Pilot-operated flat gate valve

Abstract

This utility model relates to the technical field of gate valves, and in particular to a pilot-operated flat gate valve, which reduces driving force and damage to the sealing surface, is economical, reliable, and easy to disassemble; it includes a valve body, a valve seat, a main gate, a gate frame, a drive assembly, and a small gate assembly. The valve body has symmetrical valve seats inside, which are welded to the valve body as a whole. The gate frame is located at the center of the valve body, and a guide hole is opened in the middle of the gate frame. Two symmetrical main gates are fixed in the guide hole of the gate frame. A pilot hole is opened in the center of the main gate. The drive assembly is installed at the top of the valve body, and the small gate assembly is installed in the middle of the gate frame.

Description

Technical Field

[0001] This utility model relates to the technical field of gate valves, and in particular to pilot-operated flat gate valves. Background Technology

[0002] Pilot-operated flat gate valves are widely used in high-temperature and high-pressure pipelines in power plants. They consist of two parallel gate plates mounted on a gate frame. For example, a flat gate valve, as described in prior art publication CN206889953U, includes a valve body, gate plates, and a valve stem. The valve body has a flow channel that is closed or opened by the gate plates, with an inlet and an outlet. The valve is characterized by further including an external pipe, which is respectively fitted onto the outer circumference of the valve body at the inlet and outlet. An axial limiting mechanism is provided between the inner circumference of the external pipe and the outer circumference of the valve body. A limiting reinforcement auxiliary mechanism that applies pressure to the external pipe is also provided on the outer circumference of the external pipe. Nuclear power plants commonly use two main types of parallel gate valves: parallel double-gate valves with spring preload and parallel double-gate valves with a top block for support. The two types of gate valves have different structures and performance: the parallel double-gate valve with spring preload has the advantage that the load on the gate does not increase sharply when closing, but at the same time, the spring force causes the gate to remain on the valve seat during opening and closing, resulting in relatively greater wear on the sealing surface. Additionally, the gate sealing assembly has more parts, making assembly inconvenient. The parallel double-gate valve with a top block uses a top block to offset the two gates along an inclined plane to ensure a tight seal, providing a more reliable seal, but it also suffers from having more parts in the gate sealing assembly.

[0003] The parallel gate valve structure described above shares another common problem: it requires a relatively large operating force. If the operating force could be reduced, valves that would normally require a speed reducer could be operated using a handwheel. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a pilot-operated flat gate valve that reduces driving force and damage to the sealing surface, is economical, reliable, and easy to disassemble.

[0005] This utility model discloses a pilot-operated flat gate valve, comprising a valve body, valve seats, main gate plates, gate frame, drive assembly, and small gate assembly. The valve body contains symmetrical valve seats welded integrally with it. The gate frame is located at the center of the valve body, with a guide hole in its center. Two symmetrical main gate plates are fixed within the guide hole of the gate frame, with a pilot hole at the center of each main gate plate. The drive assembly is mounted at the top of the valve body, and the small gate assembly is mounted in the middle of the gate frame. During valve closure, medium always flows through the pilot hole, balancing the pressure difference between the valve inlet and outlet. This pilot-operated structure can meet the requirements of high medium pressure differences and low leakage. Through structural design, it reduces driving force and damage to the sealing surface, offering economic and reliable characteristics. It has significant practical value, and its widespread application will generate substantial economic benefits.

[0006] Preferably, the drive assembly includes a nut, a middle flange gasket, a valve cover, studs, and a rotating component. The middle flange gasket is installed between the valve cover and the valve body, and the valve cover and the valve body are fastened together by studs and nuts.

[0007] Preferably, the rotating component includes a valve stem, a bracket, a valve stem nut, and a handwheel. The bracket is installed on the top of the valve cover, and the valve stem is rotatably installed in the middle of the valve cover and the bracket. The bottom of the valve stem is connected to the gate frame, and the valve stem nut is installed inside the bracket. The valve stem and the valve stem nut cooperate with each other, and the handwheel is installed on the top of the valve stem nut. Rotating the handwheel and the valve stem nut can drive the valve to move up and down.

[0008] Preferably, the small gate assembly includes a small gate, a small valve stem, a stabilizing rod, a connecting block, and a pin. Two bosses are symmetrically arranged at the contact points between the valve body and the gate frame. The small gate is located at the center of the gate frame. A T-shaped head is provided at the lower part of the small valve stem. The small gate and the T-shaped head of the small valve stem are snapped together. The connecting block is located above the gate frame. The lower end of the valve stem is threaded to the upper part of the connecting block. The pin passes through the connecting block and connects the valve stem, the small valve stem, and the stabilizing rod to it as a whole. The lower part of the stabilizing rod is inserted into the guide hole of the main gate. The two ends of the pin are flattened to prevent slippage. After the stabilizing rod is inserted into the guide hole of the main gate, it prevents the main gate from rotating. When the main gate and the valve seat are fully aligned, the valve stem can still move downward. Pushing the small gate downwards, with a 5° incline on both sides, the small gate gradually weds the two main gates as it moves downwards. The main gates can establish an initial specific pressure, and the seal can be completed under the force of the medium. When the valve is opened, the process is exactly the opposite. The small gate opens first to balance the pressure difference between the two ends of the main gate, and then the main gate is fully raised under the action of the valve stem, thus avoiding wear on the main gate and valve seat.

[0009] Preferably, a valve stem sealing assembly is provided on the upper part of the valve cover, and the valve stem is located in the middle of the valve stem sealing assembly; the valve stem sealing assembly can ensure that no external leakage occurs when the valve stem moves up and down.

[0010] Compared with the prior art, the beneficial effects of this utility model are as follows: during the valve closing process, the pilot hole always has medium flowing through it, balancing the pressure difference between the valve inlet and outlet. The pilot-operated structure can meet the working conditions where the medium pressure difference is high and the leakage is required to be small. Through structural design, the driving force and damage to the sealing surface can be reduced. It has the characteristics of economy and reliability, has good practical value, and can generate good economic benefits after its promotion and application. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of this utility model;

[0012] Figure 2 This is a schematic diagram of the left-side cross-sectional structure of this utility model;

[0013] Figure 3 This is a structural schematic diagram of the gate valve and other components of this utility model;

[0014] Figure 4 This is a structural schematic diagram of the gate valve's closed position according to this utility model;

[0015] Figure 5 This is a structural schematic diagram of the gate valve's opening position according to this utility model;

[0016] The following are labels in the attached diagram: 1. Valve body; 2. Valve seat; 3. Main gate; 4. Gate frame; 5. Small gate; 6. Small valve stem; 7. Stabilizer bar; 8. Connecting block; 9. Pin; 10. Valve stem; 11. Nut; 12. Middle flange gasket; 13. Valve cover; 14. Stud; 15. Valve stem sealing assembly; 16. Bracket; 17. Valve stem nut; 18. Handwheel. Detailed Implementation

[0017] To facilitate understanding of this utility model, a more complete description will be given below with reference to the accompanying drawings. This utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of this utility model more thorough and complete.

[0018] like Figures 1 to 5As shown, the valve body 1 has symmetrical valve seats 2 inside, which are welded to the valve body 1 as a whole. The gate frame 4 is located at the center of the valve body 1. A guide hole is opened in the middle of the gate frame 4. Two symmetrical main gate plates 3 are fixed in the guide hole of the gate frame 4. A pilot hole is opened in the center of the main gate plate 3. A middle flange gasket 12 is installed between the valve cover 13 and the valve body 1. The valve cover 13 and the valve body 1 are fastened by studs 14 and nuts 11. The bracket 16 is installed on the top of the valve cover 13. The valve stem 10 is rotatably installed in the middle of the valve cover 13 and the bracket 16. The bottom of the valve stem 10 is connected to the gate frame 4. A valve stem nut 17 is installed inside the bracket 16. The valve stem 10 and the valve stem... Nut 17 is fitted, and handwheel 18 is fitted on the top of valve stem nut 17. Two bosses are symmetrically arranged on the left and right sides of the contact position between valve body 1 and gate frame 4. Small gate plate 5 is located in the center of gate frame 4. T-shaped head is provided at the lower part of small valve stem 6. Small gate plate 5 is snapped to the T-shaped head of small valve stem 6. Connecting block 8 is located above gate frame 4. The lower end of valve stem 10 is threaded to the upper part of connecting block 8. Pin 9 passes through connecting block 8 to connect valve stem 10, small valve stem 6 and stabilizing rod 7 to it as a whole. The lower part of stabilizing rod 7 is inserted into the guide hole of main gate plate 3. Valve stem sealing assembly 15 is provided on the upper part of valve cover 13. Valve stem 10 is located in the middle of valve stem sealing assembly 15.

[0019] Turning the handwheel 18 and engaging the valve stem nut 17 will drive the valve to move up and down. The pin 9 is flattened at both ends to prevent slippage. After the stabilizer 7 is inserted into the guide hole of the main gate 3, it prevents the main gate 3 from rotating. When the main gate 3 and the valve seat 2 are fully aligned, the valve stem 10 can still move downward. The small gate 5 is pushed downwards. The small gate 5 has a 5° slope on both sides. During the downward movement, it can gradually wed the two main gates 3. The main gates 3 can establish an initial specific pressure. Under the push of the medium force, the seal can be completed. When the valve is opened, the process is exactly the opposite. The small gate 5 opens first to balance the pressure difference between the two ends of the main gate 3. Then the main gate 3 is fully raised under the drive of the valve stem 10, avoiding wear on the main gate 3 and the valve seat 2. The valve stem sealing assembly 15 can ensure that no external leakage occurs when the valve stem 10 moves up and down. During the valve closing process, the pilot hole always has medium flowing through it to balance the pressure difference between the valve inlet and outlet. The pilot structure can meet the working conditions with high medium pressure difference and low leakage. Through structural design, the driving force and damage to the sealing surface can be reduced. It has the characteristics of economy and reliability.

[0020] like Figures 1 to 5As shown, in operation, when the pilot-operated flat gate valve of this invention is closed, after the main gate 3 and valve seat 2 are fully aligned, the valve stem 10 can still move downwards. This pushes the small gate 5 downwards. The small gate 5 has a 5° inclination on both sides, and during its downward movement, it gradually weds the two main gates 3, allowing the main gates 3 to establish an initial specific pressure. Under the force of the medium, a seal is achieved. When the valve is opened, the small gate 5 disengages from the main gate 3, allowing the medium to flow. Since balancing the pressure requires only a small flow rate, the small gate 5 does not need to be fully lifted.

[0021] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A pilot-operated flat gate valve, characterized in that, The valve body (1) includes a valve seat (2), a main gate (3), a gate frame (4), a drive assembly, and a small gate assembly. The valve body (1) has two symmetrical valve seats (2) inside, which are welded to the valve body (1) as a whole. The gate frame (4) is located in the center of the valve body (1). A guide hole is opened in the middle of the gate frame (4). Two symmetrical main gates (3) are fixed in the guide hole of the gate frame (4). A pilot hole is opened in the center of the main gate (3). The drive assembly is installed at the top of the valve body (1), and the small gate assembly is installed in the middle of the gate frame (4).

2. The pilot-operated flat gate valve as described in claim 1, characterized in that, The drive assembly includes a nut (11), a middle flange gasket (12), a valve cover (13), a stud (14), and a rotating component. The middle flange gasket (12) is installed between the valve cover (13) and the valve body (1), and the valve cover (13) and the valve body (1) are fastened together by the stud (14) and the nut (11).

3. The pilot-operated flat gate valve as described in claim 2, characterized in that, The rotating components include a valve stem (10), a bracket (16), a valve stem nut (17), and a handwheel (18). The bracket (16) is installed on the top of the valve cover (13). The valve stem (10) is rotatably installed in the middle of the valve cover (13) and the bracket (16). The bottom of the valve stem (10) is connected to the gate frame (4). The valve stem nut (17) is installed inside the bracket (16). The valve stem (10) and the valve stem nut (17) cooperate. The handwheel (18) is installed on the top of the valve stem nut (17).

4. The pilot-operated flat gate valve as described in claim 3, characterized in that, The small gate assembly includes a small gate (5), a small valve stem (6), a stabilizing rod (7), a connecting block (8), and a pin (9). Two bosses are symmetrically arranged at the contact positions of the valve body (1) and the gate frame (4). The small gate (5) is located at the center of the gate frame (4). The lower part of the small valve stem (6) is provided with a T-shaped head. The small gate (5) is snapped into the T-shaped head of the small valve stem (6). The connecting block (8) is located above the gate frame (4). The lower end of the valve stem (10) is threaded to the upper part of the connecting block (8). The pin (9) passes through the connecting block (8) to connect the valve stem (10), the small valve stem (6), and the stabilizing rod (7) to it as a whole. The lower part of the stabilizing rod (7) is inserted into the guide hole of the main gate (3).

5. The pilot-operated flat gate valve as described in claim 3, characterized in that, The valve cover (13) is provided with a valve stem sealing assembly (15) on the upper part, and the valve stem (10) is located in the middle of the valve stem sealing assembly (15).

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