A capacitive probe liquid level switch

Abstract

The present invention belongs to the technical field of liquid level switches, and specifically is a capacitive probe liquid level switch, comprising a switch assembly, a processing assembly is arranged inside the switch assembly, a connecting tube is fixed to the bottom end of the switch assembly, a mounting plate is fixed to the bottom end of the connecting tube, a capacitive probe is fixed to the bottom end of the mounting plate, the capacitive probe is electrically connected to the processing assembly, a telescopic assembly for extending the capacitive probe is arranged inside the capacitive probe; the telescopic assembly comprises a telescopic cavity opened inside the capacitive probe, a telescopic probe is arranged inside the telescopic cavity; a lifting plate can be lifted and lowered inside the telescopic cavity by driving a threaded rod to rotate through a micro motor, and during the lifting process, the lifting plate drives the telescopic probe to extend and retract inside the telescopic cavity, and the extension length of the telescopic probe can be adjusted according to demand, and the liquid level height range that can be detected by the liquid level switch can be larger by adding the lengths of the capacitive probe and the telescopic probe extending from the telescopic cavity.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid level switches, in particular to a capacitive probe liquid level switch. Background Art

[0002] A liquid level switch is a device that switches on and off based on the liquid level. A mechanical liquid level switch measures the liquid level through a mechanical structure, which can cause internal wear of the mechanical structure after multiple changes in the liquid level. Existing capacitive liquid level switches monitor the liquid level through a capacitive probe to prevent wear during use.

[0003] A patent application with the existing publication number CN115683276A discloses a capacitive liquid level switch, including a housing and a sensing control component arranged in the housing. The capacitive liquid level switch has the advantages of simple structure, high structural strength, wide application range and strong practicality.

[0004] When the above-mentioned technical solution is in use, the height of the liquid level is sensed by the sensing electrode. However, the volumes of different containers are different during use. Therefore, some containers have larger volumes and are deeper inside. When the liquid level is low, the capacitive probe cannot contact the liquid, resulting in the inability to monitor the liquid level inside the large container.

[0005] To this end, the present invention provides a capacitive probe liquid level switch. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a capacitive probe liquid level switch described in the present invention includes a switch component, a processing component is arranged inside the switch component, a connecting tube is fixed to the bottom end of the switch component, a mounting plate is fixed to the bottom end of the connecting tube, a capacitive probe is fixed to the bottom end of the mounting plate, the capacitive probe is electrically connected to the processing component, a telescopic component for extending the capacitive probe is arranged inside the capacitive probe; the telescopic component includes a telescopic cavity opened inside the capacitive probe, and a telescopic probe is arranged inside the telescopic cavity.

[0008] Preferably, the telescopic component further comprises an opening formed below the telescopic cavity, and metal springs are provided on both sides of the opening, and the metal springs are electrically connected to the processing component.

[0009] Preferably, a micro motor is installed in the middle part of the connecting tube, an output gear is fixed to the end of the rotating shaft of the micro motor, a lifting plate is fixed to the top of the telescopic probe, threaded holes are provided on both sides of the top of the lifting plate, the internal threads of the threaded holes are connected to threaded rods, the bottom end of the threaded rod is rotatably connected to the telescopic cavity, a first transmission gear is fixed to the top of the threaded rod, the outside of the threaded rod is rotatably connected to a support plate, the support plate is fixedly connected to the inner wall of the telescopic cavity, and the first transmission gear is meshed with the output gear.

[0010] Preferably, a sealing rubber ring is fixed to the outside of the lifting plate, and the outer diameter of the sealing rubber ring is larger than the inner diameter of the telescopic cavity.

[0011] Preferably, an air outlet hole is provided inside the lifting plate, an air inlet hole is provided at one end of the connecting pipe, an air outlet one-way valve is provided inside the air outlet hole, and an air inlet one-way valve is provided inside the air inlet hole.

[0012] Preferably, an air intake mesh plate is provided at one end of the air intake hole away from the air intake one-way valve plate.

[0013] Preferably, a gear ring is provided at the end of the air intake mesh plate away from the air intake check valve plate, and a cleaning brush is fixed to the end of the gear ring close to the air intake mesh plate, and the end of the cleaning brush away from the gear ring is in close contact with the surface of the air intake mesh plate, and the external thread of the gear ring is connected to a supporting gear, and four supporting gears are provided, and the supporting gear is rotatably connected to the end of the air intake hole close to the air intake mesh plate, and a transmission rod is fixed at one end of one of the supporting gears, and the transmission rod passes through the interior of the connecting pipe, and a second transmission gear is provided inside the connecting pipe, and the second transmission gear is meshingly connected to one of the first transmission gears, and the top end of the second transmission gear is fixedly connected to a toothed disk via a connecting rod, and the connecting rod of the second transmission gear is rotatably connected to the interior of the connecting pipe via a connecting plate, and a gear is fixed at the end of the transmission rod away from the supporting gear, and the gear is meshingly connected to the top end of the toothed disk.

[0014] Preferably, an oil tank is fixed to the top of the lifting plate, four cotton swabs are inserted at equal intervals at the bottom of the oil tank, a brush ring is fixed to the end of the cotton swab away from the oil tank, and a plurality of bristles are fixed at equal intervals on the outside of the brush ring.

[0015] Preferably, a through hole is opened at the top of the oil tank, and an elastic sealing sheet is arranged below the through hole, and the outer diameter of the elastic sealing sheet is larger than the inner diameter of the through hole of the oil tank.

[0016] Preferably, an oil guide pipe is fixed inside the connecting pipe, a top pipe is fixed to the bottom end of the oil guide pipe, the top pipe is arranged in the middle of the connecting pipe, the outer diameter of the top pipe is smaller than the inner diameter of the oil tank through hole, an oil inlet is fixed to the top end of the oil guide pipe, and a sealing plug is arranged inside the oil inlet.

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

[0018] 1. The capacitive probe liquid level switch described in the present invention can lift the lifting plate inside the telescopic cavity by rotating the threaded rod driven by a micro motor. During the lifting process, the lifting plate drives the telescopic probe to extend and retract inside the telescopic cavity. The extension length of the telescopic probe can be adjusted according to demand. By adding the lengths of the capacitive probe and the telescopic probe extending from the telescopic cavity, the liquid level switch can detect a larger range of liquid level heights.

[0019] 2. The capacitive probe liquid level switch described in the present invention fills the space between the lifting plate and the telescopic chamber with a sealing rubber ring, so that when the lifting plate moves downward, the air inside the telescopic chamber can be discharged to the outside through the opening. At this time, the moisture that enters the telescopic chamber through the opening can be discharged to the outside, which can prevent the moisture from affecting the inside of the telescopic chamber. Lubricating oil can be brushed on the inner wall of the telescopic chamber by using the bristles, which can reduce the wear of the sealing rubber ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Figure 1 is a stereogram of the present invention;

[0022] Figure 2 It is a partial structural exploded diagram of the present invention;

[0023] Figure 3 is a cross-sectional view of the mounting plate in the present invention;

[0024] Figure 4 It is a schematic diagram of the threaded rod structure in the present invention;

[0025] Figure 5 It is a schematic diagram of the lifting plate structure in the present invention;

[0026] Figure 6 is a cross-sectional view of the mounting plate in the present invention;

[0027] Figure 7 It is a schematic diagram of the gear ring structure in the present invention;

[0028] Figure 8 It is a schematic diagram of the oil guide pipe structure in the present invention.

[0029] In the figure: 1. switch assembly; 11. processing assembly; 2. connecting pipe; 21. micro motor; 211. output gear; 22. threaded rod; 221. first transmission gear; 222. support plate; 23. air inlet; 231. air inlet check valve; 232. air inlet mesh plate; 233. gear ring; 234. cleaning brush; 235. support gear; 24. second transmission gear; 241. toothed disc; 242. transmission rod; 3. installation Mounting plate; 4. Capacitance probe; 41. Telescopic cavity; 42. Metal spring; 43. Opening; 5. Telescopic probe; 51. Lifting plate; 511. Threaded hole; 52. Air outlet; 521. Air outlet one-way valve plate; 53. Sealing rubber ring; 54. Oil tank; 541. Cotton swab; 542. Brush ring; 543. Brush; 544. Elastic sealing plate; 55. Oil guide pipe; 551. Top pipe; 552. Oil inlet; 553. Sealing plug. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0031] like Figures 1 to 3 As shown, a capacitive probe liquid level switch according to an embodiment of the present invention comprises a switch assembly 1, a processing assembly 11 is arranged inside the switch assembly 1, a connecting tube 2 is fixed to the bottom end of the switch assembly 1, a mounting plate 3 is fixed to the bottom end of the connecting tube 2, a capacitive probe 4 is fixed to the bottom end of the mounting plate 3, the capacitive probe 4 is electrically connected to the processing assembly 11, a telescopic assembly for extending the capacitive probe 4 is arranged inside the capacitive probe 4; the telescopic assembly comprises a telescopic cavity 41 opened inside the capacitive probe 4, and a telescopic probe 5 is arranged inside the telescopic cavity 41;

[0032] When the capacitive probe liquid level switch is used, the mounting plate 3 is bolted to the top of the container whose liquid level needs to be monitored, the capacitive probe 4 is inserted into the interior of the container, and then the switch component 1 is connected to an external power supply. During use, the capacitive probe 4 is immersed in the liquid, and the liquid fills between the plates of the capacitive probe 4 to form an equivalent capacitor. When the liquid level changes, when the liquid level rises, the contact area between the liquid and the probe increases, and the capacitance value also increases accordingly. When the liquid level drops, the capacitance value decreases synchronously. The capacitance value of the capacitive probe 4 is transmitted to the processing component 11 in real time, and the processing component 11 The circuit 1 is composed of a voltage stabilizing protection circuit, a conduction and radiation anti-interference circuit, a calibration data storage circuit and an output end protection circuit. The processing component 11 stores the capacitance value of the capacitance probe 4 and transmits an electrical signal to the outside through the switch component 1. The switch of the external device can be controlled by the electrical signal. When in use, the volume of some containers is large, and the capacitance probe 4 inside is deep. When the liquid level is lower than the bottom height of the capacitance probe 4, it cannot monitor the liquid inside the container. At this time, the telescopic probe 5 extends from the inside of the telescopic cavity 41. The telescopic probe 5 can extend the length of the capacitance probe 4, which can make the capacitance probe 4 more applicable.

[0033] like Figures 1 to 3 As shown, the telescopic assembly further includes an opening 43 provided below the telescopic cavity 41, and metal springs 42 are provided on both sides of the opening 43, and the metal springs 42 are electrically connected to the processing assembly 11;

[0034] When the telescopic probe 5 extends from the telescopic cavity 41, the telescopic probe 5 will pass through the opening 43. When passing through the opening 43, the metal springs 42 on both sides will contact the two sides of the telescopic probe 5. At this time, the telescopic probe 5 is electrically connected to the processing component 11 through the metal springs 42, so that the length of the capacitive probe 4 can be extended through the telescopic probe 5.

[0035] like Figures 1 to 5 As shown, a micro motor 21 is installed in the middle of the connecting tube 2, an output gear 211 is fixed to the end of the rotating shaft of the micro motor 21, a lifting plate 51 is fixed to the top of the telescopic probe 5, threaded holes 511 are provided on both sides of the top of the lifting plate 51, a threaded rod 22 is threadedly connected to the inner thread of the threaded hole 511, the bottom end of the threaded rod 22 is rotatably connected to the telescopic cavity 41, a first transmission gear 221 is fixed to the top of the threaded rod 22, a support plate 222 is rotatably connected to the outside of the threaded rod 22, the support plate 222 is fixedly connected to the inner wall of the telescopic cavity 41, and the first transmission gear 221 is meshedly connected to the output gear 211;

[0036] When the telescopic probe 5 is extended from the inside of the telescopic cavity 41, the micromotor 21 is started to drive the output gear 211 to rotate, and the output gear 211 drives the two first transmission gears 221 to rotate. When the first transmission gear 221 rotates, it drives the threaded rod 22 to rotate. At this time, the threaded rod 22 drives the lifting plate 51 to move downward through the threaded hole 511. When the lifting plate 51 moves downward, it drives the telescopic probe 5 to move downward. When it moves to a suitable position, the micromotor 21 is stopped. At this time, the extended length of the telescopic probe 5 plus the length of the capacitance probe 4 is the current monitorable liquid level height range. When a larger monitoring range is not needed, the micromotor 21 is started to rotate in the opposite direction to retract the telescopic probe 5 into the telescopic cavity 41, so that the liquid level height range monitored by the capacitance probe 4 can be automatically adjusted.

[0037] like Figures 1 to 5 As shown, a sealing rubber ring 53 is fixed to the outside of the lifting plate 51, and the outer diameter of the sealing rubber ring 53 is larger than the inner diameter of the telescopic cavity 41;

[0038] During the lifting process of the lifting plate 51 , the sealing rubber ring 53 fills the gap between the lifting plate 51 and the telescopic cavity 41 , thereby isolating the space above and below the lifting plate 51 and preventing moisture from entering the space above the lifting plate 51 and affecting the micro motor 21 .

[0039] like Figures 1 to 5 As shown, an air outlet hole 52 is provided inside the lifting plate 51, an air inlet hole 23 is provided at one end of the connecting pipe 2, an air outlet check valve 521 is provided inside the air outlet hole 52, and an air inlet check valve 231 is provided inside the air inlet hole 23;

[0040] When the telescopic probe 5 is extended from the inside of the telescopic cavity 41, the lifting plate 51 moves downward inside the telescopic cavity 41. At this time, the air outlet one-way valve plate 521 inside the air outlet hole 52 is closed, and the space of the telescopic cavity 41 in the area below the lifting plate 51 gradually shrinks. During this process, the lifting plate 51 can discharge the air inside the space of the telescopic cavity 41 in the area below the lifting plate 51 through the gap between the opening 43 and the telescopic probe 5 to the outside of the telescopic cavity 41. During this process, the moisture entering the telescopic cavity 41 through the opening 43 can be discharged to the outside of the telescopic cavity 41 by air, so as to keep the inside of the telescopic cavity 41 in a dry state. At the same time, the space of the telescopic cavity 41 in the area above the lifting plate 51 gradually increases, and the space of the telescopic cavity 41 in the area above the lifting plate 51 generates a negative pressure. In order to balance the pressure inside the telescopic cavity 41, the air inlet one-way valve plate 231 inside the air inlet hole 23 will open as the lifting plate 51 moves downward. At this time, air enters the space of the telescopic cavity 41 in the area above the lifting plate 51, which can balance the pressure inside the telescopic cavity 41.

[0041] When it is necessary to retract the telescopic probe 5 into the telescopic chamber 41 during use, the lifting plate 51 moves upward. At this time, the air inlet check valve 231 inside the air inlet hole 23 is in a closed state. At the same time, the lifting plate 51 rises, which squeezes the air inside the telescopic chamber 41 in the area above the lifting plate 51. The upper air pressure becomes larger and pushes the air outlet check valve 521 through the air outlet hole 52. At this time, the air outlet check valve 521 is pushed open, and air enters the telescopic chamber 41 in the area below the lifting plate 51 through the air outlet hole 52. At this time, the air pressure inside the telescopic chamber 41 can be kept in the original pressure state, which can prevent the telescopic chamber 41 in the area below the lifting plate 51 from generating negative pressure during the upward movement of the lifting plate 51, thereby sucking in moisture inside the container through the opening 43, thereby affecting normal use.

[0042] like Figures 1 to 7 As shown, an air intake mesh plate 232 is provided at one end of the air intake hole 23 away from the air intake check valve plate 231;

[0043] During use, air enters the connecting pipe 2 through the air inlet 23, and there may be dust and impurities in the air. At this time, the air inlet mesh plate 232 can filter out the dust and impurities, thereby preventing the dust and impurities from entering the interior of the connecting pipe 2 and affecting normal use.

[0044] like Figures 1 to 7 As shown, a gear ring 233 is provided at one end of the air intake mesh plate 232 away from the air intake check valve plate 231, and a cleaning brush 234 is fixed at one end of the gear ring 233 close to the air intake mesh plate 232. The end of the cleaning brush 234 away from the gear ring 233 is tightly attached to the surface of the air intake mesh plate 232. The external thread of the gear ring 233 is connected to a supporting gear 235. Four supporting gears 235 are provided. The supporting gears 235 are rotatably connected to one end of the air intake hole 23 close to the air intake mesh plate 232. One end of one of the supporting gears 235 is fixed A transmission rod 242 is provided, the transmission rod 242 runs through the interior of the connecting tube 2, a second transmission gear 24 is provided inside the connecting tube 2, the second transmission gear 24 is meshed and connected with one of the first transmission gears 221, the top of the second transmission gear 24 is fixedly connected with a toothed disc 241 through a connecting rod, the connecting rod of the second transmission gear 24 is rotatably connected to the interior of the connecting tube 2 through a connecting plate, a gear is fixed to the end of the transmission rod 242 away from the supporting gear 235, and the gear is meshed and connected with the top of the toothed disc 241;

[0045] After the air intake mesh plate 232 has filtered out dust and impurities for a long time, its interior will be blocked. At this time, the air intake hole 23 cannot continue to enter the air. Therefore, it is necessary to clean the surface of the air intake mesh plate 232. While the output gear 211 drives the two first transmission gears 221 to rotate, one of the first transmission gears 221 drives the second transmission gear 24 to rotate, and the second transmission gear 24 drives the toothed plate 241 to rotate. The toothed plate 241 drives the transmission rod 242 to rotate through the gear, and the transmission rod 242 drives one of the supporting gears 235 to rotate. The supporting gear 235 drives the ring gear 233 to rotate. The ring gear 233 drives the cleaning brush 234 to clean the surface of the air intake mesh plate 232, so as to prevent the air intake mesh plate 232 from being blocked and causing the air intake hole 23 to be unable to enter the air normally.

[0046] like Figures 1 to 5 As shown, an oil tank 54 is fixed to the top of the lifting plate 51, and four cotton swabs 541 are inserted at equal intervals at the bottom of the oil tank 54. A brush ring 542 is fixed to the end of the cotton swab 541 away from the oil tank 54, and a plurality of bristles 543 are fixed at equal intervals on the outside of the brush ring 542.

[0047] During the use of the sealing rubber ring 53, the lifting plate 51 moves up and down inside the telescopic cavity 41, which will cause wear to the sealing rubber ring 53. Therefore, lubricating oil is applied to the inner wall of the telescopic cavity 41 to reduce the wear of the sealing rubber ring 53 and extend its service life. However, the lubricating oil will be consumed after repeated use, which will aggravate the wear of the sealing rubber ring 53. Therefore, an oil tank 54 is arranged at the top of the lifting plate 51. The interior of the oil tank 54 is filled with lubricating oil. The lubricating oil can be absorbed by dipping a cotton swab 541 into the interior of the oil tank 54. Then the cotton swab 541 transmits the lubricating oil to the brush ring 542. The brush ring 542 evenly disperses the lubricating oil and contacts the interior of the telescopic cavity 41 through the bristles 543. During the up and down movement of the lifting plate 51, the bristles 543 can apply the lubricating oil to the inner wall of the telescopic cavity 41, so as to achieve continuous lubrication of the sealing rubber ring 53 and extend the service life of the sealing rubber ring 53.

[0048] like Figures 1 to 5 As shown, a through hole is formed at the top of the oil tank 54, and an elastic sealing sheet 544 is disposed below the through hole. The outer diameter of the elastic sealing sheet 544 is larger than the inner diameter of the through hole of the oil tank 54;

[0049] When the bristles 543 apply the lubricating oil to the inner wall of the telescopic cavity 41, the lubricating oil inside the brush ring 542 will be consumed. During this process, the cotton swab 541 will continuously absorb the lubricating oil and replenish the inside of the brush ring 542. During the consumption of the lubricating oil inside the oil tank 54, negative pressure will be generated in the upper area inside the oil tank 54. Excessive negative pressure will affect the amount of lubrication absorbed by the cotton swab 541. To prevent this problem, an elastic sealing sheet 544 is provided. After negative pressure is generated inside the oil tank 54, the air pressure above the oil tank 54 is greater than the internal pressure of the oil tank 54. Therefore, the air outside the oil tank 54 will push the elastic sealing sheet 544 to open. At this time, air enters the oil tank 54 through the top through hole. At this time, the internal pressure of the oil tank 54 can be balanced, which can prevent the negative pressure inside the oil tank 54 from causing the cotton swab 541 to absorb the lubricating oil.

[0050] like Figures 1 to 8 As shown, an oil guide pipe 55 is fixed inside the connecting pipe 2, a top pipe 551 is fixed at the bottom end of the oil guide pipe 55, and the top pipe 551 is arranged in the middle of the connecting pipe 2. The outer diameter of the top pipe 551 is smaller than the inner diameter of the through hole of the oil tank 54. An oil inlet 552 is fixed at the top end of the oil guide pipe 55, and a sealing plug 553 is arranged inside the oil inlet 552.

[0051] After long-term use, the internal lubricating oil of the oil tank 54 will be consumed, and the inner wall of the telescopic chamber 41 cannot be lubricated anymore. Therefore, it is necessary to regularly replenish the lubricating oil inside the oil tank 54. When the lifting plate 51 moves to the top position inside the telescopic chamber 41, the top pipe 551 is pushed into the through hole of the oil tank 54 during this process. The top pipe 551 can push open the elastic sealing sheet 544. At this time, the sealing plug 553 is screwed out from the inside of the oil inlet 552, and then the lubricating oil can be poured in through the oil inlet 552. The lubricating oil enters the top pipe 551 through the oil guide pipe 55, and the lubricating oil can be injected into the inside of the oil tank 54 through the top pipe 551. After the replenishment is completed, the sealing plug 553 is screwed into the inside of the oil inlet 552. Then, when the lifting plate 51 descends, the top pipe 551 can be separated from the through hole of the oil tank 54. At this time, the elastic sealing sheet 544 returns to its original position, and the through hole of the oil tank 54 can be protected to prevent the lubricating oil from leaking during use.

[0052] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A capacitive probe liquid level switch, characterized in that: The invention comprises a switch component (1), wherein a processing component (11) is arranged inside the switch component (1), a connecting tube (2) is fixed to the bottom end of the switch component (1), a mounting plate (3) is fixed to the bottom end of the connecting tube (2), a capacitance probe (4) is fixed to the bottom end of the mounting plate (3), the capacitance probe (4) is electrically connected to the processing component (11), and a telescopic component for extending the capacitance probe (4) is arranged inside the capacitance probe (4); The telescopic assembly comprises a telescopic cavity (41) opened inside the capacitance probe (4), and a telescopic probe (5) is arranged inside the telescopic cavity (41); The telescopic component further comprises an opening (43) provided below the telescopic cavity (41), metal springs (42) being provided on both sides of the opening (43), and the metal springs (42) being electrically connected to the processing component (11); A micro motor (21) is installed in the middle of the connecting tube (2), an output gear (211) is fixed to the end of the rotating shaft of the micro motor (21), a lifting plate (51) is fixed to the top of the telescopic probe (5), threaded holes (511) are provided on both sides of the top of the lifting plate (51), a threaded rod (22) is threadedly connected to the inside of the threaded hole (511), the bottom end of the threaded rod (22) is rotatably connected to the telescopic cavity (41), a first transmission gear (221) is fixed to the top of the threaded rod (22), a support plate (222) is rotatably connected to the outside of the threaded rod (22), the support plate (222) is fixedly connected to the inner wall of the telescopic cavity (41), and the first transmission gear (221) is meshingly connected to the output gear (211); A sealing rubber ring (53) is fixed to the outside of the lifting plate (51), and the outer diameter of the sealing rubber ring (53) is larger than the inner diameter of the telescopic cavity (41); An air outlet hole (52) is provided inside the lifting plate (51), an air inlet hole (23) is provided at one end of the connecting pipe (2), an air outlet one-way valve (521) is provided inside the air outlet hole (52), and an air inlet one-way valve (231) is provided inside the air inlet hole (23).

2. A capacitive probe liquid level switch according to claim 1, characterized in that: An air intake mesh plate (232) is provided at one end of the air intake hole (23) away from the air intake one-way valve plate (231).

3. A capacitive probe liquid level switch according to claim 2, characterized in that: A gear ring (233) is provided at one end of the air intake mesh plate (232) away from the air intake check valve plate (231); a cleaning brush (234) is fixed to one end of the gear ring (233) close to the air intake mesh plate (232); one end of the cleaning brush (234) away from the gear ring (233) is in close contact with the surface of the air intake mesh plate (232); a support gear (235) is connected to the outer thread of the gear ring (233); four support gears (235) are provided; the support gears (235) are rotatably connected to one end of the air intake hole (23) close to the air intake mesh plate (232); one end of one of the support gears (235) is fixed to the air intake hole (23). A transmission rod (242) is provided, the transmission rod (242) passing through the interior of the connecting tube (2), a second transmission gear (24) is provided inside the connecting tube (2), the second transmission gear (24) is meshingly connected with one of the first transmission gears (221), the top end of the second transmission gear (24) is fixedly connected with a toothed disc (241) via a connecting rod, the connecting rod of the second transmission gear (24) is rotatably connected to the interior of the connecting tube (2) via a connecting plate, a gear is fixedly provided at one end of the transmission rod (242) away from the supporting gear (235), the gear is meshingly connected with the top end of the toothed disc (241).

4. A capacitive probe liquid level switch according to claim 3, characterized in that: An oil tank (54) is fixed to the top of the lifting plate (51), four cotton swabs (541) are inserted at equal intervals into the bottom of the oil tank (54), a brush ring (542) is fixed to one end of the cotton swab (541) away from the oil tank (54), and a plurality of brush bristles (543) are fixed at equal intervals on the outside of the brush ring (542).

5. A capacitive probe liquid level switch according to claim 4, characterized in that: A through hole is provided at the top of the oil tank (54), and an elastic sealing sheet (544) is provided below the through hole. The outer diameter of the elastic sealing sheet (544) is larger than the inner diameter of the through hole of the oil tank (54).

6. A capacitive probe liquid level switch according to claim 5, characterized in that: An oil guide pipe (55) is fixed inside the connecting pipe (2), a top pipe (551) is fixed at the bottom end of the oil guide pipe (55), the top pipe (551) is arranged in the middle of the connecting pipe (2), the outer diameter of the top pipe (551) is smaller than the inner diameter of the through hole of the oil tank (54), an oil inlet (552) is fixed at the top end of the oil guide pipe (55), and a sealing plug (553) is arranged inside the oil inlet (552).

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