A non-lubricated system for pumping a gas, includes a stationary stator with a housing that includes a rotor cavity and at least one rotatable rotor element incorporated within the rotor cavity. The stator includes at least one self-supporting sealing element, incorporated within the rotor cavity between an end face of at least one of the rotor elements and an interior wall of the housing to form a seal along the corresponding end face. At least one self-supporting sealing element is provided with an abradable coating on at least one side facing the rotor.

A dry vacuum pump is provided, including two shafts, respectively supporting at least one pumping rotor being configured to synchronously rotate in reverse in order to convey a gas to be pumped from an intake of the dry vacuum pump to an outlet; and a synchronous motor configured to rotate one shaft of the two shafts, the synchronous motor including a rotor coupled to the shaft, a first stator with windings arranged around the rotor, and at least one second stator with windings arranged around the rotor, the windings of the stators being configured to be supplied individually or simultaneously in order to adapt a power of the synchronous motor to a pumping load. A method for controlling a synchronous motor of a vacuum pump is also provided.

A dry vacuum pump is provided, including two shafts, respectively supporting at least one pumping rotor being configured to synchronously rotate in reverse in order to convey a gas to be pumped from an intake of the dry vacuum pump to an outlet; and a synchronous motor configured to rotate one shaft of the two shafts, the synchronous motor including a rotor coupled to the shaft, a first stator with windings arranged around the rotor, and at least one second stator with windings arranged around the rotor, the windings of the stators being configured to be supplied individually or simultaneously in order to adapt a power of the synchronous motor to a pumping load. A method for controlling a synchronous motor of a vacuum pump is also provided.

Dual- or multi-shaft vacuum pump comprising an engine, a first shaft and at least one second shaft, wherein the first shaft and the second shaft are synchronously driven by the motor via a common drive belt. The first shaft has a pumping element and the second shaft likewise has a pumping element which cooperates with the pumping element of the first shaft in order to convey a gaseous medium from an inlet to an outlet. The first shaft has a first emergency running gear and the second shaft likewise has a second emergency running gear which meshes with the first emergency running gear.

A thermal abatement system comprises an axial inlet, radial outlet supercharger. A main case comprises at least two rotor bores, an inlet plane and an outlet plane. The inlet plane is perpendicular to the outlet plane. An inlet wall comprises an inner surface. Two rotor mounting recesses are in the inner surface, and the inlet wall is parallel to the inlet plane. An outlet is in the outlet plane. An inlet is in the inlet plane. At least two rotors are configured to move air from the inlet to the outlet. The main case comprises at least two backflow ports. An intercooler is connected to receive air expelled from the supercharger, to cool the received air, and to expel the cooled air to the at least two back flow ports.

A pumping unit is provided, including a primary vacuum pump of a multistage dry type, including at least four pumping stages fitted in series; and a two-stage Roots vacuum pump, including a first pumping stage and a second pumping stage fitted in series, the second pumping stage being fitted in series with and upstream of a first pumping stage of the primary vacuum pump in a direction of flow of gases to be pumped, in which a ratio of a volume displacement of the first pumping stage of the two-stage Roots vacuum pump to a volume displacement of the second pumping stage of the two-stage Roots vacuum pump is less than six, and in which a ratio of a volume displacement of the second pumping stage of the two-stage Roots vacuum pump to a volume displacement of the first pumping stage of the primary vacuum pump is less than six.

An internal combustion engine includes one or more pairs of non-meshing, externally timed rotors disposed within a housing in an expander module and a compressor module. Each rotor includes a cylindrical, center main body including a first end, a second end opposite the first end, an elongate portion extending between the ends and a first peripheral surface portion and a second peripheral surface portion and a bore extending through a center of the main body from the first end to the to second end. The rotors each have a groove extending along outer peripheral edge portions of the rotor. A pair of tip seals is disposed in the grooves. A pair of apex seals is disposed on the first peripheral surface portion and the second peripheral surface portion and an axially floating end plate is disposed at an end of the housing.

An exhaust gas recirculation pump system for an internal combustion engine includes an EGR gas source and an electric motor assembly. A roots device is coupled to the electric motor. The roots device includes a housing defining an internal volume wherein the housing includes a radial inlet port receiving the EGR gas source and an outlet port expelling the EGR gas from the housing. Rotors are disposed in the internal volume and connected to the electric motor. A transmission housing is attached to the housing. The transmission housing includes journals formed therein receiving bearings that support the rotors on only a single end of the rotors.

A power saving vacuum machine serves for improving vacuum ability of a condenser of a thermal power generator. The vacuum machine being installed after the condenser and includes a least one valve installed on the vacuum primary tube for sealing a vacuum primary tube to prevent air from entering into the condenser; a front stage pump has an inlet connected to an air inlet tube; at least one root vacuum pump including a main root vacuum pump; the main root vacuum pump including an inlet and a vent opening; the inlet of the main root vacuum pump being connected to a rear end of the vacuum primary tube. The at least one root vacuum pump may be only one pump which is the main root vacuum pump, or the at least one root vacuum pump is a plurality of root vacuum pumps which are connected serially.

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.