を有する。
第1送受波部21は、主面部11を伝搬する第1表面波W1を発生させ、第2送受波部22は、主面部11を経て底面部16と主面部12とを伝搬した第1表面波W1を受ける。第2送受波部22は、主面部12を伝搬する第2表面波W2を発生させ、第1送受波部21は、主面部12を経て底面部16と主面部11とを伝搬した第2表面波W2を受ける。 (1) The liquid surfaceposition detection device 100 described above includes the propagation bodies 10 and 210 in which the ratio of the portion immersed in the liquid 90 changes according to the liquid surface position of the liquid 90 (the position of the liquid surface 91). The first transmitting / receiving unit 21 that generates the first surface wave W1 in the bodies 10 and 210 and receives the second surface wave W2, and the second surface wave W2 in the propagation bodies 10 and 210 and the first surface wave W1 The second transmission / reception unit 22 to receive, the propagation time of the first surface wave W1 received by the second transmission / reception unit 22, and the propagation time of the second surface wave W2 received by the first transmission / reception unit 21 And a detection part (for example, control part 40) which detects a liquid level position based on. The propagating bodies 10 and 210 connect the main surface portion 11 (first main surface portion) and the main surface portion 12 (second main surface portion), and the main surface portion 11 and the main surface portion 12, which are in reverse relation to each other, and are curved in a side view. And a bottom surface portion 16 having a shape.
The first transmission /reception unit 21 generates a first surface wave W1 propagating through the main surface part 11, and the second transmission / reception unit 22 is transmitted through the main surface part 11 through the bottom surface part 16 and the main surface part 12. Receive wave W1. The second transmission / reception unit 22 generates a second surface wave W2 that propagates through the main surface portion 12, and the first transmission / reception unit 21 propagates through the main surface portion 12 through the bottom surface portion 16 and the main surface portion 11. Receive wave W2.
第1送受波部21は、主面部11を伝搬する第1表面波W1を発生させ、第2送受波部22は、主面部11を経て底面部16と主面部12とを伝搬した第1表面波W1を受ける。第2送受波部22は、主面部12を伝搬する第2表面波W2を発生させ、第1送受波部21は、主面部12を経て底面部16と主面部11とを伝搬した第2表面波W2を受ける。 (1) The liquid surface
The first transmission /
このように、側面視において曲面状をなす底面部16を設けたため、第1表面波W1及び第2表面波W2が底面部16へ伝搬する際の漏洩による損失を低減することができ、S/N比の悪化を低減することができる。結果として、液面位置の検出精度を良好とすることができる。また、第1表面波W1の伝搬時間と、第1送受波部21が受けた第2表面波W2の伝搬時間との少なくともいずれかに基づいて液面位置を検出するため、ノイズの重畳などにより一方の伝搬時間の検出精度が劣る場合であっても、液面位置の検出精度を良好とすることができる。
As described above, since the bottom surface portion 16 having a curved shape in the side view is provided, loss due to leakage when the first surface wave W1 and the second surface wave W2 propagate to the bottom surface portion 16 can be reduced. The deterioration of the N ratio can be reduced. As a result, the detection accuracy of the liquid surface position can be improved. Further, since the liquid surface position is detected based on at least one of the propagation time of the first surface wave W1 and the propagation time of the second surface wave W2 received by the first transmission / reception unit 21, it is possible to superimpose noise. Even when the detection accuracy of one propagation time is inferior, the detection accuracy of the liquid level can be improved.
(2)具体的には、伝搬体10、210は、第1送受波部21及び第2送受波部22と当接する当接部15を有し、主面部11は、側面視において当接部15の一端から垂下し、主面部12は、側面視において当接部15の他端から垂下する。そして、第1送受波部21は、当接部15を介して主面部11を伝搬する第1表面波W1を発生させ、第2送受波部22は、当接部15を介して主面部12を伝搬する第2表面波W2を発生させる。なお、前記の変形例で述べたように、第1送受波部21を、第1主面部11と当接して設け、第2送受波部22を、第2主面部12と当接して設ける構成を採用してもよい。
(2) Specifically, the propagation bodies 10 and 210 have the contact part 15 which contacts the 1st transmission / reception part 21 and the 2nd transmission / reception part 22, and the main surface part 11 is a contact part in side view. The main surface portion 12 hangs down from the other end of the contact portion 15 in a side view. The first wave transmitting / receiving unit 21 generates the first surface wave W1 propagating through the main surface part 11 via the contact part 15, and the second wave transmitting / receiving part 22 is transmitted through the contact part 15 to the main surface part 12. 2nd surface wave W2 which propagates is generated. As described in the modification, the first transmission / reception unit 21 is provided in contact with the first main surface portion 11, and the second transmission / reception unit 22 is provided in contact with the second main surface portion 12. May be adopted.
(3)第1送受波部21及び第2送受波部22は、第1表面波W1と、第2表面波W2を同時に発生させてもよい(第1送受波部21による第1表面波W1の発生と、第2送受波部22による第2表面波W2の発生とは同時であってもよい)。
(3) The first transmission / reception unit 21 and the second transmission / reception unit 22 may simultaneously generate the first surface wave W1 and the second surface wave W2 (the first surface wave W1 by the first transmission / reception unit 21). And the generation of the second surface wave W2 by the second transmission / reception unit 22 may be simultaneous).
(4)第2実施形態に係る伝搬体210は、当接部15から底面部16に向かって凹むとともに、側面視において主面部11と主面部12との間に位置する凹部17を有する。
この凹部17により、振動子220から伝搬体210に発生する内部伝搬波Uを低減又は消滅させることができる。これにより、液面位置検出の検出誤差を低減させることができる。 (4) The propagatingbody 210 according to the second embodiment is recessed from the contact portion 15 toward the bottom surface portion 16, and has a recess 17 located between the main surface portion 11 and the main surface portion 12 in a side view.
With thisrecess 17, the internal propagation wave U generated from the vibrator 220 to the propagation body 210 can be reduced or eliminated. Thereby, the detection error of liquid level position detection can be reduced.
この凹部17により、振動子220から伝搬体210に発生する内部伝搬波Uを低減又は消滅させることができる。これにより、液面位置検出の検出誤差を低減させることができる。 (4) The propagating
With this
(5)また、第2実施形態に係る液面位置検出装置は、伝搬体210に表面波又は板波である検出波(第1検出波D1と第2検出波D2との少なくともいずれか)を発生させる特定送受波部(第3送受波部23と第4送受波部24との少なくともいずれか)をさらに備える。特定送受波部は、当接部15を介して凹部17の内側面部を伝搬する検出波を発生させるとともに、内側面部を経て凹部17の内底面部17eで反射した検出波を受ける。検出部は、特定送受波部が受けた検出波の伝搬時間に基づいて、伝搬体210の温度を検出する。
このようにしたから、従来の液面位置検出装置に設けていたサーミスタチップなどからなる温度センサを設けずに済み、部品点数の削減が可能である。 (5) Moreover, the liquid level position detection apparatus according to the second embodiment applies a detection wave (at least one of the first detection wave D1 and the second detection wave D2) that is a surface wave or a plate wave to the propagatingbody 210. A specific transmitting / receiving unit (at least one of the third transmitting / receiving unit 23 and the fourth transmitting / receiving unit 24) to be generated is further provided. The specific transmission / reception unit generates a detection wave propagating through the inner side surface portion of the concave portion 17 via the contact portion 15 and receives the detection wave reflected by the inner bottom surface portion 17e of the concave portion 17 through the inner side surface portion. The detection unit detects the temperature of the propagation body 210 based on the propagation time of the detection wave received by the specific transmission / reception unit.
Since it did in this way, it is not necessary to provide the temperature sensor which consists of thermistor chips etc. which were provided in the conventional liquid level position detection apparatus, and reduction of a number of parts is possible.
このようにしたから、従来の液面位置検出装置に設けていたサーミスタチップなどからなる温度センサを設けずに済み、部品点数の削減が可能である。 (5) Moreover, the liquid level position detection apparatus according to the second embodiment applies a detection wave (at least one of the first detection wave D1 and the second detection wave D2) that is a surface wave or a plate wave to the propagating
Since it did in this way, it is not necessary to provide the temperature sensor which consists of thermistor chips etc. which were provided in the conventional liquid level position detection apparatus, and reduction of a number of parts is possible.
(6)また、第1送受波部21と第2送受波部22と特定送受波部は、第1表面波W1と、第2表面波W2と、検出波を同時に発生させてもよい(第1送受波部21による第1表面波W1の発生と、第2送受波部22による第2表面波W2の発生と、特定送受波部による検出波の発生とは同時であってもよい)。
(6) Moreover, the 1st transmission / reception part 21, the 2nd transmission / reception part 22, and the specific transmission / reception part may generate | occur | produce the 1st surface wave W1, the 2nd surface wave W2, and a detection wave simultaneously (1st The generation of the first surface wave W1 by the first transmission / reception unit 21, the generation of the second surface wave W2 by the second transmission / reception unit 22, and the generation of the detection wave by the specific transmission / reception unit may be simultaneous).
以上の説明では、本発明の理解を容易にするために、公知の技術的事項の説明を適宜省略した。
In the above description, in order to facilitate understanding of the present invention, descriptions of known technical matters are omitted as appropriate.
100…液面位置検出装置
10、210…伝搬体
10a…第1部分、10b…第2部分
11…主面部(第1主面部の一例)
12…主面部(第2主面部の一例)
13、14…側面部
15…当接部
16…底面部
20、220…振動子
21…第1送受波部、22…第2送受波部
W1…第1表面波、W2…第2表面波
23…第3送受波部、24…第4送受波部
D1…第1検出波、D2…第2検出波
30…送受信回路
40…制御部 DESCRIPTION OFSYMBOLS 100 ... Liquid level position detection apparatus 10, 210 ... Propagation body 10a ... 1st part, 10b ... 2nd part 11 ... Main surface part (an example of 1st main surface part)
12 ... Main surface portion (an example of a second main surface portion)
DESCRIPTION OF SYMBOLS 13, 14 ... Side surface part 15 ... Contact part 16 ... Bottom part 20, 220 ... Vibrator 21 ... 1st transmission / reception part, 22 ... 2nd transmission / reception part W1 ... 1st surface wave, W2 ... 2nd surface wave 23 ... 3rd transmission / reception part, 24 ... 4th transmission / reception part D1 ... 1st detection wave, D2 ... 2nd detection wave 30 ... Transmission / reception circuit 40 ... Control part
10、210…伝搬体
10a…第1部分、10b…第2部分
11…主面部(第1主面部の一例)
12…主面部(第2主面部の一例)
13、14…側面部
15…当接部
16…底面部
20、220…振動子
21…第1送受波部、22…第2送受波部
W1…第1表面波、W2…第2表面波
23…第3送受波部、24…第4送受波部
D1…第1検出波、D2…第2検出波
30…送受信回路
40…制御部 DESCRIPTION OF
12 ... Main surface portion (an example of a second main surface portion)
DESCRIPTION OF
Claims (6)
- 液体の液面位置に応じて、前記液体に浸る部分の割合が変化する伝搬体と、
前記伝搬体に第1表面波を発生させるとともに第2表面波を受ける第1送受波部と、
前記伝搬体に前記第2表面波を発生させるとともに前記第1表面波を受ける第2送受波部と、
前記第2送受波部が受けた前記第1表面波の伝搬時間と、前記第1送受波部が受けた前記第2表面波の伝搬時間との少なくともいずれかに基づいて前記液面位置を検出する検出部と、を備え、
前記伝搬体は、
互いに裏表の関係にある第1主面部及び第2主面部と、
前記第1主面部と前記第2主面部とを繋ぐとともに、側面視において曲面状をなす底面部と、を有し、
前記第1送受波部は、前記第1主面部を伝搬する前記第1表面波を発生させ、
前記第2送受波部は、前記第1主面部を経て前記底面部と前記第2主面部とを伝搬した前記第1表面波を受け、
前記第2送受波部は、前記第2主面部を伝搬する前記第2表面波を発生させ、
前記第1送受波部は、前記第2主面部を経て前記底面部と前記第1主面部とを伝搬した前記第2表面波を受ける、
液面位置検出装置。 A propagating body in which a ratio of a portion immersed in the liquid changes according to a liquid surface position;
A first transmission / reception unit for generating a first surface wave in the propagation body and receiving a second surface wave;
A second transmission / reception unit for generating the second surface wave in the propagating body and receiving the first surface wave;
The liquid level position is detected based on at least one of the propagation time of the first surface wave received by the second wave transmitting / receiving unit and the propagation time of the second surface wave received by the first wave transmitting / receiving unit. And a detecting unit
The propagator is
A first main surface portion and a second main surface portion, which are in reverse relation to each other;
And connecting the first main surface portion and the second main surface portion, and a bottom surface portion having a curved shape in a side view,
The first transmitting / receiving unit generates the first surface wave propagating through the first main surface unit,
The second transmission / reception unit receives the first surface wave that has propagated through the first main surface portion and the bottom surface portion and the second main surface portion,
The second wave transmitting / receiving unit generates the second surface wave propagating through the second main surface part,
The first transmission / reception unit receives the second surface wave that has propagated through the second main surface portion and the bottom surface portion and the first main surface portion,
Liquid level position detection device. - 前記伝搬体は、前記第1送受波部及び前記第2送受波部と当接する当接部を有し、
前記第1主面部は、前記側面視において前記当接部の一端から垂下し、
前記第2主面部は、前記側面視において前記当接部の他端から垂下し、
前記第1送受波部は、前記当接部を介して前記第1主面部を伝搬する前記第1表面波を発生させ、
前記第2送受波部は、前記当接部を介して前記第2主面部を伝搬する前記第2表面波を発生させる、
請求項1に記載の液面位置検出装置。 The propagation body has a contact portion that contacts the first transmission / reception unit and the second transmission / reception unit,
The first main surface portion hangs down from one end of the contact portion in the side view,
The second main surface portion hangs down from the other end of the contact portion in the side view,
The first wave transmitting / receiving unit generates the first surface wave propagating through the first main surface part via the contact part,
The second wave transmitting / receiving unit generates the second surface wave propagating through the second main surface part via the contact part.
The liquid level position detection apparatus according to claim 1. - 前記第1送受波部及び前記第2送受波部は、前記第1表面波と、前記第2表面波を同時に発生させる、
請求項1又は2に記載の液面位置検出装置。 The first transmission / reception unit and the second transmission / reception unit generate the first surface wave and the second surface wave simultaneously,
The liquid level position detection apparatus according to claim 1 or 2. - 前記伝搬体は、前記当接部から前記底面部に向かって凹むとともに、前記側面視において前記第1主面部と前記第2主面部との間に位置する凹部を有する、
請求項2に記載の液面位置検出装置。 The propagating body is recessed from the contact portion toward the bottom surface portion, and has a recess positioned between the first main surface portion and the second main surface portion in the side view.
The liquid level position detection apparatus according to claim 2. - 前記伝搬体に表面波又は板波である検出波を発生させる特定送受波部をさらに備え、
前記特定送受波部は、前記当接部を介して前記凹部の内側面部を伝搬する前記検出波を発生させるとともに、前記内側面部を経て前記凹部の内底面部で反射した前記検出波を受け、
前記検出部は、前記特定送受波部が受けた前記検出波の伝搬時間に基づいて、前記伝搬体の温度を検出する、
請求項4に記載の液面位置検出装置。 A specific transmitting / receiving unit that generates a detection wave that is a surface wave or a plate wave in the propagating body;
The specific transmission / reception unit generates the detection wave propagating through the abutment portion through the inner side surface portion of the recess, receives the detection wave reflected by the inner bottom surface portion of the recess through the inner side surface portion,
The detection unit detects the temperature of the propagation body based on the propagation time of the detection wave received by the specific transmission / reception unit,
The liquid level position detection apparatus according to claim 4. - 前記第1送受波部と前記第2送受波部と前記特定送受波部は、前記第1表面波と、前記第2表面波と、前記検出波を同時に発生させる、
請求項5に記載の液面検出装置。 The first transmission / reception unit, the second transmission / reception unit, and the specific transmission / reception unit simultaneously generate the first surface wave, the second surface wave, and the detection wave.
The liquid level detection device according to claim 5.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020503385A JP7076072B2 (en) | 2018-02-28 | 2019-02-15 | Liquid level position detector |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2018-034911 | 2018-02-28 | ||
JP2018034911 | 2018-02-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2019167660A1 true WO2019167660A1 (en) | 2019-09-06 |
Family
ID=67808894
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2019/005488 WO2019167660A1 (en) | 2018-02-28 | 2019-02-15 | Liquid level position detection device |
Country Status (2)
Country | Link |
---|---|
JP (1) | JP7076072B2 (en) |
WO (1) | WO2019167660A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4213337A (en) * | 1977-09-13 | 1980-07-22 | The Marconi Company Limited | Liquid level sensing devices |
US4920796A (en) * | 1987-11-13 | 1990-05-01 | Robert Bosch Gmbh | Tank level meter |
WO1990010849A1 (en) * | 1989-03-09 | 1990-09-20 | Robert Bosch Gmbh | Acoustic fluid level detector |
JP2004028592A (en) * | 2002-06-21 | 2004-01-29 | Nippon Soken Inc | Liquid measuring instrument |
JP2004117301A (en) * | 2002-09-27 | 2004-04-15 | Denso Corp | Oscillation type liquid level detector and liquid level detecting apparatus using the same |
-
2019
- 2019-02-15 JP JP2020503385A patent/JP7076072B2/en active Active
- 2019-02-15 WO PCT/JP2019/005488 patent/WO2019167660A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4213337A (en) * | 1977-09-13 | 1980-07-22 | The Marconi Company Limited | Liquid level sensing devices |
US4920796A (en) * | 1987-11-13 | 1990-05-01 | Robert Bosch Gmbh | Tank level meter |
WO1990010849A1 (en) * | 1989-03-09 | 1990-09-20 | Robert Bosch Gmbh | Acoustic fluid level detector |
JP2004028592A (en) * | 2002-06-21 | 2004-01-29 | Nippon Soken Inc | Liquid measuring instrument |
JP2004117301A (en) * | 2002-09-27 | 2004-04-15 | Denso Corp | Oscillation type liquid level detector and liquid level detecting apparatus using the same |
Also Published As
Publication number | Publication date |
---|---|
JP7076072B2 (en) | 2022-05-27 |
JPWO2019167660A1 (en) | 2021-02-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7966136B2 (en) | Immersed fuel level sensor | |
JPH11118774A (en) | Oil deterioration sensor | |
JP6131088B2 (en) | Liquid level position detection device and liquid level position detection method | |
JP6384382B2 (en) | Liquid level detection device | |
JP2015010878A (en) | Liquid level position detector and method for detecting liquid level position | |
WO2019167660A1 (en) | Liquid level position detection device | |
WO2013013395A1 (en) | Device and method for measuring liquid level | |
JP2020034467A (en) | Liquid surface position detector | |
JP2020139851A (en) | Liquid level position detector | |
WO2013114752A1 (en) | Apparatus and method for measuring liquid surface level | |
JP2022068840A (en) | Surface wave detection device, liquid level detection device, liquid kind determination device, solution concentration detection device, and liquid droplet detection device | |
JP2020139852A (en) | Liquid level position detector | |
JPH09229748A (en) | Ultrasonic liquid-surface level sensor | |
JP2021047081A (en) | Liquid level position detector | |
JP7333516B2 (en) | Liquid level detector | |
JP6270055B2 (en) | Liquid level detector | |
JP2016138850A (en) | Liquid level detector | |
RU2437066C1 (en) | Method for ultrasonic measurement of level of liquid in reservoirs and apparatus for ultrasonic measurement of level of liquid in reservoirs | |
JP2023116007A (en) | Surface wave detection device | |
JP7218682B2 (en) | Ultrasonic distance measuring device | |
JP7218683B2 (en) | Ultrasonic distance measuring device | |
JP2017207374A (en) | Liquid level detector | |
JP2022090517A (en) | Surface wave detection device, liquid level detection device and liquid type identifying device | |
JP2023037923A (en) | Bubble detection device | |
JP2017067474A (en) | Liquid level detector |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 19761408 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2020503385 Country of ref document: JP Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 19761408 Country of ref document: EP Kind code of ref document: A1 |