A dry vacuum pump may include a stator which defines an internal chamber in which a rotor is rotationally mounted. A sensor is mounted to the stator and has an output connected to a processing circuit arranged to analyse the output of the sensor to determine the absolute distance between a point on the surface of the rotor and internal stator surface. The rotor to stator clearance can thus be accurately determined in real time during operation of the pump, so that the pump performance can be optimised over its serviceable life.

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.

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 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 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.

A dry vacuum pump is provided, including an oil sump; a pumping stage; two rotating shafts respectively holding a rotor extending in the pumping stage, the rotor being configured to rotate in a synchronised manner in opposite directions in order to carry a gas to be pumped between an intake and a discharge of the pump, the two rotating shafts being supported by bearings lubricated by a lubricant contained in the oil sump; and a lubricant sealing device inserted between the oil sump and a pumping stage at each shaft passage, the sealing device including a disc-shaped deflector mounted on a shaft of the two rotating shafts for rotation therewith, and a disc of the deflector has an annular end on a periphery thereof, extending towards the pumping stage, forming a retaining recess.

A multi-stage positive displacement vacuum pump and a method of differentially pumping multiple vacuum chambers using such a pump is disclosed. The pump comprises a housing for housing at least one rotor mounted for rotation on a corresponding at least one shaft and for pumping gas through the multiple stages for output through an exhaust. The housing comprises a first inlet configured to admit gas to an inlet stage of said vacuum pump, and a further inlet configured to admit gas to an intermediate stage of said vacuum pump. The pump is configured such that gas admitted through each of the first and further inlets is pumped together as a combined gas flow by at least one stage of said vacuum pump downstream of said intermediate stage.

A multi-stage positive displacement vacuum pump and a method of differentially pumping multiple vacuum chambers using such a pump is disclosed. The pump comprises a housing for housing at least one rotor mounted for rotation on a corresponding at least one shaft and for pumping gas through the multiple stages for output through an exhaust. The housing comprises a first inlet configured to admit gas to an inlet stage of said vacuum pump, and a further inlet configured to admit gas to an intermediate stage of said vacuum pump. The pump is configured such that gas admitted through each of the first and further inlets is pumped together as a combined gas flow by at least one stage of said vacuum pump downstream of said intermediate stage.

A multi-stage dry Roots vacuum pump, including a pump body, multi-stage Roots working units and a plurality of drive components. The pump body is provided with a plurality of independent working chambers, and airflow channels communicating the various working chambers; the airflow channels are communicated with outside; the Roots working units of each stage include driving Roots rotors and driven Roots rotors; the driving Roots rotors and driven Roots rotors are positioned in the working chambers; and the various drive components are respectively used for driving the driving Roots rotors and driven Roots rotors positioned in the various working chambers to rotate towards opposite directions at the same rotating speed. The Roots working units of various stages may be randomly distributed at various positions of the pump body on premise of ensuring that the airflow channels can communicate the working chambers of each stage.