Valve rod sealing structure under ultralow-temperature working condition and valve

Abstract

The valve rod sealing structure under the ultralow-temperature working condition comprises a valve deck and a valve rod, a through hole is formed in the valve deck, the valve rod is in rotating fit with the through hole of the valve deck, a graphite packing set is arranged between the valve deck and the valve rod, and the valve rod sealing structure further comprises a lip-shaped ring. The lip-shaped ring comprises cobalt-based alloy and PTFE, the cobalt-based alloy is coated with the PTFE, the lip-shaped ring is arranged between the valve cover and the valve rod, the valve cover is arranged on the valve body, one end of the valve rod is located in the valve body, the lip-shaped ring is located between the valve body and the graphite packing set, the valve cover is made of austenitic stainless steel, and the graphite packing set is arranged between the valve cover and the valve rod. The valve rod is made of austenitic stainless steel, and the valve body is made of austenitic stainless steel. The utility model further discloses a valve using the valve rod sealing structure under the ultralow-temperature working condition.

Description

Technical Field

[0001] The utility model relates to the field of valve equipment, in particular to a valve stem sealing structure under ultra-low temperature conditions. Background Art

[0002] Valves are essential equipment in common industrial websites. The structure of common valves is basically as shown in patent publication document CN205780924U. In valves of this structure, the valve stem (numbered 2 in the reference) and the valve body (numbered 1 in the reference) are sealed by packing (numbered 11 in the reference, and its material is generally graphite). Since this valve relies on graphite packing for sealing, and the sealing performance of graphite packing is relatively poor, when this valve is used in a pipeline network for conveying ultra-low temperature liquids (temperature as low as minus 196 degrees Celsius), the packing is prone to ice. After freezing, abnormal noise and wear will occur when opening and closing the valve, resulting in liquid leakage. Utility Model Content

[0003] In view of the above problems, the utility model proposes a valve stem sealing structure under ultra-low temperature working conditions.

[0004] The technical solution adopted by the utility model is as follows:

[0005] A valve stem sealing structure under ultra-low temperature conditions, comprising a valve cover and a valve stem, wherein the valve cover is provided with a through hole, the valve stem and the through hole of the valve cover are rotatably matched together, a graphite packing group is arranged between the valve cover and the valve stem, and also comprises a lip ring, the lip ring comprises a cobalt-based alloy and PTFE, the PTFE covers the cobalt-based alloy, the lip ring is arranged between the valve cover and the valve stem, the valve cover is arranged on the valve body, one end of the valve stem is located in the valve body, the lip ring is located between the valve body and the graphite packing group, the valve cover is a valve cover made of austenitic stainless steel, the valve stem is a valve stem made of austenitic stainless steel, and the valve body is a valve body made of austenitic stainless steel.

[0006] In this sealing structure, the flow channel of the liquid is located in the valve body. The liquid in the valve body needs to flow out from the valve stem and the valve cover through the lip ring and the graphite packing group in sequence. In this structure, the lip ring is composed of a cobalt-based alloy and PTFE (i.e., polytetrafluoroethylene). The cobalt-based alloy is completely coated by PTFE, and the cobalt-based alloy serves as the skeleton of the entire lip ring. This butterfly valve adopts a double sealing structure between the valve stem and the extended valve cover, that is, the lip ring seal and the graphite packing group seal. If the liquid flowing through the valve body wants to overflow, it must first pass through the seal of the lip ring, and then through the seal of the graphite packing group to overflow. In this butterfly valve, since the lip ring is a composite of cobalt-based alloy and PTFE, and since PTFE has good low-temperature resistance, the entire lip ring has good low-temperature sealing performance. The entire lip ring has good low-temperature sealing performance. When the valve body is conveying ultra-low temperature liquid (the lowest temperature can be as low as minus 196 degrees Celsius), the lip ring seal can still ensure good sealing performance and will not freeze.

[0007] At the same time, in this structure, the valve body, valve stem and valve cover are all made of austenitic stainless steel. Under low temperature conditions, austenitic stainless steel has better low temperature resistance, pressure resistance, wear resistance, corrosion resistance, weldability, strength, impact toughness, relative elongation and organizational stability than other materials. Therefore, valves using this structure can ensure that the performance remains stable under low temperature conditions.

[0008] In summary, in this sealing structure, by providing a lip ring and a graphite packing group, double sealing of the valve stem is achieved, the low-temperature sealing performance between the valve stem and the extended valve cover is enhanced, and the probability of sealing leakage at low temperatures is reduced.

[0009] Also, because the graphite packing group in the present structure has good fire resistance, leakage of the medium in the valve body caused by seal damage of the graphite packing group during a fire can be avoided.

[0010] Optionally, a cover bearing is further included, wherein the cover bearing is located between the valve stem and the valve cover, and the cover bearing is located between the lip ring and the graphite packing group.

[0011] The cap bearing can separate the graphite packing group and the lip ring, and can also make the valve stem rotate more smoothly.

[0012] Optionally, a thrust washer is further included, wherein the thrust washer is arranged between the graphite packing group and the cap bearing.

[0013] Optionally, a packing ring is further included, wherein the packing ring is arranged between the valve cover and the valve stem, and the packing ring is used to compress the graphite packing group.

[0014] Optionally, a screw is provided on the valve cover, a nut is provided on the screw, a butterfly gasket and a flat gasket are provided between the nut and the packing ring, and the flat gasket and the butterfly gasket are sleeved on the screw.

[0015] The screw and nut are used to install flat washers and butterfly washers. The flat washers and butterfly washers are used to compress the packing rings so that the packing rings compress the graphite packing group.

[0016] Optionally, the flat gasket is located between the butterfly gasket and the packing ring.

[0017] Optionally, a spacer sleeve is further included, and the spacer sleeve is arranged between the valve stem and the valve body.

[0018] Optionally, a body bearing is also included, and the body bearing is arranged between the valve stem and the valve body.

[0019] Optionally, it further includes a first opening gasket and a second opening gasket, wherein the first opening gasket is arranged between the valve stem and the body bearing, and the second opening gasket is arranged between the body bearing and the valve body.

[0020] A valve comprises the valve stem sealing structure under ultra-low temperature conditions as described above.

[0021] The beneficial effects of the utility model are as follows: in this sealing structure, by providing a lip ring and a graphite packing group, double sealing of the valve stem is achieved, the low-temperature sealing performance between the valve stem and the extended valve cover is enhanced, and the probability of sealing leakage at low temperatures is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the valve stem seal under ultra-low temperature conditions;

[0023] Figure 2 yes Figure 1 An enlarged schematic diagram of point A in the middle.

[0024] The reference numerals in the figure are: 1. valve body; 2. valve cover; 201. through hole; 202. raised portion; 3. valve stem; 4. spacer; 5. body bearing; 6. first opening gasket; 7. second opening gasket; 8. lip ring; 9. cover bearing; 10. thrust gasket; 11. graphite packing group; 12. packing ring; 13. packing gland flange; 14. screw; 15. flat gasket; 16. butterfly gasket; 17. nut. DETAILED DESCRIPTION

[0025] The utility model is described in detail below in conjunction with the accompanying drawings.

[0026] As attached Figure 1 And attached Figure 2As shown, a valve stem 3 sealing structure under ultra-low temperature conditions includes a valve cover 2 and a valve stem 3, a through hole 201 is opened on the valve cover 2, the valve stem 3 and the through hole 201 of the valve cover 2 are rotatably matched together, a graphite packing group 11 is arranged between the valve cover 2 and the valve stem 3, and also includes a lip ring 8, the lip ring 8 includes a cobalt-based alloy and PTFE, PTFE covers the cobalt-based alloy, the lip ring 8 is arranged between the valve cover 2 and the valve stem 3, the valve cover 2 is arranged on the valve body 1, one end of the valve stem 3 is located in the valve body 1, the lip ring 8 is located between the valve body 1 and the graphite packing group 11, the valve cover 2 is a valve cover 2 made of austenitic stainless steel, the valve stem 3 is a valve stem 3 made of austenitic stainless steel, and the valve body 1 is a valve body 1 made of austenitic stainless steel.

[0027] In this sealing structure, the flow path of the liquid is located in the valve body 1. The liquid in the valve body 1 needs to pass through the lip ring 8 and the graphite packing group 11 in sequence to overflow from between the valve stem 3 and the valve cover 2. In this structure, the lip ring 8 is composited with a cobalt-based alloy and PTFE (i.e., polytetrafluoroethylene). The cobalt-based alloy is completely coated with PTFE, and the cobalt-based alloy serves as the skeleton of the entire lip ring 8. This butterfly valve adopts a double sealing structure between the valve stem 3 and the extended valve cover 2, namely, the lip ring 8 seals and the graphite packing group 11 seals. If the liquid flowing through the valve body 1 wants to overflow, it must first pass through the seal of the lip ring 8, and then pass through the seal of the graphite packing group 11 to overflow. In this butterfly valve, since the lip ring 8 is a composite of cobalt-based alloy and PTFE, and since PTFE has good low-temperature resistance, the entire lip ring 8 has good low-temperature sealing performance. When the valve body 1 is conveying ultra-low-temperature liquid (the temperature can be as low as minus 196 degrees Celsius), the lip ring 8 seal can still ensure good sealing performance and will not freeze.

[0028] At the same time, in this structure, the valve body 1, the valve stem 3 and the valve cover 2 are all made of austenitic stainless steel. Under low temperature conditions, austenitic stainless steel has better low temperature resistance, pressure resistance, wear resistance, corrosion resistance, weldability, strength, impact toughness, relative elongation and organizational stability than other materials. Therefore, the valve using this structure can ensure that the performance can still be stable under low temperature conditions.

[0029] In summary, in this sealing structure, by providing the lip ring 8 and the graphite packing group 11, double sealing of the valve stem 3 is achieved, the low-temperature sealing performance between the valve stem 3 and the extended valve cover 2 is enhanced, and the probability of sealing leakage at low temperatures is reduced.

[0030] Also, because the graphite packing group 11 in the present structure has good fire resistance, leakage of the medium in the valve body 1 due to seal damage of the graphite packing group 11 during a fire can be avoided.

[0031] As attached Figure 1 And attached Figure 2 As shown, a cover bearing 9 is also included. The cover bearing 9 is located between the valve stem 3 and the valve cover 2 , and the cover bearing 9 is located between the lip ring 8 and the graphite packing group 11 .

[0032] The cover bearing 9 can separate the graphite packing group 11 and the lip ring 8, and can also make the valve stem 3 rotate more smoothly.

[0033] As attached Figure 1 And attached Figure 2 As shown, a thrust washer 10 is also included, and the thrust washer 10 is arranged between the graphite packing group 11 and the cap bearing 9.

[0034] As attached Figure 1 And attached Figure 2 As shown, it also includes a packing ring 12 , which is arranged between the valve cover 2 and the valve stem 3 , and is used to compress the graphite packing group 11 .

[0035] As attached Figure 1 And attached Figure 2 As shown, a screw 14 is provided on the valve cover 2 , a nut 17 is provided on the screw 14 , a butterfly gasket 16 and a packing gland flange 13 are provided between the nut 17 and the packing ring 12 , and a flat gasket 15 and a butterfly gasket 16 are sleeved on the screw 14 .

[0036] The screw 14 and the nut 17 are used to install the flat gasket 15 and the butterfly gasket 16 . The flat gasket 15 and the butterfly gasket 16 are used to press the packing ring 12 so that the packing ring 12 presses the graphite packing set 11 .

[0037] As attached Figure 1 And attached Figure 2 As shown, the packing flange gland 13 is located between the flat gasket 15 and the packing ring 12.

[0038] As attached Figure 1 And attached Figure 2 As shown, it also includes a spacer sleeve 4, which is arranged between the valve stem 3 and the valve body 1.

[0039] As attached Figure 1 And attached Figure 2 As shown, it also includes a body bearing 5, which is arranged between the valve stem 3 and the valve body 1.

[0040] As attached Figure 1 And attached Figure 2 As shown, it also includes a first opening gasket 6 and a second opening gasket 7. The first opening gasket 6 is arranged between the valve stem 3 and the body bearing 5, and the second opening gasket 7 is arranged between the body bearing 5 and the valve body 1.

[0041] Combined with Figure 1 And attached Figure 2As shown in , one end of the valve cover 2 has a protrusion 202, which extends into the hole in the valve body 1 and contacts the top of the spacer sleeve 4, and the bottom of the spacer sleeve 4 contacts the top of the body bearing 5. The valve cover 2 is fixed to the valve body 1 by bolts. The valve cover 2 can prevent the shaft sleeve from moving upward through the spacer sleeve 4 and the body bearing 5. At the same time, the step at the bottom of the body bearing 5 contacts the step on the inner hole of the valve body 1 to prevent the body bearing 5 from moving downward, thereby ensuring that the first opening gasket 6 and the second opening gasket 7 move up and down, reducing the wear of the first opening gasket 6 and the second opening gasket 7. Similarly, the first opening gasket 6 and the second opening gasket 7 can ensure that the body bearing 5, the valve stem 3 and the valve body 1 are in a tensioned state, thereby forming another seal between the valve stem 3 and the valve body 1.

[0042] The above description is only a preferred embodiment of the present invention, and does not limit the patent protection scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, directly or indirectly used in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A valve stem sealing structure under ultra-low temperature conditions, comprising a valve cover and a valve stem, wherein the valve cover is provided with a through hole, the valve stem and the through hole of the valve cover are rotatably matched together, and a graphite packing group is arranged between the valve cover and the valve stem, characterized in that: It also includes a lip ring, which includes a cobalt-based alloy and PTFE, and the PTFE covers the cobalt-based alloy. The lip ring is arranged between the valve cover and the valve stem. The valve cover is arranged on the valve body, and one end of the valve stem is located in the valve body. The lip ring is located between the valve body and the graphite packing group. The valve cover is a valve cover made of austenitic stainless steel, the valve stem is a valve stem made of austenitic stainless steel, and the valve body is a valve body made of austenitic stainless steel.

2. The valve stem sealing structure under ultra-low temperature conditions according to claim 1, characterized in that: It also includes a cap bearing, which is located between the valve stem and the valve cover, and the cap bearing is located between the lip ring and the graphite packing group.

3. The valve stem sealing structure under ultra-low temperature conditions according to claim 2, characterized in that: Also included is a thrust washer, which is disposed between the graphite packing set and the cap bearing.

4. The valve stem sealing structure under ultra-low temperature conditions according to claim 1, characterized in that: It also includes a packing ring, which is arranged between the valve cover and the valve stem and is used to compress the graphite packing group.

5. The valve stem sealing structure under ultra-low temperature conditions according to claim 4, characterized in that: The valve cover is provided with a screw rod, a nut is provided on the screw rod, a butterfly gasket and a flat gasket are provided between the nut and the packing ring, and the flat gasket and the butterfly gasket are sleeved on the screw rod.

6. The valve stem sealing structure under ultra-low temperature conditions according to claim 5, characterized in that: The flat gasket is located between the butterfly gasket and the packing ring.

7. The valve stem sealing structure under ultra-low temperature conditions according to claim 1, characterized in that: It also includes a spacer sleeve, which is arranged between the valve stem and the valve body.

8. The valve stem sealing structure under ultra-low temperature conditions according to claim 7, characterized in that: Also included is a body bearing, which is disposed between the valve stem and the valve body.

9. The valve stem sealing structure under ultra-low temperature conditions according to claim 8, characterized in that: It also includes a first opening gasket and a second opening gasket, wherein the first opening gasket is arranged between the valve stem and the body bearing, and the second opening gasket is arranged between the body bearing and the valve body.

10. A valve, characterized in that: It comprises a valve stem sealing structure under ultra-low temperature conditions as described in any one of claims 1 to 9.

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