Self-relief differential pressure valve

Abstract

A self-relief differential pressure valve comprises a valve body, a bonnet arranged above the valve body and an opening and closing seat arranged in the middle of the valve body, an opening and closing hole is formed in the opening and closing seat, a water inlet connector is arranged at the left end of the valve body, a water outlet connector is arranged at the right end of the valve body, the water inlet connector is communicated with the water outlet connector through the opening and closing hole, and a bonnet is connected outside the upper end of the bonnet in a threaded mode. A connector is arranged on one side of the valve cover; a water inlet hole is formed in the bottom of the connector; a space defined by the valve cover and the valve bonnet is communicated with the water inlet hole through a water through hole; a deformation groove is formed in the center of the upper surface of the valve bonnet; a pressure limiting hole is formed in the center of the bottom of the deformation groove; a movable hole communicated with the pressure limiting hole is formed in the center of the lower end face of the valve bonnet. The self-relief differential pressure valve not only can automatically adjust the water flow change according to the pressure change, but also can effectively avoid the situation that the opening and closing piece is pressed and deformed due to the fact that the internal pressure is too large when the valve is closed without installing a bypass valve.

Description

Technical Field

[0001] The utility model relates to a pressure differential valve, in particular to a self-relieving pressure differential valve. Background Art

[0002] The differential pressure valve does not require external energy and can automatically adjust based on the pressure changes of the regulated medium itself, automatically eliminating the flow changes caused by the residual pressure head and pressure fluctuations in the pipeline network.

[0003] In the actual use of the differential pressure valve, in some cases, it is necessary to close the differential pressure valve. When the differential pressure valve is closed, the liquid in the water inlet pipe connected to the differential pressure valve cannot flow, and there is a pressure difference in the water inlet pipe. The pressure in the water inlet pipe will exert a huge pressure on the opening and closing parts used to close the differential pressure valve, resulting in a problem of excessive pressure. At this time, the opening and closing parts are very likely to be deformed due to being unable to withstand the high pressure, which eventually causes damage to the differential pressure valve. In order to solve the above problems, a bypass valve is generally installed. Before the differential pressure valve is closed, the bypass valve is opened to reduce the pressure in the pipeline, thereby reducing the pressure acting on the opening and closing parts. However, this solution will lead to the complication of the piping system and the increase in cost. Summary of the Invention

[0004] The utility model aims to solve the existing technical problem by providing a self-releasing pressure differential valve, which can not only automatically adjust the water flow rate according to the pressure change, but also effectively avoid the situation where the opening and closing parts are compressed and deformed due to excessive internal pressure when closing without installing a bypass valve.

[0005] The technical solution adopted by the utility model to solve the above technical problems is:

[0006] The utility model discloses a self-releasing pressure differential valve, comprising a valve body, a valve cap arranged above the valve body and an opening and closing seat arranged in the middle of the valve body, an opening and closing hole is provided on the opening and closing seat, a water inlet joint is provided at the left end of the valve body, a water outlet joint is provided at the right end of the valve body, the water inlet joint is connected with the water outlet joint through the opening and closing hole, a valve cover is externally screwed on the upper end of the valve cap; an interface is provided on one side of the valve cap; a water inlet hole is provided at the bottom of the interface; a space enclosed by the valve cap and the valve cap is connected through a water hole and the water inlet hole; a deformation groove is provided at the center of the upper surface of the valve cap; a pressure limiting hole is provided at the center of the bottom of the deformation groove; a valve cover is provided at the center of the lower end surface of the valve cap There is a movable hole that is connected with the pressure-limiting hole, and the movable hole is coaxial with the opening and closing hole; a handwheel seat is provided at the center of the upper surface of the valve cover; a handwheel matching it is screwed to the outside of the handwheel seat; an adjusting device connected to the handwheel is provided in the pressure-limiting hole; the adjusting device includes a screw rod located in the pressure-limiting hole, and an opening and closing part located in the movable hole is provided at the lower end of the screw rod; the lower end of the opening and closing part is downwardly inserted into the valve body, and a water pressure plate is provided on the outer wall of the lower end of the opening and closing part, and the diameter of the water pressure plate is larger than the diameter of the upper end of the opening and closing hole; a force relief hole is provided at the center of the lower end face of the opening and closing part; the force relief hole is connected with the pressure-limiting hole through a force relief structure provided at the lower end of the screw rod.

[0007] The de-stressing structure includes a center hole arranged at the center of the lower end surface of the screw rod; the lower outer wall of the screw rod located at the pressure limiting hole is provided with a plurality of auxiliary holes that penetrate the upper end of the center hole; the lower end of the screw rod is screwed into the hole opening at the upper end of the de-stressing hole.

[0008] The regulating device also includes a lifting hole provided at the center of the upper end face of the handwheel seat, the lifting hole is connected to the inside of the valve cover; the inner wall of the lower end of the lifting hole is provided with an annular limiting step; a valve stem matching it is provided in the lifting hole; the outer wall of the lower end of the valve stem is provided with a limiting portion that fits with the limiting step, and the limiting portion can limit the upward movement of the valve stem; the upper end of the valve stem passes upward to the outside of the lifting hole and is provided with an adjusting head connected to the handwheel; a diaphragm is provided between the valve cover and the valve cap; a through hole is provided in the center of the diaphragm, and the screw rod passes through through the diaphragm; the outer wall of the screw rod is provided with a ring-shaped positioning portion; the upper surface of the positioning portion is in contact with the lower surface of the diaphragm; the screw rod is externally screwed with an adjusting cap located below the positioning portion; the outer wall of the adjusting cap and the upper inner wall of the pressure-limiting hole are both regular hexagons; a spring is provided outside the screw rod between the upper inner wall of the adjusting cap and the bottom of the pressure-limiting hole; a limiting hole is provided at the center of the lower end face of the valve stem; a limiting head is provided at the center of the upper end face of the screw rod that matches the limiting hole; the outer wall of the limiting head and the inner wall of the limiting hole are both regular hexagons.

[0009] A groove is provided in the center of the upper surface of the handwheel; a through-hole is provided at the bottom of the groove and is connected to the inside of the handwheel; the upper end of the adjusting head is inserted upward into the groove through the through-hole; an annular limiting groove is provided on the outer wall of the upper end of the adjusting head; a plum blossom retaining ring matching it is provided in the limiting groove, and the outer edge of the plum blossom retaining ring protrudes out of the limiting groove and fits with the bottom of the groove; a regular hexagonal rotating hole is provided in the center of the upper end surface of the adjusting head.

[0010] The outer edge of the diaphragm is provided with an annular retaining portion; the upper surface of the valve cap is provided with an annular lower retaining groove; the valve cover is provided with an upper retaining groove opposite to the lower retaining groove; the retaining portion is located between the upper retaining groove and the lower retaining groove.

[0011] The valve body is provided with a hose; both ends of the hose have connecting joints, and the connecting joint at one end of the hose is screwed into the interface.

[0012] The lower surface of the valve body is provided with a left auxiliary joint that is connected to the water inlet joint; the lower surface of the valve body is provided with a right auxiliary joint that is connected to the water outlet joint; the left auxiliary joint and the right auxiliary joint are both screwed with matching plugs.

[0013] A mounting hole communicating with the interior of the valve body is provided on the upper surface of the middle portion, and the lower end of the valve cap is screwed into the mounting hole; glue is applied between the outer wall of the lower end of the valve cap and the inner wall of the mounting hole, and between the outer wall of the lower end of the screw rod and the inner wall of the upper end of the relief hole.

[0014] The beneficial effects of the utility model are:

[0015] Compared with the existing technology, the self-releasing pressure differential valve adopting the structure of the utility model can sense the pressure change through the diaphragm, thereby realizing the up and down movement of the opening and closing parts, and finally changing the opening degree of the upper end orifice of the opening and closing hole, effectively controlling the water flow rate, and when the upper end orifice of the opening and closing hole is closed by the opening and closing part, the water flow is transferred to the pressure limiting hole through the pressure relief structure, so that the water flow pressure is effectively released, achieving a pressure relief effect. At the same time, the diaphragm can also use its own elasticity to further buffer and reduce the water flow pressure, effectively avoiding the situation where the opening and closing parts are deformed and damaged due to excessive pressure when the pressure differential valve is closed. The entire buffering and pressure reduction process does not require a bypass valve to be set on the pipeline system, effectively simplifying the pipeline system and effectively reducing the cost of buffering and pressure reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a cross-sectional view of the self-releasing differential pressure valve of the utility model;

[0017] Figure 2 It is a structural diagram of the self-releasing pressure differential valve of the utility model. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0019] See also Figure 1 、 Figure 2 The utility model provides a self-releasing pressure differential valve, comprising a valve body 1, a valve cap 2 arranged above the valve body 1 and an opening and closing seat 3 arranged in the middle of the valve body 1, an opening and closing hole 4 is provided on the opening and closing seat 3, a water inlet joint 5 is provided at the left end of the valve body 1, and a water outlet joint 6 is provided at the right end of the valve body 1, the water inlet joint 5 is connected with the water outlet joint 6 through the opening and closing hole 4, a valve cap 7 is screwed onto the outer end of the valve cap 2; an interface 8 is provided on one side of the valve cap 7; a water inlet hole 9 is provided at the bottom of the interface 8; the space enclosed by the valve cap 7 and the valve cap 2 is connected with the water inlet hole 9 through a water hole 10; a deformation groove 12 is provided at the center of the upper surface of the valve cap 2; a pressure limiting hole 13 is provided at the center of the bottom of the deformation groove 12; a pressure limiting hole 13 is provided at the center of the lower end surface of the valve cap 2 3 interpenetrating movable holes 14, the movable hole 14 is coaxial with the opening and closing hole 4; a handwheel seat 15 is provided at the center of the upper surface of the valve cover 7; a handwheel 16 matching it is screwed to the outside of the handwheel seat 15; an adjusting device connected to the handwheel 16 is provided in the pressure limiting hole 13; the adjusting device includes a screw rod 17 located in the pressure limiting hole 13, and an opening and closing member 18 located in the movable hole 14 is provided at the lower end of the screw rod 17; the lower end of the opening and closing member 18 is downwardly penetrated into the valve body 1, and a water pressure plate 19 is provided on the outer wall of the lower end of the opening and closing member 18, and the diameter of the water pressure plate 19 is larger than the diameter of the upper end of the opening and closing hole 4; a force relief hole 20 is provided at the center of the lower end surface of the opening and closing member 18; the force relief hole 20 is connected with the pressure limiting hole 13 through a force relief structure provided at the lower end of the screw rod 17.

[0020] The de-stressing structure includes a center hole 21 provided at the center of the lower end surface of the screw rod 17; the lower outer wall of the screw rod 17 located at the pressure limiting hole 13 is provided with several auxiliary holes 22 that are connected to the upper end of the center hole 21; the lower end of the screw rod 17 is screwed into the upper end hole of the de-stressing hole 20.

[0021] The regulating device further comprises a lifting hole 23 provided at the center of the upper end face of the handwheel seat 15, the lifting hole 23 being in communication with the interior of the valve cover 7; an annular limiting step 24 being provided on the inner wall of the lower end opening of the lifting hole 23; a valve stem 25 matching the lifting hole 23 is provided in the lifting hole 23; a limiting portion 26 is provided on the outer wall of the lower end of the valve stem 25, which is in contact with the limiting step 24, and the limiting portion 26 can limit the upward movement of the valve stem 25; the upper end of the valve stem 25 extends upward out of the lifting hole 23 and is provided with an adjusting head 27 connected to the handwheel 16; a diaphragm 28 is provided between the valve cover 7 and the valve cap 2; a through hole 29 is provided in the center of the diaphragm 28, and the screw rod 1 7 passes through the diaphragm 28; the outer wall of the screw is provided with a ring-shaped positioning portion 48; the upper surface of the positioning portion 48 is in contact with the lower surface of the diaphragm 28; the screw 17 is externally screwed with an adjusting cap 30 located below the positioning portion 48; the outer wall of the adjusting cap 30 and the upper inner wall of the pressure-limiting hole 13 are both regular hexagons; a spring 31 is provided between the upper inner wall of the adjusting cap 30 and the bottom of the pressure-limiting hole 13 and is set on the outside of the screw 17; a limiting hole 32 is provided at the center of the lower end face of the valve stem 25; a limiting head 33 matching the limiting hole 32 is provided at the center of the upper end face of the screw 17; the outer wall of the limiting head 33 and the inner wall of the limiting hole 32 are both regular hexagons.

[0022] A groove 34 is provided at the center of the upper surface of the handwheel 16; a through-hole 35 is provided at the bottom of the groove 34 and is communicated with the interior of the handwheel 16; the upper end of the adjusting head 27 is inserted upward into the groove 34 through the through-hole 35; an annular limiting groove 36 is provided on the outer wall of the upper end of the adjusting head 27; a matching plum blossom retaining ring 37 is provided in the limiting groove 36, and the outer edge of the plum blossom retaining ring 37 protrudes out of the limiting groove 36 and fits with the bottom of the groove 34; a regular hexagonal rotating hole 38 is provided at the center of the upper end surface of the adjusting head 27.

[0023] The outer edge of the diaphragm 28 is provided with an annular retaining portion 39; the upper surface of the valve cap 2 is provided with an annular lower retaining groove 40; the valve cover 7 is provided with an upper retaining groove 41 opposite to the lower retaining groove 40; the retaining portion 39 is located between the upper retaining groove 41 and the lower retaining groove 40.

[0024] The valve body 1 has a hose 42 outside. Both ends of the hose 42 have connecting joints 43 . The connecting joint 43 at one end of the hose 42 is screwed into the interface 8 .

[0025] The lower surface of the valve body 1 is provided with a left auxiliary joint 46 that is connected to the water inlet joint 5; the lower surface of the valve body 1 is provided with a right auxiliary joint 47 that is connected to the water outlet joint 6; the left auxiliary joint 46 and the right auxiliary joint 47 are both screwed with matching plugs 44.

[0026] A mounting hole 45 communicating with the interior of the valve body 1 is provided on the upper surface of the middle portion thereof, and the lower end of the valve cap 2 is screwed into the mounting hole 45 ; glue is applied between the outer wall of the lower end of the valve cap 2 and the inner wall of the mounting hole 45 , and between the outer wall of the lower end of the screw rod 17 and the inner wall of the upper end of the relief hole 20 .

[0027] The method of using the utility model is as follows:

[0028] The water inlet joint 5 can be connected to the water inlet pipe, and the water outlet joint 6 can be connected to the water outlet pipe. The existence of the hose 42 facilitates the connection between the valve cover and the water inlet pipe, so that the water flow rate can be automatically adjusted according to the pressure change. When the pressure is too high, the water will flow into the valve cover 7 through the water inlet hole 9 and the water hole 10 in sequence, thereby squeezing the diaphragm 28 downward through the upper surface of the diaphragm 28. At this time, the diaphragm 28 is deformed and elastic. The existence of the deformation groove 12 allows the diaphragm to have sufficient deformation space. Since the lower surface of the diaphragm 28 fits with the upper surface of the positioning portion 48, when the diaphragm 28 is deformed downward under pressure, it is simultaneously compressed through the positioning portion 48. 8 pushes the screw rod 17 downward. When the screw rod 17 moves downward, the opening and closing member 18 moves downward synchronously, and the lower end of the opening and closing member 18 gradually approaches the upper end opening of the opening and closing hole 4. The closer the lower end of the opening and closing member 18 is to the lower end opening of the opening and closing hole 4, the smaller the degree of opening of the upper end of the opening and closing hole 4, thereby effectively reducing the flow rate of water flowing from the water inlet joint 5 through the opening and closing hole 4 to the water outlet joint 6. When the water pressure becomes smaller, the opening and closing member 18 will move upward accordingly, effectively increasing the water flow rate. When the water pressure returns to normal, the screw rod 17 will move upward and reset under the elastic force of the diaphragm 28 and the spring 31, thereby realizing the reset of the opening and closing member 18, thus completing the self-regulation of the water flow rate.

[0029] When the pressure differential valve needs to be closed, the handwheel 16 can be directly turned to move the handwheel 16 downward along the external thread track on the outer wall of the handwheel seat 15. When the handwheel 16 moves downward, the handwheel 16 will press down the upper end surface of the valve stem 25. When the valve stem 25 moves downward vertically, the adjusting cap 30 will not hinder the movement of the valve stem 25. At this time, the screw rod 17 and the opening and closing member 18 move downward synchronously. When the opening and closing member 18 moves downward, the water pressure plate 19 moves downward accordingly. Finally, the water pressure plate 19 covers and seals the upper end opening of the opening and closing hole 4 through its lower surface. At this time, the water flow in the water inlet pipe cannot flow into the water outlet through the water inlet joint 5. Inside the head 6, the pressure differential valve is closed. If the water pressure is too high during the closing process, the water will flow into the pressure limiting hole 13 through the relief hole 20, the center hole 21, and the auxiliary hole 22 in sequence. The existence of the pressure limiting hole 13 increases the actual volume of the water inlet joint 5 in disguised form, so that the water pressure can be effectively released. If the water pressure is still too high after the water fills the pressure limiting hole 13 and the deformation groove 12, the water will squeeze the diaphragm 28 upward through the lower surface of the diaphragm 28, causing the diaphragm 28 to deform upward and generate elastic force. This elastic force will effectively buffer and reduce the water pressure.

[0030] From the above, it can be seen that the utility model can sense pressure changes through the diaphragm 28, thereby realizing the up and down movement of the opening and closing member 18, and finally changing the opening degree of the upper end opening of the opening and closing hole 4, effectively controlling the water flow rate, and when the upper end opening of the opening and closing hole 4 is closed by the opening and closing member 18, the water flow is transferred to the pressure limiting hole 13 through the force relief structure, so that the water flow pressure is effectively released, and a force relief effect is achieved. At the same time, the diaphragm can also use its own elasticity to further buffer and reduce the water flow pressure, effectively avoiding the situation where the opening and closing member 18 is deformed and damaged due to excessive pressure when the pressure differential valve is closed. The entire buffering and pressure reduction process does not require a bypass valve to be set on the pipeline system, effectively simplifying the pipeline system and effectively reducing the cost of buffering and pressure reduction.

[0031] In the actual use of the differential pressure valve, different water conditions require different settings for the standard pressure. When the standard pressure needs to be set, one end of the hexagonal wrench that matches the rotating hole 38 can be inserted into the rotating hole 38, and then the valve stem 25 can be rotated alone. At this time, the valve stem 25 only rotates and does not move vertically. Since the outer wall of the limit head 33 and the inner wall of the limit hole 32 are both hexagonal, when the valve stem 25 rotates, the screw rod 17 rotates synchronously, and the outer wall of the adjusting cap 30 and the limit hole 32 are both hexagonal. The upper inner wall of the pressure hole 13 is hexagonal, and the upper inner wall of the pressure limiting hole 13 will limit the rotation of the adjusting cap 30. The adjusting cap 30 can only move up and down along the upper inner wall of the pressure limiting hole 13. When the screw rod 17 rotates, the adjusting cap 30 will convert the rotational force into its own up and down movement force. When the adjusting cap 30 moves downward, the distance between the adjusting cap 30 and the bottom of the pressure limiting hole 13 continues to decrease. At this time, the spring 31 is continuously compressed, and the elastic force of the spring 31 continues to increase, thereby realizing the adjustment of the standard pressure.

[0032] A groove 34 is provided in the center of the upper surface of the handwheel 16, and a through-hole 35 is provided at the bottom of the groove 34 which is connected to the inside of the handwheel 16. The upper end of the adjusting head 27 is inserted upward into the groove 34 through the through-hole, and an annular limiting groove 36 is provided on the outer wall of the upper end of the adjusting head 27. A plum blossom retaining ring 37 matching it is provided in the limiting groove 36. The outer edge of the plum blossom retaining ring 37 protrudes out of the limiting groove 36 and fits into the bottom of the groove 34. A regular hexagonal rotating hole 38 is provided in the center of the upper end surface of the adjusting head 27. This fixing method not only facilitates the disassembly and assembly between the handwheel 16 and the valve stem 25, but also can avoid the valve stem 25 and the handwheel 16 from rotating synchronously while ensuring that the height of the valve stem 25 changes with the height of the handwheel 16.

[0033] An annular retaining portion 39 is provided on the outer edge of the diaphragm 28, an annular lower retaining groove 40 is provided on the upper surface of the valve cap 2, and an upper retaining groove 41 opposite to the lower retaining groove 40 is provided on the valve cover 7. The retaining portion 39 is located between the upper retaining groove 41 and the lower retaining groove 40. The existence of the upper retaining groove 41 and the lower retaining groove 40 can effectively limit the position of the retaining portion 39, so that the outer edge of the diaphragm 28 is effectively fixed, effectively avoiding the displacement of the outer edge of the diaphragm 28 when the diaphragm 28 is squeezed.

[0034] A left auxiliary joint 46 communicating with the water inlet joint 5 is provided on the lower surface of the valve body 1, and a right auxiliary joint 47 communicating with the water outlet joint 6 is provided on the lower surface of the valve body 1. Both the left auxiliary joint 46 and the right auxiliary joint 47 are threaded with matching plugs 44. By simply unscrewing the plugs 44 from the left auxiliary joint 46 and the right auxiliary joint 47, new devices, such as other valves or pressure gauges, can be installed through the left auxiliary joint 46 and the right auxiliary joint 47.

[0035] A mounting hole 45 communicating with the interior of the valve body 1 is provided on the upper surface of the middle part thereof, and the lower end of the valve bonnet 2 is screwed into the mounting hole 45. This fixing method facilitates the disassembly and assembly between the valve body 1 and the valve bonnet 2, and glue is applied between the outer wall of the lower end of the valve bonnet 2 and the inner wall of the mounting hole 45, and between the outer wall of the lower end of the screw rod 17 and the inner wall of the upper end of the hole of the relief hole 20. The presence of glue can effectively ensure the sealing between the outer wall of the lower end of the valve bonnet 2 and the inner wall of the mounting hole 45, and between the outer wall of the lower end of the screw rod 17 and the inner wall of the upper end of the hole of the relief hole 20.

Claims

1. A self-relieving pressure differential valve, comprising a valve body, a valve cap disposed above the valve body, and an opening and closing seat disposed in the middle of the valve body, the opening and closing seat being provided with an opening and closing hole, a water inlet connector being provided at the left end of the valve body, and a water outlet connector being provided at the right end of the valve body, the water inlet connector being connected to the water outlet connector through the opening and closing hole, and characterized in that: The closure of the valve cap has a valve cover which is screwed onto the outside of the valve cap; one side of the valve cap is provided with an interface; the bottom of the interface is provided with a water inlet hole; the space enclosed by the valve cap and the valve cap is connected through a water hole and the water inlet hole; a deformation groove is provided in the center of the upper surface of the valve cap; the center of the bottom of the deformation groove is provided with a pressure limiting hole; the center of the lower end surface of the valve cap is provided with a movable hole which is connected to the pressure limiting hole, the movable hole is coaxial with the opening and closing hole; a handwheel seat is provided in the center of the upper surface of the valve cap; the handwheel seat is screwed onto a handwheel which matches it; an adjusting device connected to the handwheel is provided in the pressure limiting hole; the adjusting device includes a screw rod located in the pressure limiting hole, the lower end of the screw rod is provided with an opening and closing member located in the movable hole; the lower end of the opening and closing member is downwardly penetrated into the valve body by a water pressure plate on the outer wall of the lower end of the opening and closing member, the diameter of the water pressure plate is larger than the diameter of the upper end of the opening and closing hole; a force relief hole is provided in the center of the lower end surface of the opening and closing member; the force relief hole is connected to the pressure limiting hole through a force relief structure provided at the lower end of the screw rod.

2. The self-releasing pressure differential valve according to claim 1, characterized in that: The de-stressing structure includes a center hole arranged at the center of the lower end surface of the screw rod; the lower outer wall of the screw rod located at the pressure limiting hole is provided with a plurality of auxiliary holes that penetrate the upper end of the center hole; the lower end of the screw rod is screwed into the hole opening at the upper end of the de-stressing hole.

3. The self-releasing pressure differential valve according to claim 1, characterized in that: The regulating device also includes a lifting hole provided at the center of the upper end face of the handwheel seat, the lifting hole is connected to the inside of the valve cover; the inner wall of the lower end of the lifting hole is provided with an annular limiting step; a valve stem matching it is provided in the lifting hole; the outer wall of the lower end of the valve stem is provided with a limiting portion that fits with the limiting step, and the limiting portion can limit the upward movement of the valve stem; the upper end of the valve stem passes upward to the outside of the lifting hole and is provided with an adjusting head connected to the handwheel; a diaphragm is provided between the valve cover and the valve cap; a through hole is provided in the center of the diaphragm, and the screw rod passes through through the diaphragm; the outer wall of the screw rod is provided with a ring-shaped positioning portion; the upper surface of the positioning portion is in contact with the lower surface of the diaphragm; the screw rod is externally screwed with an adjusting cap located below the positioning portion; the outer wall of the adjusting cap and the upper inner wall of the pressure-limiting hole are both regular hexagons; a spring is provided outside the screw rod between the upper inner wall of the adjusting cap and the bottom of the pressure-limiting hole; a limiting hole is provided at the center of the lower end face of the valve stem; a limiting head is provided at the center of the upper end face of the screw rod that matches the limiting hole; the outer wall of the limiting head and the inner wall of the limiting hole are both regular hexagons.

4. The self-releasing pressure differential valve according to claim 3, characterized in that: A groove is provided in the center of the upper surface of the handwheel; a through-hole is provided at the bottom of the groove and is connected to the inside of the handwheel; the upper end of the adjusting head is inserted upward into the groove through the through-hole; an annular limiting groove is provided on the outer wall of the upper end of the adjusting head; a plum blossom retaining ring matching it is provided in the limiting groove, and the outer edge of the plum blossom retaining ring protrudes out of the limiting groove and fits with the bottom of the groove; a regular hexagonal rotating hole is provided in the center of the upper end surface of the adjusting head.

5. The self-releasing pressure differential valve according to claim 3, characterized in that: The outer edge of the diaphragm is provided with an annular retaining portion; the upper surface of the valve cap is provided with an annular lower retaining groove; the valve cover is provided with an upper retaining groove opposite to the lower retaining groove; the retaining portion is located between the upper retaining groove and the lower retaining groove.

6. The self-releasing pressure differential valve according to claim 1, characterized in that: The valve body is provided with a hose; both ends of the hose have connecting joints, and the connecting joint at one end of the hose is screwed into the interface.

7. The self-releasing pressure differential valve according to claim 1, characterized in that: The lower surface of the valve body is provided with a left auxiliary joint that is connected to the water inlet joint; the lower surface of the valve body is provided with a right auxiliary joint that is connected to the water outlet joint; the left auxiliary joint and the right auxiliary joint are both screwed with matching plugs.

8. The self-releasing pressure differential valve according to claim 2, characterized in that: A mounting hole communicating with the interior of the valve body is provided on the upper surface of the middle portion, and the lower end of the valve cap is screwed into the mounting hole; glue is applied between the outer wall of the lower end of the valve cap and the inner wall of the mounting hole, and between the outer wall of the lower end of the screw rod and the inner wall of the upper end of the relief hole.

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