Water pump with water outlet link hydraulic damping

Abstract

The utility model belongs to water pump technical field, especially point to a kind of water pump with water outlet section belt hydraulic damping, including water outlet section, form the liquid passage in water outlet section, oil cylinder is equipped in water outlet section, inner tube is equipped in oil cylinder, oil passage is formed between oil cylinder and inner tube, oil return hole and throttle hole are equipped on the lateral wall of inner tube, piston is slidably arranged in inner tube, check valve head is connected to piston rod upper end, cavity is equipped in piston, steel ball is equipped in cavity, oil return passage one is equipped in piston rod lower end, oil return passage two is equipped in piston lower end, when piston moves down, steel ball moves up and blocks oil return passage one, oil located below piston enters above piston through throttle hole, oil passage and oil return hole;When piston moves up, steel ball moves down and opens oil return passage one, oil located above piston returns below piston through oil return passage one, cavity and oil return passage two. The utility model can effectively eliminate water hammer effect, and then avoid a series of problems caused by water hammer effect, effectively prolong the service life of water pump.

Description

Technical Field

[0001] This utility model belongs to the field of water pump technology, and specifically refers to a water pump with hydraulic damping at the outlet section. Background Technology

[0002] Chinese utility model patent (publication number CN204921443U, application date 2015.08.21, publication date 2015.12.30) discloses a submersible pump for wells, which is composed of: a coupling, a frame, screws, pins, a pump sleeve, combined pump components, a hexagonal shaft, a bearing body, a shaft sleeve, a guide bearing, a check valve, and a water outlet shell. A flow-through component formed by stacking 4 to 60 combined pump components is provided on the hexagonal shaft inside the pump sleeve. A guide bearing is provided at the upper end of the pump, which cooperates with the coupling to form two-end supports. The combined pump assembly consists of an impeller sleeve, guide vanes, and an impeller. The impeller is housed within the impeller sleeve, with guide vanes on its upper part. The bottom of the impeller sleeve has an inlet, and the lower end face of the impeller inlet ring forms a small-gap plane for axial sealing with the impeller sleeve insert. The impeller is clearance-fitted with the hexagonal shaft. One end of the pump sleeve is fastened to the outlet casing by circumferentially arranged pins and screws, and the other end of the pump sleeve is fastened to the connecting frame in the same way, clamping the combined pump assembly stacked inside the pump sleeve. A check valve and bearing housing are located inside the outlet casing at the top of the pump.

[0003] The shortcomings of the aforementioned submersible pumps for wells are as follows: When the pump stops, the liquid velocity rapidly drops to zero and begins to flow backward. The check valve disc (i.e., valve plate) will abruptly close under the combined effect of the backflowing liquid and its own gravity. This sudden closure causes the liquid's kinetic energy to be instantly converted into pressure energy, generating an extremely high pressure shock wave within the pipeline, forming a water hammer effect. The destructive consequences of the water hammer effect include: 1. Pressure peak: A sudden increase in pressure within the pipeline, potentially exceeding several times the normal pressure; 2. Loud noise: The classic "pipe knocking" or "banging" sound; 3. Equipment damage: Damage to the pump impeller, pump bearings, pump mechanical seal, valves themselves, and pipe connections; 4. System damage: Severe water hammer can lead to pipe rupture, loosening of supports, and safety accidents. Utility Model Content

[0004] The purpose of this invention is to provide a water pump with hydraulic damping at the outlet, which effectively eliminates the water hammer effect, thereby avoiding a series of problems caused by the water hammer effect and effectively extending the service life of the water pump.

[0005] This utility model is implemented as follows: A water pump with hydraulic damping at the outlet section includes an outlet section. A convex ring is provided on the inner wall of the outlet section, forming a fluid passage. A hydraulic cylinder is located below the convex ring within the outlet section. The cylinder has an open upper end and a closed lower end, and is filled with hydraulic oil. The upper end is sealed by a plug. An inner tube is provided within the cylinder, with a gap between the cylinder and the inner tube forming an oil passage. A return oil hole and a throttling orifice located below the return oil hole are provided on the side wall of the inner tube. A piston slides vertically within the inner tube, and a piston rod is provided on the piston. The upper end of the piston rod extends out of the plug and connects to seal the fluid passage. The check valve head of the channel has a cavity inside the piston containing a steel ball. The lower end of the piston rod has a return oil channel one connecting the upper chamber of the piston to the cavity, and the lower end of the piston has a return oil channel two connecting the cavity to the lower chamber of the piston. When the piston moves downward, the steel ball moves upward under the pressure of the hydraulic oil, blocking the first return oil channel. The hydraulic oil located below the piston enters the upper part of the piston through the throttle orifice, the oil passage, and the return oil orifice. When the piston moves upward, the steel ball moves downward under the action of gravity, opening the first return oil channel. The hydraulic oil located above the piston returns to the lower part of the piston through the first return oil channel, the cavity, and the second return oil channel.

[0006] In the above-mentioned water pump with hydraulic damping at the outlet, the inner tube is a circular tube that runs vertically through the pipe. The lower end face of the sealing member protrudes downward to form an upper mounting post, and the inner end face of the oil cylinder protrudes upward to form a lower mounting post. The upper end of the inner tube is fitted over the upper mounting post, and the lower end is fitted over the lower mounting post. A compression spring is provided between the lower mounting post and the piston.

[0007] In the above-mentioned water pump with hydraulic damping at the outlet, the cavity is located below the piston rod, the first oil return channel includes a radial hole and a vertical hole, the outer end of the radial hole is connected to the upper chamber of the piston, the inner end is connected to the upper end of the vertical hole, and the lower end of the vertical hole is connected to the cavity, and the second oil return channel consists of multiple circular holes arranged vertically.

[0008] In the above-mentioned water pump with hydraulic damping at the outlet, the upper end of the piston is provided with a mounting hole for mounting the piston rod, the outer side wall of the lower end of the piston rod is recessed to form an annular groove, the wall of the mounting hole is provided with an annular protrusion embedded in the annular groove, and the piston and the annular protrusion are an integral structure.

[0009] In the above-mentioned water pump with hydraulic damping at the outlet, the outer wall of the sealing member is recessed to form an annular groove, the annular groove is filled with a pressure-accumulating sponge, and the lower end of the sealing member is provided with an oil passage hole that connects the annular groove and the oil passage channel.

[0010] In the above-mentioned water pump with hydraulic damping at the outlet section, a limiting nut for upper limit positioning of the sealing component is screwed to the upper end of the oil cylinder, and dustproof cotton is provided between the limiting nut and the sealing component.

[0011] In the aforementioned water pump with hydraulic damping at the outlet section, the upper end of the piston rod extends out to connect to the check valve head via a sealing component and a limit nut.

[0012] In the aforementioned water pump with hydraulic damping at the outlet, the inner pipe abuts and limits the sealing component.

[0013] In the aforementioned water pump with hydraulic damping at the outlet, the sealing component is fitted with a sealing ring for sealing the gap between the oil cylinder and the sealing component, and an oil seal is fitted on the piston rod for sealing the gap between the piston rod and the sealing component. The upper surface of the sealing component is recessed to form a stepped hole, which includes a large hole and a small hole located below the large hole. The dustproof cotton is located in the large hole, and the oil seal is located in the small hole.

[0014] In the aforementioned water pump with hydraulic damping at the outlet, both the sealing ring and the oil seal are located above the accumulator sponge.

[0015] In the aforementioned water pump with hydraulic damping at the outlet, the outer wall of the sealing member is recessed to form an annular mounting groove, and the sealing ring is disposed within the annular mounting groove.

[0016] In the above-mentioned water pump with hydraulic damping at the outlet section, an annular rubber pad is provided above the convex ring. The inner hole of the annular rubber pad includes a conical hole with a larger diameter at the top and a circular hole located below the conical hole. The lower surface of the check valve head is a downwardly convex arc surface. When the arc surface abuts against the wall of the conical hole, the check valve head blocks the liquid passage.

[0017] In the aforementioned water pump with hydraulic damping at the outlet section, a connecting shaft is provided at the upper end of the piston rod. The diameter of the connecting shaft is smaller than the diameter of the piston rod. The connecting shaft passes through the check valve head and is screwed to the cap nut. The check valve head is limited between the piston rod and the cap nut.

[0018] In the aforementioned water pump with hydraulic damping at the outlet, the walls of the conical hole and the circular hole transition through an arc surface.

[0019] In the aforementioned water pump with hydraulic damping at the outlet, the connecting shaft and the piston rod are an integral structure.

[0020] In the above-mentioned water pump with hydraulic damping at the outlet section, multiple support plates are provided between the oil cylinder and the outlet section, and a liquid outlet channel is formed between two adjacent support plates.

[0021] In the aforementioned water pump with hydraulic damping at the outlet section, the inner end of the support plate is fixed to the oil cylinder by welding, and the outer end is fixed to the outlet section by welding.

[0022] In the above-mentioned water pump with hydraulic damping at the outlet section, the outlet section has a liquid inlet at the lower end and a liquid outlet at the upper end. The liquid outlet has an internal thread that is screwed into the pipeline, and the outer circle of the liquid outlet is hexagonal. The outlet section has an installation plate with lifting holes.

[0023] The outstanding advantages of this utility model compared to the prior art are: This invention features a hydraulic cylinder filled with hydraulic oil within the water outlet section. An inner tube is installed inside the cylinder, forming an oil passage between the cylinder and the inner tube. A return oil hole and a throttling hole are located on the side wall of the inner tube. A piston, sliding within the inner tube, is positioned below the check valve head. The throttling hole allows the check valve head to slowly move downwards, effectively eliminating the water hammer effect and preventing a series of problems caused by water hammer, thus extending the water pump's service life. Simultaneously, a cavity is created inside the piston, containing steel balls. A first return oil passage is located at the lower end of the piston rod, and a second return oil passage is located at the lower end of the piston. When the piston moves downwards, the steel balls block the first return oil passage, allowing for a slow downward movement. When the piston moves upwards, the steel balls open the first return oil passage, enabling a rapid upward movement of the piston. This allows the check valve head to quickly open the liquid passage without affecting the water pump's output speed. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of the check valve head of this utility model opening the liquid passage.

[0025] Figure 2 yes Figure 1 Enlarged view of point A.

[0026] Figure 3 This is a cross-sectional view of the check valve head of this utility model, which blocks the liquid passage.

[0027] Figure 4 yes Figure 3 Enlarged view of point B.

[0028] Reference numerals: 1. Water outlet joint; 2. Convex ring; 3. Liquid passage; 4. Oil cylinder; 5. Sealing component; 6. Inner tube; 7. Oil passage; 8. Oil return hole; 9. Throttling orifice; 10. Piston; 11. Piston rod; 12. Check valve head; 13. Cavity; 14. Steel ball; 15. Oil return passage one; 15a. Radial hole; 15b. Vertical hole; 16. Oil return passage two; 17. Upper mounting post; 18. Lower mounting post; 19. Compression spring; 20. Annular protrusion; 21. Accumulator sponge; 22. Oil passage hole; 23. Limit nut; 24. Dustproof cotton; 25. Sealing ring; 26. Oil seal; 27. Annular rubber pad; 28. Support plate; 29. ​​Connecting shaft; 30. Cap nut. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments. See also: Figure 1 —4: A water pump with hydraulic damping at the outlet section includes an outlet section 1. A convex ring 2 is provided on the inner wall of the outlet section 1, forming a liquid passage 3 within the convex ring 2. A hydraulic cylinder 4 is located below the convex ring 2 within the outlet section 1. The hydraulic cylinder 4 is open at the top and closed at the bottom, filled with hydraulic oil, and its upper end is sealed by a sealing element 5. An inner tube 6 is provided within the hydraulic cylinder 4, with a gap between the cylinder 4 and the inner tube 6 forming an oil passage 7. A return oil hole 8 and a throttling hole 9 located below the return oil hole 8 are provided on the side wall of the inner tube 6. A piston 10 slides vertically within the inner tube 6, and a piston rod 11 is provided on the piston 10. The upper end of the piston rod 11 extends out of the sealing element 5 and connects to a check valve head 12 for sealing the liquid passage 3. The piston 10 has a cavity 13 inside, and a steel ball 14 is placed inside the cavity 13. The lower end of the piston rod 11 has a return oil channel 15 connecting the upper chamber of the piston 10 and the cavity 13. The lower end of the piston 10 has a return oil channel 2 16 connecting the cavity 13 and the lower chamber of the piston 10. When the piston 10 moves downward, the steel ball 14 moves upward under the action of hydraulic oil pressure to block the return oil channel 15. The hydraulic oil located below the piston 10 enters the upper part of the piston 10 through the throttle hole 9, the oil passage 7, and the return oil hole 8. When the piston 10 moves upward, the steel ball 14 moves downward under the action of gravity to open the return oil channel 15. The hydraulic oil located above the piston 10 returns to the lower part of the piston 10 through the return oil channel 15, the cavity 13, and the return oil channel 2 16.

[0030] The working principle of this utility model is as follows: Figure 1-4 As shown, when the water pump suddenly stops, the liquid pressure in the pipeline disappears instantly, and the liquid flows downwards due to its own gravity. The check valve head 12 is subjected to the gravity of the liquid and pushes the piston 10 downwards. The piston 10 is subjected to a downward force and begins to move downwards, squeezing the hydraulic oil below it. The hydraulic oil pushes the steel ball 14 upwards to block the return oil passage 15. The hydraulic oil located below the piston 10 enters above the piston 10 through the throttle hole 9, the oil passage 7, and the return oil hole 8. Due to the throttling effect of the throttle hole 9, the flow of hydraulic oil is resisted, thereby generating a damping force, which effectively slows down the downward movement speed of the piston 10. The piston 10 and the check valve head 12 move downwards slowly until the check valve head 12 falls onto the convex ring 2 to block the liquid passage 3.

[0031] When the water pump restarts, initially, the check valve head 12 is pressured by the liquid inside the water pump, causing it to tend to open. When the upward pressure of the water pump on the check valve head 12 exceeds the gravity of the liquid in the pipeline, the check valve head 12 moves upward, causing the piston 10 to move upward. The steel ball 14 moves downward under the action of gravity, opening the return oil passage 15. The hydraulic oil above the piston 10 returns to the bottom of the piston 10 through the return oil passage 15, cavity 13, and return oil passage 2 16, achieving a rapid rise of the piston 10 until the check valve head 12 fully opens the liquid passage 3.

[0032] This invention features a hydraulic cylinder 4 filled with hydraulic oil inside the water outlet section 1. An inner tube 6 is installed inside the cylinder 4, forming an oil passage 7 between the cylinder 4 and the inner tube 6. A return oil hole 8 and a throttling hole 9 are provided on the side wall of the inner tube 6. A piston 10, sliding within the inner tube 6, is positioned below the check valve head 12. The throttling effect of the throttling hole 9 on the hydraulic oil allows the check valve head 12 to slowly descend. The check valve head 12 falls onto the convex ring 2 at a controlled and stable speed, rather than suddenly slamming onto it, effectively eliminating the water hammer effect and thus preventing water hammer. The system effectively extends the service life of the water pump by addressing a series of problems caused by the water hammer effect. Simultaneously, a cavity is provided inside the piston 10, with steel balls 14 inside. A first oil return channel 15 is provided at the lower end of the piston rod 11, and a second oil return channel 16 is provided at the lower end of the piston 10. When the piston 10 moves downward, the steel balls 14 block the first oil return channel 15, not affecting the slow downward movement of the piston 10. When the piston 10 moves upward, the steel balls 14 open the first oil return channel 15, enabling the piston 10 to move upward rapidly. This allows the check valve head 12 to quickly open the liquid passage 3 without affecting the water pump's discharge speed.

[0033] Furthermore, the diameter of the throttling orifice 9 is smaller than the diameters of the return oil channel 15, the return oil channel 2 16, and the return oil hole 8.

[0034] Preferably, the diameter of the throttling orifice 9 is 1mm-2mm.

[0035] Furthermore, multiple throttling orifices 9 are provided vertically.

[0036] Water pump installation structure: such as Figure 1-4 As shown, the inner tube 6 is a circular tube that runs vertically through the pipe. The lower end face of the sealing member 5 protrudes to form an upper mounting post 17, and the inner end face of the oil cylinder 4 protrudes to form a lower mounting post 18. The upper end of the inner tube 6 is fitted over the upper mounting post 17, and the lower end is fitted over the lower mounting post 18. A compression spring 19 is provided between the lower mounting post 18 and the piston 10. The compression spring 19 is provided to assist in opening the check valve head 12. At the same time, when the water pump is used for the first time and there is no water in the pipeline, the check valve head 12 opens the liquid passage 3 under the elastic force of the compression spring 19.

[0037] The upper end of the inner tube 6 is sealed by the upper mounting post 17, and the lower end is sealed by the lower mounting post 18.

[0038] The specific structures of oil return channels 15 and 16, and their installation with the cavity 13: The cavity 13 is located below the piston rod 11. Oil return channel 15 includes a radial hole 15a and a vertical hole 15b. The outer end of the radial hole 15a connects to the upper chamber of the piston 10, and the inner end connects to the upper end of the vertical hole 15b. The lower end of the vertical hole 15b connects to the cavity 13. Oil return channel 16 consists of multiple vertically arranged circular holes. The structure is simple and easy to process and install.

[0039] The piston 10 and piston rod 11 are mounted in the following manner: The upper end of the piston 10 has a mounting hole for mounting the piston rod 11; the lower end of the piston rod 11 has an annular groove formed by an inward recess on its outer side wall; the mounting hole wall has an annular protrusion 20 embedded in the annular groove; the piston 10 and the annular protrusion 20 are integrally formed. The structure is simple and easy to process and install.

[0040] Furthermore, the outer wall of the sealing member 5 is recessed to form an annular groove, the annular groove is filled with a pressure-accumulating sponge 21, and the lower end of the sealing member 5 is provided with an oil passage hole 22 that connects the annular groove and the oil passage channel 7.

[0041] The pressure-accumulating sponge 21 is an oil-resistant microporous foam material. Its main functions are as follows: When the piston 10 moves downward and the hydraulic oil is pressurized, some of the hydraulic oil enters the annular groove through the oil hole 22, and the sponge is compressed, thereby creating a pressure-accumulating space. The oil inside the entire system reaches a balance, thus achieving force balance. The pressure-accumulating sponge 21 absorbs part of the hydraulic oil pressure to prevent excessive pressure. When the piston 10 moves upward, cavitation is prone to occur in the cavity below the piston 10. At this time, the pressure-accumulating sponge 21 expands, discharging the hydraulic oil in the annular groove and pushing the oil to smoothly fill the cavity below the piston 10, thereby continuously maintaining the oil pressure and preventing cavitation.

[0042] To prevent external dust, mud, and other contaminants from entering the oil cylinder 4 and contaminating the hydraulic oil, thus extending its service life, a limiting nut 23 is screwed onto the upper end of the oil cylinder 4 to limit the upper limit of the sealing component 5. A dustproof cotton 24 is provided between the limiting nut 23 and the sealing component 5.

[0043] Furthermore, the upper end of the piston rod 11 extends out to connect the sealing piece 5 and the limit nut 23 to the check valve head 12.

[0044] Furthermore, the inner tube 6 abuts and limits the sealing component 5.

[0045] To prevent oil leakage, the sealing component 5 is fitted with a sealing ring 25 to seal the gap between the oil cylinder 4 and the sealing component 5. The piston rod 11 is fitted with an oil seal 26 to seal the gap between the piston rod 11 and the sealing component 5. The upper surface of the sealing component 5 is recessed to form a stepped hole, which includes a large hole and a small hole located below the large hole. The dustproof cotton 24 is located in the large hole, and the oil seal 26 is located in the small hole.

[0046] Furthermore, both the sealing ring 25 and the oil seal 26 are located above the pressure-accumulating sponge 21.

[0047] Installation structure of sealing ring 25: The outer side wall of the sealing member 5 is recessed to form an annular installation groove, and the sealing ring 25 is disposed in the annular installation groove.

[0048] In order for the check valve head 12 to better seal the liquid passage 3, an annular rubber pad 27 is provided above the convex ring 2. The inner hole of the annular rubber pad 27 includes a conical hole with a larger diameter at the top and a circular hole located below the conical hole. The lower surface of the check valve head 12 is a downwardly convex arc surface. When the arc surface abuts against the wall of the conical hole, the check valve head 12 blocks the liquid passage 3.

[0049] Connection structure between piston rod 11 and check valve head 12: The upper end of piston rod 11 is provided with a connecting shaft 29. The diameter of connecting shaft 29 is smaller than the diameter of piston rod 11. Connecting shaft 29 passes through check valve head 12 and is screwed to cap nut 30. Check valve head 12 is limited between piston rod 11 and cap nut 30.

[0050] Furthermore, the walls of the conical hole and the circular hole are transitioned by an arc surface.

[0051] To reduce assembly steps and ensure a secure and reliable connection, the connecting shaft 29 and the piston rod 11 are an integral structure.

[0052] Installation structure of hydraulic cylinder 4 and water outlet section 1: as follows Figure 1-4 As shown, multiple support plates 28 are provided between the oil cylinder 4 and the water outlet section 1, and a liquid outlet channel is formed between two adjacent support plates 28.

[0053] The support plate 28 can be installed by welding the inner end of the support plate 28 to the oil cylinder 4 and welding the outer end to the water outlet section 1.

[0054] The support plate 28 can also be installed in such a way that the support plate 28, the oil cylinder 4 and the water outlet section 1 are integrally cast.

[0055] Furthermore, the water outlet section 1 has a liquid inlet at the lower end and a liquid outlet at the upper end. The liquid outlet has an internal thread for connecting to the pipeline, which facilitates pipeline connection. The outer circle of the liquid outlet is hexagonal, which facilitates force bearing. The water outlet section 1 has an installation plate with a hanging hole for easy suspension.

[0056] The enormous kinetic and pressure energy of the fluid in the pipeline is used to push the piston 10 to squeeze the hydraulic oil. In this process, the kinetic energy of the hydraulic oil is converted into pressure energy at the throttle orifice 9, and finally converted into heat energy through friction and dissipated.

[0057] The above embodiments are only one of the preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes made in accordance with the shape, structure and principle of this utility model should be covered within the protection scope of this utility model.

Claims

1. A water pump with hydraulic damping at the outlet, characterized in that: The system includes a water outlet section (1), with a convex ring (2) on its inner wall. A liquid passage (3) is formed inside the convex ring (2). A cylinder (4) is located below the convex ring (2) inside the water outlet section (1). The cylinder (4) is open at the top and closed at the bottom. The cylinder (4) is filled with hydraulic oil, and its upper end is sealed by a sealing element (5). An inner tube (6) is provided inside the cylinder (4). A gap is left between the cylinder (4) and the inner tube (6) to form an oil passage (7). A return oil hole (8) and a throttling hole (9) located below the return oil hole (8) are provided on the side wall of the inner tube (6). A piston (10) is vertically slid inside the inner tube (6). A piston rod (11) is provided on the piston (10). The upper end of the piston rod (11) extends out of the sealing element (5) and connects to a check valve head (12) used to seal the liquid passage (3). A cavity (13) is provided, and a steel ball (14) is provided inside the cavity (13). The lower end of the piston rod (11) is provided with a return oil channel one (15) connecting the upper chamber of the piston (10) and the cavity (13). The lower end of the piston (10) is provided with a return oil channel two (16) connecting the cavity (13) and the lower chamber of the piston (10). When the piston (10) moves down, the steel ball (14) moves up under the action of hydraulic oil pressure to block the return oil channel one (15). The hydraulic oil located below the piston (10) enters the upper part of the piston (10) through the throttle hole (9), the oil passage (7), and the return oil hole (8). When the piston (10) moves up, the steel ball (14) moves down under the action of gravity to open the return oil channel one (15). The hydraulic oil located above the piston (10) returns to the lower part of the piston (10) through the return oil channel one (15), the cavity (13), and the return oil channel two (16).

2. A water pump with hydraulic damping at the outlet section according to claim 1, characterized in that: The inner tube (6) is a circular tube that runs through the top and bottom. The lower end face of the sealing member (5) protrudes to form an upper mounting post (17), and the inner end face of the oil cylinder (4) protrudes to form a lower mounting post (18). The upper end of the inner tube (6) is fitted outside the upper mounting post (17), and the lower end is fitted outside the lower mounting post (18). A compression spring (19) is provided between the lower mounting post (18) and the piston (10).

3. A water pump with hydraulic damping at the outlet section according to claim 1, characterized in that: The cavity (13) is located below the piston rod (11). The first oil return channel (15) includes a radial hole (15a) and a vertical hole (15b). The outer end of the radial hole (15a) is connected to the upper chamber of the piston (10), and the inner end is connected to the upper end of the vertical hole (15b). The lower end of the vertical hole (15b) is connected to the cavity (13). The second oil return channel (16) consists of multiple circular holes arranged vertically.

4. A water pump with hydraulic damping at the outlet section according to claim 1, characterized in that: The piston (10) has an mounting hole at its upper end for mounting the piston rod (11). The piston rod (11) has an annular groove formed by the concave outer wall of its lower end. The mounting hole has an annular protrusion (20) embedded in the annular groove on its wall. The piston (10) and the annular protrusion (20) are an integral structure.

5. A water pump with hydraulic damping at the outlet section according to claim 1, characterized in that: The outer wall of the sealing member (5) is recessed to form an annular groove, and the annular groove is filled with a pressure-accumulating sponge (21). The lower end of the sealing member (5) is provided with an oil passage hole (22) that connects the annular groove and the oil passage channel (7).

6. A water pump with hydraulic damping at the outlet section according to claim 1, characterized in that: The upper end of the cylinder (4) is screwed with a limiting nut (23) to limit the upper position of the sealing component (5), and a dustproof cotton (24) is provided between the limiting nut (23) and the sealing component (5).

7. A water pump with hydraulic damping at the outlet section according to claim 6, characterized in that: The sealing element (5) is fitted with a sealing ring (25) for sealing the gap between the oil cylinder (4) and the sealing element (5). The piston rod (11) is fitted with an oil seal (26) for sealing the gap between the piston rod (11) and the sealing element (5). The upper surface of the sealing element (5) is recessed to form a stepped hole. The stepped hole includes a large hole and a small hole located below the large hole. The dustproof cotton (24) is located in the large hole, and the oil seal (26) is located in the small hole.

8. A water pump with hydraulic damping at the outlet section according to claim 1, characterized in that: An annular rubber pad (27) is provided above the convex ring (2). The inner hole of the annular rubber pad (27) includes a conical hole with a larger diameter at the top and a circular hole located below the conical hole. The lower surface of the check valve head (12) is a convex arc surface. When the arc surface abuts against the wall of the conical hole, the check valve head (12) blocks the liquid passage (3).

9. A water pump with hydraulic damping at the outlet section according to claim 1, characterized in that: Multiple support plates (28) are provided between the oil cylinder (4) and the water outlet section (1), and a liquid outlet channel is formed between two adjacent support plates (28).

Images