Large-pressure-difference labyrinth bypass drain valve pressure test tool

Abstract

The utility model discloses a large-pressure-difference labyrinth type bypass drain valve pressure test tool, and relates to the field of bypass drain valve pressure test tools. When a traditional whole-section pressing mode is used for a large-pressure-difference labyrinth bypass drain valve, the problems that pressure testing is not accurate, a local structure is prone to being damaged, and sealing performance is not stable exist. The pressure testing device comprises a valve cover pressure testing plug, a valve body connecting pipe pressure testing plug, a water spraying pipe connector plug, an outlet transition pipe plug and a valve seat pressure testing plug, all the plugs plug corresponding parts respectively, and the valve body connecting pipe pressure testing plug and the outlet transition pipe plug are provided with pressure testing holes for introducing different pressure media respectively. A blanking seamless steel pipe support is arranged between the valve seat pressure test plug and the self-sealing valve cover, the blanking seamless steel pipe is provided with a through hole, and the plugs are connected in a sealing mode through O-shaped sealing rings and bolt fasteners. Independent sealing and segmented pressing of key parts are achieved, actual stress is accurately simulated, the testing efficiency and accuracy are improved, damage to a low-pressure area structure is avoided, and the safety risk is reduced.

Description

Technical Field

[0001] This utility model relates to the field of bypass discharge valve pressure testing fixtures, and in particular to a large differential pressure labyrinth bypass discharge valve pressure testing fixture. Background Technology

[0002] In the oil, gas, chemical, and power industries, high-differential-pressure bypass valves are commonly used for high-pressure differential control. Because bypass valves typically operate in environments with a large pressure difference between the inlet and outlet, different areas within the valve body experience varying pressures. Traditional shell pressure testing methods usually involve pressurizing the entire valve body. However, for high-differential-pressure labyrinth bypass valves, the inlet and outlet pressures differ by approximately nine times. Pressurizing the entire valve body would cause the high-pressure end pressure to far exceed the structural limits of the low-pressure end, leading to damage to the low-pressure area. Therefore, segmented pressure testing is necessary. Without segmented pressure testing, there is a risk of inaccurate pressure testing, potential damage to the structure in localized low-pressure areas, and unstable sealing. Utility Model Content

[0003] The technical problem to be solved and the technical task proposed by this utility model is to improve and refine the existing technical solutions, and to provide a pressure testing fixture for a large differential pressure labyrinth-type bypass discharge valve, with the aim of improving the accuracy of pressure testing. To this end, this utility model adopts the following technical solution.

[0004] A pressure testing fixture for a large differential pressure labyrinth-type bypass discharge valve includes a valve cover pressure testing plug, a valve body connecting pipe pressure testing plug, a water spray pipe joint plug, an outlet transition pipe plug, and a valve seat pressure testing plug. The valve cover pressure testing plug is located on the upper end of the self-sealing valve cover of the discharge valve to seal the valve stem hole. The valve body connecting pipe pressure testing plug is located on the left side of the inlet flow channel on the left side of the discharge valve to seal the inlet flow channel. The valve body connecting pipe pressure testing plug has a horizontal pressure testing hole penetrating inside and outside the inlet flow channel. The water spray pipe joint plug is located on the right side of the discharge valve at the water spray pipe joint to seal the water spray pipe joint. The outlet transition pipe plug is located at the lower end of the outlet transition pipe at the bottom of the discharge valve to seal the outlet transition pipe. The outlet transition pipe plug has a penetrating vertical pressure testing hole. The valve seat pressure testing plug is located on the valve seat of the discharge valve to seal the valve outlet flow channel in the middle of the valve seat. By connecting corresponding plugs to the valve cover, flow channel inlet, water spray pipe joint, outlet transition pipe, and valve seat, independent sealing and segmented pressure testing of each key part of the discharge valve can be achieved. This accurately simulates the actual stress under large pressure differential conditions. The valve body connecting pipe test plug and the outlet transition pipe plug are respectively equipped with horizontal and vertical test holes, which facilitates the introduction of different pressure media and segmented pressure testing. The use of this tooling can effectively improve the testing efficiency and accuracy. The pressure test is highly targeted and can more realistically reflect the actual operating status of the valve. It will not damage the structure of the local low-pressure area, reduce the safety risks during the pressure test process, and protect the safety of personnel and equipment.

[0005] As a preferred technical approach: a seamless steel pipe is provided between the valve seat test plug and the self-sealing valve cover. The upper end of the seamless steel pipe is embedded in the bottom groove at the lower end of the self-sealing valve cover and is in contact with the bottom of the groove; the lower end of the seamless steel pipe is embedded in the upper shallow groove at the upper end of the valve seat test plug and is in contact with the bottom of the shallow groove; the seamless steel pipe has multiple internal and external through holes on its wall. The seamless steel pipe forms a rigid support structure, facilitating installation and providing effective support for the self-sealing valve cover. The internal and external through holes in the pipe wall allow the pressure medium to be transmitted between the valve seat and the self-sealing valve cover, ensuring uniform distribution of test pressure and avoiding local stress concentration.

[0006] As a preferred technical approach, a gap exists between the seamless steel pipe and the side wall of the bottom trough, and a gap exists between the seamless steel pipe and the side wall of the upper shallow trough. The existence of these gaps facilitates the installation and disassembly of the seamless steel pipe and reduces the requirements for processing precision.

[0007] As a preferred technical approach: the upper end of the valve seat is provided with an upward flange, and the lower end of the valve seat test plug is provided with an annular groove. The upward flange is fitted into the annular groove, and the upper flange and the inner wall of the annular groove are sealed by multiple O-rings. This effectively prevents leakage of high-pressure media, improves test reliability, and the fitting design of the flange and the annular groove increases the sealing path length, further improving sealing performance and making it better suited for high pressure differential conditions.

[0008] As a preferred technical approach, the valve seat test plug has a lifting eye bolt in the middle of its upper shallow groove. This facilitates easy disassembly and installation of the valve seat test plug using lifting equipment, improving disassembly and assembly efficiency.

[0009] As a preferred technical approach: the lower part of the valve cover pressure test plug is fitted into the upper end of the valve stem hole, and the lower outer wall of the valve cover pressure test plug is sealed with the side wall of the valve stem hole by multiple O-rings. The lower outer step of the valve cover pressure test plug is attached to the upper end surface of the self-sealing valve cover. The upper end of the valve cover pressure test plug and the self-sealing valve cover are connected and fastened by tension bolts and nuts. This structure provides a firm connection, and combined with the multiple O-ring seals, effectively prevents media leakage at the valve stem hole.

[0010] As a preferred technical approach: the right side of the valve body connector pressure test plug is fitted into the left end of the inlet flow channel, and the outer circumferential surface of the right side of the valve body connector pressure test plug and the inner circumferential surface of the inlet flow channel are sealed by multiple O-rings. A flow channel connecting clamp is provided on the outer circumference of the inlet flow channel, and the valve body connector pressure test plug and the flow channel connecting clamp are connected and secured by fasteners. This structure ensures the secure connection and sealing performance of the valve body connector pressure test plug at the inlet flow channel, effectively preventing leakage of high-pressure media at the inlet end. Fasteners can be tension bolts, nuts, etc.

[0011] As a preferred technical approach: the left side of the spray pipe connector plug is fitted into the right end of the spray pipe connector, and the outer circumferential surface of the left side of the spray pipe connector plug is sealed with the inner circumferential surface of the spray pipe connector by multiple O-rings. A spray pipe connecting clamp is provided on the outer circumference of the spray pipe connector, and the spray pipe connector plug and the spray pipe connecting clamp are connected and secured by fasteners. This structure provides a firm connection and effectively seals the spray pipe connector, preventing media leakage during testing. Fasteners can be tension bolts, nuts, etc.

[0012] As a preferred technical approach: the upper part of the outlet transition pipe plug is fitted into the lower end of the outlet transition pipe, and the upper outer circumferential surface of the outlet transition pipe plug is sealed with the lower inner circumferential surface of the outlet transition pipe by multiple O-rings. A transition pipe connecting clamp is provided on the outer circumference of the outlet transition pipe, and the outlet transition pipe plug and the transition pipe connecting clamp are connected and secured by tension bolts and nuts. This structure can firmly connect and fix the outlet transition pipe plug to the lower end of the outlet transition pipe and form an effective seal, ensuring the sealing performance of the outlet end during pressure testing, avoiding pressure loss, and achieving accurate testing.

[0013] As a preferred technical approach, the flow channel connecting clamp, the water spray pipe connecting clamp, and the transition pipe connecting clamp are all composed of two half-clamps connected by fasteners. The two half-clamps can be easily snapped into different positions on the valve using fasteners, enabling quick installation and disassembly and improving the applicability of the tooling. Fasteners can be screws, etc.

[0014] Beneficial effects: The application of this fixture enables independent sealing and segmented pressure testing of key parts of the discharge valve, accurately simulating the actual stress under large pressure differential conditions. Through the test holes at different locations, it is easy to introduce different pressure media, facilitating segmented pressure testing. The use of this fixture can effectively improve testing efficiency and accuracy, and the pressure test is highly targeted, more realistically reflecting the actual operating state of the valve. It will not damage the structure of local low-pressure areas, reduces safety risks during the pressure test process, and protects the safety of personnel and equipment. Attached Figure Description

[0015] Figure 1 This is a top view of the present invention.

[0016] Figure 2 This is a utility model Figure 1 Schematic diagram of sectional view AA.

[0017] Figure 3 This is a radial cross-sectional view of the valve seat and the valve seat test plug after separation in this utility model.

[0018] Figure 4 This is a schematic diagram of the seamless steel pipe structure for feeding in this utility model.

[0019] Figure 5 This is an enlarged schematic diagram of part B in this utility model.

[0020] Figure 6 This is an enlarged schematic diagram of part D in this utility model.

[0021] Figure 7 This is an enlarged schematic diagram of part C in this utility model.

[0022] Figure 8 This is an enlarged schematic diagram of part E in this utility model.

[0023] Figure 9 This is an enlarged schematic diagram of part F in this utility model.

[0024] In the diagram: 1. Valve body; 2. Valve seat; 3. Labyrinth sleeve assembly; 4. Inlet flow channel; 5. Lower cavity; 6. C-ring seal; 7. Valve seat pressure ring; 8. Nozzle; 9. Water spray pipe connector; 10. Outlet transition pipe; 11. Self-sealing valve cover; 12. Self-sealing ring; 13. Self-sealing pressure ring; 14. Four-ring; 15. Lower flange of valve cover pull ring; 16. Valve cover pull ring round nut; 17. Valve cover pressure test plug; 18. Valve body connecting pipe pressure test plug; 9. Spray pipe connector plug; 20. Outlet transition pipe plug; 21. Valve seat pressure test plug; 22. Seamless steel pipe for blanking; 23. O-ring seal; 24. Tightening bolt and nut fastener; 25. Flow channel connecting clamp; 26. Spray pipe connecting clamp; 27. Transition pipe connecting clamp; 28. Outer pipe; 29. ​​Eye bolt; 201. Upward flange; 2101. Upper shallow groove; 2102. Annular groove; 2201. Rectangular hole; 2202. Round hole. Detailed Implementation

[0025] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings.

[0026] Example 1

[0027] like Figure 1 , 2As shown, a pressure testing fixture for a large differential pressure labyrinth-type bypass discharge valve is disclosed. The discharge valve includes a valve body 1, a valve seat 2, a labyrinth-type sleeve assembly 3, and left and right inlet channels 4. The inlet channels 4 are welded to the left side of the valve body 1 and communicate with the inner cavity of the valve body 1. A lower cavity 5 is provided below the valve body 1. The valve seat 2 is located in the lower part of the inner cavity of the valve body 1. An axial downward valve outlet channel is provided in the middle of the valve seat 2. The labyrinth-type sleeve assembly 3 is located below the valve seat 2. A sealing groove is provided between the valve seat 2 and the labyrinth-type sleeve assembly 3, and a sealing groove is provided inside. Figure 9 The metal C-ring seal 6 shown has a valve seat pressure ring 7 on the outside of the valve seat 2. A sealing ring is provided between the lower end face of the valve seat pressure ring 7 and the outer stepped surface of the valve seat 2. The valve seat pressure ring 7 is fastened to the outer stepped surface of the valve seat 2 by a bolt, washer, and nut assembly. The main body of the labyrinth sleeve assembly 3 is located in the lower cavity 5. Nozzles 8 are evenly distributed around the lower middle part of the lower cavity 5. The outer ends of the nozzles 8 are sealed by plugs. A water spray pipe connector 9 is provided on the upper right outer side of the lower cavity 5. An outlet transition pipe 10 is welded to the lower end of the lower cavity 5. A self-sealing valve cover 11 is provided in the middle of the upper part of the valve body 1. The self-sealing valve cover 11 has a vertical valve stem hole in the middle. The lower outer periphery of the self-sealing valve cover 11 has an outer conical surface. A self-sealing ring 12 is provided on the outer conical surface. A self-sealing pressure ring 13 is provided on the self-sealing pressure ring 12. A four-open ring 14 is provided on the self-sealing pressure ring 13. The inner side of the self-sealing ring 12 is an inner conical surface that matches the lower outer conical surface of the self-sealing valve cover 11. When the self-sealing valve cover 11 floats upward under the pressure of the fluid in the inner cavity of the valve body 1, the two conical surfaces press together to seal. A valve cover pull ring lower flange 15 is provided between the inner side of the four-open ring 14 and the self-sealing valve cover 11. A valve cover pull ring round nut 16 is provided on the upper part of the valve cover pull ring lower flange 15. The two are fixed by bolts. The valve cover pull ring round nut 16 is fixed to the outer periphery of the self-sealing valve cover 11 by threads.

[0028] The pressure testing fixture includes a valve cover pressure test plug 17, a valve body connecting pipe pressure test plug 18, a water spray pipe connector plug 19, an outlet transition pipe plug 20, and a valve seat pressure test plug 21. The valve cover pressure test plug 17 is located on the upper end of the self-sealing valve cover 11 of the discharge valve to seal the valve stem hole. The valve body connecting pipe pressure test plug 18 is located on the left side of the inlet flow channel 4 on the left side of the discharge valve to seal the inlet flow channel 4. The valve body connecting pipe pressure test plug 18 has a horizontal pressure test hole that penetrates the inside and outside of the inlet flow channel 4. The water spray pipe connector plug 19 is located at the water spray pipe connector 9 on the right side of the discharge valve to seal the water spray pipe connector 9. The outlet transition pipe plug 20 is located at the lower end of the outlet transition pipe 10 at the bottom of the discharge valve to seal the outlet transition pipe 10. The outlet transition pipe plug 20 has a through vertical pressure test hole. The valve seat pressure test plug 21 is located on the valve seat 2 to seal the valve outlet flow channel in the middle of the valve seat 2.

[0029] To facilitate installation and provide effective structural support for the self-sealing valve cover 11, such as Figure 2 , 3As shown in Figure 4, a seamless steel pipe 22 is provided between the valve seat test plug 21 and the self-sealing valve cover 11 above it. The upper end of the seamless steel pipe 22 is embedded in the bottom groove at the lower end of the self-sealing valve cover 11, and the upper end of the seamless steel pipe 22 is in contact with the bottom of the groove. The lower end of the seamless steel pipe 22 is embedded in the upper shallow groove 2101 at the upper end of the valve seat test plug 21, and is in contact with the bottom of the upper shallow groove 2101. The lower part of the pipe wall of the seamless steel pipe 22 is provided with two symmetrically arranged inner and outer through rectangular holes 2201, and the upper part of the pipe wall of the seamless steel pipe 22 is provided with two symmetrically arranged inner and outer through circular holes 2202. The rectangular holes 2201 and the circular holes 2202 are arranged at a 90-degree angle. The seamless steel pipe 22 forms a rigid support structure, which facilitates installation and provides effective structural support for the self-sealing valve cover 11. The inner and outer through holes in the steel pipe wall allow the pressure medium to be transmitted between the valve seat 2 and the self-sealing valve cover 11, ensuring uniform distribution of test pressure and avoiding local stress concentration.

[0030] To facilitate the installation and disassembly of the seamless steel pipe 22, a gap exists between the seamless steel pipe 22 and the side wall of the bottom groove, and a gap also exists between the seamless steel pipe 22 and the side wall of the upper shallow groove 2101. The existence of these gaps facilitates the installation and disassembly of the seamless steel pipe 22 and reduces the requirements for processing accuracy.

[0031] To improve the sealing performance of the valve seat test plug 21, such as Figure 3 As shown, the upper end of the valve seat 2 is provided with an upward flange 201, and the lower end of the valve seat test plug 21 is provided with an annular groove 2102. The upward flange 201 is fitted into the annular groove 2102, and the inner wall of the upward flange 201 and the annular groove 2102 are sealed by two O-rings 23. In this embodiment, the two O-rings 23 are located in two sealing grooves on the inner wall of the annular groove 2102. This effectively prevents leakage of high-pressure media, improves test reliability, and the fitting design of the flange and the annular groove 2102 increases the sealing path length, further improving sealing performance and making it better suited for high pressure differential conditions.

[0032] To ensure the sealing performance of the valve cover test plug 17, such as Figure 5 As shown, the lower part of the valve cover test plug 17 is fitted into the upper end of the valve stem hole, and the lower outer wall of the valve cover test plug 17 is sealed to the side wall of the valve stem hole by two O-rings 23. The lower outer step of the valve cover test plug 17 is attached to the upper end surface of the self-sealing valve cover 11. The upper ends of the valve cover test plug 17 and the self-sealing valve cover 11 are connected and fastened by tension bolts, nuts, and fasteners 24. This structure is firmly connected, and combined with the seal of the two O-rings 23, it effectively prevents media leakage at the valve stem hole and ensures the sealing performance of the valve cover test plug 17.

[0033] To ensure the sealing performance of the valve body connector pressure test plug 18, such as Figure 6As shown, the right side of the valve body connector pressure test plug 18 is fitted into the left end of the inlet flow channel 4, and the outer circumferential surface of the right side of the valve body connector pressure test plug 18 and the inner circumferential surface of the inlet flow channel 4 are sealed by three O-rings 23. A flow channel connecting clamp 25 is provided on the outer circumference of the inlet flow channel 4, and the valve body connector pressure test plug 18 and the flow channel connecting clamp 25 are connected and secured by tension bolts, nuts, and fasteners 24. This structure ensures the secure connection and sealing performance of the valve body connector pressure test plug 18 at the inlet flow channel 4, effectively preventing leakage of high-pressure media at the inlet end.

[0034] To ensure the sealing performance of the water spray pipe connector plug 19, such as Figure 7 As shown, the left side of the water spray pipe connector plug 19 is fitted into the right end of the water spray pipe connector 9, and the outer circumferential surface of the left side of the water spray pipe connector plug 19 is sealed with the inner circumferential surface of the water spray pipe connector 9 by three O-rings 23. A water spray pipe connecting clamp 26 is provided on the outer circumference of the water spray pipe connector 9. The water spray pipe connector plug 19 and the water spray pipe connecting clamp 26 are connected and secured by tension bolts, nuts, and fasteners 24. This structure provides a firm connection, effectively sealing the water spray pipe connector 9, preventing media leakage during testing, and ensuring the sealing performance of the water spray pipe connector plug 19.

[0035] To ensure the sealing of the outlet end during pressure testing, such as Figure 8 As shown, the upper part of the outlet transition pipe plug 20 is fitted into the lower end of the outlet transition pipe 10, and the upper outer circumferential surface of the outlet transition pipe plug 20 is sealed with the lower inner circumferential surface of the outlet transition pipe 10 by three O-rings 23. A transition pipe connecting clamp 27 is provided on the outer circumference of the outlet transition pipe 10. The outlet transition pipe plug 20 and the transition pipe connecting clamp 27 are connected and fastened by tension bolts, nuts, and fasteners 24. This structure can firmly connect and fix the outlet transition pipe plug 20 to the lower end of the outlet transition pipe 10 and form an effective seal, ensuring the sealing performance of the outlet end during pressure testing, avoiding pressure loss, and achieving accurate testing.

[0036] In this embodiment, each O-ring 23 is disposed in the sealing ring groove on one side of each plug.

[0037] Before pressure testing the discharge valve, first remove the valve core and self-sealing valve cover 11 from the upper part of the valve body 1. Then, install the valve seat pressure test plug 21 and the seamless steel pipe 22 in sequence. Next, install the self-sealing valve cover 11, self-sealing ring 12, self-sealing pressure ring 13, four-open ring 14, valve cover pull ring lower flange 15, and valve cover pull ring round nut 16. Then, install the valve body connecting pipe pressure test plug 18. The horizontal pressure test hole of the valve body connecting pipe pressure test plug 18 is connected to the high-pressure water pump through the connecting pipe. Gradually increase the pressure to 63.0 MPa, and then hold the pressure for no less than 180 seconds. If there is no visible leakage, the test conditions are met, and the high-pressure test of the valve body 1 cavity is completed.

[0038] When conducting a low-pressure test on the lower cavity 5, after installing the valve seat test plug 21, install the outlet transition pipe plug 20 and the spray pipe connector plug 19 to disconnect the inner cavity of the valve body 1 and the inner cavity of the lower cavity 5, ensuring that the high and low pressure cavities do not interfere with each other. Then, connect the low-pressure water pump through the vertical test hole of the outlet transition pipe plug 20 and the pressure is increased to 7.5MPa. Hold the pressure for no less than 180s. If there is no visible leakage, it indicates that the test conditions are met. The fluid in the lower cavity 5 reaches the spray hole through each nozzle 8 and the outer pipe 28 to test the entire lower cavity 5 and the fluid channel outside the lower cavity 5.

[0039] Another method for low-pressure testing of the lower cavity 5 is to seal the vertical test hole of the outlet transition pipe plug 20, connect the water pump from the water spray pipe joint 9, and let the fluid enter the lower cavity 5 through the outer pipe 28 and each nozzle 8 to conduct a low-pressure test.

[0040] During the test, the pressure sensor will record the pressure changes in the two chambers in real time, so that the pressure fluctuates within a stable range.

[0041] After the test is completed, disassemble the pressure testing fixture and check the condition of valve body 1 and the fixture to confirm whether there is any damage or leakage. Return the fixture and self-sealing assembly to their initial state for next use.

[0042] Example 2

[0043] Unlike the above embodiment, as Figure 2 , 3 As shown, to facilitate the disassembly and installation of the valve seat test plug 21, a lifting eye screw 29 is provided in the middle of the upper shallow groove 2101 of the valve seat test plug 21. This facilitates the disassembly and installation of the valve seat test plug 21 using lifting equipment, thereby improving disassembly and installation efficiency.

[0044] Example 3

[0045] Unlike embodiments one or two above, the flow channel connecting clamp 25, the water spray pipe connecting clamp 26, and the transition pipe connecting clamp 27 are all composed of two half-clamps connected by hexagonal socket head cap screws. The two half-clamps can be easily snapped into different positions on the valve by screws, enabling quick installation and disassembly and improving the applicability of the tooling.

[0046] above Figure 1-9 The pressure testing fixture for a large differential pressure labyrinth bypass discharge valve shown is a specific embodiment of this utility model, which embodies the substantial features and progress of this utility model. Based on actual usage needs, equivalent modifications in shape, structure, etc., can be made to it under the guidance of this utility model, all of which are within the protection scope of this solution.

Claims

1. A pressure testing fixture for a large differential pressure labyrinth bypass discharge valve, characterized in that: The pressure testing fixture includes a valve cover pressure testing plug, a valve body connecting pipe pressure testing plug, a water spray pipe joint plug, an outlet transition pipe plug, and a valve seat pressure testing plug. The valve cover pressure testing plug is located on the upper end of the self-sealing valve cover of the discharge valve to seal the valve stem hole. The valve body connecting pipe pressure testing plug is located on the left side of the inlet flow channel on the left side of the discharge valve to seal the inlet flow channel. The valve body connecting pipe pressure testing plug has a horizontal pressure testing hole penetrating inside and outside the inlet flow channel. The water spray pipe joint plug is located at the water spray pipe joint on the right side of the discharge valve to seal the water spray pipe joint. The outlet transition pipe plug is located at the lower end of the outlet transition pipe at the bottom of the discharge valve to seal the outlet transition pipe. The outlet transition pipe plug has a penetrating vertical pressure testing hole. The valve seat pressure testing plug is located on the valve seat of the discharge valve to seal the valve outlet flow channel in the middle of the valve seat.

2. A large differential pressure labyrinth bypass drain valve pressure testing fixture as defined in claim 1, wherein: A seamless steel pipe is provided between the valve seat test plug and the self-sealing valve cover above. The upper end of the seamless steel pipe is embedded in the bottom groove at the lower end of the self-sealing valve cover and is in contact with the bottom of the groove. The lower end of the seamless steel pipe is embedded in the upper shallow groove at the upper end of the valve seat test plug and is in contact with the bottom of the shallow groove. The seamless steel pipe has multiple internal and external through holes on its wall.

3. A large differential pressure labyrinth bypass discharge valve pressure testing fixture according to claim 2, characterized in that: There is a gap between the seamless steel pipe being fed and the side wall of the bottom trough, and there is a gap between the seamless steel pipe being fed and the side wall of the upper shallow trough.

4. A large differential pressure labyrinth bypass drain valve pressure testing fixture as defined in claim 3, wherein: The valve seat has an upward flange at its upper end and an annular groove at its lower end. The upward flange is fitted into the annular groove, and the upward flange and the inner wall of the annular groove are sealed by multiple O-rings.

5. A large differential pressure labyrinth bypass drain valve pressure testing fixture as defined in claim 4, wherein: The valve seat pressure test plug has a lifting eye screw in the middle of the upper shallow groove.

6. A large differential pressure labyrinth bypass drain valve pressure testing fixture as defined in claim 5, wherein: The lower part of the valve cover pressure test plug is fitted into the upper end of the valve stem hole, and the lower outer wall of the valve cover pressure test plug is sealed with the side wall of the valve stem hole by multiple O-rings. The lower outer step of the valve cover pressure test plug is attached to the upper end surface of the self-sealing valve cover. The valve cover pressure test plug and the upper end of the self-sealing valve cover are connected and fastened by tension bolts and nuts.

7. A large differential pressure labyrinth bypass drain valve pressure testing fixture as defined in claim 6, characterized in that: The right side of the valve body connector pressure test plug is fitted into the left end of the inlet flow channel, and the outer circumferential surface of the right side of the valve body connector pressure test plug and the inner circumferential surface of the inlet flow channel are sealed by multiple O-rings. The outer circumference of the inlet flow channel is provided with a flow channel connecting hoop. The valve body connector pressure test plug and the flow channel connecting hoop are connected and fastened by tension bolts and nuts.

8. The pressure testing fixture for a large differential pressure labyrinth bypass discharge valve according to claim 7, characterized in that: The left part of the spray pipe connector plug is fitted into the right end of the spray pipe connector, and the outer peripheral surface of the left part of the spray pipe connector plug is sealed with the inner peripheral surface of the spray pipe connector by multiple O-rings. The outer peripheral surface of the spray pipe connector is provided with a spray pipe connecting clamp. The spray pipe connector plug and the spray pipe connecting clamp are connected and fastened by fasteners.

9. A large differential pressure labyrinth bypass drain valve pressure testing fixture as defined in claim 8, wherein: The upper part of the outlet transition pipe plug is fitted into the lower end of the outlet transition pipe, and the upper outer circumferential surface of the outlet transition pipe plug and the lower inner circumferential surface of the outlet transition pipe are sealed by multiple O-rings. The outer circumference of the outlet transition pipe is provided with a transition pipe connecting clamp. The outlet transition pipe plug and the transition pipe connecting clamp are connected and fixed by fasteners.

10. A large differential pressure labyrinth bypass drain valve pressure testing tool according to claim 9, characterized in that: The valve body pipe connection clamp, the water spray pipe connection clamp, and the outlet transition pipe connection clamp are all composed of two half clamps connected by fasteners.

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