Abstract: A system for a cooler comprises: a heat exchange tube receiving a supply of pressurized gas, a gas escape aperture communicating with the interior of the heat exchange tube for permitting escape of the pressurized gas and expansion thereof during cooling mode, and a bypass assembly associated with said heat exchange tube and located after said gas escape aperture which during a cleaning mode enables most of the pressurized gas to exit the heat exchange tube without flowing through said gas escape aperture. The bypass assembly comprises a flush valve which is closed during said cooling mode and which is opened during said cleaning mode. According to a preferred embodiment, the heat exchange tube is helically wound over a cylindrical core and installed inside an insulated housing. The system may also be utilized as a gas purity tester, optionally with an additional gas pressure regulator, wherein a sensor will indicate the extent of the gas purity.

Abstract: The present invention relates to a particular needle-orifice fluid flow regulator to be used in a cryocooler. The flow regulator comprises a fluid outlet port adapted to receive therethrough a pressurized cooling fluid via a conduit. The needle is arranged for variable positioning relative to said outlet and temperature responsive needle positioning means for positioning said needle relative to said port as a function of temperature, whereby the needle is floatingly mounted relative to said needle positioning means. The positioning means is adapted to apply displacement forces to the needle along an axis which extends through said fluid outlet port, being constructed in a manner which enables to maintain the needle substantially coaxial with the outlet port. The fluid outlet port has a funnel shaped portion with a relatively narrow end arranged for fluid communication with said conduit configured to engage and guide the needle into mating engagement with the fluid outlet port.