US 11,656,009 B2
Cooling system with oil return to accumulator
Shitong Zha, Snellville, GA (US); and Augusto Zimmermann, Lilburn, GA (US)
Assigned to Heatcraft Refrigeration Products LLC, Stone Mountain, GA (US)
Filed by Heatcraft Refrigeration Products LLC, Stone Mountain, GA (US)
Filed on Apr. 21, 2022, as Appl. No. 17/725,967.
Application 17/725,967 is a continuation of application No. 16/803,611, filed on Feb. 27, 2020, granted, now 11,371,756.
Prior Publication US 2022/0243963 A1, Aug. 4, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. F25B 31/00 (2006.01); F25B 5/02 (2006.01); F25B 49/02 (2006.01); F25B 43/02 (2006.01); F25B 43/00 (2006.01)
CPC F25B 31/004 (2013.01) [F25B 5/02 (2013.01); F25B 43/006 (2013.01); F25B 49/02 (2013.01); F25B 43/02 (2013.01); F25B 2600/2501 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A system comprising:
a flash tank configured to store a primary refrigerant;
a first low side heat exchanger;
a first accumulator;
a first compressor;
a second accumulator;
a second compressor;
a first valve;
a second valve; and
a third valve, wherein:
during a first mode of operation:
the first, second, and third valves are closed;
the first low side heat exchanger uses primary refrigerant from the flash tank to cool a secondary refrigerant;
the first accumulator receives primary refrigerant from the first low side heat exchanger;
the first compressor compresses primary refrigerant from the first accumulator;
the second accumulator receives primary refrigerant from the first compressor; and
the second compressor compresses primary refrigerant from the second accumulator; and
during a second mode of operation:
the first valve is open and directs primary refrigerant from the first low side heat exchanger and an oil from the first low side heat exchanger to a vessel;
the second valve is closed; and
the third valve is open and directs primary refrigerant from the vessel to the first accumulator.