Patent ID: 7610766

Claim:
A defrost refrigeration system of the type having a main refrigeration circuit operating a refrigeration cycle, wherein a refrigerant goes through at least a compressing stage having at least a first and a second compressor, wherein said refrigerant is compressed to a high-pressure gas state to then reach a condensing stage, wherein said refrigerant in said high-pressure gas state is condensed at least partially to a high-pressure liquid state to then reach an expansion stage, wherein said refrigerant in said high-pressure liquid state is expanded to a first low-pressure liquid state to then reach an evaporator stage, wherein said refrigerant in said first low-pressure liquid state is evaporated, at least partially to a first low-pressure gas state by absorbing heat, to then return to said compressing stage, said defrost refrigeration system comprising a first line extending from said first compressor to the evaporator stage and adapted to receive all of the discharged refrigerant from said first compressor, a valve for stopping a suction by the compressing stage of said refrigerant in said first low-pressure liquid state in at least one evaporator of the evaporator stage and directing a flow of said discharged refrigerant to release heat to defrost the at least one evaporator and thereby changing phase at least partially to a second low-pressure liquid state, a second line for directing all of said refrigerant having released heat to the expansion stage of the refrigeration cycle, and a pressure reducing device downstream of the condensing stage for adjusting a pressure of the refrigerant in the high-pressure liquid state mixing with said refrigerant having released heat.