Two-way sealing seat structure and ultra-low temperature top entry trunnion ball valve

Abstract

The invention discloses a ball valve, in particular to an ultralow temperature top-assembled fixed ball valve, and provides the ultralow temperature top-assembled fixed ball valve capable of setting pressure relief direction during mounting. The ball valve comprises a valve body, wherein the valve body comprises a valve cavity and two connection parts at the two ends of the valve cavity; the two connection parts are named as a first connection part and a second connection part respectively; the end, towards the valve cavity, of the first connection part is provided with a one-way sealing valve seat structure; the end, towards the valve cavity, of the second connection part is provided with a bidirectional sealing valve seat structure; an elastic seat is arranged on the second connection part; a matching section of the bidirectional sealing valve seat structure is inserted into the second connection part; a piston ring is positioned between an outer ring of the matching section and an inner ring of the second connection part and can axially move; the inner ring of the second connection part is provided with a limiting ring which can be tightly attached to and matched with the piston ring; the axial movement of the piston ring is limited between a matching surface of a valve cavity section of a supporting ring and the limiting ring.

Description

technical field [0001] The invention relates to a sealing valve seat structure, in particular to a bidirectional sealing valve seat structure. In addition, the present invention also relates to a ball valve, in particular to an ultra-low temperature top entry fixed ball valve. Background technique [0002] Under ultra-low temperature conditions, the volume of the medium is concentrated, such as: liquid nitrogen, LNG, etc. However, under abnormal conditions, if the temperature of the valve rises, the medium in the valve cavity will be vaporized, resulting in an abnormal increase in the pressure in the valve cavity. Then, it is necessary to require the valve cavity of the valve to have the ability of automatic pressure relief. [0003] At present, the sealing methods realized by ultra-low temperature top entry trunnion ball valves are as follows: [0004] (1) The sealing between the valve body and the valve seat support ring is completed by two lip seals with opposite insta...

AI Technical Summary

Problems solved by technology

In doing so, the valve has four more leakage points. Once there is a problem with the welding quality, it will cause the valve to leak

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