A screw compressor for a heating, ventilation, and air conditioning (HVAC) system. The screw compressor includes a housing having an inlet end and an outlet end for refrigerant to pass into and out of the housing. A motor is within the housing. A plurality of screw sets are arranged about the motor. The screw sets receive refrigerant entering through the inlet, compress the refrigerant between meshed rotors of the plurality of screw sets, and direct refrigerant out of the housing through the outlet end of the housing.

The present invention relates to a pumping system to generate a vacuum (SP), comprising a main vacuum pump which is a claw pump (3) having a gas suction inlet (2) connected to a vacuum chamber (1) and a gas discharge outlet (4) leading into a gas evacuation conduit (5) in the direction of a gas exhaust outlet (8) outside the pumping system. The pumping system comprises a non-return valve (6) positioned between the gas discharge outlet (4) and the gas exhaust outlet (8), and an auxiliary vacuum pump (7) connected in parallel to the non-return valve. In a pumping method by means of this pumping system (SP), the main vacuum pump (3) is started up in order to pump the gases contained in the vacuum chamber (1) and to discharge these gases through its gas discharge outlet (4), simultaneously to which the auxiliary vacuum pump (7) is started up. Moreover the auxiliary vacuum pump (7) continues to pump all the while that the main vacuum pump (3) pumps the gases contained in the vacuum chamber (1) and/or all the while that the main vacuum pump (3) maintains a defined pressure in the vacuum chamber (1).

A compressor or vacuum pump including: a casing having a cooling gas inlet and a cooling gas outlet for allowing a cooling gas to flow therethrough; a fan mounted at the cooling gas inlet, including a fan housing and configured to blow said cooling gas into said casing; a compression or vacuum chamber including a first housing, a process gas inlet and outlet for allowing a process gas to flow therethrough and at least one rotating element; a driving module including a second housing and at least one bearing for supporting said at least one rotating element; a silencer including a cover and configured to attenuate noise generated by the compressor or vacuum pump. The silencer includes a recess structure on its cover, configured to deflect the cooling gas flow from the fan towards the driving module.

A vacuum system is disclosed. The vacuum system includes a first pump bay and a second pump bay enclosed by an enclosure. Each pump bay houses a motor and a vacuum pump driven by the motor. An inlet manifold and an exhaust manifold are in fluid communication with the first and second pump bays. The inlet manifold and the exhaust manifold are arranged to flow air through the pump bays to cool at least the vacuum pumps.

A twin-shaft pump comprising: a pumping chamber; two rotatable shafts each mounted on bearings is disclosed. Each of the two rotatable shafts comprises at least one rotor element, the rotor elements being within the pumping chamber and the two rotatable shafts extending beyond the pumping chamber to a support member. The support member comprises mounting means for mounting the bearings at a predetermined distance from each other, the predetermined distance defining a distance between the two shafts. A thermal break between the pumping chamber and the support member is provided for impeding thermal conductivity between the pumping chamber and the support member, such that the pumping chamber and support member can be maintained at different temperatures. The support member and the rotor elements are formed of different materials, a coefficient of thermal expansion of a material forming the support member being higher than a coefficient of thermal expansion of a material forming the rotor elements.

A screw compressor for a heating, ventilation, and air conditioning (HVAC) system. The screw compressor includes a housing having an inlet end and an outlet end for refrigerant to pass into and out of the housing. A motor is within the housing. A plurality of screw sets are arranged about the motor. The screw sets receive refrigerant entering through the inlet, compress the refrigerant between meshed rotors of the plurality of screw sets, and direct refrigerant out of the housing through the outlet end of the housing.

A rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

A Rotary Claw Pump with at least one pair of intermeshing rotors has the same shape within a tolerance of 3% of the radii from edges to rotational centers. A convex portion of the claws has a nominal uniform rate of radius change with angle of rotation. There may be multiple stages wherein the thickness of each successive rotor pair maintains profile but has a thickness within 20% of the thickness of the first stage rotor pair multiplied by the inverse products of the compression ratios of the preceding stages. A discharge port is at least partially uncovered at any position of rotation from where intermeshing claw rotor tips are closest to where they are most distant. The discharge port is at least partially connected with a region connected with the rotor tips of both claws during rotation. The discharge port limits pressure increase in the region.

A dry roughing vacuum pump includes a valve (10; 15) with a through-passage arranged in the discharge line (9), the valve (10) with a through-passage being able to move between a closed position in which the valve (10; 15) with a through-passage is in contact with a seat of a mouth (12) of the discharge line (9) and an open position in which the valve with a through-passage is moved away from the mouth (12) of the discharge line (9), the vacuum pump including a motor gas injection device (13) that is configured to inject a motor gas into the inlet (11a) of the Venturi-effect passage (11).

A pump includes a first housing part defining a first portion of a bore extending within the first housing part and shaped to receive a rotor; and a second housing part defining a second portion of the bore extending within the second housing part and shaped to receive the rotor. The first housing part has a first face abutable against an opposing second face of the second housing part to position the first portion of the bore with the second portion of the bore to receive the rotor. The first portion of the bore has a first circular cross-section portion centered along the first face and the second portion of the bore having a second circular cross-section portion centered, within the second housing part, at a distance from the second face.