Eine Vakuumpumpe, insbesondere Drehschieberpumpe, umfasst wenigstens eine Pumpstufe zum Pumpen eines Fluids von einem Einlass der Pumpstufe zu einem Auslass der Pumpstufe, einen Sumpf, insbesondere Ölsumpf, für ein Betriebsmittel, insbesondere ein Öl, zum Schmieren und Abdichten der Pumpstufe, und wenigstens einen Kanal zur Führung des Betriebsmittels in der Pumpe, wobei der Kanal eine Mündung in den Sumpf aufweist, die unterhalb eines für das Betriebsmittel vorgesehenen Mindestpegels liegt.

The application relates to a method for controlling the water supply of a water-injected gas compressor which has a cooling water circuit into which is injected, as fresh water, demineralized water and non-demineralized water. The method according to the application comprises the following steps: determination of the electrical conductivity of the non- demineralized water; determination of a proportion of the demineralized water that must be added to the non-demineralized water, to provide a resulting mixture with a desired conductivity; addition of the specified proportion of demineralized water to the non-demineralized water and supplying the resulting mixture as the fresh water for the cooling water circuit; supply of the fresh water to the cooling water circuit in a desired amount. Further, the application relates to a Water-injected gas compressor comprising a compression stage, a cooling water circuit, and a water mixing unit.

The application relates to a method for controlling the water supply of a water-injected gas compressor which has a cooling water circuit into which is injected, as fresh water, demineralized water and non-demineralized water. The method according to the application comprises the following steps: determination of the electrical conductivity of the non- demineralized water; determination of a proportion of the demineralized water that must be added to the non-demineralized water, to provide a resulting mixture with a desired conductivity; addition of the specified proportion of demineralized water to the non-demineralized water and supplying the resulting mixture as the fresh water for the cooling water circuit; supply of the fresh water to the cooling water circuit in a desired amount. Further, the application relates to a Water-injected gas compressor comprising a compression stage, a cooling water circuit, and a water mixing unit.

A rotary compressor, comprising: a housing (12), comprising a lubricant oil storage part for containing lubricating oil; a compression mechanism (20) disposed in the housing (12); a driving mechanism (30) driving the compression mechanism (20), the driving mechanism (30) comprising a rotation shaft (50), through-holes (54, 56) extending along the axial direction of the rotating shaft (50) are disposed inside the rotating shaft (50), and the rotation shaft (50) is in fluid connection with the lubricating oil storage part via the through-holes (54, 56); and an oil level sensor (120) in fluid connection with the through-holes (54, 56) inside the rotation shaft (50) via a pressurized collection channel (110). Also disclosed is a rotation mechanism, comprising an oil level sensor (120) in fluid connection with the through-holes (54, 56) inside the rotation shaft (50) via the pressurized collection channel (110). Accurate and reliable detection of the lubricating oil in a compressor can be done using the pressurized collection channel and the oil level sensor, thus greatly saving cost and improving compressor reliability.

A motor controller for a motor-driven compressor (10) includes a compressing body (11) for compressing and discharging a refrigerant and a motor (M) including a rotary shaft (12), the motor (M) for driving the compressing body (11) through the rotary shaft (12). A coil (252) of the motor (M) is arranged in a refrigerant containing area (181) in the motor-driven compressor (10). The motor controller includes a determining section (C1) for determining whether liquid refrigerant is present in the refrigerant containing area (181) and a modulation control section (27) for driving the motor (M) in accordance with three phase modulation control or two phase modulation control based on a determination result of the determining section (C1).

A fluid machine (101) includes a first compressor (107) and a second compressor (108). The first compressor (107) has a first closed casing (111), a first compression mechanism (102a), an expansion mechanism (104), and a shaft (113). A first oil reservoir (112) is formed in the first closed casing (111). The second compressor (108) has a second closed casing (125) and a second compression mechanism (102b). A second oil reservoir (126) is formed at a bottom portion in the second closed casing (125). The first closed casing (111) and the second closed casing (125) are connected to each other by an oil passage (109) so that a lubricating oil can flow between the first oil reservoir (112) and the second oil reservoir (126). An opening (109a) of the oil passage (109) on a side of the first closed casing (111) is located above the expansion mechanism (104) with respect to the vertical direction. This configuration prevents the high temperature lubricating oil in a surrounding space of the expansion mechanism (104) and the high temperature lubricating oil in the second compressor (108) from flowing. Thereby, the heat transfer between the first compressor (107) and the second compressor (108) is suppressed.

A scroll-type compressor is disclosed which includes both a high pressure lubricant sump and a low pressure lubricant sump. Lubricant from the low pressure lubricant sump is supplied to the various bearing, thrust surfaces and other moving parts to lubricate same and a portion thereof is also supplied to the suction gas entering the compressor to replenish the lubricant in the high pressure sump. An oil separator is disposed in a discharge chamber to separate entrained oil from the compressed gas. A level control assembly is also provided in the discharge chamber and serves to return excessive accumulations of oil from the high pressure sump to the low pressure sump. In one embodiment, the compressor is specifically designed for compression of helium while in a second embodiment, the compressor is adapted for use as an air compressor.

A scroll-type compressor is disclosed which includes both a high pressure lubricant sump and a low pressure lubricant sump. Lubricant from the low pressure lubricant sump is supplied to the various bearing, thrust surfaces and other moving parts to lubricate same and a portion thereof is also supplied to the suction gas entering the compressor to replenish the lubricant in the high pressure sump. A first and a second oil separator are disposed in a discharge chamber to separate entrained oil from the compressed gas. A level control assembly is also provided in the discharge chamber and serves to return excessive accumulations of oil from the high pressure sump to the low pressure sump. In one embodiment, the compressor is specifically designed for compression of helium while in a second embodiment, the compressor is adapted for use as an air compressor.

Surplus portions of a lubricating oil L in closed casings 100 of compressors 1a, 1b and 1c flow into oil pipes 14a, 14b and 14c, individually. The lubricating oil L having flowed into these oil pipes is supplied to the respective closed casings 100 of the compressors 1a, 1b and 1c through oil pipes 18a, 18b and 18c and refrigerant inlet pipes 12a, 12b and 12c.

A scroll-type compressor is disclosed which includes both a high pressure lubricant sump and a low pressure lubricant sump. Lubricant from the low pressure lubricant sump is supplied to the various bearing, thrust surfaces and other moving parts to lubricate same and a portion thereof is also supplied to the suction gas entering the compressor to replenish the lubricant in the high pressure sump. An oil separator is disposed in a discharge chamber to separate entrained oil from the compressed gas. A level control assembly is also provided in the discharge chamber and serves to return excessive accumulations of oil from the high pressure sump to the low pressure sump. In one embodiment, the compressor is specifically designed for compression of helium while in a second embodiment, the compressor is adapted for use as an air compressor.