Low-temperature top-assembling type fixed ball valve

Abstract

The invention discloses a low-temperature top-assembling type fixed ball valve and belongs to the technical field of ball valves of liquefied natural gas pipelines. The low-temperature top-assembling type fixed ball valve comprises a valve body, a ball body, an upstream valve seat, a downstream valve seat, a valve cover, a valve rod, a connecting support and an actuator; an upper short shaft and a lower short shaft are arranged at the upper end and the lower end of the ball body correspondingly, the upper short shaft, the lower short shaft and the ball body are of an integrated structure, and the valve rod is connected with the upper short shaft; first elastic compensating components and spring seal rings are arranged between the upstream valve seat and the valve body and between the downstream valve seat and the valve body; the upstream valve seat is of a step-type structure and can move in the horizontal direction; and the downstream valve seat is of a step-type structure and can move in the horizontal direction. The low-temperature top-assembling type fixed ball valve is high in size accuracy, good in the sealing property, long in service life and capable of meeting the demand that the ball valve is used at the temperature of minus 162 DEG C. Even if a caliber reaches six inches or above, all properties of the low-temperature top-assembling type fixed ball valve can still meet the demand.

Description

technical field [0001] The invention relates to the technical field of liquefied natural gas pipeline ball valves, in particular to a low-temperature top-loading fixed ball valve. Background technique [0002] Liquefied Natural Gas (LNG) is colorless, odorless, non-toxic and non-corrosive. It is recognized as the cleanest energy source on earth, and its main component is methane. Liquefied natural gas is obtained by cooling gaseous natural gas to -162°C at atmospheric pressure. [0003] Cryogenic top-entry fixed ball valves are commonly used ball valves on process pipelines such as natural gas liquefaction stations and receiving stations. They are used to cut off liquefied natural gas. Maintenance of fixed ball valves. In the existing low-temperature top entry fixed ball valve, one end of the valve stem is connected to the ball through a key connection, and the other end is connected to the actuator after passing through the valve cover. The actuator drives the ball to rot...

AI Technical Summary

Problems solved by technology

[0004] To sum up, in the process of realizing the present invention, the inventors found that there are at least the following problems in the prior art: the existing low-temperature top-entry trunnion ball valve uses the pan-seal ring to release the pressure, which easily leads to the deterioration of the sealing performance of the pan-seal ring; After the ball and the valve stem are connected, it is difficult to ensure the overall position tolerance, which leads to the insufficient tightness between the upstream and downstream sealing rings of the valve seat and the ball, resulting in seal leakage; Not conducive to seat sealing

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