A Method and Device for Preventing Residues in a Capacitive Sensor

Abstract

The present invention belongs to the technical field of capacitive sensors, and specifically relates to a method and device for preventing residues in a capacitive sensor, including the following preparation steps: In the capacitive sensor housing, the metal plate in the capacitive sensor housing is connected to the oscillator circuit, and the target to be detected serves as the other electrode of the capacitor. The capacitive sensor housing includes a high-frequency oscillator formed by two metal electrodes on its sensing surface; when liquid wall hanging occurs, press the button block to start the capacitive sensor housing and start the high-frequency oscillator, which is formed by two metal electrodes on its sensing surface. Once an object approaches the sensing surface, it will move into the electrostatic field of the electrode and change the capacitance of the oscillator, thereby cleaning the liquid wall hanging, avoiding being affected by the wall hanging residues, causing misoperation, and reducing quality problems such as accidental equipment shutdown and product defects.

Description

Technical Field

[0001] The present invention belongs to the technical field of capacitive sensors, and specifically relates to a method and device for preventing residues in a capacitive sensor. Background Art

[0002] A capacitive sensor uses various types of capacitors as sensing elements to convert the measured physical quantity or mechanical quantity into a change in capacitance. In fact, it is a capacitor with variable parameters; a typical capacitive sensor consists of upper and lower electrodes, an insulator, and a substrate.

[0003] A capacitive proximity switch belongs to a position sensor with a switching output. Its measuring head is usually one plate of the capacitor, and the other plate is the object itself. When the object moves towards the proximity switch, the capacitance value between the object and the proximity switch changes, causing the circuit state connected to the measuring head to also change accordingly, thereby controlling the on and off of the switch.

[0004] In the current prior art, the detected objects of such proximity switches are not limited to metal conductors, but can also be insulating liquids or powdered objects. When detecting liquids, due to the switching between the full state and the empty state, the liquid is prone to wall hanging phenomenon. Conventional capacitive proximity switches are easily affected by the wall hanging residues, resulting in misoperation. Solid powder detection objects also have residual situations in different air humidity environments, similar to mis-triggering situations, causing quality problems such as accidental shutdown of equipment and product defects, which will directly or indirectly cause economic losses. Here, we provide a method and device for preventing residues in a capacitive sensor. Summary of the Invention

[0005] In order to solve the above problems, the present invention proposes a method and device for preventing residues in a capacitive sensor.

[0006] The technical solution adopted by the present invention to solve its technical problems is: A method for preventing residues in a capacitive sensor according to the present invention is characterized in that it includes the following preparation steps:

[0007] S1. In the capacitive sensor housing, the metal plate in the capacitive sensor housing is connected to the oscillator circuit, and the detected target serves as the other plate of the capacitor. The capacitive sensor housing includes a high-frequency oscillator, and its sensing surface is formed by two metal electrodes; once an object approaches the sensing surface, it will move into the electrostatic field of the electrodes and change the capacitance of the oscillator;

[0008] S2. When there is no residual substance, when the object to be measured approaches the capacitive sensor housing, after the capacitance of the oscillator changes, the F / V conversion circuit outputs a corresponding change; after the MCU microprocessor detects the F / V conversion change, it outputs a corresponding result; when there is a residual substance between the object to be measured and the capacitive sensor housing, the approach of the object will be affected by the residue.

[0009] S3. Through the state of the MCU with residual substances, the superimposed influence of the residual substances can be eliminated; through the temperature compensation function, the capacitive sensor housing can have a stable and linear working range between -40°C and +70°C; the capacitive sensor housing includes two metal plates, the distance between them is "h", and the area is "A".

[0010] A capacitive sensor anti-residue device, the capacitive sensor housing includes a shielding copper ring; a shielding copper ring is installed inside the capacitive sensor housing; an induction pole piece is fixedly connected to the side end of the shielding copper ring; a circuit board is fixedly connected inside the shielding copper ring; a tail plug is installed at the side end of the capacitive sensor housing; a key block is installed inside the tail plug; a connecting cable is fixedly connected to the side end of the tail plug.

[0011] Preferably, an electric push rod is installed on one side of the capacitive sensor housing; a positioning arc plate is fixedly connected to the top end of the electric push rod; a motor is fixedly connected to the top end of the positioning arc plate; a cleaning disc is installed at the output end of the motor; multiple plastic scraping blades are fixedly connected to the side end of the cleaning disc; a soft brush is fixedly connected to the side end of the cleaning disc, and a soft brush is fixedly connected to one side of the plastic scraping blade.

[0012] Preferably, a top rod is fixedly connected to one end of the positioning arc plate; a conduit is installed at the top end of the cleaning disc; a water pipe is fixedly connected to the side end of the conduit; a plug block is slidably connected inside the conduit; a top rod is fixedly connected to the side end of the plug block.

[0013] Preferably, multiple rubber support elastic rods are fixedly connected to the side end of the positioning arc plate; one end of the plastic scraping blade is connected to a rubber support elastic rod.

[0014] Preferably, a retaining plate is fixedly connected to the output end of the motor; a limiting telescopic rod is fixedly connected to the side end of the retaining plate; a connecting plate is fixedly connected to the end of the limiting telescopic rod away from the retaining plate; a spring is fixedly connected to the side end of the retaining plate.

[0015] Preferably, a cleaning disc is installed at the side end of the connecting plate, and the cleaning disc is connected to the connecting plate by a magic tape; a tearing piece is fixedly connected to one end of the positioning arc plate.

[0016] Preferably, a positioning sleeve is rotatably connected to the outer side wall of the capacitive sensor housing; the positioning sleeve is threadedly connected to the capacitive sensor housing.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The present invention provides a method and device for preventing residues in a capacitive sensor. After the liquid generates a wall hanging phenomenon, pressing the button block activates the capacitive sensor housing and starts the high-frequency oscillator. Its sensing surface is formed by two metal electrodes. Once an object approaches the sensing surface, it will move into the electrostatic field of the electrodes and change the capacitance of the oscillator, thereby cleaning the wall hanging generated by the liquid, avoiding being affected by the wall hanging residues, causing misoperation, and reducing quality problems such as accidental shutdown of the equipment and product defects.

[0019] 2. The present invention provides a method and device for preventing residues in a capacitive sensor. By means of the electric push rod, the positioning arc plate moves upward. The movement of the positioning arc plate further causes the motor to move upward, so that the cleaning disc moves to the side end of the induction pole piece. The output of the motor causes the cleaning disc to rotate. The rotation of the cleaning disc causes the plastic scraper and the soft brush to rotate. The rotation of the soft brush and the plastic scraper can clean the residues on the induction pole piece, thereby avoiding the performance test of the induction pole piece by the residues. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0021] Figure 1 is the flowchart of the method of the present invention;

[0022] Figure 2 is the schematic diagram of the capacitive proximity switch of the present invention;

[0023] Figure 3 is the three-dimensional view of the present invention;

[0024] Figure 4 is the cross-sectional view of the present invention;

[0025] Figure 5 is the three-dimensional view of the cleaning disc structure of the present invention;

[0026] Figure 6 is the three-dimensional view of the retaining plate structure of the present invention;

[0027] Legend Explanation:

[0028] 1. Capacitive sensor housing; 12. Shielding copper ring; 13. Inductive pole piece; 14. Circuit board; 15. Tail plug; 16. Button block; 17. Connecting cable; 18. Positioning sleeve; 19. Electric push rod; 20. Positioning arc plate; 21. Motor; 22. Cleaning disc; 23. Plastic scraper; 24. Rubber support elastic rod; 25. Soft brush; 26. Tearing piece; 27. Duct; 28. Blocking block; 29. Water pipe; 30. Retaining plate; 31. Limit telescopic rod; 32. Spring; 33. Connecting plate; 34. Thrust rod. Detailed implementation manners

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Please refer to Figures 1 - 6 As shown, a method for preventing residues in a capacitive sensor includes the following preparation steps:

[0031] S1. In the capacitive sensor housing 1, the metal plate in the capacitive sensor housing 1 is connected to the oscillator circuit, and the object to be detected serves as the other electrode of the capacitor. The capacitive sensor housing 1 includes a high-frequency oscillator, and its sensing surface is formed by two metal electrodes; once an object approaches the sensing surface, it will move into the electrostatic field of the electrode and change the capacitance of the oscillator.

[0032] S2. When there is no residual substance, when the object to be detected approaches the capacitive sensor housing 1 and changes the capacitance of the oscillator, the F / V conversion circuit outputs a corresponding change amount; after the MCU microprocessor detects the F / V conversion change amount, it outputs a corresponding result; when there is a residual substance between the object to be detected and the capacitive sensor housing 1, the approach of the object will be affected by the fixation of the residual substance.

[0033] S3. Through the state of the MCU with residual substances, the superimposed influence of the residual substances can be eliminated; through the temperature compensation function, the capacitive sensor housing 1 can have a stable and linear working range between -40°C and +70°C; the capacitive sensor housing 1 includes two metal plates, the distance between them is "h", and the area is "A".

[0034] Therefore, the capacitance "C" between the two terminals can be given by the following expression; ; where: "C" is the capacitance value between the pole pieces, " " is the relative dielectric constant of the insulator, " " is the permittivity of free space, "A" is the overlapping area of the two polar plates, and "h" is the width of the gap between the two plates.

[0035] Align the detection face of the capacitive sensor housing 1 with the detected object. After pressing the touch button for more than 3 s and less than 10 s and then releasing it, the capacitive sensor housing 1 enters the state of cleaning residues, and the LED indicator flashes. The LED stops flashing indicating that the cleaning is completed; NPN / PNP, normally open / normally closed output mode switching: After pressing the touch button for more than 10 s, the capacitive sensor housing 1 starts to switch the output mode, and the color of the LED indicator changes, which are red, blue, yellow, and green in sequence; Different colors of the indicator light on represent different output modes; There are a total of 4 output modes, which are: 1. NPN normally open; 2. NPN normally closed; 3. PNP normally open; 2. PNP normally closed.

[0036] A capacitive sensor anti-residue device, the capacitive sensor housing includes a shielding copper ring 12; a shielding copper ring 12 is installed inside the capacitive sensor housing 1; an induction pole piece 13 is fixedly connected to the side end of the shielding copper ring 12; a circuit board 14 is fixedly connected inside the shielding copper ring 12; a tail plug 15 is installed at the side end of the capacitive sensor housing 1; a button block 16 is installed inside the tail plug 15; a connecting cable 17 is fixedly connected to the side end of the tail plug 15.

[0037] During operation, the object detected by this proximity switch is not limited to metal conductors, but can also be insulating liquids or powdered objects. When detecting liquids, due to the switching between full and empty states, the liquid is prone to wall hanging. Conventional capacitive proximity switches are easily affected by the wall hanging residues, resulting in false operations. Solid powder detection objects also have residue situations in different air humidity environments, similar to false triggering situations, causing quality problems such as unexpected equipment shutdowns and product defects, which will directly or indirectly cause economic losses. Before work, install the shielding copper ring 12 and the circuit board 14 inside the capacitive sensor housing 1, install the induction pole piece 13 at the side end of the capacitive sensor housing 1, then install the tail plug 15 at the other end of the capacitive sensor housing 1, connect the cable 17 to the shielding copper ring 12, and operate the circuit board 14 and the induction pole piece 13 through the key block 16. The staff installs the capacitive sensor housing 1 inside the positioning sleeve 18, rotates the capacitive sensor housing 1 to complete the connection with the positioning sleeve 18, and fixedly installs the capacitive sensor housing 1 at the designated position. Align the detection surface of the capacitive sensor housing 1 with the detection object, press and hold the touch key for more than 3 s and less than 10 s and then release it. The capacitive sensor housing 1 enters the state of cleaning residues, and the LED indicator flashes. When the LED stops flashing, it indicates that the cleaning is completed; NPN / PNP, normally open / normally closed output mode switching: Press and hold the touch key for more than 10 s, and the capacitive sensor housing 1 starts to switch the output mode, and the color of the LED indicator changes, which are red, blue, yellow, and green in sequence; Different colors of the indicator light on represent different output modes; There are a total of 4 output modes, which are: 1. NPN normally open; 2. NPN normally closed; 3. PNP normally open; 2. PNP normally closed. When the liquid has a wall hanging phenomenon, press the key block 16 to start the capacitive sensor housing 1 and start the high-frequency oscillator. Its sensing surface is formed by two metal electrodes. Once an object approaches the sensing surface, it will move into the electrostatic field of the electrode and change the capacitance of the oscillator, thereby cleaning the wall hanging generated by the liquid, avoiding being affected by the wall hanging residues, causing false operations, and reducing quality problems such as unexpected equipment shutdowns and product defects.

[0038] As a specific embodiment of the present invention, an electric push rod 19 is installed on one side of the capacitive sensor housing 1; the top end of the electric push rod 19 is fixedly connected with a positioning arc plate 20; the top end of the positioning arc plate 20 is fixedly connected with a motor 21; the output end of the motor 21 is installed with a cleaning disc 22; multiple plastic scraping blades 23 are fixedly connected to the side end of the cleaning disc 22; a soft brush 25 is fixedly connected to the side end of the cleaning disc 22, and a soft brush 25 is fixedly connected to one side of the plastic scraping blade 23.

[0039] During operation, when the residue is strongly sticky and adsorbed on the capacitive sensor housing 1, the staff starts the electric push rod 19, and the operation of the electric push rod 19 causes the positioning arc plate 20 to move upward, and the movement of the positioning arc plate 20 causes the motor 21 to move upward, so that the cleaning disk 22 moves to the side end of the inductive pole piece 13, and the output of the motor 21 causes the cleaning disk 22 to rotate, and the rotation of the cleaning disk 22 causes the plastic scraper 23 and the soft brush 25 to rotate, and the rotation of the soft brush 25 and the plastic scraper 23 can clean the residue on the inductive pole piece 13. The plastic scraper 23 is made of hard plastic material and can cope with residues with strong viscosity. The soft brush 25 is a soft brush that can absorb and clean liquid. The rotation of the cleaning disk 22 can make the plastic scraper 23 cooperate with the soft brush 25 to clean the residue on the sensing pole piece 13, thereby avoiding the residue from affecting the performance test of the sensing pole piece 13. The rubber support spring rod 24 is made of rubber material and has good elasticity. The rubber support spring rod 24 can support the position of the plastic scraper 23, thereby ensuring that the plastic scraper 23 can scrape on the surface of the sensing pole piece 13, thereby extending the working performance of the plastic scraper 23. The retaining plate 30 can limit the position of the limiting telescopic rod 31, and the elasticity of the spring 32 can make the cleaning disk 22 move toward the sensing pole piece 13. The direction of the electrode 13 is fitted, so that the soft brush 25 and the plastic scraper 23 can fit tightly on the surface of the sensing electrode 13, and the residue of the sensing electrode 13 is cleaned by the soft brush 25 and the plastic scraper 23. The limit telescopic rod 31 can limit the position of the spring 32 and the connecting plate 33. The extension and contraction of the spring 32 can make the limit telescopic rod 31 extend and contract together. The cleaning disk 22 needs to be regularly maintained and replaced. The cleaning disk 22 is installed on the connecting plate 33 by Velcro. When the staff needs to maintain or replace the cleaning disk 22, the staff pulls the tear sheet 26 to detach the cleaning disk 22 On the connecting plate 33, regular maintenance of the cleaning disk 22 can ensure the cleaning performance of the plastic scraper 23 and the soft brush 25 on the sensing pole piece 13. The electric push rod 19 causes the positioning arc plate 20 to slide upward, thereby causing the top rod 34 to slide upward. The sliding of the top rod 34 causes the block 28 to slide upward. After the block 28 slides, the water inside the water pipe 29 can enter the conduit 27 normally and flow. The water flows to the cleaning disk 22 and the sensing pole piece 13 through the conduit 27. The water cooperates with the rotation of the cleaning disk 22 to improve the cleaning of the residue, thereby improving the cleanliness of the bottom end of the surface of the sensing pole piece 13 and reducing the impact of the residue on the test of the sensing pole piece 13.

[0040] As a specific embodiment of the present invention, one end of the positioning arc plate 20 is fixedly connected to a push rod 34; a conduit 27 is installed at the top of the cleaning disk 22; a water pipe 29 is fixedly connected to the side end of the conduit 27; a blocking block 28 is slidably connected inside the conduit 27; and a push rod 34 is fixedly connected to the side end of the blocking block 28.

[0041] During operation, the operation of the electric push rod 19 causes the positioning arc plate 20 to move upward. The movement of the positioning arc plate 20 further causes the motor 21 to move upward, so that the cleaning disc 22 moves to the side end of the induction pole piece 13. The output of the motor 21 causes the cleaning disc 22 to rotate. The rotation of the cleaning disc 22 causes the plastic scraping blade 23 and the soft brush 25 to rotate. The rotation of the soft brush 25 and the plastic scraping blade 23 can clean the residues on the induction pole piece 13. The plastic scraping blade 23 is made of hard plastic material and can deal with residues with strong viscosity. The soft brush 25 is a soft brush that can absorb and sweep liquids. By the rotation of the cleaning disc 22, the plastic scraping blade 23 can cooperate with the soft brush 25 to clean the residues on the induction pole piece 13, thus avoiding the performance test of the induction pole piece 13 by the residues. The electric push rod 19 causes the positioning arc plate 20 to slide upward, thus causing the ejector rod 34 to slide upward. The sliding of the ejector rod 34 causes the blocking block 28 to slide upward. After the blocking block 28 slides, the water inside the water pipe 29 can normally enter the conduit 27 and flow. The water flows from the conduit 27 to the cleaning disc 22 and the induction pole piece 13. The water cooperating with the rotation of the cleaning disc 22 can improve the cleaning of the residues, thus improving the cleanliness of the bottom end of the surface of the induction pole piece 13 and reducing the test influence of the residues on the induction pole piece 13.

[0042] As a specific embodiment of the present invention, a plurality of rubber support elastic rods 24 are fixedly connected to the side end of the positioning arc plate 20; one end of the plastic scraping blade 23 is connected to a rubber support elastic rod 24.

[0043] During operation, the operation of the electric push rod 19 causes the positioning arc plate 20 to move upward. The movement of the positioning arc plate 20 further causes the motor 21 to move upward, so that the cleaning disc 22 moves to the side end of the induction pole piece 13. The output of the motor 21 causes the cleaning disc 22 to rotate. The rotation of the cleaning disc 22 causes the plastic scraping blade 23 and the soft brush 25 to rotate. The rotation of the soft brush 25 and the plastic scraping blade 23 can clean the residues on the induction pole piece 13. The plastic scraping blade 23 is made of hard plastic material and can deal with residues with strong viscosity. The soft brush 25 is a soft brush that can absorb and sweep liquids. By the rotation of the cleaning disc 22, the plastic scraping blade 23 can cooperate with the soft brush 25 to clean the residues on the induction pole piece 13, thus avoiding the performance test of the induction pole piece 13 by the residues. The rubber support elastic rod 24 is made of rubber material and has good elasticity. The rubber support elastic rod 24 can support the position of the plastic scraping blade 23, thus ensuring that the plastic scraping blade 23 can scrape on the surface of the induction pole piece 13, and further extending the working performance of the plastic scraping blade 23.

[0044] As a specific embodiment of the present invention, a retaining plate 30 is fixedly connected to the output end of the motor 21; a limiting telescopic rod 31 is fixedly connected to the side end of the retaining plate 30; a connecting plate 33 is fixedly connected to the end of the limiting telescopic rod 31 away from the retaining plate 30; a spring 32 is fixedly connected to the side end of the retaining plate 30.

[0045] During operation, the operation of the electric push rod 19 causes the positioning arc plate 20 to move upward. The movement of the positioning arc plate 20 further causes the motor 21 to move upward, thereby moving the cleaning disc 22 to the side end of the induction pole piece 13. The output of the motor 21 causes the cleaning disc 22 to rotate. The rotation of the cleaning disc 22 causes the plastic scraping blade 23 and the soft brush 25 to rotate. The rotation of the soft brush 25 and the plastic scraping blade 23 can clean the residues on the induction pole piece 13, thereby avoiding the performance test of the induction pole piece 13 by the residues. The retaining plate 30 can limit the position of the limit telescopic rod 31. The elasticity of the spring 32 can make the cleaning disc 22 fit towards the induction pole piece 13, so that the soft brush 25 and the plastic scraping blade 23 can tightly adhere to the surface of the induction pole piece 13. The residues on the induction pole piece 13 are cleaned by the soft brush 25 and the plastic scraping blade 23. The limit telescopic rod 31 can limit the positions of the spring 32 and the connecting plate 33. The expansion and contraction of the spring 32 can cause the limit telescopic rod 31 to expand and contract together. The cleaning disc 22 needs to be maintained and replaced regularly. The cleaning disc 22 is installed on the connecting plate 33 through Velcro. When the staff needs to maintain and replace the cleaning disc 22, the staff pulls the tearing piece 26 to separate the cleaning disc 22 from the connecting plate 33. Regularly maintaining the cleaning disc 22 can ensure the cleaning performance of the plastic scraping blade 23 and the soft brush 25 on the induction pole piece 13.

[0046] As a specific embodiment of the present invention, a cleaning disc 22 is installed at the side end of the connecting plate 33, and the cleaning disc 22 is connected to the connecting plate 33 through Velcro; one end of the positioning arc plate 20 is fixedly connected with a tearing piece 26.

[0047] During operation, the operation of the electric push rod 19 causes the positioning arc plate 20 to move upward. The movement of the positioning arc plate 20 further causes the motor 21 to move upward, thereby moving the cleaning disc 22 to the side end of the induction pole piece 13. The output of the motor 21 causes the cleaning disc 22 to rotate. The rotation of the cleaning disc 22 causes the plastic scraping blade 23 and the soft brush 25 to rotate. The rotation of the soft brush 25 and the plastic scraping blade 23 can clean the residues on the induction pole piece 13. The plastic scraping blade 23 is made of hard plastic material and can deal with residues with strong viscosity. The soft brush 25 is a soft brush and can absorb and clean liquids. By rotating the cleaning disc 22, the plastic scraping blade 23 can cooperate with the soft brush 25 to clean the residues on the induction pole piece 13, thereby avoiding the performance test of the induction pole piece 13 by the residues. The retaining plate 30 can limit the position of the limit telescopic rod 31. The cleaning disc 22 needs to be maintained and replaced regularly. The cleaning disc 22 is installed on the connecting plate 33 through Velcro. When the staff needs to maintain and replace the cleaning disc 22, the staff pulls the tearing piece 26 to separate the cleaning disc 22 from the connecting plate 33. Regularly maintaining the cleaning disc 22 can ensure the cleaning performance of the plastic scraping blade 23 and the soft brush 25 on the induction pole piece 13.

[0048] As a specific embodiment of the present invention, a positioning sleeve 18 is rotatably connected to the outer side wall of the capacitive sensor housing 1; the positioning sleeve 18 is threadedly connected to the capacitive sensor housing 1.

[0049] During operation, before working, the shielding copper ring 12 and the circuit board 14 are installed inside the capacitive sensor housing 1, the induction pole piece 13 is installed at the side end of the capacitive sensor housing 1, and then the tail plug 15 is installed at the other end of the capacitive sensor housing 1. The connecting cable 17 is connected to the shielding copper ring 12, and the circuit board 14 and the induction pole piece 13 are operated through the button block 16. The staff installs the capacitive sensor housing 1 inside the positioning sleeve 18, rotates the capacitive sensor housing 1 to complete the connection with the positioning sleeve 18, and fixedly installs the capacitive sensor housing 1 at a designated position.

[0050] Working principle: The object detected by this proximity switch is not limited to metal conductors, but can also be insulating liquids or powdered objects. When detecting liquids, due to the switching between full and empty states, the liquid is prone to wall hanging phenomenon. Conventional capacitive proximity switches are easily affected by the wall hanging residues, resulting in misoperation. Solid powder detection objects also have residue situations in different air humidity environments, similar to mis-triggering situations, causing quality problems such as accidental equipment shutdown and product defects, which will directly or indirectly cause economic losses. Before working, install the shielding copper ring 12 and the circuit board 14 inside the capacitive sensor housing 1, install the induction pole piece 13 at the side end of the capacitive sensor housing 1, and then install the tail plug 15 at the other end of the capacitive sensor housing 1. Connect the cable 17 to the shielding copper ring 12 and operate the circuit board 14 and the induction pole piece 13 through the button block 16. The staff installs the capacitive sensor housing 1 inside the positioning sleeve 18, rotates the capacitive sensor housing 1 to complete the connection with the positioning sleeve 18, and fixedly installs the capacitive sensor housing 1 at the specified position. Align the detection surface of the capacitive sensor housing 1 with the detection object. After pressing the touch button for more than 3 s and less than 10 s and then releasing it, the capacitive sensor housing 1 enters the state of cleaning residues, and the LED indicator flashes. The LED stops flashing indicating that the cleaning is completed; NPN / PNP, normally open / normally closed output mode switching: After pressing the touch button for more than 10 s, the capacitive sensor housing 1 starts to switch the output mode, and the color of the LED indicator changes, which are red, blue, yellow, and green in sequence; Different colors of the indicator light on represent different output modes. There are a total of 4 output modes, which are: 1. NPN normally open; 2. NPN normally closed; 3. PNP normally open; 2. PNP normally closed. When the liquid has a wall hanging phenomenon, press the button block 16 to start the capacitive sensor housing 1 and start the high-frequency oscillator. Its sensing surface is formed by two metal electrodes. Once an object approaches the sensing surface, it will move into the electrostatic field of the electrode and change the capacitance of the oscillator, thereby cleaning the wall hanging generated by the liquid, avoiding being affected by the wall hanging residues, causing misoperation, and reducing quality problems such as accidental equipment shutdown and product defects.

[0051] The above shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A method for preventing residues in a capacitive sensor, characterized in that: It includes the following preparation steps: S1. In the capacitive sensor housing, the metal plate inside the capacitive sensor housing is connected to the oscillator circuit, and the object to be detected serves as the other electrode of the capacitor. The capacitive sensor housing includes a high-frequency oscillator, and its sensing surface is formed by two metal electrodes; once an object approaches the sensing surface, it will move into the electrostatic field of the electrodes and change the capacitance of the oscillator; S2. When there is no residual substance, when the object to be measured approaches the capacitive sensor housing and the capacitance of the oscillator changes, the F / V conversion circuit outputs a corresponding change; after the MCU microprocessor detects the F / V conversion change, it outputs a corresponding result; when there is a residual substance between the object to be measured and the capacitive sensor housing, the approach of the object will be affected by the residue fixed; S3. Through the state of the MCU with residual substances, the superimposed influence of the residual substances can be eliminated; through the temperature compensation function, the capacitive sensor housing can have a stable and linear working range between -40°C and +70°C; the capacitive sensor housing includes two metal plates, the distance between them is "h", and the area is "A"; Therefore, the capacitance "C" between the two terminals is given by the following expression; where: "C" is the capacitance value between the electrode plates, " " is the relative permittivity of the insulator, " " is the permittivity of free space, "A" is the overlapping area of the two electrode plates, and "h" is the width of the gap between the two plates; The capacitive sensor housing includes a shielding copper ring; the shielding copper ring is installed inside the capacitive sensor housing; the side end of the shielding copper ring is fixedly connected with an induction pole piece; the circuit board is fixedly connected inside the shielding copper ring; the side end of the capacitive sensor housing is installed with a tail plug; the key block is installed inside the tail plug; the connecting cable is fixedly connected to the side end of the tail plug; An electric push rod is installed on one side of the capacitive sensor housing; the top end of the electric push rod is fixedly connected with a positioning arc plate; the top end of the positioning arc plate is fixedly connected with a motor; the output end of the motor is installed with a cleaning disc; multiple groups of plastic scraping blades are fixedly connected to the side end of the cleaning disc; a soft brush is fixedly connected to the side end of the cleaning disc, and a soft brush is fixedly connected to one side of the plastic scraping blade.

2. A device for preventing residues in a capacitive sensor according to the method for preventing residues in a capacitive sensor described in claim 1, characterized in that: One end of the positioning arc plate is fixedly connected with a push rod; a conduit is installed at the top end of the cleaning disc; a water pipe is fixedly connected to the side end of the conduit; a plug block is slidably connected inside the conduit; the side end of the plug block is fixedly connected with a push rod.

3. A device for preventing residues in a capacitive sensor according to the device for preventing residues in a capacitive sensor described in claim 2, characterized in that: Multiple groups of rubber support elastic rods are fixedly connected to the side end of the positioning arc plate; one end of the plastic scraping blade is connected with a rubber support elastic rod.

4. A device for preventing residues in a capacitive sensor according to the device for preventing residues in a capacitive sensor described in claim 3, characterized in that: The output end of the motor is fixedly connected with a retaining plate; a limiting telescopic rod is fixedly connected to the side end of the retaining plate; the connecting plate is fixedly connected to the end of the limiting telescopic rod away from the retaining plate; a spring is fixedly connected to the side end of the retaining plate.

5. A device for preventing residues in a capacitive sensor according to the device for preventing residues in a capacitive sensor described in claim 4, characterized in that: A cleaning disc is installed at the side end of the connecting plate, and the cleaning disc is connected to the connecting plate by Velcro; a tearing piece is fixedly connected to one end of the positioning arc plate.

6. A device for preventing residues in a capacitive sensor according to the device for preventing residues in a capacitive sensor described in claim 5, characterized in that: A positioning sleeve is rotatably connected to the outer side wall of the capacitive sensor housing; the positioning sleeve is threadedly connected to the capacitive sensor housing.

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