An oil-free water-injected screw air compressor comprises a housing that encloses two rotors for generating compressed air, and an air water separator for separating the water from the compressed air. Water injection can effectively cool a compressor, and some embodiments provide a sealing system for isolation of compressor bearing lubricant from water used for cooling.

A positive displacement pump assembly includes a rotor housing defining a rotor cavity, and an end plate configured to at least partially close one end of the rotor cavity. Rotors are supported on and fixed to rotor shafts and extend through the rotor cavity. A first pair of bearings fixing the rotor shafts to the end plate. A second pair of bearings fixes the rotor shafts to the rotor housing, preventing relative axial movement between the rotor shafts and the rotor housing. The end plate is axially movable with the rotor shafts when the rotor shafts vary in axial length due to thermal fluctuations so that changes in an axial clearance at end faces of the rotors are reduced.

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.

A unique compressor system may include a compressor having a compressor housing. The compressor housing may include an oil drainage passage formed therein. The passage may be configured to drain oil from bearings and other oil-lubricated components of the compressor. The compressor may be coupled to a gearbox or an oil tank. The gearbox or oil tank may include a passage that is in fluid communication with the oil drainage passage. The gearbox or oil tank passage may be operative to receive the drained oil and to direct the drained oil to an oil tank.

A bearing assembly includes a bearing defining a bearing bore therethrough with a plurality of spring bores circumferentially distributed around the bearing bore. A respective spring is seated in each of the spring bores. Each spring is has a flared end that is larger in diameter than a main section of the spring. The flared end of each spring engages its respective spring bore.

A gear pump or a gear motor includes a casing, a helical drive gear, a helical driven gear, a drive-side space, and an idler-side space. The drive and driven gears mesh with each other in the casing to partition inside of the casing so as to include high and low pressure spaces. The drive-side and idler-side spaces are each configured to allow pressure therein to become higher than a pressure in the low-pressure space. The drive-side space faces an end portion of a drive shaft rotatably supporting the drive gear. The idler-side space faces an end portion of an idler shaft rotatably supporting the driven gear. The end portion of the drive shaft is pushed in a predetermined direction by working fluid supplied to the drive-side space. The end portion of the idler shaft is pushed in the predetermined direction by working fluid supplied to the idler-side space.

A pump as provided includes an inlet, an outlet, and a scroll pumping element. The scroll pumping element includes a fixed scroll component having one or more fixed scrolls and orbiting scroll component having one or more orbiting scrolls for fluid pumping. The fixed scroll component and the orbiting scroll component are arranged so as to be capable of providing pressurized fluid to a thrust bearing and prevent contact between the fixed scroll component and the orbiting scroll component.

This electric horizontal scroll compressor (1) comprises an oil reservoir (13) in which lubricating oil that is separated from refrigerant passing through a compressing mechanism (20) is temporarily stored, and an oil return flow channel (15, 24) by which lubricating oil stored in the oil reservoir (13) is returned further upstream than the compressing mechanism (20). A main bearing (35) is fit into a holding face (14a) of an inner housing (14) by way of a clearance fit, and lubricating oil stored in the oil reservoir (13) is supplied to the region of the fit via the oil return flow channel (15, 24).

A compressor crankshaft assembly includes a crankshaft and an eccentric drive pin extending from one end of the crankshaft. The shape of the drive pin viewed into the exposed end of the drive pin is defined by the intersection of a first cylinder that is coaxial with the axis of a substantially cylindrical orbital bearing journaled and installed to receive the eccentric drive pin and a second cylinder that is coaxial with the axis of a substantially cylindrical main bearing journaled and installed to rotatably receive the crankshaft, such that the area defined by the intersecting portion is less than the area defined by either cylinder.

A scroll compressor including a first bearing rotatably supporting a rotary shaft relative to a casing at one side of the rotary shaft with respect to a motor, a second bearing rotatably supporting the rotary shaft relative to the casing at the other side of the rotary shaft with respect to the motor, and a third bearing rotatably supporting the rotary shaft relative to an orbiting scroll at the opposite side of the first bearing with respect to the second bearing. The distance between a first bearing center and a third bearing center is a predetermined distance, the distance between a motor center and the third bearing center is longer than the distance between the motor center and the first bearing center, and the distance between a second bearing center and the motor center is longer than the distance between the second bearing center and the third bearing center.