Patent ID: 9146046
Filing Date: 2015-09-29
Classification: F25B

Abstract:
1. A refrigerator comprising: a primary compressor; a secondary compressor connected to an outlet side pipe of the primary compressor and configured to perform a secondary compression for a refrigerant primarily compressed in the primary compressor; a condenser connected to an outlet side pipe of the secondary compressor; a first evaporator diverged from the condenser and connected to an inlet side pipe of the primary compressor; a second evaporator diverged from the condenser together with the first evaporator and connected between the outlet side pipe of the primary compressor and an inlet side pipe of the secondary compressor; a refrigerant switching valve installed such that an inlet side of the first evaporator and an inlet side of the second evaporator are connected to an outlet side of the condenser in parallel and configured to control the refrigerant to flow toward the first evaporator or the second evaporator; and an oil balancing unit having at least one path to allow oil to be transferred from a compressor containing more oil to another compressor containing less oil of the plurality of compressors, wherein the oil balancing unit comprises an oil separating portion configured to separate oil from a refrigerant, and an oil collecting portion configured to collect the oil separated in the oil separating portion into the corresponding compressor, wherein the oil separating portion is located between an outlet side pipe of the secondary compressor and an inlet side pipe of the condenser, wherein the oil collecting portion has a first outlet connected between the inlet side pipe of the primary compressor and the outlet pipe of the first evaporator and a second outlet connected between the inlet side pipe of the secondary compressor and the outlet of the second evaporator, wherein the oil collecting portion has inlets connected to the oil separating portion via a valve configured to selectively open or close a corresponding outlet, and wherein the valve is a three-way valve having an inlet connected to the oil separating portion, and outlets respectively connected to the inlets of the oil collecting portion.