Ultra-low temperature freezer, refrigeration system and vacuum apparatus

摘要

In an ultra-low temperature freezer (R) using refrigerant mixture in which plural kinds of refrigerants having different boiling points are mixed, in order to ensure the flow rate of liquid refrigerant into a supercooler (31) and enhance the cooling efficiency of a cryocoil (32), the ultra-low temperature freezer (R) comprises: a main refrigerant circuit (38) provided with the cryocoil (32) and a capillary tube (29); and a sub refrigerant circuit (39) that is connected at the upstream end to the upstream end of the main refrigerant circuit (38) to branch off therefrom and provided with a capillary tube (28), and the ultra-low temperature freezer (R) is configured so that the sub refrigerant circuit (39) is lower in height than the main refrigerant circuit (38). Thus, gas-liquid mixture refrigerant discharged from the primary side (31a) of the supercooler (31) flows into the sub refrigerant circuit (39) at a higher rate than into the main refrigerant circuit (38) and, in turn, liquid refrigerant flows more into the sub refrigerant circuit (39) than into the main refrigerant circuit (38).