阅读说明：本技术 一种用于低温球阀的密封装置 (Sealing device for low-temperature ball valve ) 是由 邬佑清 邬挺之 黄永萍 于 2020-04-15 设计创作，主要内容包括：本发明提供一种用于低温球阀的密封装置,包括阀体、金属阀座和球体,所述阀体和所述金属阀座之间的空间内装有环形的金属支撑环和环形的第一唇式密封圈,所述第一唇式密封圈包括二个第一唇边,所述第一唇边之间为环形凹槽,所述第一唇式密封圈的外侧与所述阀体相抵压,所述第一唇式密封圈的内侧与所述金属阀座相抵压；所述金属支撑环的一端为突出头部,所述金属支撑环的另一端为一组圆孔,所述突出头部抵压在所述第一唇式密封圈的环形凹槽内；所述金属支撑环的圆孔内设有推力弹簧,所述推力弹簧的另一端抵靠在所述阀体上。本发明用于低温球阀的密封装置,具有很好的低温密封性能。(The invention provides a sealing device for a low-temperature ball valve, which comprises a valve body, a metal valve seat and a ball body, wherein an annular metal support ring and an annular first lip type sealing ring are arranged in a space between the valve body and the metal valve seat, the first lip type sealing ring comprises two first lip edges, an annular groove is formed between the first lip edges, the outer side of the first lip type sealing ring is pressed against the valve body, and the inner side of the first lip type sealing ring is pressed against the metal valve seat; one end of the metal support ring is a protruding head, the other end of the metal support ring is a group of round holes, and the protruding head is pressed in the annular groove of the first lip type sealing ring; and a thrust spring is arranged in the round hole of the metal support ring, and the other end of the thrust spring is abutted against the valve body. The sealing device for the low-temperature ball valve has good low-temperature sealing performance.)

1. A sealing device for a low-temperature ball valve comprises a valve body, a metal valve seat and a ball body, and is characterized in that an annular metal support ring and an annular first lip type sealing ring are arranged in a space between the valve body and the metal valve seat, the first lip type sealing ring comprises two first lip edges, an annular groove is formed between the first lip edges, the outer side of the first lip type sealing ring is pressed against the valve body, and the inner side of the first lip type sealing ring is pressed against the metal valve seat; one end of the metal support ring is a protruding head, the other end of the metal support ring is a group of round holes, and the protruding head is pressed in the annular groove of the first lip type sealing ring; and a thrust spring is arranged in the round hole of the metal support ring, and the other end of the thrust spring is abutted against the valve body.

2. The sealing device for the cryogenic ball valve as defined in claim 1, further comprising another first lip seal and a metal support ring, wherein a partition is disposed between the two first lip seals, the partition is taken as a symmetry line, and the two first lip seals and the two metal support rings are symmetrically arranged back to back.

3. The sealing device for the cryogenic ball valve according to claim 1, wherein a pressing plate is further installed in a space between the valve body and the metal valve seat, an annular first toe heel is connected to the outer side of the first lip-type sealing ring, a notch is formed in the valve body, the first toe heel is pressed on the notch, the pressing plate is fixed on the valve body through a screw, the first lip-type sealing ring is pressed against the pressing plate and the valve body, a second thrust spring is installed between the pressing plate and the metal valve seat, one end of the second thrust spring is embedded into the metal valve seat, and the other end of the second thrust spring is pressed against the pressing plate.

4. A sealing device for a cryogenic ball valve according to any one of claims 1 to 3, wherein the metal valve seat is embedded with an annular sealing ring on the face contacting the ball.

5. The sealing device for the cryogenic ball valve according to claim 1, wherein a pressing plate is further installed in a space between the valve body and the metal valve seat, a first toe heel is connected to the outer side of the first lip-type sealing ring, a notch is formed in the valve body, the first toe heel is pressed on the notch, the first lip-type sealing ring is pressed against the pressing plate and the valve body, a metal ring is arranged on the other side of the pressing plate, the number of the metal rings is four, the four metal rings form a discontinuous circle, an annular groove is formed in the inner wall of the valve body, the metal ring is embedded into the annular groove of the valve body, a screw hole is formed in the metal ring, the pressing plate is pressed on the valve body through the screw hole formed in the metal ring by a screw, and a second thrust spring is installed between the pressing plate and the metal valve seat.

6. The sealing device for a cryogenic ball valve according to claim 5, wherein a second lip seal and a compression ring are arranged in the space between the metal valve seat and the ball body, the second lip seal comprises two second lip edges, an annular groove is arranged between the second lip edges, one of the second lip edges abuts against the metal valve seat, the other second lip edge abuts against the ball body, an annular second toe-heel is connected to the second lip seal, and the compression ring presses against the second toe-heel of the second lip seal and is fixed to the metal valve seat through a compression screw.

7. The seal for a cryogenic ball valve of claim 6, wherein the annular groove of the second lip seal houses an open U-shaped metal spring.

8. The sealing device for a cryogenic ball valve according to any one of claims 5 to 7, wherein an annular gap is formed in the valve body between the first toe and the first lip, a third lip seal is embedded in the annular gap, the third lip seal comprises two third lips, an annular groove is formed between the third lips, and a U-shaped metal spring is installed in the annular groove of the third lip seal; one of the third lip edges abuts against the valve body and the other third lip edge abuts against the first toe heel.

9. The sealing device for a cryogenic ball valve of claim 1, wherein the protruding head is truncated cone shaped, a top edge of the protruding head is rounded, and the protruding head and the annular groove of the first lip seal are contacted by a slope.

10. The sealing device for a cryogenic ball valve according to claim 1, wherein the annular groove of the first lip seal is a tapered cylindrical surface; the first lip type sealing seat is made of PTFE plastic, PCTFE plastic or polyimide.

Technical Field

The invention belongs to the technical field of sealing valve seats of low-temperature ball valves, and particularly relates to a sealing device for a low-temperature ball valve.

Background

A fixed ball valve used in cryogenic liquid such as liquid oxygen, liquid nitrogen, liquefied natural gas (L NG) or other cryogenic media, a traditional seal seat, adopts a standard first lip type seal ring of a tetrafluoroethylene plastic built-in metal spring, which is called L ip seal, to prevent leakage between a metal valve seat and a valve body, when the temperature is reduced to minus 75 ℃ or lower, the leakage occurs, the requirement of sealing becomes more and more difficult, so that the technical standard established in China and abroad also allows leakage at the temperature of minus 196 ℃, and the requirement of bubble-level zero leakage cannot be met.

Fig. 1 is a conventional sealing structure of a cryogenic ball valve. The valve comprises a valve body 11, a first lip type sealing ring 12, a spring 13 in the first lip type sealing ring, a metal valve seat 14, a PTFE spherical sealing ring 15, a back thrust spring 16 and a ball 17.

The leakage is caused by the shrinkage and hardening of the tetrafluoro plastic caused by the difference of thermal expansion coefficients of the tetrafluoro plastic sealing material and the metal valve seat at low temperature. The spring 13 in the first lip seal, which is not sufficiently resilient to overcome its deformation, is the root cause of the leakage, which is the contact force necessary to maintain contact with the valve body 11.

Disclosure of Invention

Aiming at the problem that the existing low-temperature ball valve is likely to leak under the low-temperature condition, the invention provides the sealing device for the low-temperature ball valve, which has good low-temperature sealing performance.

The technical scheme for solving the technical problems is as follows: a sealing device for a low-temperature ball valve comprises a valve body, a metal valve seat and a ball body, wherein an annular metal support ring and an annular first lip type sealing ring are arranged in a space between the valve body and the metal valve seat, the first lip type sealing ring comprises two first lip edges, an annular groove is formed between the first lip edges, the outer side of the first lip type sealing ring is pressed against the valve body, and the inner side of the first lip type sealing ring is pressed against the metal valve seat; one end of the metal support ring is a protruding head, the other end of the metal support ring is a group of round holes, and the protruding head is pressed in the annular groove of the first lip type sealing ring; and a thrust spring is arranged in the round hole of the metal support ring, and the other end of the thrust spring is abutted against the valve body.

The invention provides a sealing device for a low-temperature ball valve, which has good low-temperature sealing property. The first lip edges on the two sides of the first lip type sealing ring are pushed by an annular metal supporting ring, under the pushing of medium pressure and a group of thrust springs, the contact force between the first lip edges and the valve body and the metal valve seat is greatly increased through the wedge effect generated by the abutting pressure of the metal supporting ring and the first lip edges of the first lip type sealing ring, and the contraction of the first lip edges on the outer sides of the annular first lip type sealing ring is limited at low temperature, so that the deformation of the first lip edges is overcome at low temperature, enough contact force is still kept, and the leakage of low-temperature medium is prevented.

The invention is further provided with another first lip type sealing ring and a metal supporting ring, a partition plate is arranged between the two first lip type sealing rings, the partition plate is taken as a symmetrical line, and the two first lip type sealing rings and the two metal supporting rings are symmetrically arranged in a back-to-back mode.

The invention is further arranged in that a pressing plate is further arranged in a space between the valve body and the metal valve seat, the outer side of the first lip type sealing ring is connected with an annular first toe heel, a notch is arranged on the valve body, the first toe heel is pressed on the notch, the pressing plate is fixed on the valve body through a screw, the first lip type sealing ring is pressed against the pressing plate and the valve body, a second thrust spring is arranged between the pressing plate and the metal valve seat, one end of the second thrust spring is embedded into the metal valve seat, and the other end of the second thrust spring is pressed against the pressing plate. The first toe heel is pressed by the pressure plate to provide a secondary plane seal, thereby further preventing the leakage of the low-temperature medium.

The invention is further provided that the metal valve seat is embedded with an annular sealing ring on the surface contacting with the ball body.

The invention is further provided that a pressure plate is arranged in the space between the valve body and the metal valve seat, the outer side of the first lip type sealing ring is connected with a first toe heel, the valve body is provided with a gap, the first toe is pressed on the notch, the first lip type sealing ring is pressed on the pressure plate and the valve body, the other side of the pressure plate is provided with four metal rings, the four metal rings form a discontinuous circle, the inner wall of the valve body is provided with an annular groove, the metal ring is embedded into the annular groove of the valve body, the metal ring is provided with a screw hole, the pressure plate is pressed on the valve body by a screw which passes through the screw hole of the metal ring, and a second thrust spring is arranged between the pressing plate and the metal valve seat, one end of the second thrust spring is embedded into the metal valve seat, and the other end of the second thrust spring is pressed on the pressing plate in a propping manner.

The invention is further arranged in that a second lip type sealing ring and a pressing ring are arranged in a space between the metal valve seat and the ball body, the second lip type sealing ring comprises two second lip edges, an annular groove is arranged between the second lip edges, one second lip edge is abutted against the metal valve seat, the other second lip edge is abutted against the ball body, an annular second toe heel is connected onto the second lip type sealing ring, and the pressing ring is pressed on the second toe heel of the second lip type sealing ring and is fixed onto the metal valve seat through a pressing screw. The second lip type sealing ring is pushed by medium force and U-shaped metal spring force to provide a dynamic sealing structure, meanwhile, the second toe heel is pressed on the metal valve seat to provide a secondary plane sealing structure for the ball sealing end of the metal valve seat, and leakage of the medium is thoroughly blocked.

The invention is further provided that an open U-shaped metal spring is arranged in the annular groove of the second lip type sealing ring.

The invention is further arranged that an annular gap is arranged on the valve body between the first toe-heel and the first lip edge, a third lip type sealing ring is embedded in the annular gap and comprises two third lip edges, an annular groove is arranged between the third lip edges, and a U-shaped metal spring is arranged in the annular groove of the third lip type sealing ring; one of the third lip edges abuts against the valve body and the other third lip edge abuts against the first toe heel. The invention further provides a third lip type sealing ring for occasions with special sealing requirements, such as the sealing requirements of zero leakage of shell standard in high-pressure, high-temperature and low-temperature cycle tests, the third lip type sealing ring is arranged at the front end of the first toe heel, secondary sealing is adopted on a plane sealing surface, the third lip type plane sealing is lip type medium dynamic sealing, the first toe heel is compressed into plane static sealing, and low-temperature medium leakage is blocked.

The invention is further arranged in that the outer side of the metal support ring connected with the protruding head part is an outer circle, the protruding head part and the outer circle are rounded off, the protruding head part is contacted with the annular groove of the first lip type seal ring, and the outer circle is contacted with the end part of the first lip type seal ring.

The invention is further provided that the annular groove of the first lip type sealing ring is a tapered inclined cylindrical surface.

The first lip seal holder is further provided with a material such as PTFE plastic, PCTFE plastic, or polyimide.

In conclusion, the sealing device for the low-temperature ball valve has good low-temperature sealing performance.

Drawings

FIG. 1 is a schematic view of a conventional sealing structure of a low temperature ball valve in the background art of the present invention;

FIG. 2 is a schematic sectional view of a portion of a sealing device of the low temperature ball valve in the embodiment 1 of the present invention;

FIG. 3 is a schematic sectional view of a portion of a sealing device of the low temperature ball valve in the embodiment 2 of the present invention;

FIG. 4 is a schematic sectional view of a portion of a sealing device of the low temperature ball valve in the embodiment 3 of the present invention;

FIG. 5 is a schematic sectional view of a portion of a sealing device of the low temperature ball valve according to the embodiment 4 of the present invention;

fig. 6 is a schematic sectional view of a part of a sealing device of the low temperature ball valve according to the embodiment 5 of the present invention.

In fig. 2, 21, a valve body; 22. a metal support ring; 23. a first lip seal; 24. a metal valve seat; 25. an annular seal ring; 26. a thrust spring; 27. a sphere.

In fig. 3, 31, valve body; 32. a metal support ring; 33. a first lip seal; 34. a metal valve seat; 35. an annular seal ring; 36. a thrust spring; 37. a sphere; 38. a separator.

In fig. 4, 41, valve body; 42. a metal support ring; 43. a first lip seal; 44. a metal valve seat; 45. an annular seal ring; 46. a thrust spring; 47. a sphere. 48. A screw; 49. pressing a plate; 410. a second thrust spring; 411. the first toe and the heel.

In fig. 5, 51, valve body; 52. a metal support ring; 53. a first lip seal; 54. a metal valve seat; 55. a second lip seal ring; 56. a thrust spring; 57. a sphere; 58. a screw; 59. pressing a plate; 510. a second thrust spring; 511. a metal ring; 512. a compression ring; 513. a compression screw; 514. a U-shaped metal spring; 515. a first toe; 516. the second toe.

In fig. 6, 61, valve body; 62. a metal support ring; 63. a first lip seal; 64. a metal valve seat; 65. a second lip seal ring; 66. a thrust spring; 67. a sphere; 68. a screw; 69. pressing a plate; 610. a second thrust spring; 611. a metal ring; 612. a compression ring; 613. a compression screw; 614. a U-shaped metal spring; 615. a first toe; 616. a second toe; 617. a third lip seal ring; 618. a U-shaped metal spring.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.