Self-pressure-relief lip-shaped sealing valve seat structure

Abstract

The utility model relates to a self pressure relief lip-shaped sealing valve seat structure which comprises a valve seat and a valve body, one end of the valve seat is sequentially provided with a first step groove, a second step groove and a third step groove, the other end of the valve seat is provided with a valve seat sealing ring in a pressing mode, an elastic piece is connected between the first step groove and the valve body in a pressing mode, and the elastic piece is connected with the valve body in a pressing mode. A first stepped groove is clamped in the valve body, a second stepped groove is clamped in the first stepped groove, a lip-shaped sealing assembly is connected between the second stepped groove and the valve body in a pressing mode, a metal check ring is clamped in the third stepped groove, the metal check ring is connected with the lip-shaped sealing assembly in a pressing mode, the horizontal distance between the first stepped groove and the valve body is L1, and the horizontal distance between the third stepped groove and the valve body is L2. The self-pressure-relief lip-shaped sealing valve seat structure has the advantages of automatically relieving pressure, improving the safety of the valve, simplifying the structure, being convenient to install and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of ball valve seat structures, in particular to a self-pressure relief lip-shaped sealing valve seat structure. Background Art

[0002] At present, PTFE spring preloaded lip seal packing (referred to as Lip Seal) has been more and more widely used in ball valves due to its excellent corrosion resistance, high and low temperature resistance and other remarkable characteristics. Although the conventional Lip Seal valve seat sealing structure is simple, due to the limitation of Lip Seal installation structure and design size, it is impossible to achieve pressure relief at low pressure in many designs, which is very disadvantageous in some working conditions with sensitive inner cavity pressure, such as liquefied natural gas and liquefied petroleum gas working conditions.

[0003] For this reason, we have developed a self-depressurizing lip seal valve seat structure to solve the above problems. Utility Model Content

[0004] The utility model aims to overcome the deficiencies of the prior art and to provide a self-depressurizing lip-shaped sealing valve seat structure, which has the advantages of automatic pressure relief, improved valve safety, simplified structure, convenient installation, etc.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a self-relieving lip-shaped sealing valve seat structure, comprising a valve seat and a valve body, a first step groove, a second step groove and a third step groove are sequentially arranged at one end of the valve seat, and a valve seat sealing ring is pressed at the other end, an elastic member is crimped between the first step groove and the valve body, a lip-shaped sealing assembly is crimped between the second step groove and the valve body, a metal retaining ring is clamped on the third step groove, the metal retaining ring is crimped to the lip-shaped sealing assembly, the horizontal distance between the first step groove and the valve body is L1, and the horizontal distance between the third step groove and the valve body is L2.

[0006] Preferably, the lip seal assembly comprises a filler, a filler ring and a PTFE lip seal which are crimped in sequence, and the PTFE lip seal is crimped to the metal retaining ring.

[0007] Preferably, the PTFE lip seal comprises a circular skeleton and a T-shaped pressure head, and the circular skeleton and the T-shaped pressure head are crimped.

[0008] Preferably, the filler is any one of polytetrafluoroethylene, graphite, and asbestos packing.

[0009] Preferably, the horizontal distance L2 is greater than or equal to the horizontal distance L1.

[0010] Preferably, the third stepped groove is provided with a first annular groove, and the metal retaining ring is clamped with the first annular groove.

[0011] Preferably, the first stepped groove is provided with a blind hole, and the elastic member is crimped between the blind hole and the valve body.

[0012] Preferably, the elastic member is a cylindrical helical spring.

[0013] Preferably, a second annular groove is provided at one end of the valve seat, a convex ring is provided at the opening of the second annular groove, and the second annular groove is pressed to the ball through the valve seat sealing ring.

[0014] Preferably, the outer diameter of the PTFE lip seal is D3, and the inner diameter is D2, and the outer diameter of the packing and the outer diameter of the packing ring are the same as D3.

[0015] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0016] The self-pressure-relieving lip-shaped sealing valve seat structure of the utility model designs a lip-sealed valve seat structure, so that the valve seat can realize automatic pressure relief under a relatively low middle cavity pressure; the automatic pressure relief of the valve seat refers to the valve seat sealing ring being out of contact with the ball, so that the medium in the middle cavity of the valve body can be discharged from between the ball seat, thereby ensuring the safety of the valve; while simplifying the structure, it is also convenient for factory installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the self-pressure relief lip sealing valve seat structure of the utility model. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0019] Figure 1 In the invention, a self-relieving lip-shaped sealing valve seat structure includes a valve seat 2 and a valve body 4. A first step groove 201, a second step groove 202 and a third step groove 203 are sequentially arranged at one end of the valve seat 2, and a valve seat sealing ring 1 is pressed at the other end. An elastic member 3 is pressed between the first step groove 201 and the valve body 4, and the elastic member 3 is a cylindrical helical spring. A lip-shaped sealing assembly is pressed between the second step groove 202 and the valve body 4, and a metal retaining ring 8 is clamped on the third step groove 203. The metal retaining ring 8 is pressed against the lip-shaped sealing assembly. The horizontal distance between the first step groove 201 and the valve body 4 is L1, and the horizontal distance between the third step groove 203 and the valve body 4 is L2.

[0020] The lip seal assembly includes a packing 5, a packing ring 6 and a PTFE lip seal 7 which are crimped in sequence. The packing 5 is any one of polytetrafluoroethylene, graphite and asbestos packing, preferably graphite. The PTFE lip seal 7 includes a circular skeleton 71 and a T-shaped pressure head 72, and the circular skeleton 71 is crimped with the T-shaped pressure head 72. The PTFE lip seal 7 is crimped with a metal retaining ring 8.

[0021] The first stepped groove 201 is provided with a blind hole 22 , and the elastic member 3 is pressed between the blind hole 22 and the valve body 4 . The third stepped groove 203 is provided with a first annular groove 23 , and the metal retaining ring 8 is clamped with the first annular groove 23 .

[0022] A second annular groove 21 is provided at one end of the valve seat 2, a convex ring is provided at the opening of the second annular groove 21, and the second annular groove 21 is pressed to the ball on the left through the valve seat sealing ring 1. The horizontal distance L2 is greater than or equal to the horizontal distance L1. When L1=0, the cylindrical helical spring is compressed into the blind hole 22, and L2≥0.

[0023] The outer diameter of the PTFE lip seal 7 is D3, and the inner diameter is D2. The outer diameter of the packing 5 and the outer diameter of the packing ring 6 are the same as D3. When the pressure in the middle cavity increases, the graphite packing 5, packing ring 6, and PTFE lip seal 7 in the structure will be pushed to the end of the valve by the medium force. At this time, the valve seat needs to achieve automatic pressure relief, and the backward thrust F1 of the medium on the valve seat must be greater than the forward thrust F2 given by the elastic member 3, and F1 = 0.25*π*(D2 2 -D1 2 )*P, where P is the medium pressure in the middle cavity. In the formula, D2 must have a large difference with D1, so that F1 can be greater than the spring force F2 when the middle cavity pressure P is small. D1 is the rotation radius of the contact point between the inclined surface 11 of the valve seat sealing ring 1 and the sphere. In actual design, due to the value of D3-D2, that is, the cross-sectional width of the PTFE lip seal 7 is wider, and if a larger D3 value is designed to meet the larger D2-D1, then when the end is pressed and sealed, the pressure on the valve seat sealing ring 1 will be too large, and it will cause excessive torque on the valve, which is very unfavorable to the service life of the valve. Therefore, it is very difficult for this structure to realize automatic pressure relief of the valve seat at a lower middle cavity pressure.

[0024] In the figure, the metal gasket 8 is designed on the valve seat, and the metal gasket 8 fits with the PTFE lip seal 7. When the pressure in the middle cavity increases, the PTFE lip seal packing is subjected to thrust, which is transmitted to the metal gasket 8, and the metal gasket 8 then transmits it to the valve seat 2, moving the valve seat together in the direction of leaving the ball. Therefore, this structure allows the valve to achieve a force greater than the spring force F1 under a relatively small middle cavity pressure P, so that the valve seat can automatically release pressure under relatively low pressure.

[0025] The above are only specific application examples of the utility model, and do not constitute any limitation on the protection scope of the utility model. Any technical solution formed by equivalent transformation or equivalent replacement falls within the protection scope of the utility model.

Claims

1. A self-depressurizing lip-shaped sealing valve seat structure, characterized in that: The invention comprises a valve seat (2) and a valve body (4), wherein a first step groove (201), a second step groove (202) and a third step groove (203) are sequentially arranged at one end of the valve seat (2), and a valve seat sealing ring (1) is pressed at the other end, an elastic member (3) is crimped between the first step groove (201) and the valve body (4), a lip sealing assembly is crimped between the second step groove (202) and the valve body (4), a metal retaining ring (8) is clamped on the third step groove (203), and the metal retaining ring (8) is crimped to the lip sealing assembly, a horizontal distance between the first step groove (201) and the valve body (4) is L1, and a horizontal distance between the third step groove (203) and the valve body (4) is L2.

2. The self-depressurizing lip seal valve seat structure according to claim 1, characterized in that: The lip seal assembly comprises a packing (5), a packing ring (6) and a PTFE lip seal (7) which are crimped in sequence, and the PTFE lip seal (7) is crimped to the metal retaining ring (8).

3. The self-depressurizing lip seal valve seat structure according to claim 2, characterized in that: The PTFE lip seal (7) comprises a circular frame (71) and a T-shaped pressing head (72), and the circular frame (71) and the T-shaped pressing head (72) are crimped.

4. The self-depressurizing lip seal valve seat structure according to claim 2, characterized in that: The filler (5) is any one of polytetrafluoroethylene, graphite, and asbestos packing.

5. The self-depressurizing lip seal valve seat structure according to claim 1, characterized in that: The horizontal distance L2 is greater than or equal to the horizontal distance L1.

6. The self-depressurizing lip seal valve seat structure according to claim 1, characterized in that: The third stepped groove (203) is provided with a first annular groove (23), and the metal retaining ring (8) is clamped with the first annular groove (23).

7. The self-depressurizing lip seal valve seat structure according to claim 1, characterized in that: The first stepped groove (201) is provided with a blind hole (22), and the elastic member (3) is pressed between the blind hole (22) and the valve body (4).

8. The self-depressurizing lip seal valve seat structure according to claim 7, characterized in that: The elastic member (3) is a cylindrical helical spring.

9. The self-depressurizing lip seal valve seat structure according to claim 1, characterized in that: A second annular groove (21) is provided at one end of the valve seat (2), a convex ring is provided at the opening of the second annular groove (21), and the second annular groove (21) is pressed to the ball through the valve seat sealing ring (1).

10. The self-depressurizing lip seal valve seat structure according to claim 2, characterized in that: The outer diameter of the PTFE lip seal (7) is D3, and the inner diameter is D2. The outer diameter of the packing (5) and the outer diameter of the packing ring (6) are the same as D3.

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