초록 ▼

A refrigerating circuit in which a compressor, a gas cooler, a first pressure reducing unit and an evaporator are successively annularly connected to one another via pipes includes a second pressure reducing unit and a liquid receiver between the gas cooler and the first pressure reducing unit, and

A refrigerating circuit in which a compressor, a gas cooler, a first pressure reducing unit and an evaporator are successively annularly connected to one another via pipes includes a second pressure reducing unit and a liquid receiver between the gas cooler and the first pressure reducing unit, and the liquid receiver is connected to the suction port of the compressor via a pipe. Then, the opening/closing degree of the second pressure reducing unit is controlled in accordance with a pressure difference between the discharge-side pressure of the compressor and the suction-side pressure thereof, whereby the amount of the refrigerant to be circulated is increased when the refrigerating ability runs short, and the excessive refrigerant is received in the liquid receiver when the refrigerating ability becomes excessive, so that the amount of the refrigerant to be circulated can be adjusted.

대표청구항 ▼

1. A refrigerating apparatus in which a compressor, a gas cooler, a first pressure reducing unit and an evaporator are connected to one another via pipes and which is capable of operating with a natural refrigerant, the apparatus comprising: a first opening/closing valve in parallel with a second pr

1. A refrigerating apparatus in which a compressor, a gas cooler, a first pressure reducing unit and an evaporator are connected to one another via pipes and which is capable of operating with a natural refrigerant, the apparatus comprising: a first opening/closing valve in parallel with a second pressure reducing unit and a liquid receiver, wherein the liquid receiver has an inlet at top of the liquid receiver, a first outlet at a side of the liquid receiver, and a second outlet at bottom of the liquid receiver, wherein the first opening/closing valve, the second outlet of the liquid receiver, and the second pressure reducing unit are disposed between the gas cooler and the first pressure reducing unit, wherein the first outlet of the liquid receiver is connected to a suction port of the compressor via a first pipe and a second opening/closing valve, andan inner heat exchanger having a high-pressure-side circuit and a low-pressure-side circuit, wherein the high-pressure-side circuit is disposed between the gas cooler and the second pressure reducing unit,wherein an outlet of the evaporator is directly connected to the suction port of the compressor via a second pipe and a third opening/closing valve in parallel with a third pipe which connects the outlet of the evaporator to the suction port of the compressor via a fourth opening/closing valve and the low-pressure-side circuit of the inner heat exchanger,wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with a pressure difference between the discharge-side pressure of the compressor and the suction-side pressure thereof,wherein, according to when refrigerating ability of the refrigerating apparatus is low, the natural refrigerant flows on a first path from the compressor, to the gas cooler, to the high-pressure-side circuit of the inner heat exchanger, to the second expansion valve, to the liquid receiver, to the first expansion valve, to the evaporator, and to the compressor, and a gas refrigerant flows from the liquid receiver to the compressor,wherein, according to when refrigerating ability of the refrigerating apparatus is normal, the natural refrigerant flows on a second path from the compressor, to the gas cooler, to the high-pressure-side circuit of the inner heat exchanger, to the first opening/closing valve, to the first expansion valve, to the evaporator, to the fourth opening/closing valve, to the low-pressure-side circuit of the inner heat exchanger, and to the compressor,wherein, according to when refrigerating ability of the refrigerating apparatus is high, the natural refrigerant flows on a third path from the compressor, to the gas cooler, to the high-pressure-side circuit of the inner heat exchanger, to the first opening/closing valve, to the first expansion valve, to the evaporator, to the fourth opening/closing valve, to the low-pressure-side circuit of the inner heat exchanger, and to the compressor, and the natural refrigerant flows from the high-pressure-side circuit of the inner heat exchanger to the second expansion valve, and to the liquid receiver, and a gas/liquid refrigerant flows from the liquid receiver to the compressor. 2. The refrigerating apparatus according to claim 1, wherein an intermediate portion between the inner heat exchanger and the second pressure reducing unit is connected to an intermediate portion between the liquid receiver and the first pressure reducing unit via the first opening/closing valve and a pipe. 3. The refrigerating apparatus according to claim 1, wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with the suction-side pressure of the compressor. 4. A refrigerating apparatus in which a multi-stage compressor, a gas cooler, a first pressure reducing unit and an evaporator are connected to one another via pipes and which is capable of operating with a natural refrigerant, the apparatus comprising: a second pressure reducing unit and a liquid receiver between the gas cooler and the first pressure reducing unit, wherein the liquid receiver has a first outlet and a second outlet,a first pipe having a first opening/closing valve, wherein the first opening/closing valve has a first side and a second side, wherein the first side of the first opening/closing valve is directly connected to the first outlet of the liquid receiver, wherein the second side of the first opening/closing valve is directly connected to an intermediate pressure portion of the multi-stage compressor, andan inner heat exchanger having a high-pressure-side circuit and a low-pressure-side circuit, wherein the high-pressure-side circuit is disposed between the gas cooler and the second pressure reducing unit,wherein an outlet of the evaporator is connected to a suction port of the compressor via a second pipe and a second opening/closing valve, and is connected to the suction port of the multi-stage compressor via a third opening/closing valve and the low-pressure-side circuit of the inner heat exchanger,wherein a first intermediate portion directly connects the high-pressure-side circuit of the inner heat exchanger to the second pressure reducing unit,wherein a second intermediate portion directly connects the second outlet of the liquid receiver to the first pressure reducing unit,wherein the first intermediate portion is directly connected to a first side of a fourth opening/closing valve,wherein the second intermediate portion is directly connected to a second side of the fourth opening/closing valve,wherein a third intermediate portion is disposed to directly connect the outlet of the evaporator to a first side of the second opening/closing valve and to a first side of the third opening/closing valve,wherein a second side of the third opening/closing valve is directly connected to the low-pressure-side circuit of the inner heat exchanger,wherein a fourth intermediate portion is disposed to directly connect the low-pressure-side circuit of the inner heat exchanger to the suction port of the multi-stage compressor and to a second side of the second opening/closing valve,wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with a pressure difference between the discharge-side pressure of the multi-stage compressor and the suction-side pressure thereof,wherein the opening/closing degree of the second pressure reducing unit is controlled so that the pressure at the discharge-side pressure of the multi-stage compressor is a predetermined value or is less than the predetermined value,wherein, according to when refrigerating ability of the refrigerating apparatus is low, the natural refrigerant flows on a first path from the compressor, to the gas cooler, to the high-pressure-side circuit of the inner heat exchanger, to the second expansion valve, to the liquid receiver, to the first expansion valve, to the evaporator, and to the compressor, and a gas refrigerant flows from the liquid receiver to the compressor,wherein, according to when refrigerating ability of the refrigerating apparatus is normal, the natural refrigerant flows on a second path from the compressor, to the gas cooler, to the high-pressure-side circuit of the inner heat exchanger, to the first opening/closing valve, to the first expansion valve, to the evaporator, to the fourth opening/closing valve, to the low-pressure-side circuit of the inner heat exchanger, and to the compressor,wherein, according to when refrigerating ability of the refrigerating apparatus is high, the natural refrigerant flows on a third path from the compressor, to the gas cooler, to the high-pressure-side circuit of the inner heat exchanger, to the first opening/closing valve to the first expansion valve, to the evaporator, to the fourth opening/closing valve, to the low-pressure-side circuit of the inner heat exchanger, and to the compressor, and the natural refrigerant flows from the high-pressure-side circuit of the inner heat exchanger to the second expansion valve, and to the liquid receiver, and a gas/liquid refrigerant flows from the liquid receiver to the compressor. 5. The refrigerating apparatus according to claim 4, wherein the first intermediate portion between the high-pressure-side circuit of the inner heat exchanger and the second pressure reducing unit is connected to the second intermediate portion between the second outlet of the liquid receiver and the first pressure reducing unit via the fourth opening/closing valve. 6. The refrigerating apparatus according to claim 5, wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with the suction-side pressure of the multi-stage compressor. 7. The refrigerating apparatus according to claim 4, wherein the first intermediate portion between the inner heat exchanger and the second pressure reducing unit is connected to the second intermediate portion between the second outlet of the liquid receiver and the first pressure reducing unit via the fourth opening/closing valve. 8. The refrigerating apparatus according to claim 7, wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with the suction-side pressure of the multi-stage compressor. 9. The refrigerating apparatus according to claim 7, wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with a pressure difference between the discharge-side pressure of the multi-stage compressor and the suction-side pressure thereof. 10. The refrigerating apparatus according to claim 4, wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with the suction-side pressure of the multi-stage compressor. 11. The refrigerating apparatus according to claim 4, wherein the opening/closing degree of the second pressure reducing unit is controlled in accordance with a pressure difference between the discharge-side pressure of the multi-stage compressor and the suction-side pressure thereof.