A gear configured to rotate as a unit with a shaft, the gear includes: a plurality of annular grooves formed on both side surfaces of the gear in a direction of a rotation axis of the shaft, at least partially overlapped when viewed from the direction of the rotation axis, and at least partially overlapped in a radial direction with respect to the rotation axis.

A multi-stage vacuum pump, expander, or compressor, that incorporates one or more stages of a fixed scroll(s) and orbiting scroll(s) that operates simultaneously. The motor drives the orbiting scroll(s) within the structure, and the various fixed and orbiting scrolls are arranged for either parallel generation of a vacuum or high pressure gas, or arranged in series for generating of a significantly high vacuum or gaseous pressure, or a combination of parallel arranged and series arranged fixed and orbiting scrolls may be embodied within the structure, operated by a single motor means, in order to attain the high efficiencies of operation as a vacuum pump, or a gaseous compressor, during its functioning. The various combinations of orbiting and fixed scrolls, when arranged as aforesaid, can be reduced in size, or miniaturized, and used in conjunction with small appliances, or even in hand-held instruments, as for example, for use in conducting mass spectrometry, or for other purposes. The actual structure of the multi-stage devices can include the fixed and orbiting scrolls adjacent the motor, or the singular motor may be located intermediate various stages of the formed vacuum pump/compressor, in its assembly.

A multistage pump assembly with at least one co-used shaft comprises a first pump set including at least two vacuum chambers. Each vacuum chamber of the first pump set is installed with at least one rotor and a first driving shaft, the rotor is installed to the first driving shaft in the same vacuum chamber of the first pump set. The first driving shafts in the first pump set are co-shafted, that is, rotors in the at least two vacuum chambers of the first pump set are installed at the same first driving shaft. A second pump set includes at least one vacuum chamber which includes at least one rotor and a second driving shaft. An outlet of the second pump set is connected to an inlet of the first pump set through an air tube.

A rotation shaft of a scroll compressor that includes an oil flow path formed therein, an upper frame support portion which is inserted into an upper frame, a boss insertion portion which is recessed from an upper surface of the upper frame support portion for insertion of the boss portion, and an oil residual groove which is recessed at a predetermined depth from a bottom portion of the boss insertion portion.

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.

Method for installing a transmission between a drive with a driveshaft and a load with a driven shaft, whereby this transmission includes a housing and at least a drive gear and a driven gear, wherein the method consists of first affixing the transmission over the driveshaft and fastening the housing of the transmission to the housing of the drive and then affixing a shaft seal over the driveshaft.

A multi-stage compressor unit including at least a first compressor stage including a first compressor element driven through a first gear-transmission and a second compressor stage including a second compressor element driven through a separate second gear-transmission. The first and second gear transmissions include a driving gear and a driven gear configured to be a multiplier, each of the driven gears is connected to a shaft of a rotor of the first compressor element or second compressor element respectively, where the first motor and the second motor re adapted to drive the first compressor stage and the second compressor stage separately. The gear ratio between the driven gear and the driving gear of either one of the first gear transmission and second gear transmission is situated between two and six.

A positive displacement rotary compressor is designed for near isothermal compression, high pressure ratios, high revolutions per minute, high efficiency, mixed gas/liquid compression, a low temperature increase, a low outlet temperature, and/or a high outlet pressure. Liquid injectors provide cooling liquid that cools the working fluid and improves the efficiency of the compressor. A gate moves within the compression chamber to either make contact with or be proximate to the rotor as it turns.

A conical screw compressor or pump comprising: an inner element configured to rotate around a first axis; and an outer element configured to rotate around a second axis; wherein an outer surface of the inner element and an inner surface of the outer element comprise cooperating grooves and teeth that intermesh on rotation; the first axis and the second axis are each stationary and the first axis is inclined relative to the second axis; and the inner element and the outer element are configured to be, in operation, synchronously rotated, thereby to reduce or eliminate force exerted by the inner element on the outer element or vice versa.

A compressor having a torque load reducing unit to move a center of weight to which a gas force is applied is provided. As the torque load reducing unit is formed at an oval-shaped roller, a distance between a rotation center of the roller and an operation point to which a gas force is applied is shortened. This may reduce a torque load to the roller, and may enhance a compression efficiency.