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.