A variable displacement lubricant pump includes a housing, a control ring arranged in the housing, an inlet chamber and an outlet chamber, and a lateral slide bearing. The control ring is shiftable, radially confines a pumping chamber, and comprises a drainage channel. The outlet chamber and the inlet chamber are arranged at opposite lateral sides of the control ring. The lateral slide bearing is arranged at the lateral side of the control ring where the outlet chamber is arranged and comprises a first lateral slide bearing surface defined by the static housing, a second lateral slide bearing surface arranged opposite to the first lateral slide bearing surface which is defined by the control ring, and a lateral slide bearing gap defined between the first and second lateral slide bearing surfaces. The drainage channel of the control ring fluidically connects the lateral slide bearing gap with the inlet chamber.

A stator for an eccentric screw pump with an internal hollow space with a helically coiled inner contour for accommodating a rotor. The stator includes a stator core arranged in a stator casing, which stator core includes at least two radially separable core parts. According to the invention, the at least two radially separable core parts are each made from a metallic material or a technical ceramic material. The stator casing is a stator tube and is made of a metallic material. The stator casing is shrink-fitted onto the stator core. The invention also relates to an eccentric screw pump and a method for producing a stator.

A variable displacement lubricant pump includes a housing, a control ring arranged in the housing, an inlet chamber and an outlet chamber, and a lateral slide bearing. The control ring is shiftable, radially confines a pumping chamber, and comprises a drainage channel. The outlet chamber and the inlet chamber are arranged at opposite lateral sides of the control ring. The lateral slide bearing is arranged at the lateral side of the control ring where the outlet chamber is arranged and comprises a first lateral slide bearing surface defined by the static housing, a second lateral slide bearing surface arranged opposite to the first lateral slide bearing surface which is defined by the control ring, and a lateral slide bearing gap defined between the first and second lateral slide bearing surfaces. The drainage channel of the control ring fluidically connects the lateral slide bearing gap with the inlet chamber.

A scroll compressor is provided which comprises: a housing; a driving motor; an orbiting scroll rotated by the driving motor; a fixed scroll; a suction port provided in the housing and suctioning a refrigerant; an oil separator in the housing at one side of the fixed scroll; and a discharge port for discharging, to the outside of the housing, the refrigerant from which oil is separated in the oil separator. The scroll compressor includes an intermediate housing; a back pressure chamber in the intermediate housing at one side of the orbiting scroll, first and second back pressure seal members in the intermediate housing; a plurality of anti-rotation rings in the intermediate housing; and a plurality of anti-rotation pins at the orbiting scroll to be inserted into each of the plurality of anti-rotation rings.

A scroll compressor includes a refrigerant discharge flow passage and an oil recovery flow passage that are separated from each other. The scroll compressor further includes a flow passage separation unit configured to separate an intermediate space between a drive portion and a compression portion into an inner space communicating with the refrigerant flow passage and an outer space communicating with the oil flow passage to separate the refrigerant discharge path from the oil recovery path.

A back pressure chamber forming portion forms a back pressure chamber configured to accumulate a high pressure refrigerant discharged from a working chamber and thereby generate a refrigerant pressure, which urges a movable scroll against a stationary scroll. A balancer is placed at an inside of the back pressure chamber and is configured to be rotated by a rotatable shaft. The back pressure chamber forming portion has a discharge hole that communicates between a radially outer side of the back pressure chamber, which is located radially outward in a radial direction of an axis of the rotatable shaft, and a suction chamber to discharge a liquid phase refrigerant from the back pressure chamber into the suction chamber when the liquid phase refrigerant flows from the working chamber into the back pressure chamber.

A pump for pumping a gas, the pump comprising: a rotor and a stator; the rotor comprising at least one liquid opening configured for fluid communication with a liquid source. The liquid opening is configured such that in response to a driving force a stream of liquid is output from the opening, the stream of liquid forming a liquid blade between the rotor and the stator, gas confined by the stator, the rotor and the liquid blade being driven through the pump along a pumping channel from a gas inlet towards a gas outlet in response to relative rotational motion of the rotor and the stator. A cross sectional area of the pumping channel is configured to increase from the gas inlet to the gas outlet.

A pump unit includes a rough-vacuum pump and a Roots vacuum pump connected in series and upstream of the rough-vacuum pump in the direction of flow of the pumped gases. The Roots vacuum pump has three pumping stages in which the rotors are designed to be driven simultaneously in rotation by a motor of the Roots vacuum pump. A ratio of the flow rate generated by the first pumping stage of the rough-vacuum pump in the direction of flow of the pumped gases over the flow rate generated by the last pumping stage of the rough-vacuum pump is less than or equal to four.

A pump unit includes a rough-vacuum pump and a Roots vacuum pump connected in series and upstream of the rough-vacuum pump in the direction of flow of the pumped gases. The Roots vacuum pump has three pumping stages in which the rotors are designed to be driven simultaneously in rotation by a motor of the Roots vacuum pump. A ratio of the flow rate generated by the first pumping stage of the rough-vacuum pump in the direction of flow of the pumped gases over the flow rate generated by the last pumping stage of the rough-vacuum pump is less than or equal to four.

A stator includes a stator core having a plurality of slots in a circumferential direction about an axis and having an end surface in a direction of the axis, and a first coil and a second coil of different phases which are wound on the stator core in distributed winding. A winding factor is 1. Each of the first coil and the second coil has winding portions, the number of which corresponds to the number of poles. The winding portions include first and second winding portions adjacent to each other in the circumferential direction. The first and second winding portions are inserted into one slot of the plurality of slots and extend from the one slot to both sides in the circumferential direction on the end surface. The first and second coils are annularly disposed in different positions in a radial direction about the axis on the end surface.