High-performance stable opening and closing nitrogen seal valve

Abstract

The utility model relates to nitrogen seal valve technical field, concretely for a kind of high-performance stable opening and closing nitrogen seal valve, including valve body, valve cover, valve rod, valve seat, valve flap and actuating mechanism, valve rod includes upper valve rod and lower valve rod, by setting up middle cavity sealing mechanism in upper and lower valve rod connecting part, double sealing guarantee is provided for actuating mechanism, when the sliding seal of valve rod and actuating mechanism appears wear and causes sealing failure, sealing diaphragm still can guarantee sealing effect, make lower membrane chamber be in stable operation state, guarantee the normal operation of actuating mechanism;Lower spring is set at bottom cover, by the collaborative work of lower spring and upper spring, make valve rod produce more linear, more accurate displacement response to slight pressure change, to improve overall control precision, make valve operation more stable.

Description

Technical Field

[0001] This utility model relates to the field of nitrogen sealing valve technology, specifically a high-performance, stable on / off nitrogen sealing valve. Background Technology

[0002] Nitrogen blanketing devices are mainly used at the top of storage tanks to maintain a slight positive pressure, isolate materials from external contact, reduce material volatilization and waste, and protect the safety of the storage tank.

[0003] The stem of a self-operated nitrogen sealing valve typically reciprocates up and down under the control of a diaphragm actuator. The diaphragm actuator consists of an upper and lower chamber. The upper chamber connects to the gas storage tank, and the lower chamber connects to the atmosphere. The diaphragm is fixedly and sealed to the valve stem. When the gas pressure in the storage tank decreases, the diaphragm moves the valve stem upwards, causing the valve disc to move away from the valve seat sealing surface, thus opening the flow path. When the gas pressure in the storage tank increases, the diaphragm moves the valve stem downwards, pressing the valve disc against the valve seat sealing surface to form a seal. Throughout this process, all the energy for the valve stem's movement comes from the pressure of nitrogen itself, requiring no external power or gas source, making it ideal for applications such as chemical plants. However, the valve stem is usually sealed to the diaphragm actuator using sealing packing and sealing rings. During the frequent up-and-down movements of the valve stem, repeated friction between the valve stem and the sealing packing or sealing rings can cause wear, leading to a decrease in the sealing performance of the diaphragm actuator and preventing normal operation, thus affecting the equipment's service life. Utility Model Content

[0004] The purpose of this invention is to provide a high-performance, stable nitrogen sealing valve to solve the problems mentioned in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A high-performance, stable nitrogen sealing valve includes a valve body, a valve cover, a valve stem, a valve seat, a valve disc, and an actuator. The valve body has an inlet flow channel and an outlet flow channel. The valve seat is fixedly installed on the flow channel wall between the inlet and outlet flow channels. The upper end of the valve body is bolted to the valve cover, and the lower end is bolted to a bottom cover. The upper end of the valve cover is fixedly connected to the actuator, and the upper end of the actuator is connected to a spring cavity. An upper spring is fixedly installed in the spring cavity. The valve stem includes an upper valve stem and a lower valve stem. The valve disc is located below the valve seat on the lower valve stem. The upper sealing surface of the valve disc and the lower sealing surface of the valve seat form a sealing pair. The upper end of the upper valve stem is drively connected to the actuator, and the lower end passes through the valve cover and extends into the inlet flow channel. A cavity sealing mechanism is provided between the upper valve stem and the lower valve stem. The cavity sealing mechanism includes a radial frustum arranged along the outer circular wall of the lower end of the upper valve stem, a valve stem bushing, a sealing diaphragm, a positioning bushing, and a valve stem sleeve. The valve stem bushing is fixedly installed on the lower end face of the radial frustum. The valve stem bushing is tightly fitted onto the upper end of the lower valve stem. The valve stem sleeve is fixedly fitted onto the outer circular wall of the valve stem bushing. A radial step is formed on the inner wall of the upper end of the valve body. The upper end of the positioning bushing is a radially protruding annular boss. The annular boss is fixedly engaged within the radial step. The outer peripheral edge of the sealing diaphragm is sealed and clamped between the upper end face of the positioning bushing and the lower end face of the valve cover. The center part of the sealing diaphragm is sealed and clamped between the lower end face of the radial frustum and the upper end face of the valve stem sleeve.

[0007] Preferably, a valve disc base is provided on the lower end face of the valve disc, and a lower positioning bushing is provided on the bottom cover at a position corresponding to the lower valve stem. A lower guide sleeve is fixedly installed inside the lower positioning bushing. The inner circular wall of the lower guide sleeve and the outer circular wall of the lower valve stem slide in fit. A lower spring is fixedly provided between the upper end face of the lower guide sleeve and the lower end face of the valve disc base.

[0008] Preferably, an annular sealing groove is formed on the valve seat sealing surface, and a valve seat sealing ring is detachably installed in the annular sealing groove. The valve seat sealing ring and the valve disc sealing surface are sealed together to form a sealing pair.

[0009] Preferably, the actuator cavity is divided into an upper diaphragm chamber and a lower diaphragm chamber by an actuator diaphragm. The actuator is equipped with a valve stem stabilizing device, including an upper positioning plate, a lower positioning plate, and a sealing sleeve. The upper and lower positioning plates are fixedly installed in the middle of the upper and lower end faces of the actuator diaphragm, respectively. The upper valve stem passes through the center of the actuator diaphragm, the upper positioning plate, and the lower positioning plate. The sealing sleeve is installed at the connection between the upper and lower positioning plates and the upper valve stem. The sealing sleeve is sealed on the outer circular wall of the upper valve stem. The outer end faces of the upper and lower positioning plates away from the upper valve stem are respectively connected to upper and lower push rods. Each upper and lower push rod includes a base and a telescopic rod. The base is fixedly installed on the bottom wall of the upper and lower diaphragm chambers, respectively. The telescopic rod is placed in the inner cavity of the base and is slidably guided to the inner wall of the base. One end is fixedly connected to the upper and lower end faces of the upper and lower positioning plates. As the upper and lower positioning plates move, the telescopic rod extends out of the base or retracts into the base. The upper and lower push rods are arranged in pairs, with two pairs corresponding to each other, along the virtual diameter of the positioning plates.

[0010] Preferably, the upper membrane chamber is provided with an atmospheric vent that connects to the atmosphere, and the lower membrane chamber is provided with a pressure guide pipe interface that connects to the storage tank. The spring cavity is fixedly and sealed to the upper end of the upper membrane chamber, the upper end of the upper valve stem extends into the spring cavity, the upper end of the upper spring is fixedly connected to the inner wall of the upper end of the spring cavity, and the lower end is fixedly connected to the upper valve stem through an upper spring base that is fixedly sleeved on the upper end of the upper valve stem.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. By setting up a central cavity sealing mechanism, a double sealing guarantee is provided for the actuator. When wear occurs at the sliding seal of the valve stem and the actuator, resulting in seal failure, the sealing diaphragm can still ensure the sealing effect, keeping the lower diaphragm chamber in a stable operating state and ensuring the normal operation of the actuator.

[0013] 2. By working together with the upper and lower springs, the valve stem produces a more linear and precise displacement response to minute pressure changes, thereby improving the overall control accuracy and forming a precise force balance system. At the critical point of valve action, the preload of the lower spring can ensure that the transmission components are always in close contact, effectively preventing the valve from shaking or fluttering due to pressure fluctuations when it is slightly open, making the valve operate more smoothly. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0015] Figure 2 This is an enlarged view of section A of this utility model.

[0016] In the diagram: 1. Valve body; 2. Outlet flow channel; 3. Bottom cover; 4. Lower positioning bushing; 5. Lower guide sleeve; 6. Lower valve stem; 7. Lower spring; 8. Valve disc base; 9. Valve disc; 10. Valve seat; 11. Inlet flow channel; 12. Positioning bushing; 13. Sealing diaphragm; 14. Radial frustum; 15. Upper valve stem; 16. Telescopic rod; 17. Upper diaphragm chamber; 18. Actuator; 19. Sealing jacket; 20. Upper spring; 21. Actuating diaphragm; 22. Upper positioning plate; 23. Lower positioning plate; 24. Pressure guide pipe interface; 25. Valve cover; 26. Valve stem sleeve; 27. Valve stem bushing; 28. Radial step; 29. ​​Lower diaphragm chamber; 30. Valve seat sealing ring. Detailed Implementation

[0017] 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.

[0018] like Figure 1-2 As shown, this utility model provides a technical solution:

[0019] A high-performance, stable nitrogen sealing valve includes a valve body 1, a valve cover 25, a valve stem, a valve seat 10, a valve disc 9, and an actuator 18. The valve body 1 has an inlet flow channel 11 and an outlet flow channel 2 inside its cavity. The valve seat 10 is fixedly installed on the flow channel wall between the inlet flow channel 11 and the outlet flow channel 2. The upper end of the valve body 1 is bolted to the valve cover 25, and the lower end is bolted to a bottom cover 3. The actuator 18 is fixedly connected to the upper end of the valve cover 25. The upper end of the actuator 18 is connected to a spring cavity, and an upper spring 20 is fixedly installed inside the spring cavity. The valve stem includes an upper valve stem 15 and a lower valve stem 6. The lower valve stem 6 is located at the valve... A valve disc 9 is positioned below the seat 10. The upper sealing surface of the valve disc 9 and the lower sealing surface of the valve seat 10 form a sealing pair. The upper end of the upper valve stem 15 is connected to the actuator 18 for transmission, and the lower end passes through the valve cover 25 and extends into the inner cavity of the inlet flow channel 11. A middle cavity sealing mechanism is provided between the upper valve stem 15 and the lower valve stem 6. The middle cavity sealing mechanism includes a radial frustum 14 arranged along the outer circular wall at the lower end of the upper valve stem 15, a valve stem bushing 27, a sealing diaphragm 13, a positioning bushing 12, and a valve stem sleeve 26. The valve stem bushing 27 is fixedly mounted on the lower end face of the radial frustum 14. The valve stem sleeve 27 is securely fitted onto the upper end of the lower valve stem 6. The valve stem sleeve 26 is fixedly fitted onto the outer circular wall of the valve stem sleeve 27. A radial step 28 is formed on the inner wall of the upper end of the valve body 1. The upper end of the positioning sleeve 12 is a radially protruding annular boss, which is fixedly engaged within the radial step 28. The outer periphery of the sealing diaphragm 13 is sealed and clamped between the upper end face of the positioning sleeve 12 and the lower end face of the valve cover 25. The center of the sealing diaphragm 13 is sealed and clamped between the lower end face of the radial frustum 14 and the upper end face of the valve stem sleeve 26. The central cavity sealing mechanism provides double sealing for the actuator 18. To ensure sealing, when wear occurs at the sliding seal of the valve stem and actuator 18, leading to seal failure, the sealing diaphragm 13 can still maintain the sealing effect, keeping the lower diaphragm chamber 29 in a stable operating state and ensuring the normal operation of the actuator 18. When the upper valve stem 15 drives the lower valve stem 6 to move up and down under the action of the actuator 18, the upper end of the lower valve stem 6 is fixed in the valve stem bushing 27 and is in a relatively stationary state, avoiding repeated friction between the lower valve stem 6 and the inner wall of the valve body 1 or the sealing packing during movement, thus achieving friction-free operation of the lower valve stem 6 throughout its movement and extending the service life of the equipment.

[0020] A valve disc base 8 is provided on the lower end face of the valve disc 9. A lower positioning sleeve 4 is provided on the bottom cover 3 at the corresponding position of the lower valve stem 6. A lower guide sleeve 5 is fixedly installed inside the lower positioning sleeve 4. The inner circular wall of the lower guide sleeve 5 and the outer circular wall of the lower valve stem 6 slide in fit. The lower guide sleeve 5 ensures that the valve stem always moves along a vertical axis when it moves up and down, and there will be no radial swing or deviation. A lower spring 7 is fixedly installed between the upper end face of the lower guide sleeve 5 and the lower end face of the valve disc base 8. The lower spring 7 works in conjunction with the upper spring 20 to make the valve stem produce a more linear and precise displacement response to small pressure changes, thereby improving the overall control accuracy and forming a precise force balance system. At the critical point of valve action, the preload of the lower spring 7 can ensure that the transmission components are always in close contact, effectively preventing the valve from shaking or chattering due to pressure fluctuations in the slightly open state, making the valve operation more stable.

[0021] An annular sealing groove is provided on the sealing surface of the valve seat 10. The valve seat sealing ring 30 is detachably installed in the annular sealing groove. The valve seat sealing ring 30 and the valve disc 9 sealing surface are sealed together to form a sealing pair. When the valve seat sealing ring 30 is worn, it can be easily disassembled for repair or directly replaced without removing the entire valve seat 10, which provides convenience for maintenance.

[0022] The inner cavity of the actuator 18 is divided into an upper diaphragm chamber 17 and a lower diaphragm chamber 29 by the actuator diaphragm 21. The actuator 18 is equipped with a valve stem stabilizing device, including an upper positioning plate 22, a lower positioning plate 23, and a sealing sleeve 19. The upper positioning plate 22 and the lower positioning plate 23 are fixedly mounted on the middle of the upper and lower end faces of the actuator diaphragm 21, respectively. The upper valve stem 15 passes through the center of the actuator diaphragm 21, the upper positioning plate 22, and the lower positioning plate 23. The sealing sleeve 19 is installed at the connection points between the upper positioning plate 22 and the lower positioning plate 23 and the upper valve stem 15. The sealing sleeve 19 is fitted onto the outer circular wall of the upper valve stem 15. This valve stem stabilizing device, through the two positioning plates and the sealing sleeve 19, raises the actuator diaphragm... The stability of plate 21 and upper valve stem 15 during vertical movement; upper positioning plate 22 and lower positioning plate 23 are respectively connected to upper and lower push rods on their outer end faces away from upper valve stem 15. Each upper and lower push rod includes a base and a telescopic rod 16. The base is fixedly installed on the bottom wall of the upper and lower membrane chambers, and the telescopic rod 16 is placed in the inner cavity of the base and slidably guided to the inner wall of the base. One end is fixedly connected to the upper and lower end faces of the upper and lower positioning plates. As the upper and lower positioning plates move, the rod extends out of the base or retracts into the base. The upper and lower push rods are arranged in pairs with corresponding upper and lower positions, and two sets are arranged along the virtual diameter of the positioning plate to further increase the stability of upper valve stem 15 during vertical movement.

[0023] The upper membrane chamber 17 is provided with an atmospheric vent that connects to the atmosphere, and the lower membrane chamber 29 is provided with a pressure guide pipe interface 24 that connects to the storage tank. The spring cavity is fixedly and sealed to the upper end of the upper membrane chamber 17. The upper end of the upper valve stem 15 extends into the spring cavity. The upper end of the upper spring 20 is fixedly connected to the inner wall of the upper end of the spring cavity, and the lower end is fixedly connected to the upper valve stem 15 through an upper spring base that is fixedly sleeved on the upper end of the upper valve stem 15. The pressure reference is set by the upper spring 20 to provide a constant reference force for valve operation. By adjusting the compression of the spring, the target pressure value that the storage tank needs to maintain is set.

[0024] Working principle:

[0025] When the tank pressure is lower than the set value, the thrust of the tank pressure on the actuator diaphragm 21 is less than the elastic force of the upper spring 20. The upper spring 20 pushes the valve stem downward, and the sealing surface of the valve disc 9 moves downward away from the sealing surface of the valve seat 10. The inlet flow channel 11 and the outlet flow channel 2 are connected, and gas is supplied to the outlet pipe. When the tank pressure is higher than the set value, the thrust of the tank pressure on the actuator diaphragm 21 is greater than the elastic force of the upper spring 20. The tank pressure lifts the actuator diaphragm 21 and compresses the upper spring 20. The sealing surface of the valve disc 9 presses upward against the sealing surface of the upper valve seat 10, causing the valve to close. During the valve opening and closing process, in addition to the first layer of sealing between the valve stem and the actuator 18, the middle cavity sealing mechanism provides double sealing protection for the actuator 18. When wear occurs at the sliding seal, leading to seal failure, the sealing diaphragm 13 can still ensure the sealing effect, keeping the lower diaphragm chamber 29 in a stable operating state and ensuring the normal operation of the actuator 18. A lower spring 7 is set between the valve disc 9 and the bottom cover 3, so that the lower spring 7 is sleeved on the outer circular wall of the lower valve stem 6, so that it works in conjunction with the upper spring 20, making the valve stem produce a more linear and precise displacement response to small pressure changes, thereby improving the overall control accuracy and forming a precise force balance system. At the critical point of valve action, the preload of the lower spring 7 can ensure that the transmission components are always in close contact, effectively preventing the valve from shaking or fluttering due to pressure fluctuations in the slightly open state, making the valve operation more stable.

[0026] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A high-performance, stable nitrogen sealing valve, comprising a valve body (1), a valve cover (25), a valve stem, a valve seat (10), a valve disc (9), and an actuator (18), wherein an inlet flow channel (11) and an outlet flow channel (2) are opened in the inner cavity of the valve body (1), and the valve seat (10) is fixedly installed on the flow channel wall between the inlet flow channel (11) and the outlet flow channel (2), the upper end of the valve body (1) is bolted to the valve cover (25), and the lower end is bolted to the bottom cover (3), the upper end of the valve cover (25) is fixedly connected to the actuator (18), the upper end of the actuator (18) is connected to a spring cavity, and an upper spring (20) is fixedly installed in the spring cavity, and the valve stem includes an upper valve stem (15) and a lower valve stem (6), characterized in that: A valve disc (9) is located below the valve seat (10) on the lower valve stem (6). The upper sealing surface of the valve disc (9) and the lower sealing surface of the valve seat (10) form a sealing pair. The upper part of the upper valve stem (15) is connected to the actuator (18) for transmission. The lower end passes through the valve cover (25) and extends into the inner cavity of the inlet flow channel (11). A middle cavity sealing mechanism is provided between the upper valve stem (15) and the lower valve stem (6). The middle cavity sealing mechanism includes a radial frustum (14) set along the outer circular wall of the lower end of the upper valve stem (15), a valve stem bushing (27), a sealing diaphragm (13), a positioning bushing (12), and a valve stem sleeve (26). The radial frustum (14) 14) A valve stem bushing (27) is fixedly installed on the lower end face. The valve stem bushing (27) is tightly fitted on the upper end of the lower valve stem (6). A valve stem sleeve (26) is fixedly fitted on the outer circular wall of the valve stem bushing (27). A radial step (28) is opened on the inner wall of the upper end of the valve body (1). The upper end of the positioning bushing (12) is a radially protruding annular boss. The annular boss is fixedly clamped in the radial step (28). The outer peripheral edge of the sealing diaphragm (13) is sealed and clamped between the upper end face of the positioning bushing (12) and the lower end face of the valve cover (25). The center part of the sealing diaphragm (13) is sealed and clamped between the lower end face of the radial frustum (14) and the upper end face of the valve stem sleeve (26).

2. The high-performance stable on / off nitrogen sealing valve as described in claim 1, characterized in that: A valve disc base (8) is provided on the lower end face of the valve disc (9). The bottom cover (3) is provided with a lower positioning bushing (4) at the corresponding position of the lower valve rod (6). A lower guide sleeve (5) is fixedly installed inside the lower positioning bushing (4). The inner circular wall of the lower guide sleeve (5) and the outer circular wall of the lower valve rod (6) slide together. A lower spring (7) is fixedly installed between the upper end face of the lower guide sleeve (5) and the lower end face of the valve disc base (8).

3. The high-performance, stable on / off nitrogen sealing valve as described in claim 2, characterized in that: An annular sealing groove is provided on the valve seat sealing surface, and a valve seat sealing ring (30) is detachably installed in the annular sealing groove. The valve seat sealing ring (30) and the valve disc (9) sealing surfaces are sealed together to form a sealing pair.

4. The high-performance stable on / off nitrogen sealing valve as described in claim 3, characterized in that: The inner cavity of the actuator (18) is divided into an upper diaphragm chamber (17) and a lower diaphragm chamber (29) by the actuator diaphragm (21). The actuator (18) is equipped with a valve stem stabilizing device, including an upper positioning plate (22), a lower positioning plate (23) and a sealing jacket (19). The upper positioning plate (22) and the lower positioning plate (23) are fixedly installed in the middle of the upper and lower end faces of the actuator diaphragm (21). The sealing jacket (19) is installed at the connection between the upper positioning plate (22) and the lower positioning plate (23) and the upper valve stem (15). The sealing jacket (19) is sealed on the outer circular wall of the upper valve stem (15). The upper and lower push rods are respectively connected to the outer end faces of the upper positioning plate (22) and the lower positioning plate (23) away from the upper valve stem. The upper and lower push rods each include a base and a telescopic rod (16). The telescopic rod (16) is placed in the inner cavity of the base and is slidably connected to the inner wall of the base. The end face of the telescopic rod (16) is fixedly connected to the upper and lower end faces of the upper and lower positioning plates.

5. A high-performance, stable on / off nitrogen sealing valve as described in claim 4, characterized in that: The upper membrane chamber (17) is provided with an atmospheric vent that connects to the atmosphere, and the lower membrane chamber (29) is provided with a pressure guide pipe interface (24) that connects to the storage tank. The spring cavity is fixedly and sealed to the upper end of the upper membrane chamber (17). The upper end of the upper valve stem extends into the spring cavity. The upper end of the upper spring (20) is fixedly connected to the inner wall of the upper end of the spring cavity, and the lower end is fixedly connected to the upper valve stem (15) through the upper spring base that is fixedly sleeved on the upper end of the upper valve stem (15).

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