Large flow pressure reducing valve for nuclear power

Abstract

A large flow pressure reducing valve for nuclear power station comprises a housing and a valve core inside the housing, a diaphragm assembly is arranged in the housing and connected with the valve core by a valve face hard seal, and a spiral filter is arranged below the inlet of the housing for guiding and filtering water flow. The metal diaphragm is used to replace the conventional rubber diaphragm, the service life and the ability to resist harsh environment of the pressure reducing valve are improved without reducing the flow rate of the pressure reducing valve. Meanwhile, the spiral filter is used to replace the conventional cylindrical filter, the vortex phenomenon of the air flow at the inlet of the pressure reducing valve is solved, and the flow rate of the pressure reducing valve is improved. The valve face hard seal is used between the valve core and the diaphragm assembly to replace the conventional non-metallic soft seal, the ability to resist harsh environment of the pressure reducing valve is improved under the premise of ensuring zero leakage. All dynamic seals are hard seals, and the ability to resist radiation and high temperature of the pressure reducing valve is ensured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pressure reducing valves, and particularly relates to a large-flow pressure reducing valve for nuclear power. BACKGROUND

[0002] With the continuous development of the domestic nuclear power field, the safety of nuclear power units is also increasingly high, and the reliability requirement of nuclear power products is also increasingly high. The existing pressure reducing valve is used in a high-temperature, high-humidity and high-radiation environment, which leads to the reduction of the service life of the internal conventional rubber diaphragm and the non-metallic soft seal between the valve core and the diaphragm assembly, and is not conducive to long-term use. At the same time, the conventional cylindrical filter is easy to produce airflow vortex at the inlet of the pressure reducing valve, which affects the flow capacity of the pressure reducing valve, so it is necessary to design a pressure reducing valve resistant to high temperature, high humidity and high radiation environment to solve the problem of failure of the pressure reducing valve in the nuclear power field under high temperature, high humidity and high radiation environment. SUMMARY

[0003] The present application provides a large-flow pressure reducing valve for nuclear power, which aims to solve the problems raised in the background art.

[0004] The technical scheme of the present application is as follows: a casing and a valve core located inside the casing are provided, a diaphragm assembly connected with the valve core by a valve face hard seal is arranged inside the casing, and a spiral filter for guiding and filtering water flow is further arranged below the inlet of the casing.

[0005] The casing comprises an upper cover, an intermediate casing and a bottom cover casing from top to bottom, and they are all connected by sealing rings, opposite sides of the intermediate casing are respectively provided with an inlet and an outlet, and both are connected with the inside of the bottom cover casing, the upper cover and the bottom cover casing are connected by the valve core in the intermediate casing, and the valve core is also connected with the outlet.

[0006] The spiral filter is arranged inside the bottom cover casing and located at the bottom of the valve core,

[0007] The outer wall of the spiral filter is provided with spiral blades and located below the inlet of the bottom cover casing.

[0008] The bottom of the spiral filter is provided with a filter core screw nut for installing a filter core screw rod in the inside of the spiral filter, and the upper end of the filter core screw rod is installed at the lower part of the valve core.

[0009] The valve core comprises a three-way channel connected with the upper cover, the bottom cover casing and the outlet, a guide sleeve is installed at the upper end of the main channel connected with the upper cover and the bottom cover casing in the three-way channel, a valve seat is installed at the lower end of the main channel, a blocking plug and a return spring are installed at the lower end of the valve seat, and the return spring is installed in the accommodation hole opened at the upper end of the filter core screw rod.

[0010] The center of the valve seat is provided with a through hole, the blocking plug comprises a cone head and a plug rod installed on the top of the cone head, the plug rod penetrates the through hole and the guide sleeve, and the upper end is abutted against the lower surface of the diaphragm assembly, and the cone head is blocked at the inlet of the through hole.

[0011] The diaphragm assembly comprises a diaphragm fixed in the upper cover, an upper diaphragm pressing plate is arranged above the diaphragm, a spring tray is arranged on the diaphragm pressing plate, a center overflow valve seat is arranged on the diaphragm pressing plate and the spring tray, the center of the overflow valve seat is provided with a vent hole, and a valve surface is arranged at the lower end of the vent hole and is inserted with the upper end of the plug rod.

[0012] The upper end of the upper cover is provided with a screw rod, a spring seat is arranged at the lower end of the screw rod in the upper cover, and a pressure regulating spring is arranged between the spring seat and the spring tray.

[0013] The diaphragm is formed into a bowl shape by stamping and is a 0.1mm-thick stainless steel diaphragm.

[0014] The inside of the upper cover is divided into a lower diaphragm chamber and an upper cavity by the diaphragm assembly, a constant flow hole for connecting the outlet and the diaphragm chamber is arranged between the outlet and the diaphragm chamber, and the cavity is connected with the outside through an exhaust hole.

[0015] Compared with the prior art, the beneficial effects of the present application are that the large-flow pressure reducing valve for nuclear power adopts a metal diaphragm to replace a conventional rubber diaphragm, improves the service life and the ability to resist harsh environments of the pressure reducing valve without reducing the flow rate of the pressure reducing valve.

[0016] Meanwhile, a spiral filter is adopted to replace a conventional cylindrical filter, so that the vortex phenomenon of the gas flow at the inlet of the pressure reducing valve is solved, thereby improving the flow rate of the pressure reducing valve.

[0017] The valve core and the diaphragm assembly adopt a valve surface hard seal to replace a conventional non-metallic soft seal, so that the ability to resist harsh environments of the pressure reducing valve is improved under the premise of ensuring zero leakage.

[0018] All dynamic seals adopt hard seals, so that the ability to resist radiation and high temperature of the pressure reducing valve is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 It is a cross-sectional structure schematic diagram of the present application;

[0020] Fig. 2 It is an appearance structure schematic diagram of the present application;

[0021] Fig. 3 It is a diaphragm assembly structure schematic diagram in the present application;

[0022] In the drawings:

[0023] 1. Housing; 11. Upper cover; 111. Diaphragm chamber; 112. Cavity; 113. Exhaust hole; 12. Intermediate housing; 121. Inlet; 122. Outlet; 123. Constant flow hole; 13. Bottom cover;

[0024] 2. Valve core; 21. Three-channel; 22. Guide sleeve; 23. Valve seat; 231. Through hole; 24. Stop plug; 241. Cone head; 242. Insert rod; 25. Return spring;

[0025] 3. Spiral filter; 31. Filter element nut; 32. Filter element screw; 321. Receiving hole;

[0026] 4. Diaphragm assembly; 41. Diaphragm; 42. Diaphragm pressure plate; 43. Spring tray; 44. Overflow valve seat; 441. Vent hole; 442. Valve surface;

[0027] 5. Screw;

[0028] 6. Spring seat;

[0029] 7. Pressure regulating spring. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] See also Figs. 1-3 , the present invention provides a technical solution:

[0032] A large-flow pressure reducing valve for nuclear power includes a housing 1 and a valve core 2 located inside the housing 1. A diaphragm assembly 4 is provided inside the housing 1 and is hard-sealed with the valve core 2 using a valve face 442. A spiral filter 3 for guiding and filtering water flow is also provided below the inlet 121 of the housing 1.

[0033] In this embodiment, a metal diaphragm 41 is used in place of a conventional rubber diaphragm 41 in the diaphragm assembly 4, thereby increasing the service life and resistance to harsh environments of the pressure reducing valve without reducing the flow rate of the pressure reducing valve. Furthermore, a spiral filter 3 is used instead of a conventional cylindrical filter to resolve the vortex generation phenomenon in the airflow at the pressure reducing valve inlet 121, thereby increasing the flow rate of the pressure reducing valve. A hard seal with a valve face 442 is used between the valve core 2 and the diaphragm assembly 4, replacing the conventional non-metallic soft seal. This improves the pressure reducing valve's resistance to harsh environments while ensuring zero leakage. All dynamic seals are hard seals, ensuring the pressure reducing valve's resistance to radiation and high temperatures.

[0034] The shell 1 comprises, from top to bottom, an upper cover 11, an intermediate shell 12 and a bottom cover shell 13, which are connected by sealing rings. The intermediate shell 12 has an inlet 121 and an outlet 122, which are connected to the inside of the bottom cover shell 13. The upper cover 11 is connected to the bottom cover shell 13 through the valve core 2 in the intermediate shell 12, and the valve core 2 is also connected to the outlet 122.

[0035] The upper cover 11 and the intermediate shell 12 are sealed by a sealing ring, the intermediate shell 12 and the bottom cover shell 13 are sealed by a sealing ring, the valve seat 23 and the intermediate shell 12 are sealed by a sealing ring, and the overflow valve seat 44 and the diaphragm 41 in the diaphragm assembly 4 are sealed by a sealing ring.

[0036] The spiral filter 3 is arranged inside the bottom cover shell 13 and located at the bottom of the valve core 2.

[0037] The outer wall of the spiral filter 3 is provided with spiral vanes and located below the inlet of the inlet 121 into the bottom cover shell 13. The bottom of the spiral filter 3 is provided with a filter core screw nut 31, and the filter core screw rod 32 is installed in the inside of the spiral filter 3, and the upper end of the filter core screw rod 32 is installed in the lower part of the valve core 2.

[0038] The spiral filter 3 regulates the gas flow state of the inlet 121 of the pressure reducing valve, avoids turbulent flow and vortex state, improves the inlet efficiency of the pressure reducing valve, and improves the air flow of the pressure reducing valve under the same inlet area. When the gas enters the bottom cover shell 13 from the inlet 121 of the pressure reducing valve, it directly contacts the spiral filter 3, and the spiral vanes of the spiral filter 3 regulate the original turbulent flow field to laminar flow state, avoiding the vortex of the inlet in the bottom cover shell 13, and improving the flow efficiency. At the same time, the spiral filter 3 guides the inlet gas flow to be spiral flow, and the large particle impurities are thrown to the surrounding during the spiral rotation and then sink into the bottom cover shell 13, avoiding the blockage of the filter by large particle impurities.

[0039] The valve core 2 comprises a three-way channel 21 connected to the upper cover 11, the bottom cover shell 13 and the outlet 122. The main channel of the three-way channel 21 is provided with a guide sleeve 22 at the upper end and a valve seat 23 at the lower end. The lower end of the valve seat 23 is provided with a blocking plug 24 and a return spring 25, which is installed in the accommodation hole 321 at the upper end of the filter core screw rod 32. The center of the valve seat 23 is provided with a through hole 231, and the blocking plug 24 comprises a tapered head 241 and an insertion rod 242 installed on the top of the tapered head 241. The insertion rod 242 penetrates the through hole 231 and the guide sleeve 22, and the upper end is located on the lower surface of the diaphragm assembly 4. The tapered head 241 blocks the inlet of the through hole 231.

[0040] The diaphragm assembly 4 includes a diaphragm 41 fixed in the upper cover 11, and a diaphragm pressing plate 42 is arranged above the diaphragm 41, a spring tray 43 is arranged on the diaphragm pressing plate 42, a center of the diaphragm pressing plate 42 and the spring tray 43 is provided with an overflow valve seat 44, a vent hole 441 is arranged in the center of the overflow valve seat 44, a valve surface 442 is arranged at a lower end of the vent hole 441 and is connected with an upper end of the plug rod 242. The diaphragm 41 is formed into a bowl shape by stamping, and the diaphragm 41 is made of 0.1mm thick stainless steel.

[0041] The valve surface 442 between the overflow valve seat 44 of the diaphragm assembly 4 and the upper end of the plug rod 242 of the blocking plug 24 is a metal hard seal, which avoids the use of non-metal seals and improves the service life and high temperature and radiation resistance of the pressure reducing valve under the premise of zero leakage. The plug rod 242 of the blocking plug 24 adopts an outer convex arc surface, the valve surface 442 of the overflow valve seat 44 adopts an inner concave arc surface, the arc radius of the inner concave arc surface is equal to the arc radius of the outer convex arc surface, the combination of the plug rod 242 and the overflow valve seat 44 has high joint degree of the two arc surfaces, and the two arc surfaces have low processing requirements and no accurate position positioning requirements, which provides necessary conditions for floating assembly of the valve core 2 under the premise of meeting the sealing. The diaphragm 41 is made of 0.1mm thick stainless steel diaphragm 41, and the effective stroke of the diaphragm 41 can reach 2.6mm by stamping forming method, which improves the service life of the pressure reducing valve under the premise of ensuring the performance of the pressure reducing valve. The 0.1mm thick stainless steel sheet is directly stamped into a bowl shape by a die, and the toughness of the 0.1mm thick diaphragm 41 is utilized to provide a 2.6mm stroke while ensuring the strength of the diaphragm 41.

[0042] An upper end of the upper cover 11 is provided with a screw rod 5, a spring seat 6 is arranged inside the upper cover 11 at a lower end of the screw rod 5, and a pressure regulating spring 7 is arranged between the spring seat 6 and the spring tray 43. The design of the diaphragm pressing plate 42 and the spring tray 43 on the diaphragm assembly 4 ensures that the force of the pressure regulating spring 7 can uniformly act on the diaphragm 41, and avoids uneven force on the diaphragm 41. The inside of the upper cover 11 is divided into a lower diaphragm chamber 111 and an upper cavity 112 by the diaphragm assembly 4, a constant flow hole 123 is arranged between the outlet 122 and the diaphragm chamber 111 to communicate the two, and the cavity 112 is connected with the outside through the exhaust hole 113.

[0043] In the embodiment, the compression degree of the pressure regulating spring 7 is controlled by rotating the screw 5 on the upper cover 11, and the pressure from the constant flow hole 123 at the outlet 122 enters the diaphragm chamber 111, the diaphragm 41 in the diaphragm chamber 111 is pushed upward, the overflow valve group is also pushed upward, the blocking plug 24 pushed by the reset spring 25 is also moved upward, the process of plugging is continued, and the gap between the blocking plug 24 and the through hole 231 in the valve seat 23 is further blocked, so that the gap between the blocking plug 24 and the through hole 231 in the valve seat 23 is reduced, and the like. The cavity 112 is connected with the outside through the exhaust hole 113, so that the gas in the cavity 112 is adjusted when the diaphragm assembly 4 moves.

[0044] The working principle and use process of the present application are as follows:

[0045] The compressed air with the pressure P1 is input from the inlet 121 at the left end of the middle shell 12, throttled by the valve core 2, and output with the pressure P2, and the size of P2 can be adjusted by the pressure regulating spring 7. The specific process is as follows: the screw 5 is rotated clockwise, the length of the screw 5 in the upper cover 11 changes, the spring seat 6 is driven by the screw 5, the pressure regulating spring 7 is compressed, the diaphragm assembly 4 is pushed downward by the pressure regulating spring 7, the blocking plug 24 is pushed downward by the diaphragm assembly 4, the gap between the taper head 241 of the blocking plug 24 and the valve seat 23 is increased, the opening degree between the taper head 241 of the blocking plug 24 and the valve seat 23 is increased, P2 is increased, and the pressure gas enters the diaphragm chamber 111 in the upper cover 11 through the constant flow hole 123 at the outlet 122, an upward thrust is generated on the diaphragm assembly 4, and when the thrust and the force of the pressure regulating spring 7 are balanced, the pressure of the outlet 122 is stable at a certain value. If the screw 5 is rotated counterclockwise, the opening degree between the taper head 241 of the blocking plug 24 and the valve seat 23 is reduced, and P2 is reduced.

[0046] If the pressure of the inlet 121 is unchanged and the output flow changes, the pressure P2 of the outlet 122 fluctuates (increases or decreases), the blocking plug 24 is pushed up and down by the overflow effect of the constant flow hole 123 and the balancing effect of the force on the diaphragm assembly 4, and the stable pressure effect can still be achieved.

[0047] When the output flow is zero, the pressure enters the diaphragm chamber 111 through the constant flow hole 123, the diaphragm assembly 4 is pushed upward, the blocking plug 24 is pushed upward by the reset spring 25, the through hole 231 of the valve group is closed, and the pressure of the outlet 122 is constant. When the output flow is very large, the high-speed airflow generates negative pressure at the constant flow hole 123, part of the gas in the diaphragm chamber 111 is discharged, the pressure of the diaphragm chamber 111 is reduced, the opening degree of the through hole 231 of the valve group is increased, and the force balance on the diaphragm 41 can still be maintained.

[0048] The above merely describes preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A large flow pressure reducing valve for nuclear power plants, characterized by: The invention comprises a housing (1) and a valve core (2) located inside the housing (1); a diaphragm assembly (4) is provided inside the housing (1) and is hard-sealed with the valve core (2) using a valve face (442). A spiral filter (3) for guiding and filtering water flow is also provided below the inlet (121) of the housing (1); The housing (1) comprises, from top to bottom, an upper cover (11), an intermediate shell (12), and a bottom cover shell (13), which are all sealed and connected to each other using sealing rings. An inlet (121) and an outlet (122) are respectively provided on opposite sides of the intermediate shell (12), and both are connected to the interior of the bottom cover shell (13). The upper cover (11) is connected to the bottom cover shell (13) via the valve core (2) in the intermediate shell (12), and the valve core (2) is also connected to the outlet (122); The bottom of the spiral filter (3) is mounted on the filter element screw (32) inside the spiral filter (3) via a filter element nut (31), and the upper end of the filter element screw (32) is mounted on the lower part of the valve core (2); The valve core (2) comprises three channels (21) communicating with the upper cover (11), the bottom cover (13) and the outlet (122); a guide sleeve (22) is installed at the upper end of a main channel communicating with the upper cover (11) and the bottom cover (13) among the three channels (21); a valve seat (23) is installed at the lower end; a blocking plug (24) and a return spring (25) are installed at the lower end of the valve seat (23); the return spring (25) is installed in a receiving hole (321) opened at the upper end of the filter element screw (32); A through hole (231) is provided at the center of the valve seat (23), and the blocking plug (24) includes a cone head (241) and a plug rod (242) mounted on the top of the cone head (241), the plug rod (242) passes through the through hole (231) and the guide sleeve (22), and the upper end is pressed against the lower surface of the diaphragm assembly (4), and the cone head (241) blocks the entrance of the through hole (231); The diaphragm assembly (4) includes a diaphragm (41) fixed in the upper cover (11), a diaphragm pressure plate (42) is provided above the diaphragm (41), a spring tray (43) is provided on the diaphragm pressure plate (42), an overflow valve seat (44) is provided at the center of the diaphragm pressure plate (42) and the spring tray (43), a vent hole (441) is provided at the center of the overflow valve seat (44), and a valve surface (442) is provided at the lower end of the vent hole (441) of the overflow valve seat (44) and is plugged into the upper end of the insertion rod (242); The plug rod (242) of the blocking plug (24) adopts an outer convex arc surface, and the valve surface (442) of the overflow valve seat (44) adopts an inner concave arc surface, and the arc radius of the inner concave arc surface is equal to the arc radius of the outer convex arc surface; The diaphragm (41) is formed into a bowl shape by stamping and is a 0.1 mm thick stainless steel diaphragm, so that the effective stroke of the diaphragm (41) can reach 2.6 mm.

2. A large flow pressure reducing valve for nuclear power plants according to claim 1, characterized in that: The spiral filter (3) is arranged inside the bottom cover (13) and at the bottom of the valve core (2), The outer wall of the spiral filter (3) is provided with spiral blades and is located below the entrance of the inlet (121) into the bottom cover (13).

3. A large flow pressure reducing valve for nuclear power plants according to claim 1, characterized in that: The upper end of the upper cover (11) is provided with a screw rod (5), and the inside of the upper cover (11) is provided with a spring seat (6) at the lower end of the screw rod (5), and a pressure regulating spring (7) is arranged between the spring seat (6) and the spring tray (43).

4. A large flow pressure reducing valve for nuclear power plants according to claim 1, characterized in that: The inside of the upper cover (11) is divided into a lower diaphragm chamber (111) and an upper cavity (112) by a diaphragm assembly (4), a constant flow hole (123) for connecting the diaphragm chamber (111) and the outlet (122) is arranged between the diaphragm chamber (111) and the outlet (122), and the cavity (112) is connected with the outside through an exhaust hole (113).

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