SEAL STRUCTURE, AND TEMPERATURE EXPANSION VALVE

摘要

PROBLEM TO BE SOLVED: To seal a space between a valve housing 10 and a diaphragm device 20 and provide high sealing performance even when pressure is increased.

SOLUTION: A male screw part 11 and a step part 12 are formed on the outer periphery of a first cylindrical part 1 of the valve housing 10. A female screw part 21 is formed on the inner periphery of a second cylindrical part 2 of a lower lid 20b of the diaphragm device 20. A projection 22 is formed at an opening end 2A of the second cylindrical part 2. Opposing faces of the step part 12 and the projection 22 serve as a first seal face 12A and a second seal face 22A, respectively. An area of the second seal face 22A is made smaller than that of the first seal face 12A. For example, the second seal face 22A is a flat face perpendicular to an axial line L, and the first seal face 12A is a tapered face. By thrust force generated by fastening of the second cylindrical part 2 and the first cylindrical part 1, inward stress is generated at the opening end 2A of the second cylindrical part 2.

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