The structure of the dorsal spine of the deep sea squaloid shark Centrophorus acus and its utility f

A refrigerating system having, arranged to form a closed circuit, a refrigerant compressor, a condensor, a receiver and a plurality of sets of evaporators and expansion valves with all the sets connected in parallel with one another. The system further includes a throttle mounted in the circuit between the condenser and the receiver, a branch line and change-over valves for selectively connecting the circuit on the delivery side of the compressor to each evaporator and a passage connecting each evaporator to the receiver by bypassing the associated expansion valve, so that the refrigerantin the state of a compressed gas can be supplied to a desired evaporator to defrost the same and the refrigerant condensed in the defrosted evaporator can be returned to the receiver. The system further includes a bypass line having a throttle, connecting a gas compartment in the upper portion of the receiver to a line on the suction side of the compressor, for returning to the line on the suction side of the compressor, flash gas incorporated in the liquid refrigerant returned from the defrosted evaporator to the receiver.