阅读说明：本技术 超低温波纹管闸阀 (Ultra-low temperature bellows gate valve ) 是由 曹高志 尤晓女 鲁秋翔 张朝华 于 2021-08-04 设计创作，主要内容包括：本发明涉及闸阀技术领域,具体涉及超低温波纹管闸阀,包括阀体,所述阀体一侧设置有进液口,所述阀体另一侧设置有出液口；所述阀体内设置有上下间隔布置的进液腔及出液腔,所述进液腔与进液口连通,所述出液腔与出液口连通；所述进液腔及出液腔之间设置有阀座,所述阀座内设置有上下贯通的连通通道,所述阀座上端设置有能够堵住连通通道的阀板；本发明通过挡液环组件及耐低温密封圈设置,能够实现阀杆与阀盖之间的二次密封,提高密封效果,避免低温高压的液体天然气有少量泄露的情况,进而避免导致外部含水分的空气与其在阀杆与阀盖上端碰撞凝结成冰的情况,使得闸阀能够正常使用。(The invention relates to the technical field of gate valves, in particular to an ultralow-temperature corrugated pipe gate valve which comprises a valve body, wherein a liquid inlet is formed in one side of the valve body, and a liquid outlet is formed in the other side of the valve body; a liquid inlet cavity and a liquid outlet cavity which are arranged at an upper interval and a lower interval are arranged in the valve body, the liquid inlet cavity is communicated with the liquid inlet, and the liquid outlet cavity is communicated with the liquid outlet; a valve seat is arranged between the liquid inlet cavity and the liquid outlet cavity, a communicating channel which is communicated up and down is arranged in the valve seat, and a valve plate which can block the communicating channel is arranged at the upper end of the valve seat; according to the invention, through the arrangement of the liquid blocking ring assembly and the low-temperature resistant sealing ring, secondary sealing between the valve rod and the valve cover can be realized, the sealing effect is improved, the condition that a small amount of low-temperature high-pressure liquid natural gas leaks is avoided, and the condition that moisture-containing air outside collides with the upper end of the valve rod and the upper end of the valve cover to condense into ice is further avoided, so that the gate valve can be normally used.)

1. The ultralow-temperature corrugated pipe gate valve is characterized by comprising a valve body (1), wherein a liquid inlet (2) is formed in one side of the valve body (1), and a liquid outlet (3) is formed in the other side of the valve body (1); a liquid inlet cavity (7) and a liquid outlet cavity (8) which are arranged at an upper and lower interval are arranged in the valve body (1), the liquid inlet cavity (7) is communicated with the liquid inlet (2), and the liquid outlet cavity (8) is communicated with the liquid outlet (3); a valve seat (9) is arranged between the liquid inlet cavity (7) and the liquid outlet cavity (8), a communicating channel which is communicated up and down is arranged in the valve seat (9), and a valve plate (10) which can block the communicating channel is arranged at the upper end of the valve seat (9); the upper end of the valve body (1) is provided with a valve cover (5), and the valve cover (5) is fixedly connected with the valve body (1) through a pressure plate (4) and bolts which are arranged on the periphery of the valve cover; the upper end of the valve plate (10) is connected with a valve rod (6), the valve rod (6) penetrates through the valve cover (5) and extends to the outside of the valve body (1) to be connected with an external handle, and a through hole matched with the valve rod (6) is formed in the valve cover (5); a leakage-proof isolation net (12), a low-temperature-resistant sealing ring (13) and a liquid-blocking ring assembly (14) are sequentially arranged between the valve rod (6) and the through hole from top to bottom, and the low-temperature-resistant sealing ring (13) and the liquid-blocking ring assembly (14) are in sealing fit with the valve rod (6); the leakage-proof isolation net (12) is an annular hollow metal net sleeved outside the valve rod (6), the leakage-proof isolation net (12) and the valve rod (6) are in clearance fit, and a moisture-proof filler (11) is filled in the leakage-proof isolation net.

2. The ultra-low temperature bellows gate valve of claim 1, wherein the liquid barrier ring assembly (14) is a metal gasket molded of a flexible metal material.

3. An ultra-low temperature bellows gate valve according to claim 2, characterized in that a sealing groove for accommodating the low temperature resistant sealing ring (13) is arranged in the valve cover (5), the low temperature resistant sealing ring (13) comprises an inner sealing ring (131) made of metal material and an outer sealing ring (132) made of rubber material, the cross section of the outer sealing ring (132) is in a shape like a Chinese character '7', the inner sealing ring (131) is wrapped on the inner side surface of the outer sealing ring (132) and the inner side surface of the inner sealing ring is in sealing fit with the valve rod (6); the upper end of the inner sealing ring (131) is horizontal and can wrap the upper end of the outer sealing ring (132) in the inner sealing ring, and the lower end of the inner sealing ring (131) is bent outwards and extends into the lower end of the outer sealing ring (132) to be connected with the outer sealing ring (132) into a whole; the outer sealing ring (132) middle part outside and the lower part outside all set up the first seal lip (133) of upwards extending in the slant, end face seal between the side of first seal lip (133) and seal groove.

4. The ultra-low temperature bellows gate valve of claim 3, wherein a space between the first sealing lip (133) of the middle portion and the upper end of the outer sealing ring (132) constitutes a mounting groove (135), an annular coil spring (134) is disposed in the mounting groove (135), and a minimum distance at an opening of the mounting groove (135) is smaller than a diameter of the coil spring (134).

5. An ultra-low temperature bellows gate valve according to claim 4, characterized in that the lower end of the outer sealing ring (132) is provided with an inclined plane (139) with a high outer part and a low inner part towards one side of the valve rod (6), the upper end of the inclined plane (139) extends to the bending part of the inner sealing ring (131), a gap exists between the lower end of the inclined plane (139) and the valve rod (6), and a liquid filling cavity is formed between the inner side surfaces of the bending parts of the inclined plane (139) and the inner sealing ring (131) and the outer wall of the valve rod (6).

6. The ultra-low temperature bellows gate valve of claim 5, wherein an annular metal elastic sheet (136) with a U-shaped section is arranged between the first sealing lips (133), and the opening of the annular metal elastic sheet (136) faces outwards.

7. The ultra-low temperature bellows gate valve of claim 6, wherein the free ends of the first sealing lips (133) are each provided with a flange (138) extending toward and wrapping an end of an annular metal leaf (136).

8. The ultra-low temperature bellows gate valve according to claim 7, wherein a second seal lip (137) extending obliquely downward is provided on the outer seal ring (132) below the inclined surface (139), and the second seal lip (137) can be attached to a bottom surface of the seal groove.

Technical Field

The invention relates to the technical field of gate valves, in particular to an ultralow-temperature corrugated pipe gate valve.

Background

With the rapid development of Liquefied Natural Gas (LNG), fluid control devices on LNG receiving stations and transportation equipment are increasing, such as ultra-low temperature gate valves, which are indispensable devices for fluid pipelines of LNG receiving stations and transportation equipment and often work in an ultra-low temperature state.

In the prior art, the sealing ring is generally sealed by using an elastomer body such as rubber, namely, the sealing force is provided by the elasticity of the sealing ring which is made of rubber. However, the elasticity of the sealing ring made of the rubber material is reduced or lost due to external environments such as pressure and temperature change or long-term abrasion and material aging, so that the sealing performance is poor, and in an ultralow-temperature environment, the rubber material shrinks and loses the rigidity of elasticity, so that the overall sealing effect is affected; simultaneously, present ultra-low temperature gate valve is in the use, because the valve rod temperature is less than all ring edge border temperature, moisture in the environment meets low temperature valve rod and valve gap department condensation and becomes ice, leads to the valve rod switching to be obstructed easily, influences valve normal use.

Disclosure of Invention

Solves the technical problem

Aiming at the defects in the prior art, the invention provides the ultralow-temperature corrugated pipe gate valve which can effectively solve the problem that in the prior art, the opening and closing of a valve rod are easily blocked because water in the environment is condensed into ice at the valve rod and a valve cover when meeting low temperature.

Technical scheme

In order to achieve the purpose, the invention is realized by the following technical scheme:

the invention provides an ultralow temperature corrugated pipe gate valve which comprises a valve body, wherein a liquid inlet is formed in one side of the valve body, and a liquid outlet is formed in the other side of the valve body; a liquid inlet cavity and a liquid outlet cavity which are arranged at an upper interval and a lower interval are arranged in the valve body, the liquid inlet cavity is communicated with the liquid inlet, and the liquid outlet cavity is communicated with the liquid outlet; a valve seat is arranged between the liquid inlet cavity and the liquid outlet cavity, a communicating channel which is communicated up and down is arranged in the valve seat, and a valve plate which can block the communicating channel is arranged at the upper end of the valve seat; the upper end of the valve body is provided with a valve cover which is fixedly connected with the valve body through a pressing plate and bolts which are arranged on the periphery of the valve cover; the upper end of the valve plate is connected with a valve rod, the valve rod penetrates through the valve cover to extend out of the valve body to be connected with an external handle, and a through hole matched with the valve rod is formed in the valve cover; a leakage-proof isolation net, a low-temperature-resistant sealing ring and a liquid-blocking ring assembly are sequentially arranged between the valve rod and the through hole from top to bottom, and the low-temperature-resistant sealing ring and the liquid-blocking ring assembly are in sealing fit with the valve rod; the leakage-proof isolation net is an annular hollow metal net sleeved outside the valve rod, the leakage-proof isolation net and the valve rod are in clearance fit, and a moisture-proof filler is filled in the leakage-proof isolation net.

When the valve is used, ultralow-temperature liquid enters the liquid inlet cavity from the liquid inlet and moves to the valve seat, the valve rod is driven to rotate and move upwards by rotating the handle, the valve plate moves upwards, the communication channel of the valve seat is opened, and the ultralow-temperature liquid can enter the liquid outlet cavity through the communication channel and then is discharged from the liquid outlet; through the arrangement of the liquid blocking ring assembly and the low-temperature resistant sealing ring, secondary sealing between the valve rod and the valve cover can be realized, the sealing effect is improved, the condition that a small amount of low-temperature high-pressure liquid natural gas leaks is avoided, and the condition that air containing moisture outside collides with the upper end of the valve rod and the upper end of the valve cover to condense into ice is further avoided, so that the gate valve can be normally used; set up with valve rod clearance fit's leak protection separation net, on the one hand, avoid it to lead to the valve rod to scrape the flower with the valve rod collision, on the other hand also can effectively draw in and place dampproofing filler in, makes it can absorb steam around the valve gap upper end, avoids freezing between valve rod and valve gap to influence normal use.

Further, the liquid blocking ring component is a metal sealing gasket formed by die pressing of a flexible metal material. Because the liquid blocking ring subassembly is made for flexible metal material, the shrinkage of metal material under the ultra-low temperature is less, not only can avoid under the ultra-low temperature condition the too big sealing performance that influences of shrinkage, it still has higher shock resistance moreover, consequently satisfies the user demand among the high pressure environment.

Furthermore, a sealing groove for accommodating a low-temperature-resistant sealing ring is arranged in the valve cover, the low-temperature-resistant sealing ring comprises an inner sealing ring made of a metal material and an outer sealing ring made of a rubber material, the cross section of the outer sealing ring is in a 7 shape, the inner sealing ring is wrapped on the inner side surface of the outer sealing ring, and the inner side surface of the inner sealing ring is in sealing fit with the valve rod; the upper end of the inner sealing ring is horizontal and can wrap the upper end of the outer sealing ring in the inner sealing ring, and the lower end of the inner sealing ring is bent outwards and extends into the lower end of the outer sealing ring to be connected with the outer sealing ring into a whole; the outer seal ring is characterized in that the outer side of the middle part and the outer side of the lower part of the outer seal ring are respectively provided with a first seal lip extending upwards in an inclined mode, and the end faces of the first seal lips and the side faces of the seal grooves are sealed. Through the arrangement of the inner sealing ring and the outer sealing ring, the inner sealing ring is made of metal materials, so that the inner sealing ring can improve the supporting force and reverse elasticity in an ultralow-temperature environment, the integral inward shrinkage and generated centripetal extrusion force of the outer sealing ring are avoided, the situation that the sealing effect is reduced and even the outer sealing ring is damaged due to the overlarge shrinkage of the outer sealing ring is further avoided, the sealing performance is ensured, and the service life is prolonged; through the setting of two sets of first seal lips, when the valve rod extrudeed the inner seal ring, the inner seal ring drove the outer seal ring and removes to the seal groove, and then makes the side of first seal lip and seal groove closely laminate, has improved sealed effect.

Furthermore, a mounting groove is formed in a space between the first sealing lip in the middle and the upper end of the outer sealing ring, an annular spiral spring is arranged in the mounting groove, and the minimum distance of the opening of the mounting groove is smaller than the diameter of the spiral spring. Through the arrangement of the spiral spring, on one hand, the spiral spring generates inward contraction force, the inner side surface of the inner sealing ring can be tightly attached to the surface of the valve rod, and the sealing effect of the inner side is improved; meanwhile, the spiral spring can generate elastic force opposite to the flowing direction of liquid for the first sealing lip on the upper layer, so that the deformation of the first seal is prevented, and the sealing effect on the outer side is improved.

Furthermore, an inclined plane with a high outer part and a low inner part is arranged on one side, facing the valve rod, of the lower end of the outer sealing ring, the upper end of the inclined plane extends to the bending part of the inner sealing ring, a gap exists between the lower end of the inclined plane and the valve rod, and a liquid filling cavity is formed by cavities between the inner side surfaces of the inclined plane and the bending part of the inner sealing ring and the outer wall of the valve rod. Through the arrangement of the liquid filling cavity, low-temperature high-pressure liquid can be directly filled in the liquid filling cavity, and further the lower ends of the outer sealing ring and the inner sealing ring generate a small amount of deflection outwards around the bending part of the inner sealing ring, so that the first sealing lip can be attached to the inner wall of the sealing groove more tightly; because the whole height of the outer sealing ring is slightly smaller than the height of the sealing groove for convenient installation, the lower end of the outer sealing ring and the lower end of the sealing groove are in a separated state, and therefore after the liquid filling cavity is filled with liquid, downward component force can be generated by the force acting on the inclined surface, the lower end of the outer sealing ring can be attached to the end face of the sealing groove, primary sealing is added before the liquid flows to the first sealing lip, and the whole sealing effect is greatly improved.

Furthermore, an annular metal elastic sheet with a U-shaped section is arranged between the first sealing lips, and an opening of the annular metal elastic sheet faces outwards. Through the setting of annular metal shrapnel, can increase the first seal lip extrusion force of downside, and then improve sealed effect.

Furthermore, the free ends of the first sealing lips are provided with flanges which extend towards the end parts of the annular metal elastic sheets and cover the end parts of the annular metal elastic sheets. Through the setting of flange, not only can the cladding annular metal shell fragment, avoid annular metal shell fragment tip to scrape colored seal groove inner wall when following the action of first seal lip, and then guarantee sealed effect, can restrict annular metal shell fragment between first seal lip in addition, make first seal lip and annular metal shell fragment form a whole, consequently under the ultra-low temperature environment, the elasticity of annular metal shell fragment can supply the centripetal force of first seal lip shrink, avoid the shrink of first seal lip too big and influence the condition of sealing performance.

Furthermore, the outer sealing ring below the inclined surface is provided with a second sealing lip extending towards the inclined lower side, and the second sealing lip can be attached to the bottom surface of the sealing groove. Through the setting of second seal lip, can further improve the laminating degree of external seal ring lower extreme and seal groove lower extreme, and then guarantee sealed effect.

Advantageous effects

Compared with the known public technology, the technical scheme provided by the invention has the following beneficial effects:

according to the invention, through the arrangement of the liquid blocking ring assembly and the low-temperature resistant sealing ring, secondary sealing between the valve rod and the valve cover can be realized, the sealing effect is improved, the condition that a small amount of low-temperature high-pressure liquid natural gas leaks is avoided, and the condition that moisture-containing air outside collides with the upper end of the valve rod and the upper end of the valve cover to condense into ice is further avoided, so that the gate valve can be normally used.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a cross-sectional view of the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a perspective view of a low temperature resistant seal ring used in the present invention;

fig. 5 is a sectional view of a low temperature-resistant seal ring used in the present invention.

The reference numerals in the drawings denote: 1. a valve body; 2. a liquid inlet; 3. a liquid outlet; 4. pressing a plate; 5. a valve cover; 6. a valve stem; 7. a liquid inlet cavity; 8. a liquid outlet cavity; 9. a valve seat; 10. a valve plate; 11. moisture-proof filler; 12. a leakage-proof isolation net; 13. a low temperature resistant seal ring; 131. an inner seal ring; 132. an outer seal ring; 133. a first seal lip; 134. a coil spring; 135. mounting grooves; 136. an annular metal spring sheet; 137. a second sealing lip; 138. a flange; 139. an inclined surface; 14. liquid-stop ring component.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all 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.

The present invention will be further described with reference to the following examples.

Example (b):

as shown in fig. 1-5, the ultralow temperature corrugated pipe gate valve comprises a valve body 1, wherein one side of the valve body 1 is provided with a liquid inlet 2, and the other side of the valve body 1 is provided with a liquid outlet 3; a liquid inlet cavity 7 and a liquid outlet cavity 8 which are arranged at intervals up and down are arranged in the valve body 1, the liquid inlet cavity 7 is communicated with the liquid inlet 2, and the liquid outlet cavity 8 is communicated with the liquid outlet 3; a valve seat 9 is arranged between the liquid inlet cavity 7 and the liquid outlet cavity 8, a communicating channel which is communicated up and down is arranged in the valve seat 9, and a valve plate 10 which can block the communicating channel is arranged at the upper end of the valve seat 9; the upper end of the valve body 1 is provided with a valve cover 5, and the valve cover 5 is fixedly connected with the valve body 1 through a pressure plate 4 and bolts which are arranged on the periphery of the valve cover 5; the upper end of the valve plate 10 is connected with a valve rod 6, the valve rod 6 penetrates through the valve cover 5 and extends to the outside of the valve body 1 to be connected with an external handle, and a through hole matched with the valve rod 6 is formed in the valve cover 5; a leakage-proof isolation net 12, a low-temperature-resistant sealing ring 13 and a liquid blocking ring assembly 14 are sequentially arranged between the valve rod 6 and the through hole from top to bottom, and the low-temperature-resistant sealing ring 13 and the liquid blocking ring assembly 14 are in sealing fit with the valve rod 6; the leakage-proof isolation net 12 is an annular hollow metal net sleeved outside the valve rod 6, the leakage-proof isolation net 12 and the valve rod 6 are in clearance fit, and the leakage-proof isolation net is filled with a moisture-proof filler 11.

When the valve is used, ultralow-temperature liquid enters the liquid inlet cavity 7 from the liquid inlet 2 and moves to the valve seat 9, the valve rod 6 is driven to rotate and move upwards by rotating the handle, the valve plate 10 moves upwards, the communication channel of the valve seat 9 is opened, and the ultralow-temperature liquid can enter the liquid outlet cavity 8 through the communication channel and then is discharged from the liquid outlet 3; through the arrangement of the liquid blocking ring assembly 14 and the low-temperature resistant sealing ring 13, secondary sealing between the valve rod 6 and the valve cover 5 can be realized, the sealing effect is improved, the condition that a small amount of low-temperature high-pressure liquid natural gas leaks is avoided, and the condition that air containing moisture outside collides with the upper end of the valve rod 6 and the upper end of the valve cover 5 and condenses into ice is further avoided, so that the gate valve can be normally used; the setting and 6 clearance fit's of valve rod leak protection separation net 12, on the one hand, avoid it to lead to valve rod 6 to scrape the flower with 6 collisions of valve rod, on the other hand also can effectively draw in and place dampproofing filler 11 in, makes it can absorb the steam around the valve gap 5 upper end, avoids freezing between valve rod 6 and valve gap 5 and influences normal use.

As an alternative, the liquid blocking ring assembly is a metal sealing gasket molded by a flexible metal material. Because the liquid blocking ring subassembly is made for flexible metal material, the shrinkage of metal material under the ultra-low temperature is less, not only can avoid under the ultra-low temperature condition the too big sealing performance that influences of shrinkage, it still has higher shock resistance moreover, consequently satisfies the user demand among the high pressure environment.

As an optional scheme, a sealing groove for accommodating the low-temperature-resistant sealing ring 13 is arranged in the valve cover 5, the low-temperature-resistant sealing ring 13 includes an inner sealing ring 131 made of a metal material and an outer sealing ring 132 made of a rubber material, the cross section of the outer sealing ring 132 is shaped like a Chinese character '7', the inner sealing ring 131 is wrapped on the inner side surface of the outer sealing ring 132, and the inner side surface of the inner sealing ring 131 is in sealing fit with the valve rod 6; the upper end of the inner sealing ring 131 is horizontal and can wrap the upper end of the outer sealing ring 132 in the inner sealing ring, and the lower end of the inner sealing ring 131 is bent outwards and extends into the lower end of the outer sealing ring 132 to be connected with the outer sealing ring 132 into a whole; the outer side of the middle part and the outer side of the lower part of the outer sealing ring 132 are both provided with a first sealing lip 133 which extends upwards in an inclined mode, and the end face between the first sealing lip 133 and the side face of the sealing groove is sealed. Through the arrangement of the inner sealing ring 131 and the outer sealing ring 132, because the inner sealing ring 131 is made of metal materials, the inner sealing ring 131 can improve the supporting force and reverse elastic force in an ultralow-temperature environment, the phenomenon that the outer sealing ring 132 integrally contracts inwards and generates centripetal extrusion force is avoided, the phenomenon that the sealing effect is reduced and even the outer sealing ring 132 is damaged due to overlarge contraction amount of the outer sealing ring 132 is further avoided, and the service life is prolonged while the sealing performance is ensured; through the setting of two sets of first seal lips 133, when the interior sealing ring 131 of valve rod 6 extrusion, interior sealing ring 131 drives outer seal ring 132 and removes to the seal groove, and then makes the side of first seal lip 133 and seal groove closely laminate, has improved sealed effect.

As an alternative, a space between the first sealing lip 133 at the middle part and the upper end of the outer sealing ring 132 forms a mounting groove 135, an annular coil spring 134 is arranged in the mounting groove 135, and the minimum distance at the opening of the mounting groove 135 is smaller than the diameter of the coil spring 134. Through the arrangement of the spiral spring 134, on one hand, the spiral spring 134 generates inward contraction force, the inner side surface of the inner sealing ring 131 can be tightly attached to the surface of the valve rod 6, and the inner side sealing effect is improved; meanwhile, the spiral spring 134 itself can generate an elastic force opposite to the liquid flowing direction to the first sealing lip 133 on the upper layer, so as to prevent the deformation of the first seal, and further improve the sealing effect on the outer side.

As an optional scheme, an inclined surface 139 with a high outer part and a low inner part is arranged at the lower end of the outer sealing ring 132, which faces the valve rod 6, the upper end of the inclined surface 139 extends to the bent part of the inner sealing ring 131, a gap exists between the lower end of the inclined surface 139 and the valve rod 6, and a liquid filling cavity is formed between the inclined surface 139 and the inner side surface of the bent part of the inner sealing ring 131 and the outer wall of the valve rod 6. Through the arrangement of the liquid filling cavity, low-temperature high-pressure liquid can be directly filled in the liquid filling cavity, and further the lower ends of the outer sealing ring 132 and the inner sealing ring 131 are deflected outwards around the bending part of the inner sealing ring 131 by a small amount, so that the first sealing lip 133 can be attached to the inner wall of the sealing groove more tightly; because the whole height of the outer sealing ring 132 is slightly smaller than the height of the sealing groove for convenient installation, the lower end of the outer sealing ring 132 is in a separated state from the lower end of the sealing groove, and therefore after the liquid filling cavity is filled with liquid, downward component force can be generated by the force acting on the inclined surface 139, the lower end of the outer sealing ring 132 can be attached to the end face of the sealing groove, one sealing is added before the liquid flows to the first sealing lip 133, and the whole sealing effect is greatly improved.

As an alternative, an annular metal elastic sheet 136 with a U-shaped cross section is disposed between the first sealing lips 133, and an opening of the annular metal elastic sheet 136 faces outward. Through the setting of annular metal shrapnel 136, can increase the first seal lip 133 extrusion force of downside, and then improve sealed effect.

As an alternative, the free ends of the first sealing lips 133 are each provided with a flange 138 extending towards and wrapping the end of the annular metal dome 136. Through the setting of flange 138, not only can cladding annular metal shrapnel 136, avoid annular metal shrapnel 136 tip to scrape colored seal groove inner wall when moving along with first seal lip 133, and then guarantee sealed effect, and can restrict annular metal shrapnel 136 between first seal lip 133, make first seal lip 133 and annular metal shrapnel 136 form a whole, consequently under the ultra-low temperature environment, the elasticity of annular metal shrapnel 136 can supply the centripetal force that first seal lip 133 was shrink, avoid first seal lip 133 shrink too big and influence the condition of sealing performance.

As an alternative, the outer sealing ring 132 below the inclined surface 139 is provided with a second sealing lip 137 extending obliquely downward, and the second sealing lip 137 can be attached to the bottom surface of the sealing groove. Through the setting of second seal lip 137, can further improve the laminating degree of outer seal ring 132 lower extreme and seal groove lower extreme, and then guarantee sealed effect.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention.