CN218270954U - Liquid level detection device - Google Patents
Liquid level detection device Download PDFInfo
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- CN218270954U CN218270954U CN202222213182.3U CN202222213182U CN218270954U CN 218270954 U CN218270954 U CN 218270954U CN 202222213182 U CN202222213182 U CN 202222213182U CN 218270954 U CN218270954 U CN 218270954U
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Abstract
The utility model discloses a liquid level detection device, which is characterized in that a first electrode plate and a second electrode plate are integrated on a FPC flexible printed circuit board to form a parallel plate capacitor; charging the parallel plate capacitor through a voltage stabilizing resistor R4 and a charging resistor R3; when the height of the liquid level of the medium in the container or the pipeline changes, the capacitance value between the two electrode plates correspondingly changes; when the resistance values of the voltage stabilizing resistor R4 and the charging resistor R3 are fixed, the capacitance value of the parallel plate capacitor is in direct proportion to the electrifying time constant; according to the fact that the dielectric constant of the medium in the container or the pipeline is different from that of the air, whether the liquid level of the medium in the container or the pipeline has different rise time can be obtained, and therefore whether the medium exists in the container or the pipeline or not can be judged.
Description
Technical Field
The utility model belongs to the technical field of medium liquid level position height detection in container or the pipeline, concretely relates to liquid level detection device.
Background
With the popularization and improvement of products in various industries in the aspect of intelligent control technology, the intelligent control technology cannot monitor factors such as environment, position, distance, material consumption and the like in real time, so that various induction detection technologies are increasingly applied to intelligent control systems of various products; for example, in smart devices for domestic and industrial use, it is often necessary to monitor the level of a liquid in a container or a pipe transporting the liquid in real time; in the conventional technology, the liquid level position detection devices in the following forms are generally adopted to monitor the liquid level position in a container or a pipeline in real time: the liquid level position detection devices in the various forms have certain defects, and the ultrasonic water flow meter needs to be added with high cost in the manufacturing and using processes; the detection electrode of the electrode type device is directly contacted with liquid, so that the liquid is easily polluted and leaked; the detection effect of the infrared tube type detection device is unstable.
The non-contact capacitance type liquid detection technology is generally adopted in the prior art, although the defects can be overcome, the capacitance type liquid detection product in the prior art is formed by combining structures such as metal sheets, springs or conductive cloth, and the like, and the problems of complex structure, large number of parts, inconvenient installation and operation, poor consistency of the spacing between the pole pieces, high detection cost and poor stability still exist.
SUMMERY OF THE UTILITY MODEL
In order to solve the problems existing in the prior art, the utility model aims to provide a liquid level detection device, simple structure is compact, installation connection convenient operation, low cost, testing result reliable and stable.
The utility model discloses the technical scheme who adopts does:
a liquid level detection device comprises a first electrode plate, a second electrode plate, a pole piece carrier and a detection circuit;
the pole piece carrier is arranged on the outer wall of a target device to be detected, and the first electrode piece and the second electrode piece are arranged on the pole piece carrier side by side to form a parallel plate capacitor; the first electrode plate and the second electrode plate are electrically connected to the detection circuit;
the first electrode plate and the second electrode plate are used for detecting liquid level position information of the target device; the detection circuit comprises an input end, a sensitivity adjusting module, a voltage stabilizing module, a charging and discharging module, a signal optimizing module and an output end; the first electrode plate and the second electrode plate are electrically connected to an input end, and the input end is connected to an output end through a sensitivity adjusting module, a voltage stabilizing module and a signal optimizing module in sequence;
the charging and discharging module is connected with the signal optimizing module in parallel and then is connected to the sensitivity adjusting module through the voltage stabilizing module;
the output end is used for outputting the detection value.
The pole piece carrier is an FPC (flexible printed circuit board), and the first electrode plate and the second electrode plate are integrally arranged on the FPC; the FPC is provided with a wire holder, and the first electrode plate and the second electrode plate are electrically connected to the detection circuit through the wire holder to form the input end of the detection circuit.
The input side of the wire holder is connected to the FPC through welding, riveting or splicing and is electrically connected to the first electrode plate and the second electrode plate; the output side of the wire holder is connected to the detection circuit through a first wire and a second wire.
The sensitivity adjusting module is provided with a level adjusting unit and a capacitance adjusting unit;
the level adjusting unit is provided with a first level adjusting resistor R8 and a second level adjusting resistor R9 in parallel, and the first level adjusting resistor R8 and the second level adjusting resistor R9 are connected to the second electrode slice; the first level adjusting resistor R8 and the second level adjusting resistor R9 are used for pulling up or pulling down the level of the second electrode slice;
the capacitance adjusting unit is provided with a first charging capacitor C5 and a first capacitor resistor R7, and the first charging capacitor C5 is used for adjusting the sensitivity of the circuit.
The voltage stabilizing module is provided with a voltage stabilizing resistor R4 and a voltage stabilizing capacitor C6.
The charging and discharging module is provided with a charging and discharging power supply, a starting resistor R10, a pull-up resistor R5, a third charging capacitor C3, a field effect transistor Q1, a second charging capacitor C4, a charging resistor R3 and a discharging resistor R6; the charging and discharging power supply (405) is connected to a G pole of the field effect transistor Q1 through a starting resistor R10, the third charging capacitor C3 is connected to an S pole of the field effect transistor Q1, a pull-up resistor R5 is connected between the S pole and the G pole of the field effect transistor Q1, the second charging capacitor C4 is connected to a D pole of the field effect transistor Q1, one end of the charging resistor R3 and a discharging resistor R6 are connected to the second charging capacitor C4 in parallel, and the other end of the charging resistor R3 is connected to the sensitivity adjusting module through a voltage stabilizing resistor R4; the signal optimization module is connected between the charging resistor R3 and the voltage stabilizing resistor R4.
The capacitance value of the third charging capacitor C3 is greater than that of the second charging capacitor C4;
the capacitance value of the third charging capacitor C3 and the capacitance value of the second charging capacitor C4 are in a proportional relationship of more than 200:1.
the signal optimization module comprises a signal amplification unit and a signal enhancement unit, wherein the signal amplification unit is provided with an operational amplifier U1A and a decoupling capacitor C1, and the signal enhancement unit is provided with an RC filter circuit.
The first electrode, the voltage stabilizing resistor R4, the charging resistor R3 and the discharging resistor R6 are all connected to the reference ground, so that the first electrode is at a low level.
The first level adjusting resistor R8 is connected with a first direct-current power supply, and the first direct-current power supply supplements energy for the first level adjusting resistor R8;
the third charging capacitor C3 is connected with a second direct-current power supply, and the second direct-current power supply is the third charging capacitor C3;
the operational amplifier U1A is connected with a third direct-current power supply, and the third direct-current power supply supplies power to the operational amplifier U1A;
the first charging capacitor C5 is a variable capacitor;
the detection circuit is arranged on the MCU or the CPU.
The utility model has the advantages that:
a liquid level detection device is characterized in that a first electrode plate and a second electrode plate are integrally arranged on an FPC (flexible printed circuit) to form a parallel plate capacitor; charging the parallel plate capacitor through a voltage stabilizing resistor R4 and a charging resistor R3; when the height of the liquid level of the medium in the container or the pipeline changes, the capacitance value between the two electrode plates correspondingly changes; according to a time constant formula, when the resistance values of the voltage stabilizing resistor R4 and the charging resistor R3 are fixed, the capacitance value of the parallel plate capacitor is in direct proportion to the electrification time constant; according to the fact that the dielectric constant of the medium in the container or the pipeline is different from that of the air, whether the liquid level of the medium in the container or the pipeline has different rise time can be obtained, and therefore whether the medium exists in the container or the pipeline or not can be judged.
The time constant is in the range which can be stably detected by the single chip microcomputer by adjusting the resistance values of the voltage stabilizing resistor R4 and the charging resistor R3, and the part with steep rising slope is reserved by setting the rising voltage trigger threshold value of the single chip microcomputer, so that the precision can be improved; the structure is simple and compact, the installation and connection operation is convenient, the cost is low, and the detection result is stable and reliable.
Drawings
FIG. 1 is a schematic perspective view of the liquid level detecting device of the present invention;
FIG. 2 is a schematic view of the liquid level detection device of the present invention attached to the surface of a pipe or a container;
FIG. 3 is a schematic perspective view of another viewing angle when the liquid level detecting device of the present invention is attached to the surface of a pipe or a container;
fig. 4 is a schematic circuit diagram of the liquid level detecting device of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by a person skilled in the art without making any inventive step are within the scope of protection of the present invention.
As shown in fig. 1 to 4, the present invention provides a liquid level detecting device, which has the following general inventive concept: the basic structure is mainly composed of a first electrode plate 10, a second electrode plate 20, a pole piece carrier 30 and a detection circuit;
fixedly mounting a pole piece carrier 30 on the outer wall of a target device 50 to be detected, and arranging a first electrode piece 10 and a second electrode piece 20 on the pole piece carrier 30 side by side to form a parallel plate capacitor; the first electrode plate 10 and the second electrode plate 20 are electrically connected to a detection circuit through conducting wires; when the liquid level detection circuit is used, the parallel plate capacitor formed by the first electrode plate 10 and the second electrode plate 20 can detect the liquid level position information of a target device, convert the liquid level position information into current information through the parallel plate capacitor, transmit the current information to the detection circuit, and convert the current information into output information through the detection circuit.
Due to the difference between the dielectric constant of the liquid and the air, when the liquid level in the pipeline or the container of the target device changes, the capacitance value between the two electrode plates of the first electrode plate 10 and the second electrode plate 20 changes.
According to the time constant formula, tau = R C, when the series resistance R is fixed, the size of the parallel plate capacitor is obtained to be proportional to the power-on time constant.
According to the parallel plate capacitance principle, when the dielectric constant of the filling medium between the electrodes is different, the capacitance value of the parallel plate capacitor is also different. According to the rising time formula tau = R × C of the RC filter, when the capacitance in the circuit is fixed, the rising time tau in the detection process is proportional to the capacitance value of the parallel plate capacitor. The capacitance of the parallel plate capacitor is related to the dielectric permittivity. The rise time tau of the presence or absence of the liquid in the pipeline is obtained according to the difference of the dielectric constant of the air and the dielectric constant of the liquid. So that it can be judged whether the flowing liquid exists in the pipeline.
The first embodiment is as follows:
as shown in fig. 1, the target device 50 is exemplified by a pipe.
An FPC flexible printed circuit board is adopted as a pole piece carrier 30, and a first electrode piece 10 and a second electrode piece 20 are integrally arranged on the FPC flexible printed circuit board; a wire holder 51 is arranged on the FPC flexible printed circuit board, and the first electrode plate 10 and the second electrode plate 20 are electrically connected to the detection circuit through the wire holder 51 to form an input end 401 of the detection circuit
Specifically, the input side of the wire holder 51 is fixedly connected to the FPC flexible printed wiring board by soldering, riveting, inserting, or other means; the contact pins of the terminal block 51 are connected to the first and second electrode pads 10 and 20, respectively, through the inner printed wiring of the FPC flexible printed wiring board. The first electrode plate 10, the second electrode plate 20, the wire holder 51 and the FPC are of an integrated structure, and are fixedly mounted on the outer wall of a target device 50 to be detected through the FPC, so that the mounting complexity can be greatly reduced, the FPC manufacturing process is stable, the precision is high, the mass production is easy, and the manufacturing cost and the use cost are reduced. The distance consistency of the two electrode plates can be ensured, and the quality is stable. And the back of the FPC is provided with the gum, and the gum can be conveniently attached to the outer wall of a pipeline or a container, so that the capacitive liquid level detection is realized, and the pipeline or the container is not damaged.
As shown in fig. 2 to 3, after the FPC flexible printed circuit board is fixedly attached to the outer wall of the pipeline to be detected, the first electrode sheet 10 and the second electrode sheet 20 form a parallel plate capacitor structure parallel to each other, the fluid medium inside the pipeline is spaced between the first electrode sheet 10 and the second electrode sheet 20, and the change of the liquid level position of the fluid medium inside the pipeline causes the change of the capacitance value between the two electrode sheets.
The junction on the output side of the wire holder corresponding to the first electrode tab 10 is connected to the detection circuit through the first wire 11, and the junction on the output side of the wire holder corresponding to the second electrode tab 20 is connected to the detection circuit through the second wire 21.
The structure of the wire holder in the detection circuit is represented by a terminal holder J1, a contact 1 of the terminal holder J1 is connected with the first electrode plate 10, and a contact 2 is connected with the second electrode plate 20.
Further, the specific structure of the detection circuit is formed by combining an input end 401, a sensitivity adjusting module 402, a voltage stabilizing module 403, a charging and discharging module 404, a signal optimizing module and an output end 408; the first electrode plate 10 and the second electrode plate 20 are electrically connected to the input end 401 through wires, and the first electrode plate 10 and the second electrode plate 20 are connected to the input end 401, and are connected to the output end 408 through the sensitivity adjusting module 402, the voltage stabilizing module 403 and the signal optimizing module in sequence.
After the liquid level position information detected by the first electrode plate 10 and the second electrode plate 20 is input through the input end 401, the liquid level position information sequentially passes through the sensitivity adjusting module 402, the voltage stabilizing module 403 and the signal optimizing module through the circuit to be processed, and finally the detection information is output through the output end 408.
The parallel plate capacitor is charged through the charge-discharge module and the voltage-stabilizing module, so that the capacitance value between the two electrode plates of the first electrode plate 10 and the second electrode plate 20 can change along with the change of the liquid level in a pipeline or a container of the target device; after being connected in parallel with the signal optimization module, the charging and discharging module 404 is connected to the sensitivity adjustment module 402 through the voltage stabilization module 403, and the input end 401 is connected to the sensitivity adjustment module 402; the output 408 is connected to the signal optimization module.
The sensitivity can be adjusted through the sensitivity adjusting module, the signal is amplified and enhanced through the signal optimizing module, and after a final detection result is obtained, a final detection value is output through the output end. The structure is simple and compact, the installation and connection operation is convenient, the cost is low, and the detection result is stable and reliable.
Further, the specific structural form of each module of the detection circuit is as follows:
the sensitivity adjusting module 402 is formed by combining a level adjusting unit and a capacitance adjusting unit;
the level adjusting unit is provided with a first level adjusting resistor R8 and a second level adjusting resistor R9 which are connected in parallel, the first level adjusting resistor R8 and the second level adjusting resistor R9 are connected to the second electrode slice 20, and the first level adjusting resistor R8 and the second level adjusting resistor R9 are used for pulling up or pulling down the level of the second electrode slice 20.
The first level adjustment resistor R8 is connected to a first dc power supply, and the first level adjustment resistor R8 is supplied with energy through the first dc power supply, so that the level of the second electrode piece 20 can be pulled up through the first level adjustment resistor R8, or the level of the second electrode piece 20 can be pulled down through the second level adjustment resistor R9.
The level of the second electrode pad 20 may be pulled down by the first level adjustment resistor R8, or the level of the second electrode pad 20 may be pulled up by the second level adjustment resistor R9.
The capacitance adjusting unit is provided with a first charging capacitor C5 and a first capacitance resistor R7, the voltage rising slope of the electrode plate is reduced through the first capacitance resistor R7, and the stability of circuit testing is improved. The first charging capacitor C5 is a variable capacitor whose capacitance can be adjusted within a certain range.
Further, the voltage stabilizing module 403 is provided with a voltage stabilizing resistor R4 and a voltage stabilizing capacitor C6, so that the voltage stability of the circuit can be improved.
Further, the charge-discharge module 404 is formed by combining a charge-discharge power source 405, a starting resistor R10, a pull-up resistor R5, a third charging capacitor C3, a field effect transistor Q1, a second charging capacitor C4, a charging resistor R3 and a discharging resistor R6;
a charging and discharging power supply 405 is connected to a G electrode of a field effect transistor Q1 through a starting resistor R10, a first detection capacitor C3 is connected to an S electrode of the field effect transistor Q1, a pull-up resistor R5 is connected between the S electrode and the G electrode of the field effect transistor Q1, and a second detection capacitor C4 is connected to a D electrode of the field effect transistor Q1; the charging and discharging power supply 405 can control the on or off of the field effect transistor Q1 through the starting resistor R10; one end of the charging resistor R3 and the discharging resistor R6 are connected to the second charging capacitor C4 in parallel, and the other end of the charging resistor R3 is connected to the sensitivity adjusting module through the voltage stabilizing resistor R4; the signal optimization module is connected between the charging resistor R3 and the voltage stabilizing resistor R4.
Before the test, the charging and discharging power supply 405 outputs a high level to the G pole of the effect transistor Q1 through the starting resistor R10, and the effect transistor Q1 is closed; the first electrode 10, the stabilization resistor R4, the charging resistor R3, and the discharging resistor R6 are all connected to the reference ground, so that the first electrode 10 is set to a low level.
When the test is started, the charging and discharging power supply 405 controls the field effect transistor Q1 to be conducted and started through the starting resistor R10, so that a current signal can be controlled to charge the first electrode plate through the charging resistor R3 and the voltage stabilizing resistor R4, the charging test step of the electrode plate is completed, and the second charging capacitor C4 is charged simultaneously in the charging test process; and then the field effect transistor Q1 is turned off, the second charging capacitor C4 discharges through the discharging resistor R6, and simultaneously the first electrode plate is discharged through the discharging resistor R6, the charging resistor R3 and the voltage stabilizing resistor R4, so that the discharging test step of the electrode plate is completed.
And a second direct current power supply is connected to the third charging capacitor C3, energy is supplemented to the third charging capacitor C3 through the second direct current power supply, and the third charging capacitor C3 is kept charged continuously.
Further, the capacitance value of the third charging capacitor C3 is greater than that of the second charging capacitor C4, so that the charging speed of the second charging capacitor C4 is greater than that of the third charging capacitor C3, and the response speed of the circuit is increased.
To ensure the circuit response speed is fast enough, the proportional relationship between the capacitance value of the third charging capacitor C3 and the capacitance value of the second charging capacitor C4 is greater than 200:1, so that the second charging capacitor C4 can be instantaneously charged to ensure the circuit can instantaneously respond.
The utility model discloses in rising time formula tau = R C according to RC wave filter, the series resistance R is established ties by charging resistor R3 and voltage stabilization resistor R4 and is formed, and C comprises parallel plate capacitor and first charging capacitor C5. The parallel plate capacitor is charged through the series resistance R. According to the time constant formula τ = R × C, when the series resistor R is fixed, that is, the resistances of the voltage stabilizing resistor R4 and the charging resistor R3 are fixed, the capacitance value of the parallel plate capacitor is in direct proportion to the power-on time constant. According to the fact that the dielectric constant of the medium in the container or the pipeline is different from that of the air, whether the liquid level of the medium in the container or the pipeline has different rise times can be obtained, and therefore whether the medium exists in the container or the pipeline or not can be judged.
The sensitivity of the circuit can be adjusted by means of the first charging capacitor C5. After the first charging capacitor C5 is fixed, the test rise time τ is proportional to the capacitance value of the parallel plate capacitor.
Further, the signal optimization module is formed by combining a signal amplification unit 406 and a signal enhancement unit 407.
The core structure of the signal amplification unit 406 specifically consists of an operational amplifier U1A and a decoupling capacitor C1; amplifying the detection signal by an operational amplifier U1A and isolating interference processing; a third direct current power supply is connected to the operational amplifier U1A and supplies power to the operational amplifier U1A; coupling interference is avoided by the decoupling capacitor C1.
The specific structure of the signal enhancement unit 407 is an RC filter circuit, and the RC filter circuit is formed by combining a first filter resistor R1, a second filter resistor R2 and a filter capacitor C2; the output signal can be subjected to smooth denoising processing through the RC filter circuit, so that the output signal is enhanced.
The output end is set as an ADC sampling end; after being amplified by the signal enhancement module in the charging and discharging test process, the signals are output to the ADC sampling end to be used as liquid flow detection judgment signals by the system.
Finally, the detection circuit is arranged on the MCU or the CPU, the MCU or the CPU is provided with a GPIO general input/output module, and the GPIO general input/output module is used for controlling the on/off of the field effect transistor Q1; the output end is set as an ADC sampling end.
In the actual use process, the time constant is in the range which can be stably detected by the single chip microcomputer by adjusting the R value of the series resistance, and the part with steep rising slope is reserved by setting the rising voltage trigger threshold value of the MCU or the CPU, so that the precision can be improved; the structure is simple and compact, the installation and connection operation is convenient, the cost is low, and the detection result is stable and reliable.
In order to further reduce false triggering, the method can continuously test for multiple times, and a test result is optimized through a software algorithm in the MCU or the CPU and used as a judgment condition for liquid level change in a pipeline or a container.
In order to reduce the influence caused by the interference of bubbles and the like contained in fluid media in a pipeline or a container of a target device, multiple tests can be carried out, and whether a flow liquid has an output detection result or not is optimized through an algorithm.
The utility model discloses a detection circuitry among the liquid level detection device also can launch DC _5V power supply.
The utility model discloses a liquid level detection device can be used for liquid level height detection, the lack of water detection in container or the pipeline, can wide application in intelligence draw water or watering system, for example if machine of sweeping the floor, humidifier and water purifier etc.. A first electrode plate and a second electrode plate are integrally arranged on the FPC flexible printed circuit board to form a parallel plate capacitor; charging the parallel plate capacitor through a voltage stabilizing resistor R4 and a charging resistor R3; when the height of the liquid level of the medium in the container or the pipeline changes, the capacitance value between the two electrode plates correspondingly changes; according to a time constant formula, when the resistance values of the voltage stabilizing resistor R4 and the charging resistor R3 are fixed, the capacitance value of the parallel plate capacitor is in direct proportion to the electrifying time constant; according to the fact that the dielectric constant of the medium in the container or the pipeline is different from that of the air, whether the liquid level of the medium in the container or the pipeline has different rise time can be obtained, and therefore whether the medium exists in the container or the pipeline or not can be judged.
The time constant is in the range which can be stably detected by the single chip microcomputer by adjusting the resistance values of the voltage stabilizing resistor R4 and the charging resistor R3, and the part with steep rising slope is reserved by setting the rising voltage trigger threshold value of the single chip microcomputer, so that the precision can be improved; the structure is simple and compact, the installation and connection operation is convenient, the cost is low, and the detection result is stable and reliable.
The present invention is not limited to the above-mentioned optional embodiments, and any other products in various forms can be obtained by anyone under the teaching of the present invention, and any changes in the shape or structure thereof, all the technical solutions falling within the scope of the present invention, are within the protection scope of the present invention.
Claims (10)
1. A liquid level detection device characterized in that: comprises a first electrode plate (10), a second electrode plate (20), a pole plate carrier (30) and a detection circuit;
the pole piece carrier (30) is arranged on the outer wall of a target device (50) to be detected, and the first electrode piece (10) and the second electrode piece (20) are arranged on the pole piece carrier (30) side by side to form a parallel plate capacitor; the first electrode plate (10) and the second electrode plate (20) are electrically connected to the detection circuit;
the first electrode plate (10) and the second electrode plate (20) are used for detecting liquid level position information in the target device (50); the detection circuit comprises an input end (401), a sensitivity adjusting module (402), a voltage stabilizing module (403), a charging and discharging module (404), a signal optimizing module and an output end (408); the first electrode plate and the second electrode plate are electrically connected to an input end, and the input end is connected to an output end (408) through a sensitivity adjusting module (402), a voltage stabilizing module (403) and a signal optimizing module in sequence;
the charging and discharging module (404) is connected with the signal optimizing module in parallel and then is connected to the sensitivity adjusting module (402) through the voltage stabilizing module (403);
the output (408) is used for outputting the detection value.
2. The fluid level detection apparatus of claim 1, wherein: the pole piece carrier (30) is an FPC (flexible printed circuit), and the first electrode piece (10) and the second electrode piece (20) are integrally arranged on the FPC; a wire holder (51) is arranged on the FPC, and the first electrode plate (10) and the second electrode plate (20) are electrically connected to the detection circuit through the wire holder (51) to form an input end (401) of the detection circuit.
3. The liquid level detection apparatus of claim 2, wherein: the input side of the wire holder (51) is connected to the FPC flexible printed circuit board through welding, riveting or splicing and is electrically connected to the first electrode plate (10) and the second electrode plate (20); the output side of the wire holder (51) is connected to a detection circuit through a first wire (11) and a second wire (21).
4. A liquid level detection apparatus according to any one of claims 1 to 3, wherein: the sensitivity adjusting module (402) is provided with a level adjusting unit and a capacitance adjusting unit;
the level adjusting unit is provided with a first level adjusting resistor R8 and a second level adjusting resistor R9 in parallel, and the first level adjusting resistor R8 and the second level adjusting resistor R9 are connected to a second electrode plate (20); the first level adjusting resistor R8 and the second level adjusting resistor R9 are used for pulling up or pulling down the level of the second electrode slice (20);
the capacitance adjusting unit is provided with a first charging capacitor C5 and a first capacitor resistor R7, and the first charging capacitor C5 is used for adjusting the sensitivity of the circuit.
5. The liquid level detection apparatus of claim 4, wherein: the voltage stabilizing module (403) is provided with a voltage stabilizing resistor R4 and a voltage stabilizing capacitor C6.
6. The liquid level detection device of claim 5, wherein: the charging and discharging module (404) is provided with a charging and discharging power supply (405), a starting resistor R10, a pull-up resistor R5, a third charging capacitor C3, a field effect transistor Q1, a second charging capacitor C4, a charging resistor R3 and a discharging resistor R6; the charging and discharging power supply (405) is connected to a G pole of the field effect transistor Q1 through a starting resistor R10, the third charging capacitor C3 is connected to an S pole of the field effect transistor Q1, a pull-up resistor R5 is connected between the S pole and the G pole of the field effect transistor Q1, the second charging capacitor C4 is connected to a D pole of the field effect transistor Q1, one end of the charging resistor R3 and a discharging resistor R6 are connected to the second charging capacitor C4 in parallel, and the other end of the charging resistor R3 is connected to the sensitivity adjusting module through a voltage stabilizing resistor R4; the signal optimization module is connected between the charging resistor R3 and the voltage stabilizing resistor R4.
7. The fluid level detection apparatus of claim 6, wherein: the capacitance value of the third charging capacitor C3 is greater than that of the second charging capacitor C4;
the capacitance value of the third charging capacitor C3 and the capacitance value of the second charging capacitor C4 are in a proportional relationship greater than 200:1.
8. the liquid level detection device of claim 7, wherein: the signal optimization module comprises a signal amplification unit (406) and a signal enhancement unit (407), wherein the signal amplification unit (406) is provided with an operational amplifier U1A and a decoupling capacitor C1, and the signal enhancement unit (407) is provided with an RC filter circuit.
9. The liquid level detection device of claim 8, wherein: the first electrode slice (10), the stabilizing resistor R4, the charging resistor R3 and the discharging resistor R6 are all connected to the reference ground, so that the first electrode slice (10) is at a low level.
10. The fluid level detection apparatus of claim 9, wherein: the first level adjusting resistor R8 is connected with a first direct-current power supply, and the first direct-current power supply supplements energy for the first level adjusting resistor R8;
the third charging capacitor C3 is connected with a second direct-current power supply, and the second direct-current power supply is the third charging capacitor C3;
the operational amplifier U1A is connected with a third direct-current power supply, and the third direct-current power supply supplies power to the operational amplifier U1A;
the first charging capacitor C5 is a variable capacitor;
the detection circuit is arranged on the MCU or the CPU.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222213182.3U CN218270954U (en) | 2022-08-22 | 2022-08-22 | Liquid level detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222213182.3U CN218270954U (en) | 2022-08-22 | 2022-08-22 | Liquid level detection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218270954U true CN218270954U (en) | 2023-01-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222213182.3U Active CN218270954U (en) | 2022-08-22 | 2022-08-22 | Liquid level detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218270954U (en) |
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2022
- 2022-08-22 CN CN202222213182.3U patent/CN218270954U/en active Active
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