Back sealing structure of high-pressure stop valve

Abstract

The high-pressure stop valve back sealing structure comprises a sealing seat assembly, the sealing seat assembly is arranged on the inner wall of an overflowing hole of a valve body, and the lower end of a valve rod penetrates through the sealing seat assembly to be connected with a valve clack; the outer wall of the valve rod is in sliding connection with the inner wall of the sealing seat assembly; the upper sealing face of the valve rod is connected with the sealing seat assembly in a sealing mode, and the back sealing function of the valve is achieved. The sealing seat assembly comprises a back sealing seat and a pressing ring; the hold-down ring is connected to the inner wall of the overflowing hole of the valve body, a mounting groove is formed in the lower end of the hold-down ring, and the reverse sealing seat is arranged in the mounting groove; the outer edge of the reverse sealing seat is attached to the inner wall of the overflowing hole of the valve body. The inner ring of the back sealing seat is provided with an oblique conical surface, the upper sealing surface of the valve rod is also provided with an oblique conical surface, and the oblique conical surfaces are attached and matched. The valve leakage risk can be effectively reduced.

Description

Technical Field

[0001] This invention relates to a reverse sealing structure for a high-pressure shut-off valve. Background Technology

[0002] High-pressure gate valves are forced-sealing valves, so when the valve is closed, pressure must be applied to the valve disc to ensure a leak-proof seal. When the medium enters the valve from below the valve disc, the resistance that the operating force needs to overcome is the frictional force of the valve stem and packing, plus the thrust generated by the pressure of the medium. The force required to close the valve is greater than the force required to open it, so the valve stem diameter must be large; otherwise, the valve stem may bend.

[0003] In recent years, with the advent of self-sealing valves, the flow direction of the medium in gate valves has changed to enter the valve chamber from above the valve disc. In this case, under the pressure of the medium, the force required to close the valve is smaller, while the force required to open the valve is larger, allowing for a corresponding reduction in the valve stem diameter. When a high-pressure gate valve is opened, the flow rate reaches its maximum when the valve disc opening height is 25% to 30% of the nominal diameter, indicating that the valve is fully open. Therefore, the fully open position of a gate valve should be determined by the valve disc stroke.

[0004] The back seal of a conventional gate valve is generally formed by the conical surface of the valve cover and the conical surface of the valve stem. The valve body of a high-pressure gate valve adopts a structure without a valve cover. Due to structural limitations, there is generally no back seal structure design, which may lead to the risk of valve leakage. Therefore, a back seal structure for a high-pressure gate valve is proposed to address the above problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the existing defects and provide a high-pressure shut-off valve back-sealing structure that can effectively reduce the risk of valve leakage.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-pressure shut-off valve reverse sealing structure, comprising a sealing seat assembly, wherein the sealing seat assembly is disposed on the inner wall of the flow hole of the valve body, and the lower end of the valve stem passes through the sealing seat assembly to connect the valve disc; the outer wall of the valve stem is slidably connected to the inner wall of the sealing seat assembly;

[0007] The upper sealing surface of the valve stem is sealed to the sealing seat assembly to achieve the valve's reverse sealing function.

[0008] Preferably, the sealing seat assembly includes an inverted sealing seat and a clamping ring; the clamping ring is connected to the inner wall of the flow hole of the valve body, and the lower end of the clamping ring is provided with a mounting groove, and the inverted sealing seat is disposed in the mounting groove;

[0009] The outer edge of the inverted sealing seat fits against the inner wall of the flow hole of the valve body; the inner ring of the inverted sealing seat has a tapered surface, and the upper sealing surface of the valve stem also has a tapered surface, and the two fit together perfectly.

[0010] Preferably, a limiting groove is provided at the upper end of the clamping ring, a packing support pad is provided on the limiting groove, a packing is provided on the packing support pad, a packing pressure sleeve is provided on the packing, and the packing pressure sleeve is pressed by a packing pressure plate.

[0011] Preferably, the packing pressure plate has an opening in the middle and is sleeved on the outer wall of the valve stem. It is connected to the valve body through a first screw, a first nut, and applies downward pressure to the packing pressure sleeve.

[0012] Preferably, it further includes a driving device, which is disposed above the valve stem and has its output end connected to the upper end of the valve stem.

[0013] Preferably, the drive device is connected to the top plate, and the top plate is connected to the valve body via a second screw.

[0014] Preferably, it further includes an anti-rotation block, which is sleeved on the outer wall of the valve stem to restrict the rotation of the valve stem; one end of the anti-rotation block is connected to the second screw.

[0015] Preferably, the inner wall of the flow hole of the valve body is provided with an internal thread, the outer wall of the clamping ring is provided with an external thread, and the clamping ring is threadedly connected to the inner wall of the flow hole of the valve body.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This high-pressure shut-off valve reverse sealing structure, by setting a sealing seat assembly on the inner wall of the flow hole of the valve body, with the lower end of the valve stem passing through the sealing seat assembly to connect to the valve disc; the outer wall of the valve stem and the inner wall of the sealing seat assembly are slidably connected; the upper sealing surface of the valve stem is sealed to the sealing seat assembly, realizing the reverse sealing function of the valve. The reverse sealing seat, the compression ring, the packing support pad, and the valve stem form a reverse sealing structure, effectively reducing the risk of valve leakage. When the reverse sealing seat is installed in place, its outer conical surface forms a sealing pair with the valve body, effectively preventing the risk of medium leakage from the packing and improving the sealing reliability of the packing section. The lower end of the compression ring has a protrusion that cooperates with the sealing seat, effectively positioning the sealing seat when the compression ring is tightened by threads. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a cross-sectional view of the reverse sealing structure of the high-pressure shut-off valve of the present invention;

[0019] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0020] Figure 3This is a partial detail view of the inverted sealing seat of the present invention;

[0021] Figure 4 This is a cross-sectional view of the clamping ring of the present invention;

[0022] Figure 5 This is a top view of the clamping ring of the present invention;

[0023] Figure 6 This is a top view of the packing support pad of the present invention;

[0024] Figure 7 This is a cross-sectional view of the top view of the present invention.

[0025] In the diagram: 1. Valve body; 2. Valve disc; 3. Valve stem; 4. Inverted sealing seat; 5. Compression ring; 6. Packing support pad; 7. Packing; 8. Packing sleeve; 9. Packing pressure plate; 10. First screw; 11. First nut; 12. Anti-rotation block; 13. Drive device; 14. Top plate; 15. Second screw. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] like Figure 1-7 As shown, a high-pressure shut-off valve reverse sealing structure includes a sealing seat assembly, which is disposed on the inner wall of the flow hole of the valve body 1. The lower end of the valve stem 3 passes through the sealing seat assembly and connects to the valve disc 2. The outer wall of the valve stem 3 is slidably connected to the inner wall of the sealing seat assembly. The upper sealing surface of the valve stem 3 is sealed to the sealing seat assembly to realize the reverse sealing function of the valve.

[0028] Specifically, the sealing seat assembly includes an inverted sealing seat 4 and a clamping ring 5. The clamping ring 5 is connected to the inner wall of the flow hole of the valve body 1, and an installation groove is provided at the lower end of the clamping ring 5. The inverted sealing seat 4 is disposed in the installation groove. The outer edge of the inverted sealing seat 4 fits against the inner wall of the flow hole of the valve body 1. The inner ring of the inverted sealing seat 4 has a tapered surface, and the upper sealing surface of the valve stem 3 also has a tapered surface, so the two fit together properly. The inner wall of the flow hole of the valve body 1 has an internal thread, and the outer wall of the clamping ring 5 has an external thread. The clamping ring 5 is threadedly connected to the inner wall of the flow hole of the valve body 1.

[0029] Specifically, a limiting groove is provided at the upper end of the clamping ring 5, a packing support pad 6 is provided on the limiting groove, a packing 7 is provided on the packing support pad 6, and a packing sleeve 8 is provided on the packing 7. The packing sleeve 8 is pressed by a packing pressure plate 9. The packing pressure plate 9 has an opening in the middle and is sleeved on the outer wall of the valve stem 3. It is connected to the valve body 1 through the first screw 10, the first nut 11, and applies downward pressure to the packing sleeve 8.

[0030] Specifically, it also includes a drive device 13, which is positioned above the valve stem 3 and has its output end connected to the upper end of the valve stem 3. The drive device 13 is connected to the top plate 14, which is connected to the valve body 1 via a second screw 15. It also includes an anti-rotation block 12, which is sleeved on the outer wall of the valve stem 3 to restrict the rotation of the valve stem 3; one end of the anti-rotation block 12 is connected to the second screw 15.

[0031] Specifically, valve disc 2 is installed inside valve body 1. Valve disc 2 is connected to valve stem 3 through T-slot. Valve stem 3 has a reverse sealing seat 4 at the upper end, and a clamping ring 5 is installed on the upper end of reverse sealing seat 4. The lower end of clamping ring 5 has a boss to provide better positioning for reverse sealing seat 4 during installation. The reverse sealing seat 4 and valve body 1 are machined with a slanted conical surface. The valve body cavity is disassembled by a special disassembly tool. The tool claws cooperate with the groove of clamping ring 5. At this time, the outer circle of clamping ring 5 is screwed and pressed into the inner cavity of valve body 1 through threads. This causes the outer conical sealing surface of reverse sealing seat 4 to form a sealing pair with valve body 1, realizing the sealing between reverse sealing seat 4 and valve body 1. The inner conical sealing surface of reverse sealing seat 4 forms a sealing pair with the upper sealing surface of valve stem 3. After the two match, the valve reverse sealing function is realized. To better protect the upper groove of the compression ring 5 from the effects of prolonged valve operation and to better protect the packing, a packing support pad 6 is provided on the upper end of the compression ring 5 for mutual installation. Packing 7, a packing sleeve 8, and a packing pressure plate 9 are respectively installed on the upper end of the packing support pad 6. Tightening the nut 10 on the packing pressure plate 9 compresses the packing, enabling it to perform a sealing function. The valve stem 3 is raised by the drive device 13, and the anti-rotation block 12 prevents rotation during valve opening and closing for better sealing.

[0032] This high-pressure shut-off valve features a reverse sealing structure. A sealing seat assembly is mounted on the inner wall of the flow hole in the valve body 1. The lower end of the valve stem 3 passes through the sealing seat assembly and connects to the valve disc 2. The outer wall of the valve stem 3 is slidably connected to the inner wall of the sealing seat assembly. The upper sealing surface of the valve stem 3 is sealed to the sealing seat assembly, achieving the valve's reverse sealing function. The reverse sealing seat, the compression ring, and the packing support pad, together with the valve stem, form a reverse sealing structure, effectively reducing the risk of valve leakage. When the reverse sealing seat is installed correctly, its outer conical surface forms a sealing pair with the valve body, effectively preventing the risk of medium leakage from the packing and improving the sealing reliability of the packing section. The lower end of the compression ring has a protrusion that cooperates with the sealing seat, effectively positioning the sealing seat when the compression ring is tightened by threads.

[0033] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-pressure shut-off valve reverse sealing structure, characterized in that, The valve includes a sealing seat assembly, which is disposed on the inner wall of the flow hole of the valve body (1), and the lower end of the valve stem (3) passes through the sealing seat assembly to connect the valve disc (2); the outer wall of the valve stem (3) is slidably connected to the inner wall of the sealing seat assembly. The upper sealing surface of the valve stem (3) is sealed to the sealing seat assembly to achieve the valve's reverse sealing function.

2. The high-pressure shut-off valve back-sealing structure according to claim 1, characterized in that, The sealing seat assembly includes an inverted sealing seat (4) and a clamping ring (5); the clamping ring (5) is connected to the inner wall of the flow hole of the valve body (1), and the lower end of the clamping ring (5) is provided with an installation groove, and the inverted sealing seat (4) is disposed in the installation groove; The outer edge of the inverted sealing seat (4) fits against the inner wall of the flow hole of the valve body (1); the inner ring of the inverted sealing seat (4) is provided with a sloping conical surface, and the upper sealing surface of the valve stem (3) is also provided with a sloping conical surface, and the two fit together.

3. The high-pressure shut-off valve back-sealing structure according to claim 2, characterized in that, The upper end of the clamping ring (5) is provided with a limiting groove, the limiting groove is provided with a packing support pad (6), the packing support pad (6) is provided with a packing (7), the packing (7) is provided with a packing sleeve (8), and the packing sleeve (8) is pressed by a packing pressure plate (9).

4. The high-pressure shut-off valve back-sealing structure according to claim 3, characterized in that, The packing pressure plate (9) has an opening in the middle and is sleeved on the outer wall of the valve stem (3). It is connected to the valve body (1) through the first screw (10), the first nut (11) and the packing pressure sleeve (8) to apply downward pressure.

5. The high-pressure shut-off valve back-sealing structure according to claim 1, characterized in that, It also includes a drive device (13), which is located above the valve stem (3) and has its output end connected to the upper end of the valve stem (3).

6. The high-pressure shut-off valve back-sealing structure according to claim 5, characterized in that, The drive device (13) is connected to the top plate (14), and the top plate (14) is connected to the valve body (1) via the second screw (15).

7. The high-pressure shut-off valve back-sealing structure according to claim 6, characterized in that, It also includes an anti-rotation block (12), which is sleeved on the outer wall of the valve stem (3) to restrict the rotation of the valve stem (3); one end of the anti-rotation block (12) is connected to the second screw (15).

8. The high-pressure shut-off valve back-sealing structure according to claim 2, characterized in that, The valve body (1) has an internal thread on the inner wall of the flow hole, and the clamping ring (5) has an external thread on the outer wall. The clamping ring (5) is threadedly connected to the inner wall of the flow hole of the valve body (1).

Images