System for cooling an object with coolant cycle

Abstract

An object, such as a superconductive magnet, is cooled by a coolant operating with a single or multistage coolant cycle in which the coolant, in the last stage, is partially expanded, cooled in a separator-evaporator and fed to the object to be cooled. At least a portion of the coolant fluid, following passage through the object, is expanded through a throttle to form a liquid-gas phase mixture which is separated in the separator-evaporator, the gas phase being recirculated. The expansion of the coolant fluid prior to entry into contact with the object is carried out according to the invention in one or more ejectors whose suction side or sides draws a portion of the cooling fluid from part of the cycle elsewhere into the stream fed to the object to increase the mass flow.