The liquid level of a liquid supply type compressor including a gas-liquid separator is dynamically monitored. A liquid supply type gas compressor includes a compressor body of a liquid supply type; a gas-liquid separator that separates a liquid from a compressed gas, which is discharged, to store the liquid; a liquid piping system that supplies the liquid stored to the compressor body; an internal pipe that extends in an internal space of the gas-liquid separator, and includes at least two hole portions, of which disposition positions are different from each other in a height direction, on an internal space side to communicate with the liquid piping system; and a detector that detects a pressure or a temperature of a fluid flowing through the liquid piping system. At least one of a determination as to whether or not the pressure or the temperature detected by the detector is more than a first set value set in advance and a determination as to whether or not the pressure or the temperature detected by the detector is less than a second set value which is set in advance to be less than the first set value is performed to determine which one of the gas and the liquid is the fluid flowing through the liquid piping system.

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.

The multi-compressor system (7) has a plurality of parallelly coupled compressors (8); inlet connection lines (15) each connected to a refrigerant suction fitting of a respective compressor (8); outlet connection lines (17) each connected to a refrigerant discharge fitting of a respective compressor (8); a common oil balancing line (18) and balancing connection lines (19) each connecting the common oil balancing line (18) to an oil balancing connection (21) of a respective compressor (8); and spring-loaded normally-open valves (25) each being arranged within a respective balancing connection line (19) or within an oil balancing connection (21) of a respective compressor (8) and each being configured to close when a pressure difference between a pressure prevailing in the low pressure volume of the respective compressor (8) and a pressure prevailing in the common oil balancing line (18) reaches a predetermined value.

A compressor includes a compression mechanism that compresses refrigerant, and an electromotive mechanism that drives the compression mechanism. A shell accommodates the compression mechanism and the electromotive mechanism, with a reservoir inside the shell and that stores mixed liquid including liquid refrigerant and refrigerating machine oil. An electrode is provided inside the reservoir and faces an inner surface of the shell.

A control system comprising: a suction line; an exhaust line; an operating liquid line; a liquid ring pump comprising a suction input coupled to the suction line, an exhaust output coupled to the exhaust line, and a liquid input coupled to the operating liquid line; a pump configured to pump operating liquid into the liquid ring pump via the operating liquid line and the liquid input; a motor configured to drive the pump; a first sensor configured to measure a first parameter, the first parameter being a parameter of an exhaust fluid of the liquid ring pump; a second sensor configured to measure a second parameter, the second parameter being a parameter of a fluid received by the liquid ring pump; and a controller operatively coupled to the first sensor, the second sensor, and the motor, and configured to control the motor based on sensor measurements of the first sensor and the second sensor. The control system advantageously tends to reduce or eliminate the wear caused by cavitations.

Systems and methods for providing lubricant from a first compressor to a second compressor are provided. A control module receives a start command for a climate-control system having the first and second compressors, allows lubricant from the first compressor to flow into an inlet of the second compressor, turns the second compressor to an ON-mode, and prevents lubricant from the first compressor from flowing into the inlet of the second compressor after the second compressor has been in the ON-mode for a predetermined time period.

A scroll compressor includes an oil circulation pipe having one end inserted through a casing to be connected to an oil storage space inside the casing and another end connected to a suction passage for supplying refrigerant from outside of the casing to a compression chamber, an oil circulation valve disposed between the both ends of the oil circulation pipe to selectively open or close the oil circulation pipe, and a controller to control an opening or closing operation of the oil circulation pipe to reduce or eliminate frictional loss due to a shortage of oil by adjusting an oil level of the oil storage space at an initial operation.

An expander and a fluid circulation system comprising same are disclosed. The expander comprises a housing, an expansion mechanism, an exhaust pipe, an oil sump and a lubricant discharge channel. The expansion mechanism is provided in the housing to expand a high-pressure fluid into a low-pressure fluid. The exhaust pipe discharges the low-pressure fluid out of the expander and comprises an end portion assembled in a first opening of the housing and provided with an exhaust port; the low-pressure fluid enters the exhaust pipe via the exhaust port. The oil sump stores a lubricant in the housing. The lubricant discharge channel discharges the lubricant in the oil sump into the exhaust pipe and/or an external system pipeline and comprises an inlet end having an inlet located at a predetermined oil level of the oil sump and an outlet end having an outlet.

An oil detecting device for a compressor and a compressor including an oil detecting device are provided. A casing in which oil is received has a plurality of capillary tubes in an inner space of the casing, and a condition of oil is detected on the basis of a result of a measured pressure from the plurality of capillary tubes.

A compressor system includes: a compressor having a suction side and a discharge side, wherein the compressor is operative to compress a gas using oil, wherein the suction side operates at a suction pressure and is operative to receive a the gas and the oil into the compressor; and wherein the discharge side is operative to discharge the compressed gas and the oil; a gas/oil separator tank operative to store oil separated from the compressed gas for subsequent use by the compressor; a supplemental oil reservoir in fluid communication with the suction side; and a valve operative to, when opened, expose the supplemental oil reservoir to the suction pressure of the suction side of the compressor, and draw oil from the supplemental oil reservoir by suction into the suction side of the compressor.