Expansion device

Abstract

An expansion device capable of preventing an abnormal increase in the high-pressure in a freezing cycle and having, as an integrated unit thereof, a mechanism capable of quickly responding to an abnormal increase in the high-pressure and the low-pressure is provided. A means for displacement (bellows) which becomes displaced in correspondence to the high-pressure is linked to a valve element of a restrictor valve mechanism to displace a rod provided with a safety valve mechanism . If the high-pressure reaches a level equal to or higher than a first specific pressure (the limit to the normal operating pressure), a first portion of the safety valve mechanism becomes disengaged from a relief hole that communicates between a high-pressure space and a low-pressure passage to be replaced by a second portion which allows passage through the relief hole , thereby leaking the coolant in the high-pressure space to the low-pressure passage and preventing a further increase in the high-pressure. In addition, a low-pressure side rupture disk mechanism that becomes ruptured if the low-pressure reaches a level equal to a second specific pressure to communicate between the low-pressure passage and the atmosphere is provided at the low-pressure passage . A high-pressure side rupture disk mechanism that becomes ruptured if the high-pressure reaches a level equal to or higher than a third specific pressure to communicate between the high-pressure passage and the atmosphere is provided at the high-pressure passage