Safety valve for supercritical pressure

Abstract

A safety valve for supercritical pressure relates to the technical field of valves, and is characterized in that a lower adjusting ring is in threaded connection with the upper end of a valve seat; the hot valve clack is in threaded connection with the valve clack, and the upper ends of the hot valve clack and the valve clack are welded and fixed; an elastic lip structure is arranged on the lower end sealing face of the hot valve clack and movably abuts against an upper port of the valve seat in a sealed mode. The hot valve clack is sleeved with the valve clack guiding piece, and a convex face is arranged in the middle of the valve clack guiding piece. A convex rib is arranged at the position, located above the flange plate on the support, of the valve rod, a spherical washer is placed on the convex rib and sleeved with a lower spring seat, the lower end of a spring abuts against the lower spring seat, the upper end of the spring abuts against an upper spring seat, and the valve rod is sleeved with the upper spring seat. When the steam pressure of the boiler or the pressure container exceeds a specified value, safe operation of equipment is ensured, and the device has the advantages of being large in emission coefficient, accurate in opening pressure, small in opening and closing pressure difference, good in sealing performance, convenient to adjust and the like.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, specifically to a safety valve for supercritical pressure. Background Technology

[0002] Safety valves currently used in boilers or pressure vessels generally have low discharge coefficients and cannot be adjusted to a suitable opening pressure, which urgently need improvement. Utility Model Content

[0003] The purpose of this utility model is to address the defects and shortcomings of the existing technology by providing a safety valve for supercritical pressure. When the steam pressure of a boiler or pressure vessel exceeds the specified value, it ensures the safe operation of the equipment. It features a large discharge coefficient, accurate opening pressure, small opening and closing pressure difference, good sealing performance, and convenient adjustment.

[0004] To achieve the above objectives, this utility model adopts the following technical solution: It includes a valve body, a valve seat, a valve stem, and a bracket; the inlet and outlet of the valve body are angled, and a valve seat is installed inside the inlet; the upper mounting port of the valve body is connected to the lower flange of the bracket using a bolt assembly; two screw holes are provided on the left side of the valve body's inner cavity, respectively fixing an upper fixing pin and a lower fixing pin; a small hole is provided at the bottom of the valve body's inner cavity, located on the inlet side, and a short pipe (for discharging condensate) is connected inside the small hole; the top port of the valve seat is movably sealed with the valve disc, and the valve disc is installed at the bottom end of the valve stem; it also includes:

[0005] The lower adjusting ring is threadedly connected to the upper end of the valve seat;

[0006] A thermal valve disc is threaded onto a valve disc, and the upper ends of the two are welded together; the lower sealing surface of the thermal valve disc is provided with an elastic lip structure, which is configured to movably abut against the upper port of the valve seat for sealing.

[0007] A valve disc guide is sleeved on the outside of the hot valve disc, and a convex surface is provided in the middle of the valve disc guide. A nut is pressed on the convex surface. The nut is threaded to the upper end of the valve disc and fixed by a countersunk screw.

[0008] A guide sleeve is movably fitted outside the valve disc guide, with its upper end installed in the groove between the valve body and the bracket. The upper end of the valve disc guide has a small hole. A back pressure adjusting component is placed in the recessed structure at the upper port of the guide sleeve. The valve stem passes through the back pressure adjusting component and the bushing in the flange of the bracket, and then a spring is fitted onto it. A rib is provided on the valve stem above the flange of the bracket, and a spherical washer rests on the rib. A lower spring seat is fitted onto the spherical washer, and the lower end of the spring abuts against the lower spring seat. The upper end abuts against the upper spring seat, which is sleeved on the valve stem. A planar thrust ball bearing is built into the groove at the upper end of the upper spring seat. The lower end of the adjusting nut is set on the upper end face of the planar thrust ball bearing. The adjusting nut is sleeved on the valve stem and is connected to the upper port of the spring cover through external threads and locked with a locking nut. The spring cover covers the outside of the spring, the lower spring seat, and the upper spring seat and is fixed to the upper flange of the bracket using bolt assembly one. The upper end of the valve stem passes through the adjusting nut and is connected to the lifting nut using cotter pin three.

[0009] An upper adjusting ring is threaded onto the outside of the guide sleeve.

[0010] Preferably, the lower outer circle of the upper adjusting ring is machined with gear teeth, and the inner end of the upper fixing pin is engaged with the gear teeth machined on the lower outer circle of the upper adjusting ring.

[0011] Preferably, the lower end of the lower adjusting ring has machined gear teeth on its outer circumference, and the inner end of the lower fixing pin engages with the machined gear teeth on the outer circumference of the lower adjusting ring.

[0012] Preferably, the bushing is fixed to the upper flange of the bracket using two screws.

[0013] Preferably, the top of the spring cover is externally threaded with a top cover, a wrench is rotatably connected to one side wall of the top cover by a cotter pin two, and a lever is rotatably connected to the other side wall of the top cover by a cotter pin four. The other end of the lever passes through the lifting nut and the top cover and is in movable contact with the upper end of the wrench.

[0014] Preferably, a plug is provided in the small hole at the top of the top cover.

[0015] Preferably, a retaining ring is pressed onto the outer periphery of the upper end face of the planar thrust ball bearing.

[0016] Preferably, the outer wall of the upper spring seat is provided with a guide post, which is slidably disposed in the guide groove on the outer wall of the spring cover.

[0017] Preferably, a limiting ring is provided on the outer wall of the valve stem at a position below the flange on the bracket, and the limiting ring is in movable contact with the bushing.

[0018] Preferably, the back pressure adjusting member comprises:

[0019] A back pressure adjusting seat, the lower end of which rests in a recessed structure at the upper port of the guide sleeve;

[0020] The back pressure adjusting sleeve has its lower end connected to the valve stem via an internal thread, and its upper end fixed to the valve stem by a cotter pin; the back pressure adjusting sleeve is movably inserted into the back pressure adjusting seat.

[0021] An exhaust pipe is provided, which is connected to the back pressure regulating seat; and a throttle valve is provided on the side wall of the back pressure regulating seat opposite to the exhaust pipe.

[0022] Preferably, the throttle valve comprises:

[0023] The throttle valve body is mounted on the back pressure regulating seat using screws;

[0024] A throttle valve stem is mounted on the throttle valve body using a nut.

[0025] Compared with the prior art, the beneficial effects of this utility model are: This utility model provides a safety valve for supercritical pressure, which ensures the safe operation of the equipment when the steam pressure of the boiler or pressure vessel exceeds the specified value. It has the characteristics of large discharge coefficient, accurate opening pressure, small opening and closing pressure difference, good sealing performance, and convenient adjustment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of this utility model.

[0027] Figure 2 yes Figure 1 Enlarged view of section A.

[0028] Figure 3 yes Figure 1 Enlarged view of section B in the middle.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Valve body; 2. Valve seat; 3. Short pipe; 4. Lower adjusting ring; 5. Lower fixing pin; 6. Bolt assembly II; 7. Upper adjusting ring; 8. Upper fixing pin; 9. Valve disc; 10. Thermal valve disc; 11. Valve disc guide; 12. Valve stem; 13. Guide sleeve; 14. Nut I; 15. Countersunk screw; 16. Back pressure adjusting seat; 17. Back pressure adjusting sleeve; 18. Exhaust pipe; 19. Cotter pin I; 20. Limiting ring; 21. Bracket; 22. Bushing; 23. Spring cover; 24. Spherical washer. 25. Lower spring seat, 26. Spring, 27. Wrench, 28. Upper spring seat, 29. Flat thrust ball bearing, 30. Retaining ring, 31. Adjusting nut, 32. Locking nut, 33. Cotter pin II, 34. Throttling valve stem, 35. Lever, 36. Top cover, 37. Plug, 38. Cotter pin III, 39. Lifting nut, 40. Cotter pin IV, 41. Nut II, 42. Throttling valve body, 43. Guide post, 44. Screw I, 45. Screw II, 46. Bolt assembly I. Detailed Implementation

[0031] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. The preferred embodiments described are only examples. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0032] like Figures 1-3 As shown, this specific embodiment adopts the following technical solution: It includes a valve body 1, a valve seat 2, a valve stem 12, and a bracket 21; the inlet and outlet of the valve body 1 are angled, and the valve seat 2 is installed with an internal thread at the inlet, and the valve seat 2 is provided with a welding bevel for sealing welding with the lower end of the valve body 1, and the sealing surface of the valve seat 2 is made of iron-based alloy; the upper mounting port of the valve body 1 is connected to the lower flange of the bracket 21 by bolt assembly 6; two screw holes are provided on the left side of the inner cavity of the valve body 1, and upper fixing pin 8 and lower fixing pin 5 are fixed respectively; at the bottom of the inner cavity of the valve body 1, on the inlet side, a small hole is provided, and a short pipe 3 (for discharging condensate) is connected in the small hole; the top port of the valve seat 2 is movably sealed with the valve disc 9, and the valve disc 9 is installed at the bottom end of the valve stem 12; the valve seat 2 is designed using the Raschel principle, the steam velocity at the outlet of the valve seat 2 reaches the speed of sound, the channel of the valve seat 2 is selected with the optimal line shape, and the discharge coefficient is large; it also includes:

[0033] The lower adjusting ring 4 is threadedly connected to the upper end of the valve seat 2. The top of the lower adjusting ring 4 and the lower plane of the hot valve disc 10 form an annular space. By adjusting this space, a suitable opening pressure can be obtained. Its function is to reduce forward leakage. Once the hot valve disc 10 is slightly opened, the valve disc 9 and the hot valve disc 10 will quickly rise to full opening due to the expansion of the steam action area. When the steam pressure decreases, the spring 26 has been additionally compressed, and the spring force increases. When the spring force is greater than the force exerted by the steam on the valve disc 9 and the hot valve disc, the valve disc 9 and the hot valve disc will quickly return to their seats. The lower adjusting ring 4 is connected to the valve seat 2 through an internal thread. The lower end of the lower adjusting ring 4 is machined with gear teeth to facilitate the adjustment of the upper and lower positions of the lower adjusting ring 4. After the position of the lower adjusting ring 4 is adjusted and fixed, it is fixed by the lower fixing pin 5.

[0034] A thermal valve disc 10 is threaded onto the valve disc 9, and the upper ends of the two are welded together. The lower sealing surface of the thermal valve disc 10 is provided with an elastic lip structure, which moves and seals against the upper port of the valve seat 2. The elastic lip structure ensures uniform temperature in the circumferential direction. When the steam pressure is close to the discharge pressure, the tip of the elastic lip structure contacts the valve seat 2, resulting in good sealing performance. In general, the valve disc of a safety valve causes a temperature difference when the valve is discharging and closing, generating thermal stress, which can easily lead to leakage. Even a small leakage can cause inconsistent temperature around the valve sealing surface, promoting the expansion of the leakage. The thermal valve disc 10 is made of a special alloy steel. This thermal valve disc 10 structure is used in high-temperature and high-pressure steam media, avoiding leakage caused by temperature differences, as is the case with integral sealing surface structures.

[0035] Valve guide 11 is sleeved on the outside of the hot valve disc 10, and a convex surface is provided in the middle of the valve guide 11. A nut 14 is pressed on the convex surface. The nut 14 is threaded to the upper end of the valve disc 9 and fixed by a countersunk screw 15.

[0036] A guide sleeve 13 is movably fitted outside the valve disc guide 11, and the upper end of the guide sleeve 13 is installed in the groove between the valve body 1 and the bracket 21; the upper end of the valve disc guide 11 is provided with a small hole; a back pressure adjusting component is placed in the recessed structure of the upper port of the guide sleeve 13; the valve stem 12 passes through the back pressure adjusting component and the bushing 22 in the upper flange of the bracket 21 in sequence, and then a spring 26 is fitted on it; the bushing 22 is fixed to the upper flange of the bracket 21 by screws 45; a limiting ring 20 is provided on the outer wall of the valve stem 12 at a position below the upper flange of the bracket 21, and the limiting ring 20 is movably in contact with the bushing 22; the... The valve stem 12 has a raised rib located above the flange on the bracket 21. A spherical washer 24 rests on the raised rib, and a lower spring seat 25 is fitted onto the spherical washer 24. The lower end of the spring 26 abuts against the lower spring seat 25, and the upper end of the spring 26 abuts against the upper spring seat 28, which is fitted onto the valve stem 12. A planar thrust ball bearing 29 is built into the groove at the upper end of the upper spring seat 28, and a retaining ring 30 is pressed around the upper end face of the planar thrust ball bearing 29. The lower end of the adjusting nut 31 is located on the upper end face of the planar thrust ball bearing 29, and the adjusting nut 31 is fitted onto the valve stem 12. It is connected to the spring cover 28 by external threads. The upper port of the valve stem 26 is connected and locked with the locking nut 32. The adjusting nut 31 is used to adjust the compression of the spring 26. After the adjusting nut 31 adjusts the compression of the spring 26, it is locked with the spring cover 23 by the locking nut 32. The spring cover 23 covers the outside of the spring 26, the lower spring seat 25 and the upper spring seat 28, and is fixed to the upper flange of the bracket 21 by bolt assembly 46. The outer wall of the upper spring seat 28 is provided with a guide post 43, which slides up and down in the guide groove on the outer wall of the spring cover 23. The upper end of the valve stem 12 passes through the adjusting nut 31 and is connected to the lifting nut 39 by the cotter pin 38. The top of the spring cover 23 is externally threaded with a top cover 36. One side wall of the top cover 36 is rotatably connected to a wrench 27 via a cotter pin 2 33. The other side wall of the top cover 36 is rotatably connected to a lever 35 via a cotter pin 40. The other end of the lever 35 passes through the lifting nut 39 and the top cover 36 and is in movable contact with the upper end of the wrench 27. A plug 37 is provided in the small hole at the top of the top cover 36. In case of emergency discharge, the wrench 27 can be manually operated to drive the lever 35, which in turn drives the lifting nut 39. The lifting nut 39 then drives the valve stem 12 to lift, thereby causing the valve disc 9 to pop up and discharge the medium.

[0037] The upper adjusting ring 7 is threadedly connected to the outside of the guide sleeve 13. The function of the upper adjusting ring 7 is to change the flow direction of the fluid discharged from the valve seat 2, thereby changing the force of the fluid on the valve disc 9. Specifically, when the upper adjusting ring 7 is in a higher position, the steam force is smaller, the stroke of the valve disc 9 is shorter, and the return to seat is faster; conversely, when the upper adjusting ring 7 is in a lower position, the stroke of the valve disc 9 is higher, and the return to seat is slower. The upper adjusting ring 7 is connected to the guide sleeve 13 through an internal thread. The lower end of the outer circle of the upper adjusting ring 7 is machined with gear teeth to facilitate the adjustment of the upper and lower positions of the upper adjusting ring 7. After the position of the upper adjusting ring 7 is fixed, it is fixed by the upper fixing pin 8.

[0038] The back pressure adjusting component includes:

[0039] Back pressure adjusting seat 16, the lower end of which rests in the sunken structure of the upper port of guide sleeve 13;

[0040] The back pressure adjusting sleeve 17 has its lower end connected to the valve stem 12 via an internal thread, and its upper end fixed to the valve stem 12 by a cotter pin 19; the back pressure adjusting sleeve 17 is movably inserted into the back pressure adjusting seat 16.

[0041] An exhaust pipe 18 is connected through to the back pressure regulating seat 16; a throttle valve is provided on the side wall of the back pressure regulating seat 16 opposite to the exhaust pipe 18; the throttle valve includes a throttle valve body 42 and a throttle valve stem 34; the throttle valve body 42 is mounted on the back pressure regulating seat 16 by screw 44; the throttle valve stem 34 is mounted on the throttle valve body 42 by nut 41; after the valve disc 9 and the hot valve disc 10 are opened, the discharged steam flows into the upper space of the valve disc 9 from the gap between the guide sleeve 13 and the valve disc guide 11 and the small hole on the valve disc guide 11, and is regulated by the back pressure. The tapered cross-sectional area between sleeve 17 and back pressure adjusting seat 16 adjusts the back pressure on the upper part of valve disc 9. When valve disc 9 is in the fully open position, the back pressure acting on the upper part of valve disc 9 is not large. When valve disc 9 begins to reseat, the back pressure causes valve disc 9 to close quickly. The throttle valve (throttle valve body 42, nut 2 41, throttle valve stem 34) is also used to adjust the back pressure on the upper part of valve disc 9. It serves as a supplement and fine adjustment to the back pressure adjusting sleeve 17. During normal operation, it is inconvenient to use the back pressure adjusting sleeve 17, so the throttle valve (throttle valve body 42, nut 2 41, throttle valve stem 34) can be used for fine adjustment.

[0042] Compared with the prior art, the beneficial effects of this utility model are: This utility model provides a safety valve for supercritical pressure, which ensures the safe operation of the equipment when the steam pressure of the boiler or pressure vessel exceeds the specified value. It has the characteristics of large discharge coefficient, accurate opening pressure, small opening and closing pressure difference, good sealing performance, and convenient adjustment.

[0043] For those skilled in the art, modifications can be made to the technical solutions described in the foregoing embodiments, and equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A safety valve for supercritical pressure, comprising a valve body (1), a valve seat (2), a valve stem (12), and a bracket (21); the inlet and outlet of the valve body (1) are angled, and the valve seat (2) is installed inside the inlet; the upper mounting port of the valve body (1) is connected to the lower flange of the bracket (21) by bolt assembly two (6); two screw holes are provided on the left side of the inner cavity of the valve body (1), and an upper fixing pin (8) and a lower fixing pin (5) are fixed thereon respectively; a small hole is provided at the bottom of the inner cavity of the valve body (1), located on the inlet side, and a short pipe (3) is connected inside the small hole; the top port of the valve seat (2) is movably sealed with the valve disc (9), and the valve disc (9) is installed at the bottom end of the valve stem (12); characterized in that: It also includes: The lower adjusting ring (4) is threadedly connected to the upper end of the valve seat (2); The hot valve flap (10) is threadedly connected to the valve flap (9), and the upper ends of the two are welded and fixed together; the lower end sealing surface of the hot valve flap (10) is provided with an elastic lip structure, which is in contact with the upper port of the valve seat (2) for sealing. Valve guide (11) is sleeved on the outside of the hot valve (10), and the valve guide (11) has a convex surface in the middle, and a nut (14) is pressed on the convex surface. The nut (14) is threaded to the upper end of the valve (9) and fixed by a countersunk screw (15). A guide sleeve (13) is movably sleeved outside the valve disc guide (11), and the upper end of the guide sleeve (13) is installed in the groove between the valve body (1) and the bracket (21); the upper end of the valve disc guide (11) is provided with a small hole; a back pressure adjusting component is placed in the recessed structure of the upper port of the guide sleeve (13); the valve stem (12) passes through the back pressure adjusting component and the bushing (22) in the flange of the bracket (21) in sequence, and then a spring (26) is sleeved on it; the valve stem (12) is provided with a rib at the position above the flange of the bracket (21), a spherical washer (24) is placed on the rib, a lower spring seat (25) is sleeved on the spherical washer (24), the lower end of the spring (26) abuts against the lower spring seat (25), and the upper end of the spring (26) is connected to the lower spring seat (25). The upper spring seat (28) is abutted and sleeved on the valve stem (12). A planar thrust ball bearing (29) is built into the groove at the upper end of the upper spring seat (28). The lower end of the adjusting nut (31) is set on the upper end face of the planar thrust ball bearing (29). The adjusting nut (31) is sleeved on the valve stem (12) and is connected to the upper port of the spring cover (23) by external thread and locked by the locking nut (32). The spring cover (23) covers the outside of the spring (26), the lower spring seat (25) and the upper spring seat (28) and is fixed to the upper flange of the bracket (21) by bolt assembly one (46). The upper end of the valve stem (12) passes through the adjusting nut (31) and is connected to the lifting nut (39) by cotter pin three (38). Upper adjusting ring (7) is threaded to the outside of guide sleeve (13).

2. A safety valve for supercritical pressure according to claim 1, characterized in that: The lower end of the upper adjusting ring (7) is machined with gear teeth, and the inner end of the upper fixing pin (8) is engaged with the gear teeth machined on the lower end of the upper adjusting ring (7).

3. A safety valve for supercritical pressure according to claim 1, characterized in that: The lower end of the lower adjusting ring (4) is machined with gear teeth on its outer circle, and the inner end of the lower fixing pin (5) is engaged with the gear teeth on the outer circle of the lower end of the lower adjusting ring (4).

4. A safety valve for supercritical pressure according to claim 1, characterized in that: The bushing (22) is fixed to the upper flange of the bracket (21) by screw two (45).

5. A safety valve for supercritical pressure according to claim 1, characterized in that: The top of the spring cover (23) is externally threaded with a top cover (36). A wrench (27) is rotatably connected to one side wall of the top cover (36) by a cotter pin two (33). A lever (35) is rotatably connected to the other side wall of the top cover (36) by a cotter pin four (40). The other end of the lever (35) passes through the lifting nut (39) and the top cover (36) and is in contact with the upper end of the wrench (27).

6. A safety valve for supercritical pressure according to claim 5, characterized in that: A plug (37) is provided in the small hole at the top of the top cover (36).

7. A safety valve for supercritical pressure according to claim 1, characterized in that: A retaining ring (30) is pressed onto the outer periphery of the upper end face of the planar thrust ball bearing (29).

8. A safety valve for supercritical pressure according to claim 1, characterized in that: The outer wall of the upper spring seat (28) is provided with a guide post (43), which is slidably disposed in the guide groove on the outer wall of the spring cover (23).

9. A safety valve for supercritical pressure according to claim 1, characterized in that: The outer wall of the valve stem (12) is provided with a limiting ring (20) located below the flange on the bracket (21), and the limiting ring (20) is in contact with the bushing (22).

10. A safety valve for supercritical pressure according to claim 1, characterized in that: The back pressure adjusting component includes: Back pressure adjusting seat (16), the lower end of which rests in the sunken structure of the upper port of the guide sleeve (13); Back pressure adjusting sleeve (17), the lower end of the back pressure adjusting sleeve (17) is connected to the valve stem (12) by internal thread, and the upper end is fixed to the valve stem (12) by cotter pin (19); the back pressure adjusting sleeve (17) is movably inserted into the back pressure adjusting seat (16); An exhaust pipe (18) is connected through to the back pressure regulating seat (16); and a throttle valve is provided on one side wall of the back pressure regulating seat (16) opposite to the exhaust pipe (18); the throttle valve includes: Throttling valve body (42), which is mounted on back pressure regulating seat (16) by screw one (44); Throttling valve stem (34) is mounted on throttling valve body (42) by means of nut two (41).

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