A vacuum booster assembly includes, but is not limited to, a booster housing defining a booster chamber and including a gas inlet and a gas outlet; a first rotor positioned within the booster chamber and adapted for rotation therein, the first rotor including a first shaft and at least two lobes defining a first lobe profile; and a second rotor positioned within the booster chamber and adapted for rotation therein, the second rotor including a second shaft and at least two lobes defining a second lobe profile, wherein the first and second rotors are formed from a metal having a coefficient of thermal expansion from about 1 (10.sup.−6 in/in*K) to about 13 (10.sup.−6 in/in*K), and wherein at least one of the outer surface of the first rotor, the outer surface of the second rotor, or the booster chamber includes a coating.

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 dry vacuum pump includes: at least one oil sump; at least one pumping stage; two rotary shafts respectively supporting at least one rotor extending into the at least one pumping stage, the rotors being configured to rotate in a synchronized manner in the reverse direction in order to convey a gas to be pumped between an intake and an outlet of the vacuum pump, the shafts being supported by bearings lubricated by a lubricant contained in the at least one oil sump; at least one lubricant sealing device interposed between the at least one oil sump and a pumping stage at the shaft passage; and at least one expansion device configured to reduce the pressure variations between a pumping side volume and the at least one oil sump.

The invention relates to a rotary piston pump comprising a housing with a housing interior, an inlet opening, and an outlet opening; a first rotary piston which is mounted within the housing interior in a rotational manner about a first rotational axis; and a second rotary piston which is mounted within the housing interior in a rotational manner about a second rotational axis. The first rotary piston and the second rotary piston engage into each other in a region between the first and the second axis and displace liquid. The first rotary piston has a frame assembly which comprises multiple mutually spaced plates and is at least partly filled and enveloped with a polymer material.

A multi-stage rotary piston pump comprising two shafts in a housing, which support multiple rotary pistons. Corresponding rotary pistons form a respective rotary piston pair, wherein multiple rotary piston pairs are provided which form a respective pump stage. Neighboring pump stages are each connected to one another via connection channels. The multi-stage rotary piston pump also comprises a pump inlet that is connected to the first pump stage, as well as a pump outlet that is connected to the last pump stage. The built-in volume ratio is at least 15, so that high pumping capacities of at least 1500 m.sup.3/h can be achieved.

A roots rotor for removing dust coagulum and droplets comprises a rotor body, which rotates inside the roots pump case. Both ends of the rotor body are sealing surfaces, which are meshed with the inner wall of the roots pump case. The rotor slot scraping cavities are arranged on both sides of the sealing surface. The side of the rotor slot scraping cavity close to the sealing surface is set as the scraper surface, which forms a sharp edge with the sealing surface. A guide surface is arranged on the surface of the rotor body, and the guide surface is located on the side of the rotor slot scraping cavity away from the sealing surface. The utility model overcomes the disadvantages of the prior art, and the attachment can be scraped off and gathered into the rotor slot scraping groove through the action of the scraper surface; and with the rotation of the rotor body, the particles and dust can be easily dropped outside the exhaust port of the pump; thus to achieve to avoid the accumulation of dust, coagulum and other incompressible medium in the process gas on the wall of the pump case.

A structure of rotor connection of multi-axial multi-stage roots pump comprises a rotor body, a rotor shaft is arranged on one end face of the rotor body, a sub-shaft cavity is opened in the rotor shaft, and the locating keyways are symmetrically opened on both sides inside the sub-shaft cavity; a sub-shaft is arranged on the other end face of the rotor body, the sub-shafts and the sub-shaft cavities of two adjacent rotor bodies are matched, locating keyways are symmetrically opened on both sides of the sub-shaft, and the keyways are installed and fixed through sub-rotor shaft keys in the locating keyways. The invention overcomes the disadvantages of the prior art, and the first-stage rotor body is limited and fixed by the bearing, while the second-stage rotor body is only radially limited by the bearing in the first-stage rotor body. The rotor shaft on the other side is also fixed and limited by the bearing, so the thermal expansion displacement and thermal stress of the second-stage rotor body are completely independent during operation. The thermal expansion displacement of the first-stage rotor body does not affect the second-stage rotor body, and it can also synchronously drive the second-stage rotor body.

A supercharger having twisted meshing rotors sealingly contained within a housing having an inlet port to admit air into the meshing rotors and an outlet port to expel air from the meshing rotors, the rotors having mesh points where the rotors contact one another and spaces between their mesh points to accept air from the inlet port and propel it to the outlet port as the rotors are rotated and the mesh points travel axially, the housing, inlet and rotors defining an angle known as the seal transfer angle which is greater than or equal to zero degrees when the inlet port is closed and the volume of air between rotors is sealed and has no leakage path. In the described supercharger the housing, rotors and inlet port are configured to have a negative seal transfer angle of, e.g., −10 to −40 degrees or more, up to the maximum available, and to provide a leakage path for an angular portion of the rotors' rotation, improving high end performance without degrading low end performance.

A method of designing a supercharger that yields a high isometric efficiency based on a fixed pressure ratio, a plurality of rotor leads and a plurality of rotor operating speeds is provided. An efficiency map is generated of rotor lead versus rotor operating speeds for the fixed pressure ratio. A rotor lead value is determined based on the fixed pressure ratio and rotor speed combination from the efficiency map that yields a high isometric efficiency. A supercharger is provided having the determined rotor lead and that is configured to operate with the fixed pressure ratio and the determined rotor operating speed.

An electric compressor system for a vehicle includes: an electric motor having a rotor and a motor shaft which selectively rotate in a first rotation direction or a second rotation direction; an external rotation shaft extending from the motor shaft of the electric motor; a first compressor unit connected to the external rotation shaft and selectively compressing a first fluid according to the rotation direction of the external rotation shaft; and a second compressor unit connected to the external rotation shaft and selectively compressing a second fluid according to the rotation direction of the external rotation shaft, wherein the first compressor unit and the second compressor unit are sequentially arranged on the external rotation shaft, the first compressor unit is fluidly connected to a first fluid system, and the second compressor unit is fluidly connected to a second fluid system.