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 refrigeration cycle apparatus includes: a refrigeration cycle circuit in which a compressor, a condenser, a first expansion valve, and an evaporator are connected by refrigerant pipes; an injection pipe having a refrigerant inflow side end and a refrigerant outflow side end, the refrigerant inflow side being connected between the condenser and the first expansion valve, the refrigerant outflow side end being connected to a suction side of the compressor; a second expansion valve provided at the injection pipe; and a controller that controls a rotation speed of the compressor and an opening degree of the second expansion valve. In the case of reducing a heat-exchange capability of the evaporator when the rotation speed of the compressor is a specified rotation speed, the controller performs a low load operation during which refrigeration is caused to flow through the injection pipe.

A rotary compressor includes a drive mechanism, a compression mechanism, an introduction path to introduce a fluid into a compression chamber of the compression mechanism, and a backflow suppression mechanism. At least one of a first surface and a second surface of a valve body includes an annular first non-contact region that is formed in a predetermined range extending radially inward from an outer edge of the valve body and that does not come into contact with a corresponding valve seat, an annular second non-contact region that is formed in a predetermined range extending radially outward from the hole of the valve body and that does not come into contact with a corresponding valve seat, and a contact region that is formed between the first non-contact region and the second non-contact region and that comes into contact with a corresponding valve seat.

A compressor includes three suction pipes. A first center of a first suction pipe, a second center of a second suction pipe, and a third center of a third suction pipe are positioned at vertices of a triangle. A first distance between the first center and a center of a compressor main body is smaller than a second distance between the second center and the center of the compressor main body and a third distance between the third center and the center of the compressor main body. A second flow path cross section and a third flow path cross section are positioned on opposite sides of a center connection line sandwiched therebetween. The first suction pipe is connected to a suction port which is at an uppermost position among three suction ports provided in a case.

A scroll compressor may include a casing having a low pressure portion and a high pressure portion, a refrigerant suction pipe that communicates with the low pressure portion and a refrigerant discharge pipe that communicates with the high pressure portion, a drive motor installed inside of the low pressure portion, an orbiting scroll coupled to the drive motor to perform an orbiting motion, a non-orbiting scroll engaged with the orbiting scroll to form a compression chamber, and a refrigerant guide provided on the non-orbiting scroll to guide a refrigerant suctioned into the low pressure portion to be suctioned into the compression chamber, whereby an increase in specific volume of refrigerant suctioned into the compression chamber may be suppressed, and thus, an amount of refrigerant suctioned into the compression chamber may increase, thereby improving efficiency of the compressor.

A screw spindle pump, comprising a pump housing having a lead screw received therein and at least one running spindle which meshes with said lead screw, as well as a connector housing which is placed onto the pump housing and has a suction connector and a pressure connector, the two latter fluidically communicating with a suction inlet and a pressure outlet of the pump housing, wherein the connector housing is composed of a first housing part and a second housing part, one of the two latter having the suction connector and the other having the pressure connector, both said housing parts being rotatable relative to the pump housing and both being rotatable relative to one another.

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 rough-vacuum pump of dry type includes a duct formed in the stator and of which an inlet orifice is intended to be connected to at least one source of purge gas and of which at least one outlet orifice communicates with the last pumping stage communicating with the delivery and a device for injecting a heated purge gas including a heating device to at least partly heat the purge gas injected into the duct to a temperature higher than 40° C.

A compressor includes a shell assembly, a compression mechanism and a suction fitting. The shell assembly defines a chamber. The compression mechanism is disposed within the chamber of the shell assembly and includes a suction inlet. The suction fitting is attached to the shell assembly and extends at least partially into the chamber of the shell assembly. The suction fitting defines first and second openings. The suction fitting directs working fluid through the first opening towards the compression mechanism and the suction fitting directs working fluid through the second opening away from the compression mechanism.

A screw compressor for a utility vehicle includes a housing. The housing is filled with oil. At least one pair of compressor screws are mounted in the housing and serve to compress air supplied to the screw compressor. In the assembled state, a heat exchanger is directly placed onto and installed on the housing, by which heat exchanger the temperature of the oil contained in the housing can be controlled.