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.

An air compressor apparatus is disclosed that includes an air tank. A first compressor assembly can be fluidly coupled to the air tank, the first compressor assembly including a first head unloader valve. A second compressor assembly can be fluidly coupled to the air tank, the second compressor assembly including a second head unloader valve. A control unit can be electrically coupled to the first and second compressor assemblies, the control unit operable to control the operation of the first and second compressor assemblies. During startup, the first and second air compressor assemblies can be configured to draw less than 20 amps of current combined from a single 120 volt power source. The first and second compressor assemblies can each be dual piston compressor assemblies.

A pumping system is provided, including a rough-vacuum pump; a Roots vacuum pump including a pumping stage having a stator inside which two Roots rotors are configured to rotate synchronously in opposite directions to drive a gas to be pumped between an inlet orifice and an outlet orifice; and a pipeline connecting the outlet orifice to an intake of the rough-vacuum pump, a shortest distance between an edge of the outlet orifice and each of the Roots rotors in the pumping stage being less than 3 cm, and the outlet orifice being situated at the end of an upstream tube of the pipeline that passes into the pumping stage.

A pumping system is provided, including a rough-vacuum pump; a Roots vacuum pump including a pumping stage having a stator inside which two Roots rotors are configured to rotate synchronously in opposite directions to drive a gas to be pumped between an inlet orifice and an outlet orifice; and a pipeline connecting the outlet orifice to an intake of the rough-vacuum pump, a shortest distance between an edge of the outlet orifice and each of the Roots rotors in the pumping stage being less than 3 cm, and the outlet orifice being situated at the end of an upstream tube of the pipeline that passes into the pumping stage.

A vacuum pump system comprising a main vacuum pump that is connected to a chamber that is to be evacuated. An auxiliary pump is connected to an outlet of the main vacuum pump. Furthermore, a sealing gas supply device is connected to the main vacuum pump. The sealing gas supply device is switched on and off with the aid of a control device as a function of a predetermined control variable. Additionally, a method for controlling the vacuum pump system.

A dry vacuum pump includes an elastic outer seal and at least one elastic inner seal respectively including a first and a second end annular parts parallel to one another and inserted between a respective end piece and the half-shells, and two side rails connecting the end annular parts and which are at right angles thereto, the side rails being inserted between the half-shells, the at least one inner seal being arranged inside the outer seal so that the at least one inner seal and the outer seal form at least two successive sealing barriers for the gases.

A vacuum system having a condenser and a root vacuum pump set includes an independent inlet condenser set having an inlet end for receiving vapor inputted from an output of an air cooling power generator condenser of a generator; air in the vapor being condensed, and the surplus air is outputted; a root vacuum pump set including at least one root vacuum pump; the root vacuum pump set further including an input end and an output end; the input end being connected to the independent inlet condenser set; air outputted from the independent inlet condenser set being inputted to the at least one root vacuum pump for compression and then the compressed air being outputted from the output end; and a backing pump connected to the output end of the root vacuum pump set by using an output pipe; the backing pump serving to receive air outputted from the root vacuum pump set.

A scroll compressor is provided. The scroll compressor includes a fixed scroll, an orbiting scroll configured to orbit with respect to the fixed scroll and including an orbiting end plate, and a main frame to which the orbiting scroll is coupled to orbit. The scroll compressor includes a compression chamber in which a refrigerant is compressed by the fixed scroll and the orbiting scroll, and a first back pressure chamber and a second back pressure chamber provided to communicate with the compression chamber. The first back pressure chamber and the compression chamber communicate with each other through a first flow path. The second back pressure chamber and the compression chamber communicate with each other through a second flow path. A different intermediate back pressure is formed in the first back pressure chamber and the second back pressure chamber.

Some embodiments of the present disclosure provide a compressor and an air conditioner with the compressor. The compressor includes: a first compression part, a second compression part, an intermediate cavity and an intermediate passage. Refrigerant discharged from the first compression part enters the intermediate cavity. The intermediate passage communicates with the intermediate cavity and an inner cavity of the second compression part. A bottom port of the intermediate passage is located at a bottom of the intermediate cavity, and air supplement refrigerant and/or the refrigerant discharged from the first compression part are used to convey accumulated oil in the intermediate cavity to the inner cavity of the second compression part. When only the refrigerant is used to convey the accumulated to the inner cavity of the second compression part, at least a part of the intermediate passage is located outside of a housing assembly of the compressor.

A compressor is provided. The compressor may include a fixed wrap, and an orbiting scroll having an orbiting wrap engaged with the fixed wrap to form compression chambers. The fixed wrap and the orbiting wrap may have irregular wrap curves. At least one interference avoiding portion at which a spacing between the wraps is greater than an orbiting radius or at least one gap compensating portion at which the spacing between the wraps is smaller than the orbiting radius, in a state in which a center of the fixed scroll and a center of the orbiting scroll are aligned with each other, may be provided on a sidewall surface of the fixed wrap or the orbiting wrap, whereby frictional loss or abrasion due to interference between the wraps or a refrigerant leakage due to a gap between the wraps may be prevented.