CN112924353B - Filter fault detection circuit, fault detection device and filter - Google Patents

Filter fault detection circuit, fault detection device and filter Download PDF

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Publication number
CN112924353B
CN112924353B CN202110077336.8A CN202110077336A CN112924353B CN 112924353 B CN112924353 B CN 112924353B CN 202110077336 A CN202110077336 A CN 202110077336A CN 112924353 B CN112924353 B CN 112924353B
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pressure sensor
resistor
filter
alarm
comparison circuit
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CN112924353A (en
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陈漫
马彪
刘宇键
何春平
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Beijing Institute of Technology BIT
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Beijing Institute of Technology BIT
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
    • B01D35/14—Safety devices specially adapted for filtration; Devices for indicating clogging
    • B01D35/143—Filter condition indicators
    • B01D35/1435—Filter condition indicators with alarm means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
    • G01N2015/084—Testing filters

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

The embodiment of the application provides a filter fault detection circuit, fault detection device and filter, and this filter fault detection circuit includes: the device comprises a first pressure sensor, a first pressure sensor comparison circuit and a first alarm; the output end of the first pressure sensor is connected with the input end of the comparison circuit of the first pressure sensor; the output end of the comparison circuit of the first pressure sensor is connected with the input end of the first alarm; the first pressure sensor is used for collecting the hydraulic pressure before filtration of the filter; the first pressure sensor comparison circuit is used for comparing a first difference value between the pre-filtering hydraulic pressure and a first preset threshold value; the first alarm is used for giving an alarm according to the first difference. The filter fault detection circuit, the fault detection device and the filter provided by the embodiment of the application judge whether the pressure sensor is damaged or not through the first pressure sensor comparison circuit, and can judge whether the alarm caused by the damage of the pressure sensor or the alarm caused by the problem of the filter per se.

Description

Filter fault detection circuit, fault detection device and filter
Technical Field
The invention relates to the field of electric appliance control, in particular to a filter fault detection circuit, a fault detection device and a filter.
Background
The basic principle of the filter is that the pressure of the system is used as a driving force, and a filter bag or a filter element is used as a filter medium to physically intercept impurities in the filtrate. However, the ability of the filter bag or the filter element to intercept impurities is limited, and the pressure difference between the inlet and the outlet of the filter is usually used in the filtration industry to judge whether the filter bag or the filter element needs to be replaced. Therefore, the filter fault detection device capable of giving an alarm is arranged in industrial production, and the filter fault detection device is very beneficial to production.
The existing filter failure detection apparatus includes: first pressure sensor, second pressure sensor, differential pressure switch, time relay and alarm, differential pressure switch communication connection in first pressure sensor and second pressure sensor, time relay electric connection in differential pressure switch, time relay communication connection in alarm. The filter fault detection device controls an alarm to give an alarm by setting a pressure difference threshold value and a time threshold value for a pressure difference switch and a time relay.
However, the filter fault detection device in the prior art cannot judge whether the sensor is damaged or the problem of the filter per se causes pressure difference alarm.
Disclosure of Invention
The embodiment of the application provides a filter fault detection circuit, fault detection device and filter for solve filter fault detection device among the prior art, can't judge that the problem of sensor damage or filter itself arouses the technical problem that the pressure differential reported to the police.
The embodiment of the application provides a filter fault detection circuit, includes:
the device comprises a first pressure sensor, a first pressure sensor comparison circuit and a first alarm;
the output end of the first pressure sensor is connected with the input end of the first pressure sensor comparison circuit;
the output end of the first pressure sensor comparison circuit is connected with the input end of the first alarm;
the first pressure sensor is used for collecting the hydraulic pressure before filtration of the filter;
the first pressure sensor comparison circuit is used for comparing a first difference value between the pre-filtering hydraulic pressure and a first preset threshold value;
the first alarm is used for giving an alarm according to the first difference.
According to the embodiment of the application, a filter fault detection circuit further comprises:
the second pressure sensor, the second pressure sensor comparison circuit and the second alarm are arranged on the first pressure sensor;
the output end of the second pressure sensor is connected with the input end of the comparison circuit of the second pressure sensor;
the output end of the comparison circuit of the second pressure sensor is connected with the input end of the second alarm;
the second pressure sensor is used for collecting the filtered hydraulic pressure of the filter;
the second pressure sensor comparison circuit is used for comparing a second difference value between the filtered hydraulic pressure and a second preset threshold value;
and the second alarm is used for giving an alarm according to the second difference value.
According to the embodiment of the application, a filter fault detection circuit further comprises:
the differential pressure comparison circuit is connected with the first alarm;
the output end of the first pressure sensor and the output end of the second pressure sensor are connected with the input end of the subtraction circuit;
the output end of the subtraction circuit is connected with the input end of the differential pressure comparison circuit;
the output end of the differential pressure comparison circuit is connected with the input end of the third alarm;
the subtraction circuit is used for comparing a third difference value between the pre-filtering hydraulic pressure and the post-filtering hydraulic pressure;
the differential pressure comparison circuit is used for comparing a fourth difference value between the third difference value and a third preset threshold value;
and the third alarm is used for giving an alarm according to the fourth difference value.
According to the embodiment of the application, a filter fault detection circuit further comprises:
a temperature control switch;
the first end of the temperature control switch is connected with a power supply;
the second end of the temperature control switch is connected with the power supply ends of the differential pressure comparison circuit, the first pressure sensor comparison circuit and the second pressure sensor comparison circuit;
the temperature control switch is used for controlling the power supply states of the differential pressure comparison circuit, the first pressure sensor comparison circuit and the second pressure sensor comparison circuit according to the temperature of liquid in the filter.
According to the filter fault detection circuit provided by the embodiment of the application, the first pressure sensor comparison circuit comprises a first voltage comparator, a second voltage comparator, a first fixed-value resistor, a second fixed-value resistor, a third fixed-value resistor, a fourth fixed-value resistor, a fifth fixed-value resistor and a capacitor;
the first end of the first constant value resistor is connected with the power supply, and the second end of the first constant value resistor is connected with the in-phase end of the first voltage comparator;
the output end of the first pressure sensor is connected with the inverting end of the first voltage comparator;
the output end of the first pressure sensor is connected with the in-phase end of the second voltage comparator;
the first end of the second constant value resistor is connected with the inverting end of the second voltage comparator, the second end of the second constant value resistor is connected with the first end of the capacitor, and the second end of the capacitor is grounded;
the first end of the third fixed-value resistor is connected with a power supply, the second end of the third fixed-value resistor is connected with the first end of the fourth fixed-value resistor, and the second end of the fourth fixed-value resistor is grounded;
the middle node of the third constant value resistor and the fourth constant value resistor is connected with the middle node of the second constant value resistor and the middle node of the capacitor;
the power supply ends of the first voltage comparator and the second voltage comparator are connected with the second end of the temperature control switch, and a fifth constant value resistor is connected in series between the power supply end of the second voltage comparator and the output end of the second voltage comparator;
the output end of the first voltage comparator is connected with the output end of the second voltage comparator in series, and an intermediate node between the output end of the first voltage comparator and the output end of the second voltage comparator is used as the output end of the first pressure sensor comparison circuit.
According to the filter fault detection circuit provided by the embodiment of the application, the subtraction circuit comprises an amplifier, a first fixed-value resistor, a second fixed-value resistor, a third fixed-value resistor and a fourth fixed-value resistor;
the first end of the first constant resistor is connected with the output end of the first pressure sensor, the second end of the first constant resistor is connected with the first end of the second constant resistor, the second end of the second constant resistor is grounded, and the middle node of the first constant resistor and the second constant resistor is connected with the in-phase end of the amplifier;
the first end of the third fixed-value resistor is connected with the output end of the second pressure sensor, and the second end of the third fixed-value resistor is connected with the inverting end of the amplifier;
an intermediate node between the third constant value resistor and the inverting terminal of the amplifier is connected in series with the output terminal of the amplifier through a fourth constant value resistor;
the power supply end of the amplifier is connected with a power supply;
the output end of the amplifier is used as the output end of the subtraction circuit.
According to the filter fault detection circuit provided by the embodiment of the application, the differential pressure comparison circuit comprises a voltage comparator, an adjustable resistor, a first fixed resistor, a second fixed resistor, a third fixed resistor and a capacitor;
the output end of the subtraction circuit is connected with the in-phase end of the voltage comparator;
the first end of the first constant resistor is connected with the inverting end of the voltage comparator, the second end of the first constant resistor is connected with the first end of the capacitor, and the second end of the capacitor is grounded;
the first end of the adjustable resistor is connected with a power supply, the second end of the adjustable resistor is empty, the third end of the adjustable resistor is connected with the first end of the second constant value resistor, and the second end of the second constant value resistor is grounded;
the middle node of the adjustable resistor and the second constant value resistor is connected with the middle node of the first constant value resistor and the middle node of the capacitor;
the power supply end of the voltage comparator is connected with the second end of the temperature control switch, and a third constant value resistor is connected in series between the power supply end of the voltage comparator and the output end of the voltage comparator;
the output end of the voltage comparator is used as the output end of the differential pressure comparison circuit.
According to the filter fault detection circuit provided by the embodiment of the application, the first alarm, the second alarm and the third alarm are all audible and visual alarms.
The embodiment of the present application further provides a filter fault detection device, the filter fault detection device includes: a device body and a filter failure detection circuit as described in any of the above.
The embodiment of this application still provides a filter, its characterized in that, the filter includes:
in the filter fault detection device, the first pressure sensor is arranged at the liquid inlet of the filter, and the second pressure sensor is arranged at the liquid outlet of the filter;
the liquid inlet is arranged at the top of the shell, and the liquid outlet is arranged at the bottom of the shell;
the filter body, it sets up to filter the body inside the casing, liquid passes through the inlet gets into the casing, the warp filter the body and filter and pass through the liquid outlet is discharged the casing.
The embodiment of the application provides a filter fault detection circuit, fault detection device and filter, through first pressure sensor comparison circuit and second pressure sensor comparison circuit, the hydraulic pressure before the comparison is strained and first predetermined threshold value, and the hydraulic pressure after the comparison is strained and first predetermined threshold value, judge whether first pressure sensor and second pressure sensor damage, can judge that the problem of sensor damage or filter itself arouses the pressure differential warning.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a diagram of one of the filter failure detection circuits provided in an embodiment of the present application;
FIG. 2 is a second embodiment of a filter failure detection circuit;
FIG. 3 is a third circuit for detecting filter failure according to an embodiment of the present invention;
FIG. 4 is a fourth circuit for detecting filter failure according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of a power conversion circuit according to an embodiment of the present disclosure;
fig. 6 is a schematic diagram of a comparison circuit of a first pressure sensor according to an embodiment of the present disclosure;
fig. 7 is a schematic structural diagram of a first alarm provided in an embodiment of the present application;
fig. 8 is a second schematic diagram of a comparison circuit of the first pressure sensor according to the embodiment of the present application;
fig. 9 is a second schematic structural diagram of the first alarm provided in the embodiment of the present application;
fig. 10 is a schematic structural diagram of a second alarm provided in the embodiment of the present application;
fig. 11 is a schematic diagram of a subtraction circuit according to an embodiment of the present application;
FIG. 12 is a schematic diagram of a differential pressure comparison circuit according to an embodiment of the present disclosure;
fig. 13 is a schematic structural diagram of a third alarm provided in the embodiment of the present application;
FIG. 14 is a schematic structural diagram of a filter failure detection apparatus according to an embodiment of the present disclosure;
fig. 15 is a schematic structural diagram of a filter according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection scope of the embodiments in the present application.
In order to solve the problem of the prior art, the embodiment of the application provides a filter fault detection circuit, a fault detection device and a filter. First, a filter failure detection circuit provided in an embodiment of the present application will be described below.
Fig. 1 is a diagram of a filter failure detection circuit according to an embodiment of the present disclosure, and as shown in fig. 1, the filter failure detection circuit according to the embodiment of the present disclosure includes:
the device comprises a first pressure sensor, a first pressure sensor comparison circuit and a first alarm;
the output end of the first pressure sensor is connected with the input end of the first pressure sensor comparison circuit;
the output end of the first pressure sensor comparison circuit is connected with the input end of the first alarm;
the first pressure sensor is used for collecting the hydraulic pressure before filtration of the filter;
the first pressure sensor comparison circuit is used for comparing a first difference value between the pre-filtering hydraulic pressure and a first preset threshold value;
the first alarm is used for giving an alarm according to the first difference.
As shown in fig. 1, the filter failure detection circuit includes: a first pressure sensor 101, a first pressure sensor comparison circuit 102 and a first alarm 103.
Wherein, the output end of the first pressure sensor 101 is connected with the input end of the first pressure sensor comparison circuit 102; the output end of the first pressure sensor comparison circuit 102 is connected with the input end of the first alarm 103. The first pressure sensor 101 is used for collecting the pre-filtering hydraulic pressure of the filter, and converting the pre-filtering hydraulic pressure into an electric signal to be output.
For example, the first pressure sensor 101 is a gauge pressure sensor, a differential pressure sensor, or an absolute pressure sensor.
The first pressure sensor comparison circuit 102 is configured to compare the electrical signal of the pre-filter hydraulic pressure conversion with a first preset threshold, output a first difference between the electrical signal of the pre-filter hydraulic pressure conversion and the first preset threshold, and provide an input signal for the first alarm.
For example, when the difference between the electric signal of the pre-filtering hydraulic pressure conversion and the first preset threshold value is large, the first difference value is a high voltage; and when the difference between the electric signal of the hydraulic conversion before filtering and the first preset threshold value is not large, the first difference value is low voltage.
For another example, when the difference between the electric signal of the pre-filtering hydraulic pressure conversion and the first preset threshold is large, the first difference is a low voltage; and when the difference between the electric signal of the hydraulic conversion before filtering and the first preset threshold value is not large, the first difference value is high voltage.
The first alarm 103 is used for alarming according to the first difference.
For example, when the difference between the electric signal converted by the pre-filtering hydraulic pressure and the first preset threshold is large, and the first difference is a high voltage, the first alarm 103 triggers an alarm; when the difference between the electric signal converted by the pre-filtering hydraulic pressure and the first preset threshold value is not large, and the second difference value is low voltage, the first alarm 103 does not trigger an alarm.
For another example, when the difference between the electric signal converted by the pre-filtering hydraulic pressure and the first preset threshold is large, and the first difference is a low voltage, the first alarm 103 triggers an alarm; when the difference between the electric signal converted by the pre-filtering hydraulic pressure and the first preset threshold value is not large, and the second difference value is high voltage, the first alarm 103 does not trigger an alarm.
The filter fault detection circuit provided by the embodiment of the application compares the electric signal converted by the hydraulic pressure before filtering with the first preset threshold value through the first pressure sensor comparison circuit, outputs the first difference value between the electric signal converted by the hydraulic pressure before filtering and the first preset threshold value, triggers the first alarm to alarm according to the first difference value, and can clearly alarm the alarm caused by the damage of the first pressure sensor.
Optionally, the filter failure detection circuit further includes:
the second pressure sensor, the second pressure sensor comparison circuit and the second alarm are arranged on the first pressure sensor;
the output end of the second pressure sensor is connected with the input end of the comparison circuit of the second pressure sensor;
the output end of the comparison circuit of the second pressure sensor is connected with the input end of the second alarm;
the second pressure sensor is used for collecting the filtered hydraulic pressure of the filter;
the second pressure sensor comparison circuit is used for comparing a second difference value between the filtered hydraulic pressure and a second preset threshold value;
and the second alarm is used for giving an alarm according to the second difference value.
For example, fig. 2 is a second filter failure detection circuit provided in the embodiment of the present application, and as shown in fig. 2, the filter failure detection circuit further includes: a second pressure sensor 201, a second pressure sensor comparison circuit 202 and a second alarm 203.
Wherein, the output end of the second pressure sensor 201 is connected with the input end of the second pressure sensor comparison circuit 202; the output end of the second pressure sensor comparison circuit 202 is connected with the input end of a second alarm 203; the second pressure sensor 201 is a gauge pressure sensor, a differential pressure sensor or an absolute pressure sensor, and the second pressure sensor 201 is used for collecting the filtered hydraulic pressure of the filter and converting the filtered hydraulic pressure into an electric signal to be output.
The second pressure sensor comparison circuit 202 is configured to compare the filtered hydraulically-converted electrical signal with a second preset threshold, output a second difference between the filtered hydraulically-converted electrical signal and the second preset threshold, and provide an input signal for the second alarm.
For example, when the difference between the filtered hydraulically-converted electrical signal and the second preset threshold is large, the second difference is a high voltage; and when the difference between the filtered hydraulic converted electric signal and the second preset threshold value is not large, the second difference value is low voltage.
For another example, when the difference between the filtered hydraulically-converted electrical signal and the second preset threshold is large, the second difference is a low voltage; and when the difference between the filtered hydraulic converted electric signal and the second preset threshold value is not large, the second difference value is high voltage.
And the second alarm 203 is used for giving an alarm according to the second difference.
For example, when the difference between the filtered hydraulically-converted electrical signal and a second preset threshold is large, and the second difference is high voltage, an alarm is triggered; when the difference between the filtered hydraulic converted electric signal and the second preset threshold value is not large, and the second difference value is low voltage, the alarm is not triggered.
For another example, when the difference between the filtered hydraulically-converted electric signal and a second preset threshold value is large, and the second difference value is low voltage, an alarm is triggered; when the difference between the filtered hydraulic converted electric signal and the second preset threshold value is not large, and the second difference value is high voltage, the alarm is not triggered.
The filter fault detection circuit provided by the embodiment of the application compares the filtered hydraulic pressure converted electric signal with a second preset threshold value through the second pressure sensor comparison circuit, outputs a second difference value between the filtered hydraulic pressure converted electric signal and the first preset threshold value, and triggers the second alarm to give an alarm according to the second difference value, so that the alarm can be clearly given out when the second pressure sensor is damaged.
Optionally, the filter failure detection circuit further includes:
the differential pressure comparison circuit is connected with the first alarm;
the output end of the first pressure sensor and the output end of the second pressure sensor are connected with the input end of the subtraction circuit;
the output end of the subtraction circuit is connected with the input end of the differential pressure comparison circuit;
the output end of the differential pressure comparison circuit is connected with the input end of the third alarm;
the subtraction circuit is used for comparing a third difference value between the pre-filtering hydraulic pressure and the post-filtering hydraulic pressure;
the differential pressure comparison circuit is used for comparing a fourth difference value between the third difference value and a third preset threshold value;
and the third alarm is used for giving an alarm according to the fourth difference value.
For example, fig. 3 is a third filter failure detection circuit provided in the embodiment of the present application, and as shown in fig. 3, the filter failure detection circuit further includes: a subtraction circuit 301, a differential pressure comparison circuit 302 and a third alarm 303.
Wherein, the output end of the first pressure sensor 101 and the output end of the second pressure sensor 201 are connected with the input end of the subtraction circuit 301;
the output end of the subtraction circuit 301 is connected with the input end of the differential pressure comparison circuit 302;
the output end of the differential pressure comparison circuit 302 is connected with the input end of a third alarm 303.
The subtraction circuit 301 is configured to compare the pre-filter hydraulically-converted electrical signal with the post-filter hydraulically-converted electrical signal, and output a third difference between the pre-filter hydraulically-converted electrical signal and the post-filter hydraulically-converted electrical signal.
The differential pressure comparison circuit 302 is configured to compare the third difference with a third preset threshold, and output a fourth difference between the third difference and the third preset threshold.
A third alarm 303 that gives an alarm when the fourth difference is a high voltage; and when the fourth difference is low voltage, no alarm is given.
The filter fault detection circuit that this application embodiment provided, through subtraction circuit, the signal of telecommunication of hydraulic pressure conversion before the comparison is strained and the signal of telecommunication of hydraulic pressure conversion after straining, the third difference between the signal of telecommunication of hydraulic pressure conversion before the output is strained and the signal of telecommunication of hydraulic pressure conversion after straining, through differential pressure comparison circuit, compare third difference and third preset threshold value, the fourth difference between third difference and the third preset threshold value is exported, trigger the third alarm according to the fourth difference and report to the police, can confirm that the alarm is the warning that the problem of filter itself arouses.
Optionally, the filter failure detection circuit further includes:
a temperature control switch;
the first end of the temperature control switch is connected with a power supply;
the second end of the temperature control switch is connected with the power supply ends of the differential pressure comparison circuit, the first pressure sensor comparison circuit and the second pressure sensor comparison circuit;
the temperature control switch is used for controlling the power supply states of the differential pressure comparison circuit, the first pressure sensor comparison circuit and the second pressure sensor comparison circuit according to the temperature of liquid in the filter.
For example, fig. 4 is a fourth filter failure detection circuit provided in the embodiment of the present application, and as shown in fig. 4, the filter failure detection circuit further includes a temperature control switch 401.
Wherein, the first end of the temperature control switch 401 is connected with the power supply;
the second end of the temperature control switch 401 is connected to the power supply ends of the differential pressure comparison circuit 302, the first pressure sensor comparison circuit 102 and the second pressure sensor comparison circuit 202.
The temperature control switch 401 is used to set a temperature threshold, and control the power supply states of the differential pressure comparison circuit 302, the first pressure sensor comparison circuit 102, and the second pressure sensor comparison circuit 202 according to whether the temperature of the liquid in the filter reaches the temperature threshold.
For example, the power source is a first power source or a second power source, and the first power source is converted into the second power source through the power conversion circuit.
For example, fig. 5 is a schematic structural diagram of a power conversion circuit provided in the embodiment of the present application, and as shown in fig. 5, the power conversion circuit includes a capacitor C1, a capacitor C2, an inductor L2, a power conversion chip LM2575T-5.0, and a diode D1.
The first power supply VAA is connected to a pin 1 of the power conversion chip, the first end of the capacitor C1 is connected with the first power supply VAA, and the second end of the capacitor C1 is grounded;
a pin 3 and a pin 5 of the power conversion chip are connected in series, and the middle node of the pin 3 and the pin 5 is grounded;
pin 2 of the power conversion chip is connected with the first end of the inductor L2, the middle node of the pin 2 of the power conversion chip and the inductor L2 is connected with the cathode of the diode D1, and the anode of the diode D1 is grounded;
a second end of the inductor L2 is connected with a first end of the capacitor C2, a second end of the capacitor C2 is grounded, a middle node between the inductor L2 and the capacitor C2 serves as an output end of the power conversion circuit, and the output end outputs a second power VCC;
the output end of the power conversion circuit is connected with a pin 5 of the power conversion chip to provide feedback voltage for the power conversion chip.
The power conversion circuit shown in fig. 5 converts a first power source to a second power source to provide the required power for the filter failure detection circuit.
For example, the temperature control switch 401 is connected to the first power supply VAA.
The filter fault detection circuit that this application embodiment provided, through temperature detect switch, when liquid temperature reachd the temperature threshold in the filter, for differential pressure comparison circuit, first pressure sensor comparison circuit and second pressure sensor comparison circuit provide first power, because the temperature of liquid is different, the hydraulic pressure of production is different, through temperature detect switch control filter fault detection circuit's power supply state, improves filter fault detection circuit's detection precision, has avoided the wrong report of device to warn.
Optionally, the first pressure sensor comparison circuit includes a first voltage comparator, a second voltage comparator, a first fixed-value resistor, a second fixed-value resistor, a third fixed-value resistor, a fourth fixed-value resistor, a fifth fixed-value resistor, and a capacitor.
The first end of the first constant value resistor is connected with the power supply, and the second end of the first constant value resistor is connected with the in-phase end of the first voltage comparator;
the output end of the first pressure sensor is connected with the inverting end of the first voltage comparator;
the output end of the first pressure sensor is connected with the in-phase end of the second voltage comparator;
the first end of the second constant value resistor is connected with the inverting end of the second voltage comparator, the second end of the second constant value resistor is connected with the first end of the capacitor, and the second end of the capacitor is grounded;
the first end of the third fixed-value resistor is connected with a power supply, the second end of the third fixed-value resistor is connected with the first end of the fourth fixed-value resistor, and the second end of the fourth fixed-value resistor is grounded;
the middle node of the third constant value resistor and the fourth constant value resistor is connected with the middle node of the second constant value resistor and the middle node of the capacitor;
the power supply ends of the first voltage comparator and the second voltage comparator are connected with the second end of the temperature control switch, and a fifth constant value resistor is connected in series between the power supply end of the second voltage comparator and the output end of the second voltage comparator;
the output end of the first voltage comparator is connected with the output end of the second voltage comparator in series, and an intermediate node between the output end of the first voltage comparator and the output end of the second voltage comparator is used as the output end of the first pressure sensor comparison circuit.
For example, fig. 6 is a schematic structural diagram of a first pressure sensor comparison circuit provided in the embodiment of the present application, and as shown in fig. 6, the first pressure sensor comparison circuit includes a first voltage comparator U4B, a second voltage comparator U4A, a first fixed-value resistor R14, a second fixed-value resistor R9, a third fixed-value resistor R12, a fourth fixed-value resistor R11, a fifth fixed-value resistor R5, a capacitor C4, and a temperature-controlled switch S1.
For example, the first voltage comparator U4B and the second voltage comparator U4A are model LM139 AD.
A first end of the first constant resistor R14 is connected to a second power VCC, the second power VCC serves as an upper limit of a first preset threshold, and a second end of the first constant resistor R14 is connected to a non-inverting end of the first voltage comparator U4B;
the output end of the first pressure sensor is connected with the inverting end of a first voltage comparator U4B;
the output end of the first pressure sensor is connected with the non-inverting end of a second voltage comparator U4A;
a first end of the second constant value resistor R9 is connected with the inverting end of the second voltage comparator U4A, a second end of the second constant value resistor R9 is connected with a first end of the capacitor C4, and a second end of the capacitor C4 is grounded;
a first end of the third fixed-value resistor R12 is connected with a second power supply VCC, a second end of the third fixed-value resistor R12 is connected with a first end of the fourth fixed-value resistor R11, a second end of the fourth fixed-value resistor R11 is grounded, and the voltage VL of the first end of the fourth fixed-value resistor R11 is taken as the lower limit of the first preset threshold value through voltage division of the fourth fixed-value resistor R11 and the third fixed-value resistor R12;
the middle node of the third constant resistor R12 and the fourth constant resistor R11 is connected with the middle node of the second constant resistor R9 and the capacitor C4;
the power supply ends of the first voltage comparator U4B and the second voltage comparator U4A are connected with the second end of the temperature control switch S1, the first end of the temperature control switch S1 is connected with the first power supply VAA, and a fifth constant value resistor R5 is connected between the power supply end of the second voltage comparator U4A and the output end of the second voltage comparator U4A in series;
the output terminal of the first voltage comparator U4B is connected in series with the output terminal of the second voltage comparator U4A, and the middle node between the output terminal of the first voltage comparator U4B and the output terminal of the second voltage comparator U4A serves as the output terminal of the first pressure sensor comparison circuit.
The operating principle of the first pressure sensor comparison circuit shown in fig. 6 is as follows:
when the temperature is higher than 60 ℃ (the temperature controlled switch is set), the temperature controlled switch S1 is closed, and the first voltage comparator U4B and the second voltage comparator U4A start to be powered and are connected to the first power supply.
The voltage sensorA output by the output end of the first pressure sensor is compared with the lower limit VL of the first preset threshold and the upper limit VCC of the first preset threshold, a first difference O2 is output, when VL is not less than the lower limit VL of the first preset threshold, the sensor works normally, the first difference O2 is high voltage, when SensorA is not between VL and VCC, the sensor is damaged, and the first difference O2 is low voltage.
Specifically, the first pressure sensor comparison circuit shown in fig. 6 compares the electric signal converted by the pre-filtering hydraulic pressure with the lower limit of the first preset threshold and the upper limit of the first preset threshold through the first voltage comparator and the second voltage comparator, determines whether the first pressure sensor is damaged, and provides an input signal for the first alarm.
The first pressure sensor comparison circuit provided in the embodiment of the present application adopts the circuit structure shown in fig. 6, but the embodiment of the present application is not limited thereto, and includes other comparison circuit structures capable of determining whether the first pressure sensor is damaged.
For another example, fig. 7 is a second schematic structural diagram of the comparison circuit of the first pressure sensor according to the embodiment of the present application, and as shown in fig. 7, the comparison circuit of the first pressure sensor includes an amplifier U5, a first constant resistor R3, a second constant resistor R4, a third constant resistor R1, and a fourth constant resistor R4. The resistor R1-R2-R3-R4, and the amplifier U5 is LM 2902D. A first end of the first fixed-value resistor R3 is connected with an output end of the first pressure sensor A1, a second end of the first fixed-value resistor R3 is connected with a first end of the second fixed-value resistor R4, a second end of the second fixed-value resistor R4 is grounded, and a middle node of the first fixed-value resistor R3 and the second fixed-value resistor R4 is connected with a non-inverting end of the amplifier U5; a first end of the third constant value resistor R1 is connected with the output end of the first pressure sensor A2, and a second end of the third constant value resistor R1 is connected with the inverting end of the amplifier U5; an intermediate node between the third constant value resistor R1 and the inverting terminal of the amplifier U5 is connected in series with the output terminal of the amplifier U5 through a fourth constant value resistor R4; the power supply end of the amplifier U5 is connected with the second end of the temperature control switch S1, and the first end of the temperature control switch S1 is connected with a first power supply VAA; the output of the amplifier U5 is used as the output of the first pressure sensor comparator circuit to output a first difference O2.
The operating principle of the first pressure sensor comparison circuit shown in fig. 7 is as follows:
when the temperature is higher than 60 ℃ (the temperature is set by the temperature control switch), the temperature control switch S1 is closed, the amplifier U5 is powered, and the first power supply VAA is connected.
Through an amplifier LM2902D, making a difference between the output electrical signal sensorA1 of the first pressure sensor A1 and the output electrical signal sensorA2 of the first pressure sensor A2 to obtain a first difference O2 which is sensorA1-sensorA2, wherein the first difference O2 represents the difference between the pressures of the 2 first pressure sensors before liquid filtration, and when the hydraulic pressures of the 2 first pressure sensors are greatly different, the first difference O2 is high voltage, which represents that the 2 first pressure sensors are in fault; when the hydraulic pressures measured by the 2 first pressure sensors are not different greatly, the first difference O2 is a low voltage, which indicates that the 2 first pressure sensors are working normally.
Specifically, the first pressure sensor comparison circuit shown in fig. 7 compares 2 first pressure sensors through an amplifier, determines whether the first pressure sensor is damaged, and provides an input signal for the first alarm.
The first pressure sensor comparison circuit that this application embodiment provided judges whether first pressure sensor damages, provides input signal for first alarm.
Optionally, the second pressure sensor comparison circuit has the same design principle and working principle as the first pressure sensor comparison circuit, and is not described herein again.
Optionally, the first alarm is an optical alarm, and alarms according to the output of the first pressure sensor comparison circuit.
For example, when the first pressure sensor comparator circuit uses the circuit shown in fig. 6, the output terminal of the first pressure sensor comparator circuit outputs a high level when the sensor operates in the normal range, and outputs a low level when the sensor fails. In order to realize that the indicator light is on when the sensor fails and is off when the sensor works normally, the high-low level of the output signal of the comparison circuit of the first pressure sensor needs to be converted.
For example, fig. 8 is a schematic structural diagram of a first alarm provided in the embodiment of the present application, and as shown in fig. 8, a circuit structure of the first alarm includes an Nmos tube Q1, an Nmos tube Q2, a fixed resistor R20, a fixed resistor R21, a fixed resistor R22, a fixed resistor R23, and an indicator light D2; the grid of the Nmos tube Q1 is connected with the output end of the first pressure sensor, the middle node between the output end of the first pressure sensor and the grid of the Nmos tube Q1 is connected with the first end of a constant value resistor R22, and the second end of the constant value resistor R22 is grounded; the source electrode of the Nmos tube Q1 passes through a load grounding end; the drain electrode of the Nmos tube Q1 is connected with the first end of a constant resistor R20, and the second end of the constant resistor R20 is connected with a first power supply; the first end of the constant resistor R21 is connected with the middle node A between the drain electrode of the Nmos tube Q1 and the constant resistor R20; the second end of the constant resistor R21 is connected with the grid of the Nmos tube Q2, the middle node between the constant resistor R21 and the grid of the Nmos tube Q2 is connected with the first end of the constant resistor R23, and the second end of the constant resistor R23 is grounded; the source electrode of the Nmos tube Q2 passes through a load grounding end; the drain of the Nmos tube Q2 is connected with the cathode of the indicator lamp D2, and the anode of the indicator lamp D2 is connected with the first power supply.
The first alarm shown in fig. 8 operates as follows:
when the first difference O2 outputs a high level, the voltage between the gate and the source of the Nmos transistor Q1 is greater than 0, the source and the drain of the Nmos transistor Q1 are turned on, the voltage at point a is a low voltage, the voltage between the gate and the source of the Nmos transistor Q2 is equal to 0, the source and the drain of the Nmos transistor Q2 are turned off, and the indicator light D2 does not operate.
When the first difference O2 outputs a low level, the voltage between the gate and the source of the Nmos transistor Q1 is equal to 0, the source and the drain of the Q1 are turned off, the voltage at point a is at a high level, the current passes through the R21, so that the source and the drain of the Q2 are turned on, and the indicator light D2 is turned on.
Specifically, the first alarm shown in fig. 8 switches the high and low levels of the output signal of the first pressure sensor, so that the indicator light is turned on when the sensor fails, and the indicator light is turned off when the sensor normally operates, thereby clearly prompting the failure of the first pressure sensor.
For another example, when the first pressure sensor comparator circuit adopts the circuit shown in fig. 7, when the sensor operates in the normal range, the output end of the first pressure sensor comparator circuit outputs a low level, and when a fault occurs, the output end of the first pressure sensor comparator circuit outputs a high level, and when the first pressure sensor comparator circuit outputs a high level, an alarm is given.
For example, fig. 9 is a schematic structural diagram of a first alarm provided in the embodiment of the present application, and as shown in fig. 9, the first alarm circuit includes an indicator light D1, an anode of the indicator light D1 is connected to an output terminal of the comparison circuit of the first pressure sensor shown in fig. 7, and a cathode of the indicator light D1 is grounded.
The first alarm shown in figure 9 operates as follows:
when the sensor fails, the first pressure sensor comparison circuit shown in fig. 7 outputs a high level, and the indicator lamp D1 lights up;
when the sensor operates in the normal range, the first pressure sensor comparator circuit shown in fig. 7 outputs a low level and the indicator light D1 is not lit.
Specifically, the first alarm shown in fig. 9 realizes that the indicator light is on when the sensor fails and is off when the sensor normally works according to the high-low level of the output signal of the first pressure sensor, thereby clearly prompting the failure of the first pressure sensor.
Optionally, the circuit design principle and the working principle of the second alarm are the same as those of the first alarm, and are not described herein again.
For example, fig. 10 is a schematic structural diagram of a second alarm provided in the embodiment of the present application, and as shown in fig. 10, due to the difference between the pre-filter hydraulic pressure and the post-filter hydraulic pressure, the voltages at the input ends of the first alarm and the second alarm are different, and a constant value resistor does not need to be connected in series between the input end of the second alarm and the source electrode of the Nmos tube Q3.
Optionally, the subtraction circuit comprises an amplifier, a first fixed-value resistor, a second fixed-value resistor, a third fixed-value resistor and a fourth fixed-value resistor;
the first end of the first constant resistor is connected with the output end of the first pressure sensor, the second end of the first constant resistor is connected with the first end of the second constant resistor, the second end of the second constant resistor is grounded, and the middle node of the first constant resistor and the second constant resistor is connected with the in-phase end of the amplifier;
the first end of the third fixed-value resistor is connected with the output end of the second pressure sensor, and the second end of the third fixed-value resistor is connected with the inverting end of the amplifier;
an intermediate node between the third constant value resistor and the inverting terminal of the amplifier is connected in series with the output terminal of the amplifier through a fourth constant value resistor;
the power supply end of the amplifier is connected with a power supply;
the output end of the amplifier is used as the output end of the subtraction circuit.
For example, fig. 11 is a schematic diagram of a subtraction circuit according to an embodiment of the present application, and as shown in fig. 11, the subtraction circuit includes an amplifier LM2902D, a first constant resistor R3, a second constant resistor R4, a third constant resistor R1, and a fourth constant resistor R4; wherein, the resistor R1R 2R 3R 4; a first end of the first fixed-value resistor R3 is connected with an output end of the first pressure sensor, a second end of the first fixed-value resistor R3 is connected with a first end of the second fixed-value resistor R4, a second end of the second fixed-value resistor R4 is grounded, and a middle node of the first fixed-value resistor R3 and the second fixed-value resistor R4 is connected with a non-inverting end of the amplifier LM 2902D; a first end of the third fixed resistor R1 is connected with the output end of the second pressure sensor, and a second end of the third fixed resistor R1 is connected with the inverting end of the amplifier LM 2902D; an intermediate node between the third fixed-value resistor R1 and the inverting terminal of the amplifier LM2902D is connected in series with the output terminal of the amplifier LM2902D through a fourth fixed-value resistor R4; the power supply end of the amplifier is connected with a first power supply; the output end of the amplifier is used as the output end of the subtraction circuit to output the third difference value sensorOut.
The operating principle of the subtraction circuit shown in fig. 11 is as follows:
the output electrical signal sensorra of the first pressure sensor is subtracted from the output electrical signal sensorB of the second pressure sensor by the amplifier LM2902D, resulting in a third difference sensorOUT ═ sensorra-sensorB, which represents the pre-filter pressure difference of the liquid through the filter.
The subtraction circuit provided by the embodiment of the application makes a difference between the output electric signal of the first pressure sensor and the output electric signal of the second pressure sensor through the amplifier, obtains the filtered differential pressure before filtering, and provides a differential pressure electric signal for the differential pressure comparison circuit.
Optionally, the differential pressure comparison circuit comprises a voltage comparator, an adjustable resistor, a first fixed resistor, a second fixed resistor, a third fixed resistor and a capacitor;
the output end of the subtraction circuit is connected with the in-phase end of the voltage comparator;
the first end of the first constant resistor is connected with the inverting end of the voltage comparator, the second end of the first constant resistor is connected with the first end of the capacitor, and the second end of the capacitor is grounded;
the first end of the adjustable resistor is connected with a power supply, the second end of the adjustable resistor is empty, the third end of the adjustable resistor is connected with the first end of the second constant value resistor, and the second end of the second constant value resistor is grounded;
the middle node of the adjustable resistor and the second constant value resistor is connected with the middle node of the first constant value resistor and the middle node of the capacitor;
the power supply end of the voltage comparator is connected with the second end of the temperature control switch, and a third constant value resistor is connected in series between the power supply end of the voltage comparator and the output end of the voltage comparator;
the output end of the voltage comparator is used as the output end of the differential pressure comparison circuit.
For example, fig. 12 is a schematic structural diagram of a differential pressure comparison circuit provided in the embodiment of the present application, and as shown in fig. 12, the differential pressure comparison circuit includes a voltage comparator U3A, an adjustable resistor R7, a first fixed resistor R6, a second fixed resistor R8, a third fixed resistor R5, and a capacitor C3; the model of the voltage comparator U3A is LM139 AD; the output end of the subtraction circuit is connected with the non-inverting end of the voltage comparator U3A; a first end of the first fixed-value resistor R6 is connected with an inverting end of the voltage comparator U3A, a second end of the first fixed-value resistor R6 is connected with a first end of the capacitor C3, and a second end of the capacitor C3 is grounded, wherein the capacitor C3 plays a role in filtering; the first end of the adjustable resistor R7 is connected with a second power supply VCC, the second end of the adjustable resistor R7 is empty, the third end of the adjustable resistor R7 is connected with the first end of the second fixed-value resistor R8, and the second end of the second fixed-value resistor R8 is grounded; the middle node of the adjustable resistor R7 and the second constant value resistor R8 is connected with the middle node of the first constant value resistor R6 and the capacitor C3; the power supply end of the voltage comparator U3A is connected with the second end of the temperature control switch, and a third constant value resistor R5 is connected in series between the power supply end of the voltage comparator U3A and the output end of the voltage comparator U3A; the output terminal of the voltage comparator U3A serves as the output terminal of the differential pressure comparison circuit, and outputs a fourth difference O1.
The operating principle of the differential pressure comparison circuit shown in fig. 12 is as follows:
when the temperature is higher than 60 ℃ (the temperature is set by the temperature control switch), the temperature control switch S1 is closed, the voltage comparator U3A starts to be powered, the first power supply VAA is connected, the second power supply VCC is divided by the adjustable resistor R7 and the resistor R8, the divided voltage VLadj of the resistor R8 is taken as a third preset threshold, and the third preset threshold VLadj can be adjusted because R7 is the adjustable resistor.
When the third difference value sensorOUT exceeds the third preset threshold value VLadj, the fourth difference value O1 is outputted as a low voltage through the over-voltage comparator.
When the third difference sensorOUT does not exceed the third preset threshold VLadj, the overvoltage comparator outputs a fourth difference O1 as a high voltage, which indicates that the pressure difference of the liquid before and after filtration exceeds the third preset threshold, and the filter has a problem.
Specifically, the differential pressure comparison circuit shown in fig. 12 uses the voltage comparator to compare the third difference value with a third preset threshold value, so as to obtain a fourth difference value, and provide an input signal for the third alarm.
The differential pressure comparison circuit provided by the embodiment of the application compares the differential pressure with the differential pressure threshold value to obtain a fourth difference value, and provides an input signal for the third alarm.
For example, the third alarm is an optical alarm, when the filter is not blocked, the output end of the differential pressure comparison circuit is at a low voltage, when the filter is blocked, the output end of the differential pressure comparison circuit is at a high voltage, so that the indicator light is turned on when the filter fails, and the indicator light is turned off when the filter normally works.
For example, fig. 13 is a schematic structural diagram of a third alarm provided in the embodiment of the present application, and as shown in fig. 13, the third alarm includes an indicator light D1, an anode of the indicator light D1 is connected to an output end of the differential pressure comparison circuit, and a cathode of the indicator light D1 is grounded.
The third alarm shown in figure 13 operates as follows:
the output end of the differential pressure comparison circuit outputs high voltage, which indicates that the differential pressure exceeds a third preset threshold value, the filter is blocked, and the indicator light is lighted; the output end of the differential pressure comparison circuit outputs low voltage, which indicates that the differential pressure does not exceed a third preset threshold value, the filter is not blocked, and the indicator light is not on.
Specifically, the third alarm provided by the embodiment of the application triggers the alarm to alarm according to the output of the differential pressure comparison circuit, and clearly prompts the alarm caused by filter blockage.
Optionally, the first alarm, the second alarm and the third alarm are all audible and visual alarms.
For example, the first alarm, the second alarm and the third alarm in the above embodiments alarm through the indicator lights.
For another example, the first alarm, the second alarm and the third alarm are sound alarms, and alarm is performed through a sound device.
For another example, the first alarm, the second alarm and the third alarm are audible and visual alarms, and alarm is performed by combining an acoustic device and a light-emitting device.
Particularly, first alarm, second alarm and third alarm are audible and visual alarm in the filter fault detection circuit that this application embodiment provided, can clearly indicate alarm information, strengthen filter fault detection circuit's universality, have the condition and the basis of promoting.
On the other hand, the embodiment of the present application further provides a filter failure detection apparatus, where the filter failure detection apparatus includes: a device body and a filter failure detection circuit as described in any of the above embodiments.
For example, fig. 14 is a schematic structural diagram of a filter failure detection apparatus according to an embodiment of the present application. As shown in fig. 14, the first alarm, the second alarm, and the third alarm in the filter failure detection circuit are mounted on the surface of the apparatus main body for easy observation. The first pressure sensor and the second pressure sensor in the filter fault detection circuit are arranged on the surface of the device main body, the first pressure sensor and the second pressure sensor are used as the input of other circuits in the filter fault detection circuit, and the first pressure sensor and the second pressure sensor can move to an environment needing to measure pressure, so that the pressure can be measured conveniently. The rest circuits in the filter fault detection circuit are arranged in the device main body, so that the filter fault detection circuit is prevented from being damaged due to environmental factors.
The operating principle of the filter failure detection apparatus shown in fig. 14 is as follows:
the first pressure sensor measures the hydraulic pressure before filtering of the filter, converts the hydraulic pressure before filtering into voltage, the first pressure sensor outputs the sensing voltage before filtering, the sensing voltage is input into a first pressure sensor comparison circuit in the filter fault detection circuit, a first alarm is triggered according to the output of the first pressure sensor comparison circuit, and the first alarm gives out audible and visual alarm;
the second pressure sensor measures the filtered hydraulic pressure of the filter, converts the filtered hydraulic pressure into voltage, outputs the filtered sensing voltage, inputs the filtered sensing voltage into a second pressure sensor comparison circuit in the filter fault detection circuit, triggers a second alarm according to the output of the second pressure sensor comparison circuit, and sends out audible and visual alarm;
the output end of the first pressure sensor and the output end of the second pressure sensor are connected with the input end of the subtraction circuit, the difference value of the first sensing voltage and the second sensing voltage is output by making a difference through the subtraction circuit, the output end of the subtraction circuit is connected with the input end of the differential pressure comparison circuit, the third alarm is triggered according to the output of the differential pressure comparison circuit, and the third alarm gives out audible and visual alarm.
Specifically, the filter fault detection device provided by the embodiment of the application can prompt the alarm caused by the damage of the sensor and the alarm caused by the blockage of the filter, and is suitable for various environments needing pressure measurement.
In yet another aspect, an embodiment of the present application further provides a filter, where the filter includes:
the device for detecting the fault of any one of the filters, wherein the first pressure sensor is arranged at an inlet of the filter, and the second pressure sensor is arranged at an outlet of the filter;
the liquid inlet is arranged at the top of the shell, and the liquid outlet is arranged at the bottom of the shell;
the filter body, it sets up to filter the body inside the casing, liquid passes through the inlet gets into the casing, the warp filter the body and filter and pass through the liquid outlet is discharged the casing.
For example, the filter body is a filter element or a filter bag.
For example, fig. 15 is a schematic structural diagram of a filter provided in an embodiment of the present application, and as shown in fig. 15, a first pressure sensor is disposed at an inlet of the filter, and a second pressure sensor is disposed at an outlet of the filter; the liquid inlet is arranged at the top of the shell, and the liquid outlet is arranged at the bottom of the shell; the filter body is arranged inside the shell, liquid enters the shell through the liquid inlet, and is discharged out of the shell through the liquid outlet after being filtered by the filter body.
The working principle of the filter of fig. 15 is as follows:
the liquid is input into the liquid inlet of the filter, filtered by the filter body of the filter and flows out of the liquid outlet of the filter.
When the filter body is blocked, the third alarm of the filter fault detection device gives an alarm to prompt that the filter is blocked and the filter body needs to be replaced.
When the first sensor is damaged, a first alarm of the filter fault detection device gives an alarm to prompt that the first sensor is damaged and needs to be replaced.
When the second sensor is damaged, a second alarm of the filter fault detection device gives an alarm to prompt that the second sensor is damaged and needs to be replaced.
The filter that this application embodiment provided, through filter fault detection device, can indicate the warning that the sensor damage arouses and the warning that the filter jam arouses, according to alarm information, replace the sensor of damage, or replace the filter body of jam.
It should also be noted that the exemplary embodiments mentioned in the embodiments of the present application describe some methods or apparatuses. However, the embodiments of the present application are not limited to the order of the above steps, that is, the steps may be performed in the order mentioned in the embodiments, may be performed in an order different from the order in the embodiments, or may be performed simultaneously.
The above description is only a specific implementation of the embodiments of the present application, and can be clearly understood by those skilled in the art. It should be understood that the scope of the embodiments of the present application is not limited thereto, and any person skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the embodiments of the present application, and these modifications or substitutions should be covered within the scope of the embodiments of the present application.

Claims (8)

1. A filter fault detection circuit, comprising:
the device comprises a first pressure sensor, a first pressure sensor comparison circuit and a first alarm;
the output end of the first pressure sensor is connected with the input end of the first pressure sensor comparison circuit;
the output end of the first pressure sensor comparison circuit is connected with the input end of the first alarm;
the first pressure sensor is used for collecting the hydraulic pressure before filtration of the filter;
the first pressure sensor comparison circuit is used for comparing a first difference value between the pre-filtering hydraulic pressure and a first preset threshold value;
the first alarm is used for alarming according to the first difference value;
the filter failure detection circuit further includes:
the second pressure sensor, the second pressure sensor comparison circuit and the second alarm are arranged on the first pressure sensor;
the output end of the second pressure sensor is connected with the input end of the comparison circuit of the second pressure sensor;
the output end of the comparison circuit of the second pressure sensor is connected with the input end of the second alarm;
the second pressure sensor is used for collecting the filtered hydraulic pressure of the filter;
the second pressure sensor comparison circuit is used for comparing a second difference value between the filtered hydraulic pressure and a second preset threshold value;
the second alarm is used for giving an alarm according to the second difference value;
the filter failure detection circuit is characterized by further comprising:
the differential pressure comparison circuit is connected with the first alarm;
the output end of the first pressure sensor and the output end of the second pressure sensor are connected with the input end of the subtraction circuit;
the output end of the subtraction circuit is connected with the input end of the differential pressure comparison circuit;
the output end of the differential pressure comparison circuit is connected with the input end of the third alarm;
the subtraction circuit is used for comparing a third difference value between the pre-filtering hydraulic pressure and the post-filtering hydraulic pressure;
the differential pressure comparison circuit is used for comparing a fourth difference value between the third difference value and a third preset threshold value;
and the third alarm is used for giving an alarm according to the fourth difference value.
2. The filter fault detection circuit of claim 1, further comprising:
a temperature control switch;
the first end of the temperature control switch is connected with a power supply;
the second end of the temperature control switch is connected with the power supply ends of the differential pressure comparison circuit, the first pressure sensor comparison circuit and the second pressure sensor comparison circuit;
the temperature control switch is used for controlling the power supply states of the differential pressure comparison circuit, the first pressure sensor comparison circuit and the second pressure sensor comparison circuit according to the temperature of liquid in the filter.
3. The filter fault detection circuit of claim 2, wherein the first pressure sensor comparison circuit comprises a first voltage comparator, a second voltage comparator, a first fixed-value resistor, a second fixed-value resistor, a third fixed-value resistor, a fourth fixed-value resistor, a fifth fixed-value resistor, and a capacitor;
the first end of the first constant value resistor is connected with the power supply, and the second end of the first constant value resistor is connected with the in-phase end of the first voltage comparator;
the output end of the first pressure sensor is connected with the inverting end of the first voltage comparator;
the output end of the first pressure sensor is connected with the in-phase end of the second voltage comparator;
the first end of the second constant value resistor is connected with the inverting end of the second voltage comparator, the second end of the second constant value resistor is connected with the first end of the capacitor, and the second end of the capacitor is grounded;
the first end of the third fixed-value resistor is connected with a power supply, the second end of the third fixed-value resistor is connected with the first end of the fourth fixed-value resistor, and the second end of the fourth fixed-value resistor is grounded;
the middle node of the third constant value resistor and the fourth constant value resistor is connected with the middle node of the second constant value resistor and the middle node of the capacitor;
the power supply ends of the first voltage comparator and the second voltage comparator are connected with the second end of the temperature control switch, and a fifth constant value resistor is connected in series between the power supply end of the second voltage comparator and the output end of the second voltage comparator;
the output end of the first voltage comparator is connected with the output end of the second voltage comparator in series, and an intermediate node between the output end of the first voltage comparator and the output end of the second voltage comparator is used as the output end of the first pressure sensor comparison circuit.
4. The filter fault detection circuit of claim 1, wherein the subtraction circuit includes an amplifier, a first fixed-value resistor, a second fixed-value resistor, a third fixed-value resistor, and a fourth fixed-value resistor;
the first end of the first constant resistor is connected with the output end of the first pressure sensor, the second end of the first constant resistor is connected with the first end of the second constant resistor, the second end of the second constant resistor is grounded, and the middle node of the first constant resistor and the second constant resistor is connected with the in-phase end of the amplifier;
the first end of the third fixed-value resistor is connected with the output end of the second pressure sensor, and the second end of the third fixed-value resistor is connected with the inverting end of the amplifier;
an intermediate node between the third constant value resistor and the inverting terminal of the amplifier is connected in series with the output terminal of the amplifier through a fourth constant value resistor;
the power supply end of the amplifier is connected with a power supply;
the output end of the amplifier is used as the output end of the subtraction circuit.
5. The filter fault detection circuit of claim 2, wherein the differential pressure comparison circuit comprises a voltage comparator, an adjustable resistor and first, second, third and capacitance;
the output end of the subtraction circuit is connected with the in-phase end of the voltage comparator;
the first end of the first constant resistor is connected with the inverting end of the voltage comparator, the second end of the first constant resistor is connected with the first end of the capacitor, and the second end of the capacitor is grounded;
the first end of the adjustable resistor is connected with a power supply, the second end of the adjustable resistor is empty, the third end of the adjustable resistor is connected with the first end of the second constant value resistor, and the second end of the second constant value resistor is grounded;
the middle node of the adjustable resistor and the second constant value resistor is connected with the middle node of the first constant value resistor and the middle node of the capacitor;
the power supply end of the voltage comparator is connected with the second end of the temperature control switch, and a third constant value resistor is connected in series between the power supply end of the voltage comparator and the output end of the voltage comparator;
the output end of the voltage comparator is used as the output end of the differential pressure comparison circuit.
6. The filter fault detection circuit of claim 1, wherein the first alarm, the second alarm, and the third alarm are audible and visual alarms.
7. A filter failure detection apparatus, characterized by comprising: a device body and a filter failure detection circuit as claimed in any one of claims 1 to 6.
8. A filter, comprising:
the filter failure detection device of claim 7, the first pressure sensor being disposed at an inlet of the filter, the second pressure sensor being disposed at an outlet of the filter;
the liquid inlet is arranged at the top of the shell, and the liquid outlet is arranged at the bottom of the shell;
the filter body, it sets up to filter the body inside the casing, liquid passes through the inlet gets into the casing, the warp filter the body and filter and pass through the liquid outlet is discharged the casing.
CN202110077336.8A 2021-01-20 2021-01-20 Filter fault detection circuit, fault detection device and filter Active CN112924353B (en)

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