An automatic oil level retention system for a compressor and a method for controlling a same, including: a normal oil return mode and an auxiliary oil return mode. When a lubricating oil liquid level monitored by a liquid level detection unit in real time is above a required liquid level height, the system initiates only the normal oil return mode; and when the lubricating oil liquid level monitored by the liquid level detection unit in real time is below the required liquid level height, the system initiates the auxiliary oil return mode, and the auxiliary oil return mode is closed and the normal oil return mode is initiated after the lubricating oil liquid level monitored in real time is lifted above the required liquid level height.

In a screw compressor (20), a male rotor suction end bearing (96) and discharge end bearing (90 1, 90 2, 90 3) mount the male rotor suction end shaft portion (39) and discharge end shaft portion (40). A female rotor suction end bearing (98) and discharge end bearing (92 1, 92 2) mount the female rotor suction end shaft portion (41) and discharge end shaft portion (42). At least one valve (182; 282; 382 1,382 2,382 3; 82; 582-1,582-2; 682-1,682-2; 782-1,782-2) is along a lubricant flowpath and has an energized condition and a de-energized condition. At least one restriction (184; 84-1,84-2; 84-1, 84-2,84-3; 484 1,484-2,84-3; 84 1,84 2,584; 84-1,84-2,684; 84-1,84-2,784) is along the lubricant flowpath. The at least one valve and the at least one restriction are positioned to create a lubricant pressure difference biasing the rotors away from a discharge end of the case.

The present invention belongs to the technological field of compressors for cooling systems and, according to a preferred embodiment of the present invention, the connecting device a substantially cylindrical or tubular body provided, at one of its ends, with an outer perimetral projection and co-operative with a duct or channel of a cylinder cap, wherein, preferably, the device will be produced with steel, aluminum alloy, or other metal alloy with similar structural and thermal properties, mainly due to the stresses it may suffer during use and to be able to absorb the tolerance variations and to have a resilience capable of providing resistance at the time the connection undergoes mechanical stresses of performance—especially torsion.

The present invention belongs to the technological field of compressors for cooling systems and, according to a preferred embodiment of the present invention, the connecting device a substantially cylindrical or tubular body provided, at one of its ends, with an outer perimetral projection and co-operative with a duct or channel of a cylinder cap, wherein, preferably, the device will be produced with steel, aluminum alloy, or other metal alloy with similar structural and thermal properties, mainly due to the stresses it may suffer during use and to be able to absorb the tolerance variations and to have a resilience capable of providing resistance at the time the connection undergoes mechanical stresses of performance—especially torsion.

A system for cryocooling an optical sensor on a satellite to a temperature below 200K with minimal vibration comprising a miniature conical rotary screw compressor comprising an inner element configured to only rotate around a first stationary axis and an outer element configured to only rotate around a second stationary axis so that both elements revolve with minimal vibration; with at least one of a) a length of at least one of the inner element and the outer element is between 10 mm and 100 mm; b) a diameter of at least one of the inner element and the outer element is between 2 mm and 45 mm; c) a compression ratio of the rotary screw compressor is between 1:2 and 1:20; and d) a shaft speed of the conical rotary screw compressor is between 1001 and 20000 revolutions per minute.

An air conditioning system includes a first compressor and a second compressor arranged in parallel with the first compressor. The first compressor is a first type of compressor and the second compressor is a second type of compressor different from the first type of compressor. A valve is arranged upstream from both the first compressor and the second compressor relative to a flow of a fluid. The valve is operable to selectively supply the fluid to the first compressor, the second compressor, or both the first compressor and the second compressor.

A liquefied gas cooling apparatus includes: a gas flow path for carrying a liquefied gas that is liquefied by cooling; and a refrigeration unit including a refrigerating cycle formed by an evaporator for cooling the liquefied gas flowing through the gas flow path, a compressor, a condenser, and a throttle expansion unit. The refrigeration unit includes: an inlet-side open/close valve and an outlet-side open/close valve provided in an inlet path and an outlet path of the compressor, respectively; and a service open/close valve in a refrigerant path between the inlet-side open/close valve and the outlet-side open/close valve.

The present invention provides a refrigerating machine oil composition comprising an ester-based base oil, an epoxy compound, and a carbodiimide compound, the refrigerating machine oil composition being used with a refrigerant containing a fluoropropene in a refrigerating machine comprising a member containing polyethylene terephthalate and/or a member containing hydrogenated acrylonitrile butadiene rubber.

A crankshaft, an inverter compressor and a refrigeration device are provided. The crankshaft has a main shaft, a crank, and a crank shaft at an end of the main shaft through the crank. The main shaft has an oil suction inner chamber, and an oil distribution channel penetrating the crank shaft. An outer wall surface of the main shaft has a first spiral oil groove and a second spiral oil groove. One end of each of the first spiral oil groove and a second spiral oil groove is in communication with the oil suction inner chamber. Another end of the first spiral oil groove and another end of the second spiral oil groove are formed as a first hole channel and a second hole channel in communication with the oil distribution channel, respectively.

A refrigerator according to an embodiment of the present invention includes: a compressor configured to compress a refrigerant; and an inverter module configured to control the compressor, wherein the inverter module includes: a heatsink provided with a cooling passage through which coolant passes; a coolant inlet connected to the heatsink to communicate with an inlet of the cooling passage; a coolant outlet connected to the heatsink to communicate with an outlet of the cooling passage; at least one insulated gate bipolar transistor (IGBT) disposed on a top surface of the heatsink; and at least one diode disposed to be spaced apart from the IGBT on the top surface of the heatsink, wherein the cooling passage includes: an IGBT cooling passage that is closer to the coolant inlet among the coolant inlet and the coolant outlet; and a diode cooling passage that is closer to the coolant outlet among the coolant inlet and the coolant outlet, wherein the diode cooling passage is disposed behind the IGBT cooling passage in a flow direction of the coolant.