Provided is a scroll-type fluid machine that prevents wear of the parts of the fluid machine and improves the reliability thereof by reducing the amount of dust that reaches a face seal. The present invention comprises a revolving scroll that includes an end plate and a lap part provided to the end plate, and that moves in a revolving manner; a fixed scroll that includes an end plate, a lap part provided to the end plate such that a compression chamber is formed between itself and the lap part of the revolving scroll, and a flange that opposes the end plate of the revolving scroll; and a face seal that is provided between the flange of the fixed scroll and the end plate of the revolving scroll, and that seals a space between the fixed scroll and the revolving scroll, with the scroll-type fluid machine further comprising a shield part that suppresses dust from reaching the face seal from the outside in the radial direction.

The present invention effectively cools air in a compression process at a high stage when an oil is supplied at the same pressure at a low stage and the high stage. Provided is a liquid-cooled type compressor including: a liquid-cooled type compressor body; at least one first nozzle; and at least one second nozzle, the at least one first nozzle and the at least one second nozzle each having a plurality of injection ports per nozzle and supplying a refrigerant through the injection ports into an inside of the compressor body, the second nozzle having the injection ports each having a diameter larger than a diameter of each of the injection ports of the first nozzle.

The present invention provides an oil feed type air compressor that can reduce a power consumption of a compressor body during an unload operation. The oil feed type air compressor includes: a compressor body (1) compressing air while feeding an oil into a compression chamber; a separator (4) disposed on a discharge side of the compressor body; a compressed air-feeding system (5) feeding the compressed air separated by the separator to a use destination of the compressed air; an oil-feeding system (6) feeding the oil separated by the separator to the compression chamber of the compressor body; an oil cooler (11) and a temperature sensor (12) disposed in the oil-feeding system; and a controller enabling execution of a temperature control. The temperature control by the controller is performed by variably controlling a rotation speed of a cooling fan (13) such that, during the load operation, a temperature detected by the temperature sensor is a target value T1, and during the unload operation, the temperature detected by the temperature sensor is a target value T2 (with the proviso of T1>T2).

Power systems and methods of controlling an engine driven air compressor include an air compressor driven by an engine via a clutch. A first pressure sensor configured to sense a pressure level at an outlet of the air compressor. An inlet valve configured to close in response to the first pressure sensor sensing a pressure level above a first pressure level. In addition, a second pressure sensor to sense a pressure level below a second pressure level at a housing of the air compressor, wherein the clutch is configured to disengage in response to the second pressure level, wherein the first pressure level is higher than the second pressure level.

Provided is an air compressor which helps to attain a proper discharge air temperature and which is superior in energy saving property. There are provided an air line connecting an air compressor, an oil separator, and an after cooler; an oil circulation line connecting the air compressor, the oil separator, and an oil cooler; a bearing oil supply line connecting one end of an intermediate branching portion disposed at an intermediate point of the oil circulation line between the oil cooler and the air compressor to a bearing oil supply portion of the air compressor; an intermediate portion oil supply line connecting the other end of the intermediate branching portion to an intermediate oil supply portion of the air compressor; a branching line supplying oil to the bearing oil supply portion and the intermediate oil supply portion; a blower sending air to the oil cooler and the after cooler; a bypass line connecting one end of a bypass branching portion disposed at an intermediate point of the oil circulation line between the oil separator and the oil cooler to the downstream side of the oil cooler of the bearing oil supply line; and a control valve controlling the inflow amount of the lubricating oil to the bypass line.

A fixed scroll member includes a fixed base and a spiral fixed tooth member mounted to the fixed base. An orbiting scroll member is made of a resin material and includes an orbiting base arranged to face the fixed base; and a spiral orbiting tooth member. A housing is configured to house the fixed scroll member and the orbiting scroll member with the fixed scroll member being fixed thereto. An orbiting slide surface is located to be radially outside of the orbiting base of the orbiting scroll member, and a housing slide surface is formed on a portion of the housing. The portion is made of a metal material and is arranged to face the orbiting slide surface. The orbiting slide surface is in slidable contact with the housing slide surface. The portion of the housing has an outer wall exposed to atmospheric air.

A pneumatic system installed on a vehicle and method of using the system to preheat compressor oil and/or components of the system to promote operation in cold weather conditions. The pneumatic system includes a compressor that generates compressed air in which oil is entrained, a separation tank that separates the oil from the air prior to the oil being returned to the compressor, and a heating element located within the separation tank and contacting the oil within the separation tank. Engine coolant of an engine cooling system of the vehicle flows through the heating element and the heating element transferring heat from the engine coolant to the oil within the separation tank to increase the temperature of the oil.

Power systems and methods of controlling an engine driven air compressor include an air compressor driven by an engine via a clutch. A first pressure sensor configured to sense a pressure level at an outlet of the air compressor. An inlet valve configured to close in response to the first pressure sensor sensing a pressure level above a first pressure level. In addition, a second pressure sensor to sense a pressure level below a second pressure level at a housing of the air compressor, wherein the clutch is configured to disengage in response to the second pressure level, wherein the first pressure level is higher than the second pressure level.

A screw expander includes a main body, at least an expansion screw and an adjusting component. The main body has a high pressure region, an expansion region and a low pressure region. The expansion screw is disposed at the expansion region and has an air inlet end and an air outlet end, wherein the air inlet end is connected to the high pressure region, and the air outlet end is connected to the low pressure region. The adjusting component covers the expansion screw, and is adapted to move relatively to the expansion screw to change an opening area of the air inlet end or an opening area of the air outlet end, such that a pressure of an air exhausted from the air outlet end is adjusted.

Some embodiments are directed to a positive displacement pump comprising: a pipe having a first end secured to a transmission area and a second end ending in a cylinder secured to a discharge area, the pipe comprising a suction opening and the discharge area comprising a discharge opening, a drive shaft with one end situated at the cylinder, a piston pressed against the cylinder by elastic means so as to prevent fluid from moving between the pipe and the discharge area, in which the pump further comprises means for moving the piston elastically away from the cylinder and keeping it at a predetermined distance from same. Some other embodiments are directed to a method for cleaning this pump.