A centrifugal separation type oil separator includes an oil separator body having a cylindrical body portion, and a bent pipe provided on an outer peripheral side of the body portion to surround the body portion in a circumferential direction, to introduce a fluid containing an oil into the oil separator body. The bent pipe includes an outer wall portion extending in the circumferential direction of the body portion and expanding radially outward from the body portion, and an inner wall portion extending along the outer wall portion and blocking an open part of the outer wall portion. The outer wall portion and the inner wall portion are formed by different members. An upper side of the body portion is open. The oil separator body has an upper cover blocking an open portion of the body portion. The inner wall portion and the upper cover are formed by an integral member.

A refrigeration cycle device includes: a switching valve configured to switch between a battery mode in which refrigerant flows to a battery heat exchanger and a non-battery mode in which the refrigerant bypasses the battery heat exchanger; and a controller controlling a compressor and the switching valve. The controller includes an estimation unit configured to estimate an oil stagnation amount, which is an amount of lubricating oil accumulated in the battery heat exchanger in accordance with execution of the non-battery mode. The controller includes a determination unit configured to determine whether lubricating oil in the battery heat exchanger needs to be recovered on the basis of the oil stagnation amount. The controller includes an execution unit configured to execute an oil recovery mode for recovery of lubricating oil in the battery heat exchanger when the determination unit determines that lubricating oil needs to be recovered.

A lubricant supply system is for a compressor that compresses a first working fluid in a heat transfer circuit. The lubricant supply system includes a lubricant tank, a lubricant pathway for supplying lubricant from the lubricant tank to one or more bearings of the compressor, and a lubricant refrigeration system with a lubricant heater and a lubricant cooler. The lubricant heater configured to heat the lubricant discharged from the one or more bearings and the lubricant cooler configured to cool the lubricant flowing through the lubricant pathway. A method of lubricating a compressor includes heating the lubricant, directing the lubricant from a lubricant tank through a lubricant pathway to one or more bearings of the compressor, and cooling the lubricant passing through the lubricant pathway.

A linear compressor or sealed system may include a casing, a piston, an driving coil, an inner back iron assembly, and a planar spring assembly. The casing may include a cylinder assembly defining a chamber along an axial direction. The piston may be slidably received within the chamber of the cylinder assembly. The inner back iron assembly may be positioned in the driving coil. The planar spring assembly may be mounted to the inner back iron assembly. The planar spring assembly may include a first planar spring, a second planar spring axially spaced apart from the first planar spring, and a polymer shim layer disposed between at least a portion of the first planar spring and the second planar spring.

A refrigeration system is provided and includes a common suction line, a common discharge line, first and second high-side compressors disposed in parallel to receive low-pressure refrigerant from the common suction line and to direct high-pressure refrigerant to the common discharge line, a first pipe connected to the first and second high-side compressors at vertical heights at which an oil supply is required to remain higher and a second pipe connected to the first and second high-side compressors at vertical heights sufficient to maintain gas pressure balance between the first and second high-side compressors.

A cooling system drains oil from low side heat exchangers to vessels and then uses compressed refrigerant to push the oil in the vessels back towards a compressor. Generally, the cooling system operates any number and combination of three different modes of operation: a normal mode, an oil drain mode, and an oil return mode. During the normal mode, a primary refrigerant is cycled to cool one or more secondary refrigerants. As the primary refrigerant is cycled, oil from a compressor may mix with the primary refrigerant and become stuck in a low side heat exchanger. During the oil drain mode, the oil in the low side heat exchanger is allowed to drain into a vessel. During the oil return mode, compressed refrigerant is directed to the vessel to push the oil in the vessel back towards a compressor.

A circulation system of an air conditioner, an air conditioner, and an air conditioner control method. The circulation system of the air conditioner includes a compressor, a first heat exchanger, a second heat exchanger, and a gas-liquid separation assembly. The gas-liquid separation assembly, together with the compressor, the first heat exchanger, and the second heat exchanger, forms a loop; the gas-liquid separation assembly includes two or more gas-liquid separators which are connected in series; the gas-liquid separation assembly is configured to perform gas-liquid separation for refrigerant. Further, two or more-staged gas-liquid separation can be performed for the refrigerant flowing back to the compressor, so that a problem that return oil containing liquid in the compressor can be effectively solved.

An oil return control method for a multi-split air conditioner and a system accomplishing the same includes: calculating an average exhaust pressure within an oil return period Pd_AVG; determining whether the average exhaust pressure Pd_AVG≥the set threshold Pd.sub.threshold; if Pd_AVG≥Pd.sub.threshold, maintaining the multi-split air conditioner working in heating mode to ensure an acceptable oil return performance without affecting the air conditioning effect of indoor unit in heating mode; if Pd_AVG<Pd.sub.threshold, switching the multi-split air conditioner to cooling mode, stopping a fan within those power-on indoor units and entering into a cooling oil return process and switching the multi-split air conditioner back to heating mode until the cooling oil return process ends.

A gas-liquid separation device comprises a container, an inlet tube, a liquid outlet tube, a gas outlet tube, and a swirl vane. The swirl vane is disposed in the inlet tube. A depression is provided on an inner circumferential surface of the inlet tube. The depression faces the swirl vane.

A refrigeration system includes a compressor, a condenser, a throttling device, and an evaporator, which are connected in sequence to form a cooling circuit, the refrigeration system further includes an oil recovery system which includes: an operation chamber, which includes a first port communicating with an oil-containing position in the refrigeration system through a first pipeline, and a second port communicating with a bearing chamber or a bearing lubrication pipeline of the compressor through a second pipeline; and a main piston in the operation chamber, the main piston reciprocating in the operation chamber to perform an extraction stroke and a discharge stroke; in the extraction stroke, an oil-containing refrigerant in the oil-containing position in the refrigeration system is extracted to the operation chamber; and in the discharge stroke, the oil-containing refrigerant in the operation chamber is delivered to the bearing chamber or the bearing lubrication pipeline of the compressor.