CN218913114U

CN218913114U - Water pump capable of preventing liquid from flowing back

Info

Publication number: CN218913114U
Application number: CN202223500053.9U
Authority: CN
Inventors: 胡成毅
Original assignee: Huizhou Yingyi Motor Co ltd
Current assignee: Huizhou Yingyi Motor Co ltd
Priority date: 2022-12-23
Filing date: 2022-12-23
Publication date: 2023-04-25
Anticipated expiration: 2032-12-23

Abstract

The utility model relates to a water pump capable of preventing liquid from flowing back, which comprises an upper cover, a non-return assembly, a lower cover, an air pump assembly and a motor; the upper cover, the check assembly, the lower cover, the air pump assembly and the motor are sequentially connected; the check assembly comprises a pressure spring, a water stopping cushion block, a copper pipe, a piston cap and a check valve, wherein a water inlet groove is formed in the lower cover, a water inlet hole and a mounting hole are formed in the bottom of the water inlet groove, the check valve is inserted into the mounting hole, the check valve movably seals the water inlet hole, a water outlet groove is formed in one surface, facing away from the water inlet groove, of the lower cover, a communication hole is further formed in the lower cover, the water inlet groove is communicated with the water outlet groove through the communication hole, the piston cap is arranged in the water outlet groove, and the piston cap movably seals the communication hole; the upper cover is provided with a water inlet, a water outlet and a water outlet channel, the pressure spring, the water stop cushion block and the copper pipe are sequentially arranged in the water outlet channel, the pressure spring is in butt joint with the side wall of the water outlet channel, one end of the copper pipe is in movable butt joint with the water stop cushion block, and the other side of the copper pipe is in movable butt joint with the piston cap.

Description

Water pump capable of preventing liquid from flowing back

Technical Field

The utility model relates to the technical field of water pumps, in particular to a water pump capable of preventing liquid from flowing back.

Background

A water pump is a machine that delivers or pressurizes a liquid. It transmits mechanical energy of prime mover or other external energy to liquid to increase its energy, and is mainly used for conveying liquid including water, oil, acid-alkali liquor, emulsion and suspoemulsion.

Most of the existing water pumps have the phenomenon that liquid remained in the water outlet pipe flows back into the water pump after the work is finished. This results in the next time the pump is used, contamination between different liquids occurs.

Disclosure of Invention

The present utility model is directed to a water pump for preventing backflow of liquid, which solves the above-mentioned problems of the related art.

The technical scheme of the utility model is that the water pump for preventing liquid from flowing back comprises an upper cover, a check assembly, a lower cover, an air pump assembly and a motor; the upper cover, the check assembly, the lower cover, the air pump assembly and the motor are sequentially connected; the check assembly comprises a pressure spring, a water stopping cushion block, a copper pipe, a piston cap and a check valve, wherein a water inlet groove is formed in the lower cover, a water inlet hole and a mounting hole are formed in the bottom of the water inlet groove, the check valve is inserted into the mounting hole and movably seals the water inlet hole, a water outlet groove is formed in the surface, facing away from the water inlet groove, of the lower cover, a communication hole is further formed in the lower cover, the water inlet groove is communicated with the water outlet groove through the communication hole, the piston cap is arranged in the water outlet groove, and the piston cap movably seals the communication hole; the upper cover is provided with a water inlet, a water outlet and a water outlet channel, the pressure spring, the water stop cushion block and the copper pipe are sequentially arranged in the water outlet channel, the pressure spring is in butt joint with the side wall of the water outlet channel, one end of the copper pipe is in movable butt joint with the water stop cushion block, the other side of the copper pipe is in movable butt joint with the piston cap, a runner cavity is arranged in the copper pipe, the runner cavity is communicated with the water outlet channel, the water stop cushion block is in movable seal with one side of the runner cavity, and the other side of the runner cavity is communicated with the water outlet channel; the water inlet is communicated with the water inlet channel, and the water outlet is communicated with the water outlet channel; the motor is in driving connection with the air pump component, the air pump component drives the check valve to move, and meanwhile the air pump component is used for manufacturing air pressure difference.

In one embodiment, the upper cover is provided with a plurality of limiting blocks in a protruding mode at a position close to the water outlet channel, each limiting block is arranged outside one side of the water outlet channel in a surrounding mode, and one end of the pressure spring is clamped between each limiting block.

In one embodiment, the cross-sectional size of the compression spring decreases gradually from an end near the upper cover to an end near the piston cap.

In one embodiment, the water pump for preventing the liquid from flowing back further comprises a sealing gasket, one surface of the sealing gasket is connected with the upper cover, and the other surface of the sealing gasket is connected with the lower cover.

In one embodiment, a plurality of mounting blocks are arranged on one surface of the lower cover facing the sealing gasket in a protruding manner, a plurality of mounting grooves are formed in the corresponding positions of the sealing gasket, and each mounting block is inserted into one of the mounting grooves.

In one embodiment, the check valve is umbrella-shaped, and the check valve is provided with an umbrella handle and an umbrella-shaped part, the umbrella handle is connected with the umbrella-shaped part, the umbrella handle is movably arranged in the mounting hole, and the umbrella-shaped part is movably sealed with the water inlet hole in the water inlet groove.

In one embodiment, the umbrella handle of the check valve is provided with a limiting ball in a protruding mode, and the limiting ball is clamped and arranged on one side, far away from the umbrella-shaped portion, of the mounting hole.

In one embodiment, the air pump assembly comprises a plurality of air bags, an upper shell, a swing frame, a transmission shaft, an eccentric wheel and a lower shell; the upper shell is connected with the lower cover, and the lower shell is connected with the motor; the upper shell is connected with the lower shell, the upper shell is connected with the lower shell to form an accommodating cavity, the air bags, the swing frame, the transmission shaft and the eccentric wheel are sequentially connected, the air bags, the swing frame, the transmission shaft and the eccentric wheel are all arranged in the accommodating cavity, the upper shell is provided with an air vent, the air bags are connected with the side wall of the water inlet groove through the air vent, the lower shell is provided with a transmission port, and the motor is connected with the eccentric wheel in a driving way through the transmission port.

In one embodiment, a steel ball is arranged in the eccentric wheel, and the steel ball is abutted with the transmission shaft.

In one embodiment, the upper cover is provided with a water inlet pipe and a water outlet pipe in a protruding mode at one end, facing away from the lower cover, of the upper cover, the water outlet pipe comprises a first pipe portion and a second pipe portion, the first pipe portion is connected with the upper cover, the second pipe portion is vertically arranged on the second pipe portion, the water inlet is formed in the water inlet pipe, and the water outlet is formed in the second pipe portion.

The beneficial effects provided by the utility model are as follows: a check valve is arranged in the water inlet groove, and the air pump component drives the check valve to movably seal the water inlet hole in the water groove. Specifically, when the water pump absorbs liquid, the air pump component can manufacture air pressure difference, so that the check valve is far away from the water inlet groove, and the liquid can enter the water inlet groove from the water inlet hole; when the water pump drains, the air pump component will squeeze the space in the water inlet tank, the check valve will be against the tank bottom of the water inlet tank, and the check valve will seal the water inlet hole, so that liquid can only flow into the water outlet tank from the communication hole. And a piston cap is arranged in the water outlet tank, and the piston cap movably seals the communication hole, so that when the water inlet tank is filled with liquid, the hydraulic pressure generated by the liquid pushes the piston cap to seal the communication hole, thereby playing the role of preventing the liquid from flowing back. Further, the copper pipe is fixedly arranged between the upper cover and the lower cover, one side of the copper pipe is communicated with the water outlet groove, the other side of the copper pipe is provided with a water stop cushion block, and the water stop cushion block movably seals the copper pipe through the elasticity of the pressure spring. The water stop cushion block is extruded through the liquid in the water outlet groove, so that the liquid passes through the copper pipe to the water outlet channel and is finally discharged out of the water pump. When the water pump stops working, the elastic force of the pressure spring can tightly seal the copper pipe with the water stop cushion block, thereby playing the role of preventing liquid from flowing back. The water pump for preventing liquid backflow has the advantage of well preventing liquid backflow by arranging the non-return assembly.

Drawings

FIG. 1 is a schematic perspective view of a water pump for preventing liquid backflow in one embodiment;

fig. 2 is a schematic exploded perspective view of a water pump for preventing liquid backflow in one embodiment.

Fig. 3 is a schematic exploded perspective view of a water pump for preventing backflow of liquid in another direction according to an embodiment.

In the drawing, 10, a water pump for preventing liquid from flowing back; 100. an upper cover; 110. a water inlet pipe; 111. a water inlet; 120. a water outlet pipe; 121. a first pipe section; 122. a second pipe section; 123. a water outlet; 130. a water outlet channel; 140. a limiting block; 200. a non-return assembly; 210. a pressure spring; 220. a water stop cushion block; 230. copper pipe; 231. a flow channel cavity; 240. a piston cap; 250. a check valve; 251. an umbrella handle; 252. umbrella-shaped part; 253. limiting the round beads; 260. a sealing gasket; 261. a mounting groove; 300. a lower cover; 310. a water inlet tank; 311. a water inlet hole; 312. a mounting hole; 320. a water outlet tank; 330. a communication hole; 340. a mounting block; 400. an air pump assembly; 410. an air bag; 420. an upper housing; 421. a vent; 430. a swing frame; 440. a transmission shaft; 450. an eccentric wheel; 451. steel balls; 460. a lower housing; 461. a transmission port; 500. and a motor.

Detailed Description

It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be combined with each other. The technical solution of the present utility model will be further described below with reference to the accompanying drawings of the embodiments of the present utility model, and the present utility model is not limited to the following specific embodiments.

It should be understood that the same or similar reference numerals in the drawings of the embodiments correspond to the same or similar components. In the description of the present utility model, it should be understood that, if there are terms such as "upper", "lower", "front", "rear", "left", "right", "top", "bottom", etc., that indicate an azimuth or a positional relationship based on the directions or the positional relationships shown in the drawings, it is only for convenience of describing the present utility model and simplifying the description, but not for indicating or suggesting that the apparatus or element to be referred to must have a specific azimuth, be constructed and operated in a specific azimuth, so that the terms describing the positional relationship in the drawings are merely for exemplary illustration and should not be construed as limitations of the present patent, and that the specific meanings of the terms described above may be understood by those skilled in the art according to specific circumstances.

In one embodiment, as shown in fig. 1 and 2, a water pump 10 for preventing backflow of a liquid includes an upper cover 100, a check assembly 200, a lower cover 300, an air pump assembly 400, and a motor 500; the upper cover 100, the check assembly 200, the lower cover 300, the air pump assembly 400, and the motor 500 are sequentially connected to each other; the check assembly 200 comprises a pressure spring 210, a water stop cushion block 220, a copper pipe 230, a piston cap 240 and a check valve 250, wherein a water inlet groove 310 is formed in the lower cover 300, a water inlet hole 311 and a mounting hole 312 are formed in the bottom of the water inlet groove 310, the check valve 250 is inserted into the mounting hole 312, the check valve 250 movably seals the water inlet hole 311, a water outlet groove 320 is formed in one surface, facing away from the water inlet groove 310, of the lower cover 300, a communication hole 330 is formed in the lower cover 300, the water inlet groove 310 is communicated with the water outlet groove 320 through the communication hole 330, the piston cap 240 is arranged in the water outlet groove 320, and the piston cap 240 movably seals the communication hole 330; the upper cover 100 is provided with a water inlet 111, a water outlet 123 and a water outlet channel 130, the pressure spring 210, the water stop cushion block 220 and the copper pipe 230 are sequentially arranged in the water outlet channel 130, the pressure spring 210 is abutted against the side wall of the water outlet channel 130, one end of the copper pipe 230 is movably abutted against the water stop cushion block 220, the other side of the copper pipe 230 is movably abutted against the piston cap 240, a runner cavity 231 is arranged in the copper pipe 230, the runner cavity 231 is communicated with the water outlet channel 130, one side of the runner cavity 231 is movably sealed by the water stop cushion block 220, and the other side of the runner cavity 231 is communicated with the water outlet channel 320; the water inlet 111 is communicated with the water inlet tank 310, and the water outlet 123 is communicated with the water outlet channel 130; the motor 500 is in driving connection with the air pump assembly 400, the air pump assembly 400 drives the check valve 250 to move, and the air pump assembly 400 is used for manufacturing an air pressure difference.

Specifically, the check valve 250 is disposed in the water inlet tank 310, and the air pump assembly 400 drives the check valve 250 to movably seal the water inlet hole 311 in the water tank. When the water pump 10 for preventing the backflow of the liquid sucks the liquid, the air pump assembly 400 will make an air pressure difference, so that the check valve 250 is far away from the water inlet tank 310, and the liquid is allowed to enter the water inlet tank 310 from the water inlet hole 311; when the water pump 10 preventing the backflow of the liquid discharges, the air pump assembly 400 will press the space in the water inlet tank 310, the check valve 250 will be against the bottom of the water inlet tank 310, and the check valve 250 will seal the water inlet hole 311 so that the liquid can only flow into the water outlet tank 320 from the communication hole 330. The piston cap 240 is disposed in the water outlet tank 320, and the piston cap 240 movably seals the communication hole 330, so that when the water inlet tank 310 is filled with liquid, the hydraulic pressure generated by the liquid pushes the piston cap 240 to seal the communication hole 330, thereby preventing the liquid from flowing back. Further, the copper pipe 230 is fixedly disposed between the upper cover 100 and the lower cover 300, and one side of the copper pipe 230 is communicated with the water outlet groove 320, the other side of the copper pipe 230 is provided with the water stop pad 220, and the water stop pad 220 movably seals the flow channel cavity 231 of the copper pipe 230 by the elastic force of the compression spring 210. The water stop pad 220 is extruded by the liquid in the water outlet groove 320, so that the liquid passes through the flow channel cavity 231 of the copper pipe 230 to the water outlet channel 130, and finally is discharged out of the water pump 10 for preventing the liquid from flowing back through the water outlet channel. When the water pump 10 for preventing the backflow of the liquid stops working, the elastic force of the compression spring 210 can tightly seal the water stop pad 220 to the copper pipe 230, thereby preventing the backflow of the liquid. The water inlet 111 is used for liquid to enter the water pump 10 for preventing liquid from flowing back, and the water outlet 123 is used for pumping liquid out of the water pump 10 for preventing liquid from flowing back. The water pump 10 for preventing liquid backflow provided by the utility model has a good effect of preventing liquid backflow by arranging the check assembly 200.

In order to enable the compression spring 210 to be stably mounted on the upper cover 100, in one embodiment, as shown in fig. 3, a plurality of limiting blocks 140 are convexly disposed on the upper cover 100 at a position close to the water outlet channel 130, each limiting block 140 is circumferentially disposed outside one side of the water outlet channel 130, and one end of the compression spring 210 is clamped between each limiting block 140. Specifically, three limiting blocks 140 are provided, and three limiting blocks 140 are equidistantly spaced around the water outlet channel 130. And the compression spring 210 can be just clamped between the three limiting blocks 140. With the above arrangement, the compression spring 210 can be tightly coupled with the upper cover 100.

In one embodiment, as shown in fig. 2, the cross-sectional size of the compression spring 210 gradually decreases from one end near the upper cover 100 to one end near the piston cap 240. Specifically, the cross-sectional area of the compression spring 210 near one end of the water stop pad 220 is small, and the cross-sectional area of the compression spring 210 near one end of the upper cover 100 is large. Through the above arrangement, the compression spring 210 has a better elastic force, and two ends of the compression spring 210 are respectively matched with the upper cover 100 and the water stop cushion block 220 for connection.

In order to improve the sealing performance of the water outlet tank 320, in one embodiment, as shown in fig. 2 and 3, the water pump 10 for preventing the backflow of the liquid further includes a sealing gasket 260, one surface of the sealing gasket 260 is connected to the upper cover 100, and the other surface of the sealing gasket 260 is connected to the lower cover 300. Specifically, the sealing gasket 260 is disposed between the upper cover 100 and the lower cover 300, and the sealing gasket 260 surrounds the water outlet groove 320, so that when the upper cover 100 and the lower cover 300 clamp the sealing gasket 260, the sealing gasket 260 has a sealing and waterproof function, thereby preventing liquid from leaking from the water outlet groove 320, and improving the sealing performance of the water outlet groove 320.

In order to accurately and firmly position the sealing gasket 260 on the lower cover 300, in one embodiment, as shown in fig. 2 and 3, a plurality of mounting blocks 340 are convexly disposed on a surface of the lower cover 300 facing the sealing gasket 260, and a plurality of mounting grooves 261 are disposed on the sealing gasket 260 at corresponding positions, and each of the mounting blocks 340 is inserted into one of the mounting grooves 261. Further, three mounting blocks 340 are disposed on the lower cover 300, and each of the mounting blocks 340 is disposed on the lower cover 300 at equal intervals. Three mounting grooves 261 are correspondingly formed in the sealing gasket 260. When the sealing gasket 260 is connected to the lower cover 300, each mounting block 340 is correspondingly disposed in one of the mounting grooves 261, so that the sealing gasket 260 can be accurately and firmly connected to the lower cover 300, and the sealing gasket 260 can achieve a good sealing and water leakage preventing effect.

In order to make the check valve 250 better seal the water inlet 311, in one embodiment, as shown in fig. 2, the check valve 250 has an umbrella shape, and the check valve 250 has an umbrella handle 251 and an umbrella part 252, the umbrella handle 251 is connected to the umbrella part 252, the umbrella handle 251 is movably disposed in the mounting hole 312, and the umbrella part 252 movably seals the water inlet 311 in the water inlet tank 310. Specifically, the surface of the umbrella-shaped portion 252 away from the umbrella handle 251 is formed as an arc surface, and the umbrella-shaped portion 252 is made of rubber, so that the umbrella-shaped portion 252 has flexibility. When the air bag 410 is pressed, the check valve 250 is driven by the air bag 410 to seal the water inlet 311, so that the liquid in the water inlet tank 310 can be discharged out of the water inlet tank 310 only through the communication hole 330. Thereby avoiding liquid backflow.

In order to limit the movement of the check valve 250 in the mounting hole 312, in one embodiment, as shown in fig. 2, a limiting ball 253 is protruding on the umbrella handle 251 of the check valve 250, and the limiting ball 253 is clamped on one side of the mounting hole 312 away from the umbrella 252. Specifically, the limit ball 253 is provided on the umbrella stem 251 of the check valve 250, and the diameter of the limit ball 253 is larger than the aperture of the mounting hole 312. Through the above arrangement, the limit ball 253 is clamped at one side of the mounting hole 312, and cannot pass through the mounting hole 312, so that the umbrella handle 251 can be movably inserted into the mounting hole 312 and cannot fall from the inside of the mounting hole 312.

In one embodiment, as shown in fig. 2 and 3, the air pump assembly 400 includes a plurality of air bags 410, an upper housing 420, a swing frame 430, a transmission shaft 440, an eccentric 450, and a lower housing 460; the upper housing 420 is connected to the lower cover 300, and the lower housing 460 is connected to the motor 500; the upper casing 420 and the lower casing 460 are connected and arranged, the upper casing 420 and the lower casing are connected and internally form a containing cavity, each air bag 410, the swing frame 430, the transmission shaft 440 and the eccentric wheel 450 are sequentially connected and arranged, each air bag 410, the swing frame 430, the transmission shaft 440 and the eccentric wheel 450 are all arranged in the containing cavity, the upper casing 420 is provided with an air vent 421, the air bags 410 are connected with the side wall of the water inlet tank 310 through the air vent 421, the lower casing 460 is provided with a transmission port 461, and the motor 500 is in driving connection with the eccentric wheel 450 through the transmission port 461. Specifically, each of the airbags 410 is disposed on the swing frame 430. The eccentric wheel 450 is driven to rotate by the motor 500, the eccentric wheel 450 drives the swing frame 430 to rotate by the transmission shaft 440, and the swing frame 430 sequentially presses each air bag 410; after the deformation of each extruded air bag 410 is recovered, an air pressure difference is generated, so that the liquid is sucked into the water inlet tank 310 from the water inlet hole 311, and then the liquid in the water inlet tank 310 is pumped out of the water pump 10 for preventing the liquid from flowing back through the water outlet flow passage by extruding each air bag 410.

In this embodiment, the airbag 410 is provided with three. Specifically, the water inlet tank 310 is also provided with 5 three air bags 410 aligned with the three water inlet tanks 310. The eccentric wheel 450 is driven to rotate by the motor 500, the eccentric wheel 450 drives the swing frame 430 to rotate, and the swing frame 430 rotates to press the three air bags 410 in turn; by providing three air bags 410, the water pump 10 for preventing the liquid from flowing back can have stronger water pumping capacity.

In order to enable the transmission shaft 440 to rotate more smoothly, in one embodiment, as shown in fig. 2, a steel ball 451 is disposed in the eccentric 450, and the steel ball 451 abuts against the transmission shaft 440. Specifically, by disposing the steel ball 451 in the eccentric wheel 450, and abutting the steel ball 451 against the transmission shaft 440, when the motor 500 drives the eccentric wheel 450 to rotate, the rotation of the eccentric wheel 450 drives the transmission shaft 440 to move, and by disposing the steel ball 451 in the eccentric wheel 450, the reduction can be achieved

The friction force between the eccentric 450 and the transmission shaft 440 is small, so that the eccentric 4505 can better drive the transmission shaft 440 to rotate.

In one embodiment, as shown in fig. 1, an end of the upper cover 100 facing away from the lower cover 300 is provided with a water inlet pipe 110 and a water outlet pipe 120 in a protruding manner, the water outlet pipe 120 includes a first pipe portion 121 and a second pipe portion 122, the first pipe portion 121 is connected to the upper cover 100, and the second pipe portion 122 is vertically disposed

The second pipe portion 122 is provided with the water inlet 111 formed on the water inlet pipe 110, and the water outlet 0 123 formed on the second pipe portion 122. Specifically, the water outlet pipe 120 formed by combining the first pipe portion 121 and the second pipe portion 122 has a 7-shaped outer shape, and by providing the water outlet pipe 120 in this way, the water outlet pipe 120 can discharge the liquid to the direction perpendicular to the water pump 10 for preventing the backflow of the liquid. Further, the water inlet pipe 110 is used for feeding water to the water pump, and the water outlet pipe 120 is used for discharging water from the water pump.

5 the technical features of the above-described embodiments may be arbitrarily combined, and for brevity of description, all of the possible combinations of the technical features of the above-described embodiments are not described, however, as long as there is no contradiction between the combinations of the technical features, they should be regarded as the scope of the description.

The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.

Claims

1. The water pump capable of preventing liquid from flowing back is characterized by comprising an upper cover, a check assembly, a lower cover, an air pump assembly and a motor;

the upper cover, the check assembly, the lower cover, the air pump assembly and the motor are sequentially connected;

the check assembly comprises a pressure spring, a water stopping cushion block, a copper pipe, a piston cap and a check valve, wherein a water inlet groove is formed in the lower cover, a water inlet hole and a mounting hole are formed in the bottom of the water inlet groove, the check valve is inserted into the mounting hole and movably seals the water inlet hole, a water outlet groove is formed in the surface, facing away from the water inlet groove, of the lower cover, a communication hole is further formed in the lower cover, the water inlet groove is communicated with the water outlet groove through the communication hole, the piston cap is arranged in the water outlet groove, and the piston cap movably seals the communication hole;

the upper cover is provided with a water inlet, a water outlet and a water outlet channel, the pressure spring, the water stop cushion block and the copper pipe are sequentially arranged in the water outlet channel, the pressure spring is in butt joint with the side wall of the water outlet channel, one end of the copper pipe is in movable butt joint with the water stop cushion block, the other side of the copper pipe is in movable butt joint with the piston cap, a runner cavity is arranged in the copper pipe, the runner cavity is communicated with the water outlet channel, the water stop cushion block is in movable seal with one side of the runner cavity, and the other side of the runner cavity is communicated with the water outlet channel; the water inlet is communicated with the water inlet channel, and the water outlet is communicated with the water outlet channel;

the motor is in driving connection with the air pump component, the air pump component drives the check valve to move, and meanwhile the air pump component is used for manufacturing air pressure difference.

2. The water pump for preventing backflow of liquid according to claim 1, wherein the upper cover is provided with a plurality of limiting blocks in a protruding manner at a position close to the water outlet channel, each limiting block is arranged outside one side of the water outlet channel in a surrounding manner, and one end of the pressure spring is clamped between each limiting block.

3. The water pump for preventing backflow of liquid as set forth in claim 1, wherein the cross-sectional size of said compression spring is gradually reduced from an end near said upper cover to an end near said piston cap.

4. The water pump for preventing backflow of liquid of claim 1, further comprising a sealing gasket, one face of the sealing gasket being connected to the upper cover, and the other face of the sealing gasket being connected to the lower cover.

5. The water pump for preventing backflow of liquid as set forth in claim 4, wherein a surface of said lower cover facing said sealing gasket is provided with a plurality of mounting blocks in a convex shape, said sealing gasket is provided with a plurality of mounting grooves at corresponding positions, and each of said mounting blocks is inserted into one of said mounting grooves.

6. The water pump for preventing backflow of liquid according to claim 1, wherein the check valve has an umbrella-shaped outer shape, and the check valve has an umbrella handle portion and an umbrella-shaped portion, the umbrella handle portion is connected to the umbrella-shaped portion, the umbrella handle portion is movably disposed in the mounting hole, and the umbrella-shaped portion movably seals the water inlet hole in the water inlet tank.

7. The water pump for preventing backflow of liquid of claim 6, wherein the umbrella handle portion of the check valve is provided with a limiting ball in a protruding mode, and the limiting ball is clamped and arranged on one side, far away from the umbrella-shaped portion, of the mounting hole.

8. The water pump for preventing backflow of liquid of claim 1, wherein the air pump assembly comprises a plurality of air bags, an upper housing, a swing frame, a transmission shaft, an eccentric wheel and a lower housing; the upper shell is connected with the lower cover, and the lower shell is connected with the motor; the upper shell is connected with the lower shell, the upper shell is connected with the lower shell to form an accommodating cavity, the air bags, the swing frame, the transmission shaft and the eccentric wheel are sequentially connected, the air bags, the swing frame, the transmission shaft and the eccentric wheel are all arranged in the accommodating cavity, the upper shell is provided with an air vent, the air bags are connected with the side wall of the water inlet groove through the air vent, the lower shell is provided with a transmission port, and the motor is connected with the eccentric wheel in a driving way through the transmission port.

9. The water pump for preventing backflow of liquid of claim 8, wherein steel balls are arranged in the eccentric wheel, and the steel balls are abutted with the transmission shaft.

10. The water pump according to any one of claims 1 to 9, wherein a water inlet pipe and a water outlet pipe are provided at one end of the upper cover facing away from the lower cover in a protruding manner, the water outlet pipe comprises a first pipe portion and a second pipe portion, the first pipe portion is connected with the upper cover, the second pipe portion is vertically provided on the second pipe portion, the water inlet is provided on the water inlet pipe, and the water outlet is provided on the second pipe portion.