Patent ID: 6983613

Claim:
A defrost refrigeration system of the type having a main refrigeration circuit, wherein a refrigerant goes through at least a compressing stage, 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 the compressing stage to the evaporator stage and adapted to receive a portion of said refrigerant in said high-pressure gas state, valves for stopping a flow of said refrigerant in said first low-pressure liquid state to at least one evaporator of the evaporator stage and directing a flow of said refrigerant in said high-pressure gas state 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 said refrigerant having released heat to the compressing stage, and pressure control means in said second line for limiting a maximum pressure of said refrigerant reaching the compressing stage.