Device for preventing body cavity of ultra-low temperature ball valve with self-closing function from abnormally boosting and method for preventing body cavity of ultra-low temperature ball valve from abnormally boosting thereof

Abstract

The invention discloses a device for preventing a body cavity of an ultra-low temperature ball valve with a self-closing function from abnormally boosting and a method for preventing the body cavity of the ultra-low temperature ball valve from abnormally boosting thereof. According to the device, through the compact structural design, the device for preventing the body cavity of the ultra-low temperature ball valve from abnormally boosting is arranged in a valve body flow guide hole, under normal working conditions, the device is in a closed state, the communication between the inlet end and avalve body middle cavity is prevented, and the influence of the pressure of the inlet end on a sealing structure is avoided; an LNG medium in the valve body middle cavity is gasified due to the gradual increase of the ambient temperature, when the pressure is increased, the device for preventing the body cavity of the ultra-low temperature ball valve from abnormally boosting is opened, and the excessive pressure is discharged to the inlet end, so that the pressure in the valve body middle cavity is stabilized, the effect of preventing the body cavity from abnormally boosting is achieved, andthe occurrence of dangerous situations such as sealing leakage of a valve rod, sealing leakage of a middle flange, and failure of a fastener caused by abnormal boosting is avoided; and the device adopts a magnetic part, has no mechanical abrasion, is stable and reliable in work, is durable for a long time, and can effectively prolong the service life of the ultra-low temperature ball valve.

Description

technical field [0001] The invention relates to the technical field of cryogenic ball valves, in particular to an ultra-low temperature ball valve anti-body cavity abnormal boosting device for LNG receiving stations. Background technique [0002] Under low temperature conditions, the LNG medium in the closed cavity of the ball valve may gasify due to the gradual increase of the ambient temperature. When gasified, the volume expands by about 600 times, and the pressure will increase rapidly. If the pressure cannot be removed in time, it may cause the valve The occurrence of dangerous situations such as rod seal leakage, middle flange seal leakage, and fastener failure. Therefore, the design of LNG cryogenic ball valves needs to be designed to prevent abnormal pressure increase of the body cavity, and the current design mainly adopts two methods: internal relief method and external relief method. The internal relief method is to connect the middle cavity of the valve body wit...

AI Technical Summary

Problems solved by technology

These two methods have problems and are not ideal. For the internal relief method, the pressure in the cavity of the valve body and the inlet end are always connected, so that the pressure at the inlet end always acts on the valve seal, and the long-term pressure load It will have a certain impact on the sealing and cause leakage problems; for LNG medium, there are problems such as medium leakage and difficult operation through the method of connecting an external pressure relief valve, and it is rarely used in ultra-low temperature occasions

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