Bonnet device structure to prevent ice

摘要

A pipe structure of a cryogenic bonnet is provided to protect a pipe and a bonnet from getting ice needles due to supply of low temperature liquid nitrogen, resulting in corrosion of the entire structure and a diaphragm, and prevent heat transfer to the diaphragm when hot fluid is supplied, by forming inner and outer pipes with a space between them. A pipe structure of a cryogenic bonnet(25) comprises an inner pipe(21b,21b') and an outer pipe(21a,21a') connected to the bonnet and having a space(22,22') between them. A cage(30) has a plurality of holes(32) on the lower end of assembled bonnet and the pipe structure. A stem(28) having a port(29) is inserted to the cage.