Patent ID: 8671704

Claim:
A refrigeration system, comprising: a compressor having an inlet and an outlet of refrigerant fluid in vapor form; a condenser having a vapor inlet connected to the outlet of the compressor and a liquid outlet; a high-expansion device having an inlet connected to the liquid outlet of the condenser and an outlet; a separating means having a first inlet connected to the liquid outlet of the condenser and a vapor outlet connected to the inlet of the compressor and a liquid outlet; a low-expansion device having an inlet connected to the liquid outlet of the separating means and an outlet; an evaporator having a vapor-liquid mixture inlet receiving refrigerant fluid from the separating means through the outlet of the low-expansion device and a vapor-liquid mixture outlet; and a selecting valve having: a first vapor inlet connected with the vapor-liquid mixture outlet of the evaporator; a second vapor inlet connected to the vapor outlet of the separating means; and a vapor outlet connected to the inlet of the compressor, said selecting valve maintaining the refrigerant fluid in the second vapor inlet of the selecting valve and in the interior of the separating means at a first suction pressure higher than a second suction pressure in the first vapor inlet of the selecting valve and in the vapor outlet of the evaporator and being operated to selectively and alternatingly communicate the first and second vapor inlets of the selecting valve with the vapor outlet of the selecting valve, so as to allow the compressor to draw refrigerant vapor from the separating means, in said first suction pressure, and refrigerant vapor from the evaporator, in said second suction pressure; and a control unit operatively associated with the selecting valve, so as to operate the selecting valve for maintaining the level of the liquid refrigerant fluid in the interior of the separating means within predetermined values.