Pilot operated safety valve water pressure strength test tool and method

Abstract

The application relates to a pilot safety valve water pressure strength test tool and method, and belongs to the valve test field. The tool comprises a secondary pilot valve cover, a sealing ring, a second connecting rod and a first connecting rod. The left end surface of the sealing ring is abutted and sealed with the right end surface of the secondary valve cover. The right end of the second connecting rod is connected with the sealing ring in a sealed mode. The left end of the first connecting rod is detachably connected with the secondary pilot valve cover. The secondary pilot valve cover and the sealing ring are pulled tightly through the second connecting rod. The secondary pilot valve cover blocks the first pressure relief port. The application can effectively isolate the medium inlet side from the medium outlet side, and can perform high-pressure water pressure strength test on the medium inlet side. The water pressure strength test on the low-pressure part of the medium outlet side can be performed together with the medium inlet side. The use and operation of the test tool and the test method are simple, and the operation is simple and safe.

Description

Technical Field

[0001] This invention belongs to the field of valve testing, and in particular relates to a tooling and method for testing the water pressure strength of a pilot-operated safety valve. Background Technology

[0002] A pilot-operated safety valve with a two-stage pilot valve structure, consisting of a main valve, a primary pilot valve, and a secondary pilot valve, is installed on a steam-water separator reheater. It is an overpressure protection device used to prevent damage to related equipment caused by steam pressure exceeding the design pressure in the steam-water separator reheater due to a turbine accident.

[0003] To ensure the safety of pilot-operated safety valves, the hydrostatic strength test is a crucial test for verifying product safety. It verifies that the valve's pressure-bearing components will not leak or rupture under 1.5 times the design pressure. The hydrostatic strength test for pilot-operated safety valves is divided into inlet and outlet side tests, with different test locations and pressures. The inlet side is where the pilot-operated safety valve maintains pressure during operation, while the outlet side is where the safety valve releases pressure after opening. The inlet side hydrostatic strength test pressure is higher than the outlet side hydrostatic strength test pressure. When conducting the inlet side hydrostatic test, a test fixture must be used to isolate the inlet and outlet sides. The design of the test fixture must meet the usage requirements while also considering the simplicity and ease of operation of the test method. Summary of the Invention

[0004] The purpose of this invention is to provide a hydraulic pressure testing fixture for pilot-operated safety valves, solving the problem that hydraulic pressure testing can be performed separately on the inlet and outlet sides of pilot-operated safety valves, and that the fixture is easy to operate. The technical solution adopted by this invention is as follows:

[0005] A hydraulic pressure strength testing fixture for a pilot-operated safety valve includes a main valve body in a three-way shape. The main valve body has an upper opening, a left opening, and a right opening that are connected through a main valve cavity. A main valve cover closes the right opening of the main valve body. The upper opening of the main valve body is the medium inlet, and the left opening is the medium outlet, which is tapered. A valve seat is located at the right end of the medium outlet, and the right end face of the valve seat is the main sealing surface of the pilot-operated safety valve. The left end of a secondary pilot valve body penetrates the valve cover and has a first pressure relief port. The right end of the secondary pilot valve body has a first back pressure port. The first pressure relief port and the first back pressure port are connected through a secondary pilot valve cavity, which is connected to the main valve cavity through the first pressure relief port. The secondary pilot valve chamber is connected to the medium outlet through an exhaust pipe. The secondary valve cover seals the first back pressure port. The secondary valve cover has a threaded inner hole. The lower outer wall of the secondary pilot valve body has a primary pilot valve body. The lower end face of the primary pilot valve body is machined with a primary valve outlet and a primary valve inlet sequentially from bottom to top. The upper ends of the medium inlet and the primary valve inlet are connected through an air inlet pipe. The seat end of the needle valve body passes through the right side wall of the primary valve outlet. The left end of the needle valve body has a second pressure relief port, and the right end of the needle valve body has a second back pressure port. The second back pressure port has an internal thread structure. The second pressure relief port and the second back pressure port are connected through the needle valve chamber. The needle valve chamber is connected to the primary valve outlet through the second pressure relief port. The test fixture includes:

[0006] The main valve inlet cover is equipped with a first water pressure pipe joint and is used to seal the medium inlet.

[0007] The main valve sealing surface cover is fitted with the outer circumferential conical surface of the main valve pressure plate and the inner circumferential conical surface of the medium outlet. The right end of the first connecting rod is detachably connected to the main valve sealing surface cover, and the left end of the first connecting rod is detachably connected to the main valve pressure plate. The main valve sealing surface cover and the main valve pressure plate are tightened by the first connecting rod, and the main valve sealing surface cover seals the valve seat.

[0008] The left end face of the sealing ring of the secondary pilot valve cover abuts against the right end face of the secondary valve cover for sealing. The right end of the second connecting rod is sealed to the sealing ring. The left end of the second connecting rod is detachably connected to the secondary pilot valve cover. The secondary pilot valve cover and the sealing ring are tightened by the second connecting rod. The secondary pilot valve cover blocks the first pressure relief port.

[0009] The upper end of the pilot valve plug blocks the lower end of the valve inlet.

[0010] Furthermore, a first sealing groove is provided on the lower end face of the main valve inlet cover, and a first sealing ring is provided in the first sealing groove. A flange structure is provided at the upper end of the medium inlet. The main valve inlet cover and the flange structure of the medium inlet are connected by bolts, and the main valve inlet cover and the flange structure of the medium inlet are sealed by the first sealing ring.

[0011] Furthermore, a first boss is provided on the left end face of the main valve sealing surface cover. The outer periphery of the first boss mates with the inner periphery of the valve seat. A first threaded blind hole is machined on the left end face of the first boss. The right end of the first connecting rod is threadedly engaged with the first threaded blind hole. The left end of the first connecting rod passes through the main valve pressure plate and is threadedly connected to the first nut. The first nut abuts and presses against the left end face of the main valve pressure plate. A first sealing gasket is fitted on the first boss. The left end face of the main valve sealing surface cover and the right end face of the valve seat are sealed by the first sealing gasket.

[0012] Furthermore, a second boss is provided on the right end face of the secondary pilot valve cover. The outer periphery of the second boss mates with the inner periphery of the first pressure relief port. A second sealing gasket is fitted on the second boss. The right end face of the secondary pilot valve cover and the left end face of the secondary pilot valve body are sealed by the second sealing gasket. A second threaded blind hole is provided on the right end face of the second boss. The left end of the second connecting rod is threadedly engaged with the second threaded blind hole. The right end of the second connecting rod passes through the secondary valve cover, the sealing ring, and the washer. A second sealing groove is machined on the left end face of the sealing ring. A second sealing ring is provided in the second sealing groove. A third sealing groove is machined on the inner periphery of the sealing ring. A third sealing ring is provided in the second sealing groove. The sealing ring and the second connecting rod are sealed by the third sealing ring. The outer end of the second connecting rod is threadedly connected to the second nut. The second nut presses the sealing ring onto the outer end face of the secondary valve cover through the washer. The sealing ring and the secondary valve cover are sealed by the second sealing ring.

[0013] Furthermore, it also includes a primary pilot valve cover, a primary pilot valve plug with a stepped shaft structure, a fourth sealing groove machined on the upper outer circumference of the primary pilot valve plug, a fourth sealing ring provided on the fourth sealing groove, the upper part of the primary pilot valve plug being inserted and sealed to the outer end of the primary valve inlet cavity through the fourth sealing ring, the lower diameter of the primary pilot valve plug being larger than the inner diameter of the primary valve inlet cavity, a countersunk groove machined on the upper end surface of the primary pilot valve cover, the lower end of the primary pilot valve plug engaging with the countersunk groove stop, and the primary pilot valve cover being detachably connected to the primary pilot valve body.

[0014] Furthermore, it also includes:

[0015] The main valve outlet cover is equipped with a second water pressure pipe joint, and the plug cap seals the second water pressure pipe joint. The main valve inlet cover is used to seal the medium outlet.

[0016] Secondary pilot valve plug, used to seal the threaded inner hole of the secondary valve cover;

[0017] Needle valve plugs are used to seal the second back pressure port, and the primary pilot valve cap seals the primary valve outlet.

[0018] Furthermore, a fifth sealing groove is machined on the right end face of the main valve outlet cover, and a fifth sealing ring is set in the fifth sealing groove. A flange structure is provided at the left end of the medium outlet. The main valve outlet cover and the flange structure of the medium outlet are connected by bolts. The main valve outlet cover and the flange structure of the medium outlet are sealed by the fifth sealing ring. The left end of the second water pressure pipe joint is provided with an external thread structure. The plug cap is threadedly connected to the second water pressure pipe joint. A third sealing gasket is provided inside the plug cap. The plug cap seals the second water pressure pipe joint through the third sealing gasket.

[0019] Furthermore, the upper end of the primary pilot valve cover is provided with a convex stop, and the lower end face of the primary pilot valve body is provided with a concave stop. The primary pilot valve cover and the primary pilot valve body are connected by bolts, and the convex stop and the concave stop are sealed by a fourth sealing gasket.

[0020] Furthermore, the secondary pilot valve plug is threadedly connected to the threaded inner hole of the secondary valve cover. The right end of the secondary pilot valve plug is provided with a first flange, and a sixth sealing groove is machined on the left end face of the first flange. The sixth sealing ring is set in the sixth sealing groove, and the secondary pilot valve plug is sealed against the right end face of the secondary valve cover through the sixth sealing ring.

[0021] The needle valve plug is threaded to the second back pressure port. The right end of the needle valve plug is provided with a second flange. A seventh sealing groove is machined on the left end face of the second flange. The seventh sealing ring is set in the seventh sealing groove. The secondary pilot valve plug abuts against the right end face of the needle valve body through the seventh sealing ring to seal.

[0022] This invention also provides a method for testing the water pressure strength of a pilot-operated safety valve, which is based on the aforementioned testing fixture for the water pressure strength of a pilot-operated safety valve, and includes the following steps:

[0023] Step 1: Fit the first sealing gasket onto the first boss, hoist the main valve sealing surface cover from the medium inlet to the main valve cavity, screw the inner end of the first connecting rod into the first threaded blind hole, install the main valve pressure plate into the medium outlet, and make the first connecting rod pass through the main valve pressure plate. Tighten the first nut to the outer end of the first connecting rod to achieve the first connecting rod pulling the main valve sealing surface cover tight, and the main valve sealing surface cover sealing the valve seat.

[0024] Step 2: Tighten the left end of the second connecting rod to the second threaded blind hole of the secondary pilot valve cover. Fit the second sealing gasket onto the second boss. Pass the outer end of the second connecting rod through the secondary pilot valve body and the secondary valve cover in sequence. Install the second sealing ring into the second sealing groove. Install the third sealing ring into the third sealing groove. Fit the sealing ring and gasket onto the second connecting rod in sequence. Tighten the second nut to the second connecting rod to pull the secondary pilot valve cover tight. This achieves sealing between the secondary pilot valve cover and the left end face of the secondary pilot valve body through the second sealing gasket, sealing between the sealing ring and the right end face of the secondary valve cover through the second sealing ring, and sealing between the sealing ring and the outer circumference of the second connecting rod through the third sealing ring.

[0025] Step 3: Insert the fourth sealing ring into the fourth sealing groove of the primary pilot valve plug, insert the upper part of the primary pilot valve plug into the primary valve inlet cavity, so that the primary pilot valve plug seals the primary valve inlet cavity, position the groove and the lower end of the primary pilot valve plug for positioning, and connect the primary pilot valve cover to the primary pilot valve body through the double-ended stud.

[0026] Step 4: Fill the main valve body with water through the medium inlet until the water level reaches the flange structure end face of the medium inlet;

[0027] Step 5: Install the first sealing ring into the first sealing groove, and connect the main valve inlet cap to the flange structure of the medium inlet to achieve sealing of the medium inlet;

[0028] Step 6: Connect the first water pressure pipe joint to the booster pump and conduct a water pressure strength test at the medium inlet end;

[0029] Step 7: After the water pressure strength test at the medium inlet is passed, release the water pressure;

[0030] Step 8: Insert the fifth sealing ring into the fifth sealing groove of the main valve outlet cover, and connect the main valve outlet cover to the flange structure of the medium outlet to achieve sealing of the medium outlet.

[0031] Step 9: Insert the seventh sealing ring into the seventh sealing groove of the needle valve plug, and tighten the needle valve plug and the second back pressure port so that the needle valve plug seals with the needle valve body through the seventh sealing ring, thereby sealing the second back pressure port.

[0032] Step 10: First, remove the primary pilot valve cover and the primary pilot valve plug, and quickly install the fourth sealing gasket into the recessed stop of the primary pilot valve body. Then connect the primary pilot valve cover to the primary pilot valve body, so that the primary pilot valve cover seals the primary valve outlet cavity through the fourth sealing gasket, and the water in the main valve cavity can fill the primary valve inlet cavity, the primary valve outlet cavity and the needle valve cavity.

[0033] Step 11: First, remove the second nut, washer, and sealing ring. Push the right end of the second connecting rod into the secondary pilot valve body. Then, install the sixth sealing ring into the sixth sealing groove of the secondary pilot valve plug. Finally, tighten the secondary pilot valve plug and the threaded inner hole of the secondary valve cover to seal the threaded inner hole of the secondary valve cover. The water in the main valve chamber will fill the first back pressure port and the secondary pilot valve chamber.

[0034] Step 12: Fill the medium outlet with water. After the water overflows through the second water pressure pipe joint, seal the second water pressure pipe joint with a plug cap.

[0035] Step 13: After the water pressure strength test at the medium outlet end is qualified, release the pressure and drain the water. The water pressure strength test of the pilot-operated safety valve is now complete.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] This invention fully considers the structure and working principle of pilot-operated safety valves, clearly defines the working pressure ranges of the inlet and outlet sides, and effectively isolates the medium inlet side and the medium outlet side using the test fixture of this invention. A high-pressure water pressure strength test is then performed on the medium inlet side. After the high-pressure section on the medium inlet side passes the water pressure strength test, the low-pressure section on the medium outlet side can be tested simultaneously with the medium inlet side without affecting the valve's water pressure strength test, avoiding the need to test only the medium outlet side. After completing the water pressure strength test on the medium inlet side, there is no need to remove the main valve sealing surface cover, main valve pressure plate, and first connecting rod at the valve seat. The medium outlet and medium inlet can be connected through the secondary pilot valve chamber and the exhaust pipe. The test fixture and testing method of this invention are simple to use, convenient to operate, and highly safe. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the high-pressure test conducted on the medium inlet side of the present invention;

[0039] Figure 2 yes Figure 1 Schematic diagram at point A;

[0040] Figure 3 This is a schematic diagram of the low-pressure test performed on the outlet side of the medium according to the present invention;

[0041] Figure 4 yes Figure 3 Enlarged view of point B;

[0042] Figure 5 This is a schematic diagram of the structure of the housing of a pilot-operated safety valve;

[0043] Figure 6 yes Figure 5 Enlarged view of point C;

[0044] Figure 7 yes Figure 5 A bottom view.

[0045] In the diagram, 1. Main valve body, 2. Valve seat, 3. Medium inlet, 4. Medium outlet, 5. Main valve cover, 6. Secondary pilot valve body, 7. Secondary valve cover, 8. Air inlet pipe, 9. First pressure relief port, 10. Primary pilot valve body, 11. Primary valve inlet chamber, 12. Primary valve outlet chamber, 13. Second pressure relief port, 14. Needle valve chamber, 15. Second back pressure port, 16. Needle valve body, 17. Main valve inlet cover, 18. First water pressure pipe connector, 19. First sealing ring, 20. Main valve sealing surface cover, 21. First sealing gasket, 22. Main valve pressure plate, 23. First nut, 24. First connecting rod, 25. Secondary pilot valve cover, 26. Second sealing gasket, 27. Secondary pilot valve chamber, 28. First back pressure port, 29. Second sealing ring, 30. Third sealing ring, 31. 32. Second nut, 33. Washer, 34. Sealing ring, 35. Fourth sealing ring, 36. Primary pilot valve plug, 37. Primary pilot valve cover, 38. Main valve outlet cover, 39. Fifth sealing ring, 40. Second water pressure pipe connector, 41. Plug cap, 42. Third sealing gasket, 43. Secondary pilot valve plug, 44. Sixth sealing ring, 45. Seventh sealing ring, 46. Needle valve plug, 47. Fourth sealing gasket, 48. Countersunk groove, 49. Main valve chamber, 50. Second connecting rod, 51. Exhaust pipe. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0047] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolted connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a bolted connection can be chosen for detachable connections.

[0048] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0049] Example 1: As Figures 1 to 7 As shown, a pilot-operated safety valve hydraulic strength testing fixture is provided. The pilot-operated safety valve includes a main valve body 1, which is three-way shaped. The upper opening, left opening, and right opening of the main valve body 1 are connected through a main valve chamber 48. A main valve cover 5 closes the right opening of the main valve body 1. The upper opening of the main valve body 1 is a medium inlet 3, and the left opening of the main valve body 1 is a medium outlet 4, which is tapered. A valve seat 2 is located at the right end of the medium outlet 4, and the right end face of the valve seat 2 is the main sealing surface of the pilot-operated safety valve. The left end of a secondary pilot valve body 6 penetrates the valve cover. The left end of the secondary pilot valve body 6 is provided with a first pressure relief port 9, and the right end of the secondary pilot valve body 6 is provided with a first back pressure port 28. The first pressure relief port 9 and the first back pressure port 28 are connected through a secondary pilot valve chamber 27. The secondary pilot valve chamber 27 is connected to the main valve chamber 48 through the first pressure relief port 9. 27 is connected to the medium outlet 4 through the exhaust pipe 50. The secondary valve cover 7 seals the first back pressure port 28. The secondary valve cover 7 has a threaded inner hole. The lower outer wall of the secondary pilot valve body 6 is provided with a primary pilot valve body 10. The lower end face of the primary pilot valve body 10 is sequentially machined with a primary valve outlet cavity 12 and a primary valve inlet cavity 11 from bottom to top. The upper ends of the medium inlet 3 and the primary valve inlet cavity 11 are connected through the air inlet pipe 8. The seat end of the needle valve body 16 passes through the right side wall of the primary valve outlet cavity 12. The left end of the needle valve body 16 is provided with a second pressure relief port 13. The right end of the needle valve body 16 is provided with a second back pressure port 15. The second back pressure port 15 has an internal thread structure. The second pressure relief port 13 and the second back pressure port 15 are connected through the needle valve cavity 14. The needle valve cavity 14 is connected to the primary valve outlet cavity 12 through the second pressure relief port 13. The test fixture includes:

[0050] The main valve inlet cover 17 is equipped with a first water pressure pipe joint 18. The main valve inlet cover 17 is used to block the medium inlet 3.

[0051] The main valve sealing surface cover 20 and the outer peripheral conical surface of the main valve pressure plate 22 are matched with the inner peripheral conical surface of the medium outlet 4. The right end of the first connecting rod 24 is detachably connected to the main valve sealing surface cover 20 and the left end of the first connecting rod 24 is detachably connected to the main valve pressure plate 22. The main valve sealing surface cover 20 and the main valve pressure plate 22 are tightened by the first connecting rod 24. The main valve sealing surface cover 20 blocks the valve seat 2.

[0052] The left end face of the sealing ring 33 of the secondary pilot valve cover 25 abuts against the right end face of the secondary valve cover 7 for sealing. The right end of the second connecting rod 49 is sealed and connected to the sealing ring 33. The left end of the second connecting rod 49 is detachably connected to the secondary pilot valve cover 25. The secondary pilot valve cover 25 and the sealing ring 33 are tightened by the second connecting rod 49. The secondary pilot valve cover 25 blocks the first pressure relief port 9.

[0053] The upper end of the primary pilot valve plug 35 blocks the lower end of the primary valve inlet cavity 11.

[0054] The lower end face of the main valve inlet cover 17 is provided with a first sealing groove, and the first sealing ring 19 is set in the first sealing groove. The upper end of the medium inlet 3 is provided with a flange structure. The main valve inlet cover 17 and the flange structure of the medium inlet 3 are connected by bolts, and the main valve inlet cover 17 and the flange structure of the medium inlet 3 are sealed by the first sealing ring 19.

[0055] A first boss is provided on the left end face of the main valve sealing surface cover 20. The outer periphery of the first boss mates with the inner periphery of the valve seat 2. A first threaded blind hole is machined on the left end face of the first boss. The right end of the first connecting rod 24 is threadedly engaged with the first threaded blind hole. The left end of the first connecting rod 24 passes through the main valve pressure plate 22 and is threadedly connected to the first nut 23. The first nut 23 abuts and presses against the left end face of the main valve pressure plate 22. A first sealing gasket 21 is sleeved on the first boss. The left end face of the main valve sealing surface cover 20 and the right end face of the valve seat 2 are sealed by the first sealing gasket 21.

[0056] A second protrusion is provided on the right end face of the secondary pilot valve cover 25. The outer periphery of the second protrusion mates with the inner periphery of the first pressure relief port 9. A second sealing gasket 26 is fitted onto the second protrusion. The right end face of the secondary pilot valve cover 25 and the left end face of the secondary pilot valve body 6 are sealed by the second sealing gasket 26. A second threaded blind hole is provided on the right end face of the second protrusion. The left end of the second connecting rod 49 is threaded into the second threaded blind hole. The right end of the second connecting rod 49 passes through the secondary valve cover 7, the sealing ring 33, and the washer 32. A second sealing groove is machined on the left end face of the sealing ring 33, and a second sealing ring 29 is provided in the second sealing groove. A third sealing groove is machined on the inner circumference of the sealing ring 33, and a third sealing ring 30 is provided in the second sealing groove. The sealing ring 33 and the second connecting rod 49 are sealed by the third sealing ring 30. The outer end of the second connecting rod 49 is threadedly connected to the second nut 31. The second nut 31 presses the sealing ring 33 onto the outer end face of the secondary valve cover 7 through the washer 32. The sealing ring 33 and the secondary valve cover 7 are sealed by the second sealing ring 29.

[0057] It also includes a primary pilot valve cover 36, a primary pilot valve plug 35 with a stepped shaft structure, a fourth sealing groove machined on the upper outer circumference of the primary pilot valve plug 35, a fourth sealing ring 34 provided on the fourth sealing groove, the upper part of the primary pilot valve plug 35 being inserted and sealed to the outer end of the primary valve inlet cavity 11 through the fourth sealing ring 34, the lower diameter of the primary pilot valve plug 35 being larger than the inner diameter of the primary valve inlet cavity 11, a countersunk groove 47 machined on the upper end surface of the primary pilot valve cover 36, the lower end of the primary pilot valve plug 35 being fitted with the countersunk groove 47, and the primary pilot valve cover 36 being detachably connected to the primary pilot valve body 10.

[0058] Also includes:

[0059] The main valve outlet cover 37 is equipped with a second water pressure pipe joint 39, and the plug cap 40 blocks the second water pressure pipe joint 39. The main valve inlet cover 17 is used to block the medium outlet 4.

[0060] The secondary pilot valve plug 42 is used to seal the threaded inner hole of the secondary valve cover 7;

[0061] Needle valve plug 45 is used to block the second back pressure port 15, and primary pilot valve cover 36 blocks the primary valve outlet 12.

[0062] A fifth sealing groove is machined on the right end face of the main valve outlet cover 37, and a fifth sealing ring 38 is set in the fifth sealing groove. A flange structure is provided at the left end of the medium outlet 4. The flange structure of the main valve outlet cover 37 and the medium outlet 4 are connected by bolts. The flange structure of the main valve outlet cover 37 and the medium outlet 4 are sealed by the fifth sealing ring 38. An external thread structure is provided at the left end of the second water pressure pipe joint 39. The plug cap 40 is threadedly connected to the second water pressure pipe joint 39. A third sealing gasket 41 is provided inside the plug cap 40. The plug cap 40 seals the second water pressure pipe joint 39 through the third sealing gasket 41.

[0063] The upper end of the primary pilot valve cover 36 is provided with a convex stop, and the lower end face of the primary pilot valve body 10 is provided with a concave stop. The primary pilot valve cover 36 and the primary pilot valve body 10 are connected by bolts, and the convex stop and the concave stop are sealed by a fourth sealing gasket 46.

[0064] The secondary pilot valve plug 42 is threadedly connected to the threaded inner hole of the secondary valve cover 7. The right end of the secondary pilot valve plug 42 is provided with a first flange. A sixth sealing groove is machined on the left end face of the first flange. The sixth sealing ring 43 is disposed in the sixth sealing groove. The secondary pilot valve plug 42 is sealed against the right end face of the secondary valve cover 7 through the sixth sealing ring 43.

[0065] The needle valve plug 45 is threadedly connected to the second back pressure port 15. The right end of the needle valve plug 45 is provided with a second flange. A seventh sealing groove is machined on the left end face of the second flange. The seventh sealing ring 44 is disposed in the seventh sealing groove. The secondary pilot valve plug 42 is sealed against the right end face of the needle valve body 16 through the seventh sealing ring 44.

[0066] Example 2: Figures 1 to 7 As shown, a method for testing the water pressure strength of a pilot-operated safety valve, based on the water pressure strength testing fixture for a pilot-operated safety valve described in Example 1, includes the following steps:

[0067] Step 1: Fit the first sealing gasket 21 onto the first boss, hoist the main valve sealing surface cover 20 from the medium inlet 3 to the main valve cavity 48, screw the inner end of the first connecting rod 24 into the first threaded blind hole, install the main valve pressure plate 22 into the medium outlet 4, and make the first connecting rod 24 pass through the main valve pressure plate 22. Tighten the first nut 23 to the outer end of the first connecting rod 24 to achieve the first connecting rod 24 pulling the main valve sealing surface cover 20, and the main valve sealing surface cover 20 sealing the valve seat 2.

[0068] Step 2: Tighten the left end of the second connecting rod 49 to the second threaded blind hole of the secondary pilot valve cover 25. Fit the second sealing gasket 26 onto the second boss. Pass the outer end of the second connecting rod 49 through the secondary pilot valve body 6 and the secondary valve cover 7 in sequence. Install the second sealing ring 29 into the second sealing groove. Install the third sealing ring 30 into the third sealing groove. Fit the sealing ring 33 and the washer 32 onto the second connecting rod 49 in sequence. Tighten the second nut 31 onto the second connecting rod 49 to pull the secondary pilot valve cover 25. This achieves a seal between the secondary pilot valve cover 25 and the left end face of the secondary pilot valve body 6 through the second sealing gasket 26, a seal between the sealing ring 33 and the right end face of the secondary valve cover 7 through the second sealing ring 29, and a seal between the sealing ring 33 and the outer circumference of the second connecting rod 49 through the third sealing ring 30.

[0069] Step 3: Insert the fourth sealing ring 34 into the fourth sealing groove of the primary pilot valve plug 35, insert the upper part of the primary pilot valve plug 35 into the primary valve inlet cavity 11, so that the primary pilot valve plug 35 seals the primary valve inlet cavity 11, position the groove 47 with the lower end of the primary pilot valve plug 35, and connect the primary pilot valve cover 36 to the primary pilot valve body 10 through the double-ended stud.

[0070] Step 4: Fill the main valve body 1 with water from the medium inlet 3 until the water level reaches the flange end face of the medium inlet 3;

[0071] Step 5: Install the first sealing ring 19 into the first sealing groove, and connect the main valve inlet cover 17 to the flange structure of the medium inlet 3 to achieve sealing of the medium inlet 3;

[0072] Step 6: Connect the first water pressure pipe joint 18 to the booster pump and conduct a water pressure strength test at the medium inlet 3.

[0073] Step 7: After the water pressure strength test at the three ends of the medium inlet is qualified, release the water pressure;

[0074] Step 8: Insert the fifth sealing ring 38 into the fifth sealing groove of the main valve outlet cover 37, and connect the main valve outlet cover 37 to the flange structure of the medium outlet 4 to achieve the sealing of the medium outlet 4.

[0075] Step 9: Insert the seventh sealing ring 44 into the seventh sealing groove of the needle valve plug 45, and tighten the needle valve plug 45 and the second back pressure port 15 so that the needle valve plug 45 seals with the needle valve body 16 through the seventh sealing ring 44, thereby sealing the second back pressure port 15.

[0076] Step 10: First, remove the primary pilot valve cover 36 and the primary pilot valve plug 35, and quickly install the fourth sealing gasket 46 into the recessed stop of the primary pilot valve body 10. Then connect the primary pilot valve cover 36 to the primary pilot valve body 10, so that the primary pilot valve cover 36 blocks the primary valve outlet cavity 12 through the fourth sealing gasket 46, and the water in the main valve cavity 48 can fill the primary valve inlet cavity 11, the primary valve outlet cavity 12 and the needle valve cavity 14.

[0077] Step 11: First, remove the second nut 31, washer 32 and sealing ring 33. Push the right end of the second connecting rod 49 into the secondary pilot valve body 6. Then, install the sixth sealing ring 43 into the sixth sealing groove of the secondary pilot valve plug 42. Then, tighten the secondary pilot valve plug 42 and the threaded inner hole of the secondary valve cover 7 to seal the threaded inner hole of the secondary valve cover 7. The water in the main valve chamber 48 fills the first back pressure port 28 and the secondary pilot valve chamber 27.

[0078] Step 12: Fill the medium outlet 4 with water. After the water overflows through the second water pressure pipe joint 39, seal the second water pressure pipe joint 39 with the plug cap 40.

[0079] Step 13: After the water pressure strength test at the media outlet 4 is passed, release the pressure and drain the water. The water pressure strength test of the pilot-operated safety valve is now complete.

[0080] The main valve inlet cap 17, main valve sealing surface cap 20, secondary pilot valve cap 25, sealing ring 33, and primary pilot valve plug 35 are used to isolate and seal the medium inlet 3, main valve chamber 48, and the right opening of the main valve body. This configuration allows for a high-pressure water pressure test on one side of the medium inlet 3 to determine if there are any pressure issues on that side. The main valve outlet cap 37, plug 40, secondary pilot valve plug 42, and needle valve plug 45 can seal the main valve body 1, primary pilot valve body 10, secondary pilot valve body 6, and needle valve body 16 while maintaining connectivity between them. This configuration allows for a low-pressure water pressure test to be performed simultaneously to check the overall pressure-bearing capacity.

[0081] This invention fully considers the structure and working principle of pilot-operated safety valves, clearly defines the working pressure range of the inlet and outlet sides, and utilizes the test fixture of this invention to effectively isolate the medium inlet 3 side and the medium outlet 4 side, allowing for a high-pressure water pressure strength test on the medium inlet 3 side. After the high-pressure section on the medium inlet 3 side passes the water pressure strength test, the low-pressure section on the medium outlet 4 side can be tested simultaneously with the medium inlet 3 side without affecting the valve's water pressure strength test, avoiding the need to test the water pressure strength on the medium outlet 4 side alone. After completing the water pressure strength test on the medium inlet 3 side, it is not necessary to remove the main valve sealing surface cover 20, the main valve pressure plate 22, and the first connecting rod 24 at the valve seat 2. The medium outlet 4 and the medium inlet 3 can be connected through the secondary pilot valve chamber 27 and the exhaust pipe 50. The test fixture of this invention is simple to use and operate, and the test method is convenient and safe.

[0082] The above embodiments are merely illustrative examples of the present invention and do not limit its scope of protection. Those skilled in the art can make partial changes to them, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A pilot-operated safety valve hydraulic strength testing fixture, wherein the pilot-operated safety valve includes a main valve body (1), the main valve body (1) is three-way shaped, the upper opening, left opening and right opening of the main valve body (1) are connected through a main valve chamber (48), the main valve cover (5) closes the right opening of the main valve body (1), the upper opening of the main valve body (1) is a medium inlet (3), the left opening of the main valve body (1) is a medium outlet (4), the medium outlet (4) is tapered, and a valve seat (2) is disposed at the medium outlet (4). The right end of the valve seat (2) is the main sealing surface of the pilot-operated safety valve. The left end of the secondary pilot valve body (6) penetrates the valve cover. The left end of the secondary pilot valve body (6) is provided with a first pressure relief port (9). The right end of the secondary pilot valve body (6) is provided with a first back pressure port (28). The first pressure relief port (9) and the first back pressure port (28) are connected through the secondary pilot valve chamber (27). The secondary pilot valve chamber (27) is connected to the main valve chamber (48) through the first pressure relief port (9). 27) The exhaust pipe (50) is connected to the medium outlet (4). The secondary valve cover (7) closes the first back pressure port (28). The secondary valve cover (7) is provided with a threaded inner hole. The secondary pilot valve body (6) is provided with a primary pilot valve body (10) on the lower outer wall. The lower end face of the primary pilot valve body (10) is machined with a primary valve outlet cavity (12) and a primary valve inlet cavity (11) from bottom to top. The upper ends of the medium inlet (3) and the primary valve inlet cavity (11) are connected through the air inlet pipe (8). The needle valve body (16) has its seat end passing through the right side wall of the primary valve outlet cavity (12). The left end of the needle valve body (16) has a second pressure relief port (13), and the right end of the needle valve body (16) has a second back pressure port (15). The second back pressure port (15) has an internal thread structure. The second pressure relief port (13) and the second back pressure port (15) are connected through the needle valve cavity (14). The needle valve cavity (14) is connected to the primary valve outlet cavity (12) through the second pressure relief port (13). The characteristic feature is that... The test fixture includes: The main valve inlet cover (17) is provided with a first water pressure pipe joint (18). The main valve inlet cover (17) is used to block the medium inlet (3). The main valve sealing surface cover (20) and the outer peripheral conical surface of the main valve pressure plate (22) are matched with the inner peripheral conical surface of the medium outlet (4). The right end of the first connecting rod (24) is detachably connected to the main valve sealing surface cover (20) and the left end of the first connecting rod (24) is detachably connected to the main valve pressure plate (22). The main valve sealing surface cover (20) and the main valve pressure plate (22) are tightened by the first connecting rod (24). The main valve sealing surface cover (20) seals the valve seat (2). The left end face of the sealing ring (33) of the secondary pilot valve cover (25) abuts against the right end face of the secondary valve cover (7) for sealing. The right end of the second connecting rod (49) is sealed to the sealing ring (33). The left end of the second connecting rod (49) is detachably connected to the secondary pilot valve cover (25). The secondary pilot valve cover (25) and the sealing ring (33) are tightened by the second connecting rod (49). The secondary pilot valve cover (25) blocks the first pressure relief port (9). The upper end of the primary pilot valve plug (35) blocks the lower end of the primary valve inlet cavity (11).

2. The pilot-operated safety valve water pressure strength testing fixture according to claim 1, characterized in that: The lower end face of the main valve inlet cover (17) is provided with a first sealing groove, and the first sealing ring (19) is set in the first sealing groove. The upper end of the medium inlet (3) is provided with a flange structure. The flange structure of the main valve inlet cover (17) and the medium inlet (3) is connected by bolts, and the flange structure of the main valve inlet cover (17) and the medium inlet (3) are sealed by the first sealing ring (19).

3. The water pressure strength testing fixture for a pilot-operated safety valve according to claim 2, characterized in that: The left end face of the main valve sealing surface cover (20) is provided with a first boss. The outer periphery of the first boss is matched with the inner periphery of the valve seat (2). The left end face of the first boss is machined with a first threaded blind hole. The right end of the first connecting rod (24) is threadedly matched with the first threaded blind hole. The left end of the first connecting rod (24) passes through the main valve pressure plate (22) and is threadedly connected with the first nut (23). The first nut (23) abuts against and presses against the left end face of the main valve pressure plate (22). A first sealing gasket (21) is sleeved on the first boss. The left end face of the main valve sealing surface cover (20) and the right end face of the valve seat (2) are sealed by the first sealing gasket (21).

4. The water pressure strength testing fixture for a pilot-operated safety valve according to claim 3, characterized in that: A second protrusion is provided on the right end face of the secondary pilot valve cover (25). The outer periphery of the second protrusion mates with the inner periphery of the first pressure relief port (9). A second sealing gasket (26) is fitted onto the second protrusion. The right end face of the secondary pilot valve cover (25) is sealed to the left end face of the secondary pilot valve body (6) by the second sealing gasket (26). A second threaded blind hole is provided on the right end face of the second protrusion. The left end of the second connecting rod (49) is threaded into the second threaded blind hole. The right end of the second connecting rod (49) passes through the secondary valve cover (7), the sealing ring (33), and the washer (32). The sealing ring (33) The left end face of the sealing ring (33) is machined with a second sealing groove, and a second sealing ring (29) is provided in the second sealing groove. The inner circumference of the sealing ring (33) is machined with a third sealing groove, and a third sealing ring (30) is provided in the second sealing groove. The sealing ring (33) and the second connecting rod (49) are sealed by the third sealing ring (30). The outer end of the second connecting rod (49) is threadedly connected to the second nut (31). The second nut (31) presses the sealing ring (33) onto the outer end face of the secondary valve cover (7) through the washer (32). The sealing ring (33) and the secondary valve cover (7) are sealed by the second sealing ring (29).

5. The water pressure strength testing fixture for a pilot-operated safety valve according to claim 4, characterized in that: It also includes a primary pilot valve cover (36), a primary pilot valve plug (35) with a stepped shaft structure, a fourth sealing groove machined on the upper outer periphery of the primary pilot valve plug (35), a fourth sealing ring (34) provided on the fourth sealing groove, the upper part of the primary pilot valve plug (35) is inserted and sealed with the outer end of the primary valve inlet cavity (11) through the fourth sealing ring (34), the lower diameter of the primary pilot valve plug (35) is larger than the inner diameter of the primary valve inlet cavity (11), a countersunk groove (47) is machined on the upper end surface of the primary pilot valve cover (36), the lower end of the primary pilot valve plug (35) is fitted with the stop of the countersunk groove (47), and the primary pilot valve cover (36) and the primary pilot valve body (10) are detachably connected.

6. The water pressure strength testing fixture for a pilot-operated safety valve according to claim 5, characterized in that, Also includes: The main valve outlet cover (37) is provided with a second water pressure pipe joint (39), and the plug cap (40) is used to seal the second water pressure pipe joint (39). The main valve inlet cover (17) is used to seal the medium outlet (4). Secondary pilot valve plug (42) is used to seal the threaded inner hole of the secondary valve cover (7); Needle valve plug (45) is used to block the second back pressure port (15), and primary pilot valve cover (36) blocks the primary valve outlet (12).

7. The water pressure strength testing fixture for a pilot-operated safety valve according to claim 6, characterized in that, The right end face of the main valve outlet cover (37) is machined with a fifth sealing groove, and the fifth sealing ring (38) is set in the fifth sealing groove. The left end of the medium outlet (4) is provided with a flange structure. The main valve outlet cover (37) and the flange structure of the medium outlet (4) are connected by bolts. The main valve outlet cover (37) and the flange structure of the medium outlet (4) are sealed by the fifth sealing ring (38). The left end of the second water pressure pipe joint (39) is provided with an external thread structure. The plug cap (40) is threadedly connected to the second water pressure pipe joint (39). The plug cap (40) is provided with a third sealing gasket (41). The plug cap (40) seals the second water pressure pipe joint (39) through the third sealing gasket (41).

8. The water pressure strength testing fixture for a pilot-operated safety valve according to claim 7, characterized in that, The upper end of the primary pilot valve cover (36) is provided with a convex stop, and the lower end face of the primary pilot valve body (10) is provided with a concave stop. The primary pilot valve cover (36) and the primary pilot valve body (10) are connected by bolts, and the convex stop and the concave stop are sealed by a fourth sealing gasket (46).

9. The water pressure strength testing fixture for a pilot-operated safety valve according to claim 8, characterized in that, The secondary pilot valve plug (42) is threadedly connected to the threaded inner hole of the secondary valve cover (7). The right end of the secondary pilot valve plug (42) is provided with a first flange. A sixth sealing groove is machined on the left end face of the first flange. The sixth sealing ring (43) is set in the sixth sealing groove. The secondary pilot valve plug (42) is sealed against the right end face of the secondary valve cover (7) through the sixth sealing ring (43). The needle valve plug (45) is threaded to the second back pressure port (15). The right end of the needle valve plug (45) is provided with a second flange. A seventh sealing groove is machined on the left end face of the second flange. The seventh sealing ring (44) is set in the seventh sealing groove. The secondary pilot valve plug (42) is sealed against the right end face of the needle valve body (16) through the seventh sealing ring (44).

10. A method for testing the water pressure strength of a pilot-operated safety valve, based on the water pressure strength testing fixture for a pilot-operated safety valve as described in claim 9, characterized in that, Includes the following steps: Step 1: Fit the first sealing gasket (21) onto the first boss, hoist the main valve sealing surface cover (20) from the medium inlet (3) to the main valve cavity (48), screw the inner end of the first connecting rod (24) into the first threaded blind hole, install the main valve pressure plate (22) into the medium outlet (4), and make the first connecting rod (24) pass through the main valve pressure plate (22). Tighten the first nut (23) to the outer end of the first connecting rod (24) so ​​that the first connecting rod (24) pulls the main valve sealing surface cover (20) and the main valve sealing surface cover (20) seals the valve seat (2). Step 2: Tighten the left end of the second connecting rod (49) to the second threaded blind hole of the secondary pilot valve cover (25), fit the second sealing gasket (26) onto the second boss, pass the outer end of the second connecting rod (49) through the secondary pilot valve body (6) and the secondary valve cover (7) in sequence, install the second sealing ring (29) into the second sealing groove, install the third sealing ring (30) into the third sealing groove, and fit the sealing ring (33) and gasket (32) into the second boss in sequence. On the connecting rod (49), tighten the second nut (31) to the second connecting rod (49) so that the second connecting rod (49) pulls the secondary pilot valve cover (25) tight, so that the secondary pilot valve cover (25) is sealed to the left end face of the secondary pilot valve body (6) through the second sealing gasket (26), the sealing ring (33) is sealed to the right end face of the secondary valve cover (7) through the second sealing ring (29), and the sealing ring (33) is sealed to the outer circumference of the second connecting rod (49) through the third sealing ring (30); Step 3: Insert the fourth sealing ring (34) into the fourth sealing groove of the primary pilot valve plug (35), insert the upper part of the primary pilot valve plug (35) into the primary valve inlet cavity (11) to achieve the primary pilot valve plug (35) sealing the primary valve inlet cavity (11), position the groove (47) and the lower end of the primary pilot valve plug (35) for positioning and matching, and connect the primary pilot valve cover (36) and the primary pilot valve body (10) through the double-ended stud; Step 4: Fill the main valve body (1) with water from the medium inlet (3) until the water level reaches the flange structure end face of the medium inlet (3); Step 5: Install the first sealing ring (19) into the first sealing groove, connect the main valve inlet cap (17) to the flange structure of the medium inlet (3) to achieve sealing of the medium inlet (3); Step 6: Connect the first water pressure pipe joint (18) to the booster pump and conduct a water pressure strength test at the medium inlet (3); Step 7: After the water pressure strength test at the medium inlet (3) is passed, release the water pressure; Step 8: Insert the fifth sealing ring (38) into the fifth sealing groove of the main valve outlet cover (37), and connect the main valve outlet cover (37) to the flange structure of the medium outlet (4) to achieve the sealing of the medium outlet (4); Step 9: Insert the seventh sealing ring (44) into the seventh sealing groove of the needle valve plug (45), tighten the needle valve plug (45) and the second back pressure port (15), so that the needle valve plug (45) is sealed to the needle valve body (16) through the seventh sealing ring (44), thereby sealing the second back pressure port (15). Step 10: First, remove the primary pilot valve cover (36) and the primary pilot valve plug (35), and quickly install the fourth sealing gasket (46) into the recessed stop of the primary pilot valve body (10). Then connect the primary pilot valve cover (36) to the primary pilot valve body (10) so that the primary pilot valve cover (36) blocks the primary valve outlet cavity (12) through the fourth sealing gasket (46). The water in the main valve cavity (48) can then fill the primary valve inlet cavity (11), the primary valve outlet cavity (12) and the needle valve cavity (14). Step 11: First, remove the second nut (31), washer (32) and sealing ring (33), push the right end of the second connecting rod (49) into the secondary pilot valve body (6), then install the sixth sealing ring (43) into the sixth sealing groove of the secondary pilot valve plug (42), then tighten the threaded inner hole of the secondary pilot valve plug (42) and the secondary valve cover (7) so that the secondary pilot valve plug (42) blocks the threaded inner hole of the secondary valve cover (7), and the water in the main valve chamber (48) fills the first back pressure port (28) and the secondary pilot valve chamber (27). Step 12: Fill the medium outlet (4) with water. After the water overflows through the second water pressure pipe joint (39), seal the second water pressure pipe joint (39) with a plug cap (40). Step 13: After the water pressure strength test at the medium outlet (4) is qualified, the pressure is released and the water is drained. The water pressure strength test of the pilot-operated safety valve is now complete.

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