A pilot operated safety valve

Abstract

The utility model discloses a pilot safety valve, including main valve structure and pilot valve structure, and the main valve structure includes main valve body, main valve cover, main valve cover, main valve petal, main spring and main valve seat, and the pilot valve structure includes deputy valve body, deputy valve cover, deputy valve seat, deputy valve petal, deputy spring, is equipped with the venting of intercommunication with deputy valve seat upper chamber on deputy valve body, still including has sensitivity fine adjustment mechanism, and the sensitivity fine adjustment mechanism includes the adjusting seat screw connection in deputy valve body lower extreme, and the lower guide bush is connected with adjusting seat, and the deputy valve core is set up in the lower guide bush and is set up in the limiting piece of lower guide bush lower extreme along the vertical activity, and adjusting seat side is equipped with lower through -hole, and the lower guide bush is equipped with sealing flange, and the lower end of deputy valve petal is equipped with the top rod, and the deputy valve core goes up and is sealed with sealing flange when the close -fitting of both, and the deputy valve core pushes the top rod and deputy valve petal and goes up, makes deputy valve petal separate from deputy valve seat. The utility model can realize the high accuracy regulation of pilot valve reaction sensitivity, and can adapt to the pressure fluctuation of different working conditions.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, and in particular to a pilot-operated safety valve. Background Technology

[0002] A pilot-operated safety valve is a type of non-direct-load safety valve. It consists of a main valve and a pilot valve (also known as a "slave valve"). The main valve is driven by the medium discharged from the pilot valve. Because the pressure in the system is in pulse form, it is also called a "pulse-type safety valve." Individually, the pilot valve itself is also a type of direct-load safety valve. When the medium pressure reaches the opening pressure of the pilot valve, the pilot valve opens first, and the discharged medium enters the main valve through the bypass pipe.

[0003] Currently, the pilot valve opening pressure of existing pilot-operated safety valves is entirely regulated by the pilot valve spring. Its disadvantage is that the pilot valve spring has low adjustment accuracy, which makes it impossible to achieve high-precision adjustment of the pilot valve's response sensitivity and difficult to adapt to pressure fluctuations under different working conditions.

[0004] Therefore, it is necessary to improve existing pilot-operated safety valves. Utility Model Content

[0005] The purpose of this invention is to provide a pilot-operated safety valve that can achieve high-precision adjustment of the pilot valve's response sensitivity, enabling it to adapt to pressure fluctuations under different working conditions.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a pilot-operated safety valve, comprising a main valve structure and a pilot valve structure.

[0007] The main valve structure includes a main valve body, an inlet channel and an outlet channel located at both ends of the valve body, a main valve cover located at the upper end of the main valve body, a main valve sleeve located at the inner end of the main valve cover, a main valve disc slidably located vertically within the main valve sleeve, a main spring located at the upper end of the main valve disc for applying spring force to the main valve disc, and a main valve seat located within the main valve body for cooperating with the main valve disc.

[0008] The pilot valve structure includes a secondary valve body, a secondary valve cover disposed at the upper end of the secondary valve body, a secondary valve seat disposed within the secondary valve body, a secondary valve disc disposed vertically within the secondary valve body and abutting or separating from the secondary valve seat, and a secondary spring disposed within the secondary valve cover for applying spring force to the secondary valve disc.

[0009] The inlet and outlet of the secondary valve body are connected to the main valve body through the first pipe and the second pipe, respectively. The secondary valve body is also provided with a vent that communicates with the upper chamber of the secondary valve seat.

[0010] It also includes a sensitivity fine-tuning mechanism, which includes an adjusting seat that is threaded to the lower end of the secondary valve body, is hollow and open at the upper end, a lower guide sleeve that is connected to one end of the adjusting seat that extends into the secondary valve body, a secondary valve core that is vertically movable in the lower guide sleeve, and a limiting member that is provided at the lower end of the lower guide sleeve to limit the lower stroke of the secondary valve core. The side of the adjusting seat is provided with a lower through hole that connects the interior of the adjusting seat to the inlet of the secondary valve body. The lower guide sleeve is provided with a sealing flange. The lower end of the secondary valve disc is provided with a push rod. When the secondary valve core moves upward and abuts against the sealing flange, the two are sealed together. At the same time, the secondary valve core pushes the push rod and the secondary valve disc upward, causing the secondary valve disc to disengage from the secondary valve seat.

[0011] By adopting the above technical solution and setting a sensitivity fine-tuning mechanism, namely a rotary adjusting seat, the initial distance between the secondary valve core and the sealing flange is achieved, thereby realizing the flow regulation between them. Under a certain medium pressure, the secondary valve core will rise until it abuts against the sealing flange, triggering the secondary valve core to rise further, allowing the medium to pass through the secondary valve seat and be reinjected through the vent. When rotating the adjusting seat, the larger the opening of the lower guide sleeve, the greater the flow rate and the smaller the sensitivity; the smaller the opening, the smaller the flow rate and the higher the sensitivity. This allows for high-precision adjustment of the pilot valve's response sensitivity, enabling it to adapt to pressure fluctuations under different operating conditions.

[0012] The present invention is further configured such that the upper end of the secondary valve core is provided with a lower sealing cone surface, and the sealing flange is provided with an upper sealing cone surface. When the secondary valve core falls to the upper end of the limiting member under its own weight, a first adjustment gap is formed between the lower sealing cone surface and the upper sealing cone surface.

[0013] By adopting the above technical solution, the first adjustment gap, i.e. the opening degree of the lower guide sleeve, has good sealing performance when closed and high adjustment sensitivity.

[0014] The present invention is further configured such that the lower guide sleeve is threadedly connected to the upper end of the adjusting seat, a first sealing ring is provided between the adjusting seat and the inner wall of the secondary valve body, and a second sealing ring is provided between the adjusting seat and the lower guide sleeve.

[0015] By adopting the above technical solution, the structure is easy to assemble and has good sealing performance.

[0016] The present invention is further configured such that at least one flow gap is provided between the outer circular surface of the secondary valve core and the inner circular surface of the lower guide sleeve.

[0017] By adopting the above technical solution, the medium can enter the lower guide sleeve through the flow gap between the secondary valve core and the lower guide sleeve while the secondary valve core can move up and down stably. The structure is simple, reliable and easy to process.

[0018] The present invention is further configured such that the limiting member is a threaded sleeve, the limiting member is threadedly connected to the lower end of the lower guide seat, and the lower end of the limiting member is provided with an internal hexagonal groove.

[0019] By adopting the above technical solution, the limiting component uses a threaded sleeve, which not only allows the medium to pass through, but also makes installation and operation very convenient due to the threaded connection.

[0020] The present invention is further configured to include an upper guide sleeve and a support sleeve. A support step is provided on the inner wall of the secondary valve body. The secondary valve cover presses the upper guide sleeve, the secondary valve seat, and the support sleeve onto the support step. The outer circular surface of the secondary valve disc fits against the inner circular surface of the upper guide sleeve. An upper through hole is provided on the outer periphery of the upper guide sleeve to connect its interior with the vent. A valve seat sealing ring is sandwiched between the lower end of the inner circular surface of the secondary valve seat and the upper end of the inner circular surface of the support sleeve. When the lower end of the secondary valve disc abuts against the valve seat sealing ring, the secondary valve disc and the secondary valve seat are sealed together.

[0021] By adopting the above technical solution, when the secondary valve disc disengages from the valve seat sealing ring, the pilot valve backfills; when the secondary valve disc presses against the valve seat sealing ring, the pilot valve does not backfill. This structure not only guides the secondary valve disc and improves the stability of its movement, but also makes the sealing performance more reliable when the secondary valve disc and the valve seat sealing ring on the secondary valve seat cooperate.

[0022] The present invention is further configured such that the push rod is threadedly connected to the lower end of the secondary valve disc.

[0023] By adopting the above technical solution, the connection structure is simple and reliable, and disassembly and assembly are very convenient.

[0024] The present invention is further configured to include a flow regulating mechanism, the flow regulating mechanism including an internal hexagonal adjusting stud, a threaded hole communicating with the vent on the side of the secondary valve body, the internal hexagonal adjusting stud being threaded into the threaded hole, and a tapered adjusting head being provided at the inner end of the internal hexagonal adjusting stud, the tapered adjusting head forming a second adjusting gap with the vent.

[0025] By adopting the above technical solution, the size of the second adjustment gap can be changed by adjusting the internal hexagonal adjusting stud, thereby directly affecting the opening pressure of the main valve, changing the set pressure value, and adapting to different working conditions.

[0026] The present invention is further configured such that a positioning groove is provided at the bottom of the main valve disc, and a pressure plate is connected to the positioning groove by a locking screw. An annular conical groove with a larger inner diameter and a smaller outer diameter is formed between the outer periphery of the pressure plate and the inner periphery of the positioning groove. A main sealing ring for forming a sealing fit with the main valve seat is embedded in the annular conical groove.

[0027] By adopting the above technical solution, the main sealing ring is embedded in the annular conical groove and is not easy to come out of the annular conical groove. It not only has good sealing performance when it is matched with the valve seat, but also has the advantage of strong structural stability.

[0028] The present invention is further configured such that the inner end of the positioning groove is provided with a circular groove, the upper end of the pressure plate is provided with a positioning protrusion extending into the circular groove, and the outer circular surface of the positioning protrusion is equipped with a third sealing ring for forming a sealing fit with the inner circular surface of the circular groove.

[0029] By adopting the above technical solution, a vacuum cavity is formed between the third sealing ring and the main sealing ring, preventing the main sealing ring from flying out under high pressure and further improving the firmness of the main sealing ring installation. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0031] Figure 2 This is a schematic diagram of the pilot valve structure of this utility model;

[0032] Figure 3 This utility model Figure 2 Enlarged structural diagram of section A in the middle;

[0033] Figure 4 This is a cross-sectional view of the mating structure of the lower guide sleeve and the auxiliary valve core of this utility model;

[0034] Figure 5 This utility model Figure 2 Enlarged structural diagram of section B in the middle;

[0035] Figure 6 This utility model Figure 1 Enlarged structural diagram of section C.

[0036] In the diagram: 1. Main valve structure; 2. Pilot valve structure; 3. Main valve body; 4. Inlet channel; 5. Outlet channel; 6. Main valve cover; 7. Main valve sleeve; 8. Main valve disc; 9. Main spring; 10. Secondary valve body; 11. Secondary valve cover; 12. Secondary valve seat; 13. Secondary valve disc; 14. Secondary spring; 15. First pipeline; 16. Secondary pipeline; 17. Vent port; 18. Sensitivity fine-tuning mechanism; 19. Adjusting seat; 20. Lower guide sleeve; 21. Secondary valve core; 22. Limiting element; 23. Lower through hole; 24. Sealing flange; 25. Push rod; 26. Lower sealing cone surface; 27. Upper sealing cone surface 28. First adjusting gap; 29. ​​First sealing ring; 30. Second sealing ring; 31. Flow gap; 32. Hexagonal socket groove; 33. Upper guide sleeve; 34. Support sleeve; 35. Support step; 36. Upper through hole; 37. Valve seat sealing ring; 38. Flow regulating mechanism; 39. Hexagonal socket adjusting stud; 40. Screw hole; 41. Conical adjusting head; 42. Second adjusting gap; 43. Positioning groove; 44. Locking screw; 45. Pressure plate; 46. Annular conical groove; 47. Main sealing ring; 48. Circular groove; 49. Positioning protrusion; 50. Third sealing ring; 51. Main valve seat. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0038] Example: As attached Figures 1-6The pilot-operated safety valve shown includes a main valve structure 1 and a pilot valve structure 2. The main valve structure 1 is a conventional structure, comprising a main valve body 3, an inlet channel 4 and an outlet channel 5 located at both ends of the valve body, a main valve cover 6 located at the upper end of the main valve body 3, a main valve sleeve 7 located inside the main valve cover 6, a main valve disc 8 vertically slidably disposed within the main valve sleeve 7 (the main valve disc 8 has a sealing ring on its outer periphery for forming a sealing fit with the inner wall of the main valve sleeve 7), a main spring 9 located at the upper end of the main valve disc 8 for applying spring force to the main valve disc 8, and a main valve body 9 for applying spring force to the main valve disc 8. A main valve seat 51 is located within the main valve body 3 to cooperate with the main valve disc 8; the pilot valve structure 2 includes a secondary valve body 10, a secondary valve cover 11 disposed at the upper end of the secondary valve body 10, a secondary valve seat 12 disposed within the secondary valve body 10, a secondary valve disc 13 vertically slidably disposed within the secondary valve body 10 and abutting or separating from the secondary valve seat 12, and a secondary spring 14 disposed within the secondary valve cover 11 to apply spring force to the secondary valve disc 13; the inlet of the secondary valve body 10 is connected to the inlet flow channel of the main valve body 3 through a first pipe 15, and the outlet of the secondary valve body 10 is connected to the main valve body 3 through a second pipe 16. The main valve body 3 is connected to the air chamber above the main valve disc 8. The auxiliary valve body 10 is also provided with a vent 17 that communicates with the upper chamber of the auxiliary valve seat 12. The pilot valve structure 2 also includes a sensitivity fine-tuning mechanism 18. The sensitivity fine-tuning mechanism 18 includes an adjusting seat 19 that is threaded to the lower end of the auxiliary valve body 10, is hollow and open at the upper end, a lower guide sleeve 20 that is connected to one end of the adjusting seat 19 that extends into the interior of the auxiliary valve body 10, an auxiliary valve core 21 that is vertically movable in the lower guide sleeve 20, and a component located at the lower end of the lower guide sleeve 20 that forms a downward stroke for the auxiliary valve core 21. The limiting component 22 is used for limiting the position. The side of the adjusting seat 19 is provided with a lower through hole 23 that connects the interior of the adjusting seat 19 to the inlet of the secondary valve body 10. An annular cavity is provided between the outer wall of the adjusting seat 19 and the inner wall of the secondary valve body 10 to connect the lower through hole 23 and the inlet of the secondary valve body 10. The lower guide sleeve 20 is provided with a sealing flange 24. The lower end of the secondary valve disc 13 is provided with a push rod 25. When the secondary valve core 21 moves upward and abuts against the sealing flange 24, the two are sealed together. At the same time, the secondary valve core 21 pushes the push rod 25 and the secondary valve disc 13 upward, so that the secondary valve disc 13 disengages from the secondary valve seat 12. By setting a sensitivity fine-tuning mechanism 18, i.e., a rotating adjusting seat 19, the initial distance between the secondary valve core 21 and the sealing flange 24 is achieved, thereby realizing the flow regulation between the two. Under a certain medium pressure, the secondary valve core 21 will rise until it abuts against the sealing flange 24, triggering the secondary valve core 21 to rise, allowing the medium to pass through the secondary valve seat 12 and be reinjected through the vent port 17. When rotating the adjusting seat 19, the larger the opening of the lower guide sleeve 20, the larger the flow rate and the smaller the sensitivity; the smaller the opening, the smaller the flow rate and the higher the sensitivity. This can achieve high-precision adjustment of the pilot valve's response sensitivity, enabling it to adapt to pressure fluctuations under different operating conditions.

[0039] As attached Figure 2 and attached Figure 3As shown, the upper end of the secondary valve core 21 is provided with a lower sealing cone surface 26, and the sealing flange 24 is provided with an upper sealing cone surface 27. When the secondary valve core 21 falls to the upper end of the limiting member 22 under its own weight, a first adjustment gap 28 is formed between the lower sealing cone surface 26 and the upper sealing cone surface 27. The first adjustment gap 28 is the opening degree of the lower guide sleeve 20, which has good sealing performance when closed and high adjustment sensitivity.

[0040] As attached Figure 2 As shown, the lower guide sleeve 20 is threadedly connected to the upper end of the adjusting seat 19. A first sealing ring 29 is provided between the adjusting seat 19 and the inner wall of the secondary valve body 10, and a second sealing ring 30 is provided between the adjusting seat 19 and the lower guide sleeve 20. This structure is easy to assemble and has good sealing performance.

[0041] As attached Figure 4 As shown, at least one flow gap 31 is provided between the outer circular surface of the secondary valve core 21 and the inner circular surface of the lower guide sleeve 20. More specifically, the inner cavity cross-section of the lower guide sleeve 20 is circular, and the cross-section of the secondary valve core 21 is hexagonal. This design allows the medium to enter the lower guide sleeve 20 through the flow gap 31 between the secondary valve core 21 and the lower guide sleeve 20 while the secondary valve core 21 can move stably up and down. The structure is simple, reliable, and easy to manufacture.

[0042] As attached Figure 2 As shown, the limiting member 22 is a threaded sleeve, which is threadedly connected to the lower end of the lower guide seat. Specifically, the limiting member 22 has external threads on its outer circumference, and the lower end of the lower guide seat has a threaded groove that mates with the limiting member 22. Furthermore, the lower end of the limiting member 22 is provided with an internal hexagonal groove 32. The use of a threaded sleeve for the limiting member 22 not only allows the medium to pass through but also makes installation and operation very convenient due to the threaded connection.

[0043] As attached Figure 2As shown, the pilot valve structure 2 also includes an upper guide sleeve 33 and a support sleeve 34. A support step 35 is provided on the inner wall of the secondary valve body 10. When the secondary valve cover 11 is threaded to the upper end of the secondary valve body 10, the upper guide sleeve 33, the secondary valve seat 12, and the support sleeve 34 are pressed tightly onto the support step 35. A sealing ring is provided between the secondary valve cover 11 and the upper guide sleeve 33, and a sealing ring is provided between the support sleeve 34 and the support step 35. The outer surface of the secondary valve disc 13 is flush with the upper guide sleeve 33. The inner circular surfaces of the upper guide sleeve 33 are fitted together. An upper through-hole 36 is provided on the outer periphery of the upper guide sleeve 33, connecting its interior to the discharge port 17. An annular cavity connecting the upper through-hole 36 and the discharge port 17 is formed between the outer wall of the upper guide sleeve 33 and the inner wall of the secondary valve body 10. A valve seat sealing ring 37 is sandwiched between the lower end of the inner circular surface of the secondary valve seat 12 and the upper end of the inner circular surface of the support sleeve 34. When the lower end of the secondary valve disc 13 abuts against the valve seat sealing ring 37, the secondary valve disc 13 and the secondary valve seat 12 are sealed together. When the secondary valve disc 13 disengages from the valve seat sealing ring 37, the pilot valve backflows; when the secondary valve disc 13 abuts against the valve seat sealing ring 37, the pilot valve does not backflow. This structure not only guides the secondary valve disc 13, improving the stability of its movement, but also ensures more reliable sealing performance when the secondary valve disc 13 and the valve seat sealing ring 37 on the secondary valve seat 12 are engaged.

[0044] As attached Figure 2 As shown, the push rod 25 is threaded to the lower end of the secondary valve disc 13, meaning the upper end of the push rod 25 has external threads, and the lower end of the secondary valve disc 13 has a threaded groove that mates with the upper end of the push rod 25. This design provides a simple and reliable connection structure, and is very convenient for assembly and disassembly.

[0045] As attached Figure 2 and attached Figure 5 As shown, the pilot valve structure 2 also includes a flow regulating mechanism 38. The flow regulating mechanism 38 includes an internal hexagonal adjusting stud 39. A threaded hole 40 communicating with the discharge port 17 is provided on the side of the secondary valve body 10. The internal hexagonal adjusting stud 39 is threaded into the threaded hole 40. A tapered adjusting head 41 is provided at the inner end of the internal hexagonal adjusting stud 39. A second adjusting gap 42 is formed between the tapered adjusting head 41 and the discharge port 17. By adjusting the internal hexagonal adjusting stud 39, the size of the second adjusting gap 42 can be changed, thereby directly affecting the opening pressure of the main valve, changing the set pressure value, and adapting to different operating conditions.

[0046] As attached Figure 1 and attached Figure 6As shown, the bottom of the main valve disc 8 is provided with a positioning groove 43. A pressure plate 45 is connected to the positioning groove 43 by a locking screw 44. An annular conical groove 46 with a larger inner diameter and a smaller outer diameter is formed between the outer periphery of the pressure plate 45 and the inner periphery of the positioning groove 43. A main sealing ring 47 for sealing with the main valve seat 51 is embedded in the annular conical groove 46. The main sealing ring 47 is embedded in the annular conical groove 46 and is not easy to come out of the annular conical groove 46. It not only has good sealing performance when it is in contact with the valve seat, but also has the advantage of strong structural stability.

[0047] As attached Figure 6 As shown, the inner end of the positioning groove 43 is provided with a circular groove 48, and the upper end of the pressure plate 45 is provided with a positioning protrusion 49 extending into the circular groove 48. A third sealing ring 50 is installed on the outer circular surface of the positioning protrusion 49 to form a sealing fit with the inner circular surface of the circular groove 48. A vacuum cavity is formed between the third sealing ring 50 and the main sealing ring 47 to prevent the main sealing ring 47 from flying out under high pressure, further improving the firmness of the installation of the main sealing ring 47.

Claims

1. A pilot-operated safety valve, comprising a main valve structure (1) and a pilot valve structure (2), The main valve structure (1) includes a main valve body (3), an inlet channel (4) and an outlet channel (5) located at both ends of the valve body, a main valve cover (6) located at the upper end of the main valve body (3), a main valve sleeve (7) located at the inner end of the main valve cover (6), a main valve disc (8) slidably located in the main valve sleeve (7) along the vertical direction, a main spring (9) located at the upper end of the main valve disc (8) for applying spring force to the main valve disc (8), and a main valve seat (51) located in the main valve body (3) for cooperating with the main valve disc (8). The pilot valve structure (2) includes a secondary valve body (10), a secondary valve cover (11) disposed at the upper end of the secondary valve body (10), a secondary valve seat (12) disposed in the secondary valve body (10), a secondary valve disc (13) that is vertically slidably disposed in the secondary valve body (10) and abuts or separates from the secondary valve seat (12), and a secondary spring (14) disposed in the secondary valve cover (11) for applying spring force to the secondary valve disc (13); The inlet and outlet of the secondary valve body (10) are connected to the main valve body (3) through the first pipe (15) and the second pipe (16) respectively. The secondary valve body (10) is also provided with a vent (17) that communicates with the upper chamber of the secondary valve seat (12). Its features are: It also includes a sensitivity fine-tuning mechanism (18), which includes an adjusting seat (19) that is threaded to the lower end of the secondary valve body (10), is hollow and open at the upper end, a lower guide sleeve (20) that is connected to one end of the adjusting seat (19) that extends into the secondary valve body (10), a secondary valve core (21) that is vertically movably disposed in the lower guide sleeve (20), and a limiting member (22) disposed at the lower end of the lower guide sleeve (20) that limits the lower stroke of the secondary valve core (21). The side of the regulating seat (19) is provided with a lower through hole (23) that connects the interior of the regulating seat (19) with the inlet of the secondary valve body (10). The lower guide sleeve (20) is provided with a sealing flange (24). The lower end of the secondary valve disc (13) is provided with a push rod (25). When the secondary valve core (21) moves upward and abuts against the sealing flange (24), the two are sealed together. At the same time, the secondary valve core (21) pushes the push rod (25) and the secondary valve disc (13) upward, so that the secondary valve disc (13) disengages from the secondary valve seat (12).

2. The pilot-operated safety valve according to claim 1, characterized in that: The upper end of the secondary valve core (21) is provided with a lower sealing cone surface (26), and the upper sealing cone surface (27) is provided on the sealing flange (24). When the secondary valve core (21) falls to the upper end of the limiting member (22) under its own weight, a first adjustment gap (28) is formed between the lower sealing cone surface (26) and the upper sealing cone surface (27).

3. A pilot-operated safety valve according to claim 1, characterized in that: The lower guide sleeve (20) is threaded to the upper end of the adjusting seat (19). A first sealing ring (29) is provided between the adjusting seat (19) and the inner wall of the sub-valve body (10), and a second sealing ring (30) is provided between the adjusting seat (19) and the lower guide sleeve (20).

4. A pilot-operated safety valve according to claim 1, characterized in that: At least one flow gap (31) is provided between the outer circular surface of the secondary valve core (21) and the inner circular surface of the lower guide sleeve (20).

5. A pilot-operated safety valve according to claim 1, characterized in that: The limiting member (22) is a threaded sleeve, which is threaded to the lower end of the lower guide seat, and the lower end of the limiting member (22) is provided with an internal hexagonal groove (32).

6. A pilot-operated safety valve according to claim 1, characterized in that: It also includes an upper guide sleeve (33) and a support sleeve (34). The inner wall of the secondary valve body (10) is provided with a support step (35). The secondary valve cover (11) presses the upper guide sleeve (33), the secondary valve seat (12) and the support sleeve (34) onto the support step (35). The outer circular surface of the secondary valve disc (13) is in contact with the inner circular surface of the upper guide sleeve (33). The outer periphery of the upper guide sleeve (33) is provided with an upper through hole (36) that connects its interior to the vent (17). A valve seat sealing ring (37) is sandwiched between the lower end of the inner circular surface of the secondary valve seat (12) and the upper end of the inner circular surface of the support sleeve (34). When the lower end of the secondary valve disc (13) abuts against the valve seat sealing ring (37), the secondary valve disc (13) and the secondary valve seat (12) are sealed together.

7. A pilot-operated safety valve according to claim 1, characterized in that: The push rod (25) is threaded to the lower end of the secondary valve disc (13).

8. A pilot-operated safety valve according to claim 1, characterized in that: It also includes a flow regulating mechanism (38), which includes an internal hexagonal adjusting stud (39). The side of the secondary valve body (10) is provided with a screw hole (40) that communicates with the vent (17). The internal hexagonal adjusting stud (39) is threaded into the screw hole (40). The inner end of the internal hexagonal adjusting stud (39) is provided with a conical adjusting head (41). A second adjusting gap (42) is formed between the conical adjusting head (41) and the vent (17).

9. A pilot-operated safety valve according to claim 1, characterized in that: The bottom of the main valve disc (8) is provided with a positioning groove (43). A pressure plate (45) is connected in the positioning groove (43) by a locking screw (44). An annular conical groove (46) with a larger inner diameter and a smaller outer diameter is formed between the outer periphery of the pressure plate (45) and the inner periphery of the positioning groove (43). A main sealing ring (47) for sealing with the main valve seat (51) is embedded in the annular conical groove (46).

10. A pilot-operated safety valve according to claim 9, characterized in that: The inner end of the positioning groove (43) is provided with a circular groove (48), and the upper end of the pressure plate (45) is provided with a positioning protrusion (49) extending into the circular groove (48). The outer circular surface of the positioning protrusion (49) is equipped with a third sealing ring (50) for forming a sealing fit with the inner circular surface of the circular groove (48).

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