Rotary positive displacement machines with trochoidal geometry that comprise a helical rotor that undergoes planetary motion within a helical stator are described. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some multi-stage embodiments, the rotor-stator geometry remains substantially constant along the axis of the rotary machine. In other multi-stage embodiments, the rotor-stator geometry varies along the axis of the rotary machine.

A seal member includes pushing projections that project from a seal body toward at a groove inner-side circumferential surface and are arranged at intervals in a circumferential direction of the seal body. The pushing projections push the seal body against the groove inner-side circumferential surface and a groove outer-side circumferential surface between the groove inner-side circumferential surface and the groove outer-side circumferential surface. This reduces the gap between the groove outer-side circumferential surface and the seal member in the seal accommodating groove. Thus, salt water is unlikely to collect in the gap between the groove outer-side circumferential surface of the seal accommodating groove and the seal member. This improves the corrosion resistance of the housing and the seal member.

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 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 motor-driven scroll type compressor that includes: a housing; a rotary shaft; an electric motor; and a compression part including a fixed scroll and an orbiting scroll. The housing includes a separation wall separating a back pressure chamber from a motor chamber. The separation wall includes a bearing and a seal member having an inner circumference seal portion and an outer circumference seal portion. The seal member seals the back pressure chamber and the motor chamber. An end of the inner circumference seal portion is provided closer to the bearing than an end of the outer circumference seal portion is. The separation wall includes a holding portion being in contact with the end of the outer circumference seal portion to restrict movement of the seal member toward the bearing. The end of the inner circumference seal portion is provided closer to the bearing than the holding portion is.

An insert component for a scroll compressor comprises a polymer and at least one reinforcing or lubricating particle. The insert component comprises an annular body and an axial projection. The annular body defines a first centrally-disposed opening having has a central axis extending therethrough. The annular body has a first side comprising a first contact surface configured to engage a partition plate and a second side a second contact surface configured to engage a floating seal assembly. The first contact surface defines a slope between first and second radial locations. The axial projection extends from the annular body and can be received in a second centrally-disposed opening of the partition plate. The insert component can fluidly seal both a first interface between the first contact surface and the partition plate and a second interface between the second contact surface and a floating seal assembly during operation of the scroll compressor.

The present invention relates to a two-stage liquid ring vacuum pump in which two-stage impellers are attached to an axial end portion of a main shaft (rotating shaft) of a motor. The two-stage liquid ring vacuum pump includes a first-stage impeller (4) provided in a first-stage pump chamber (1), a second-stage impeller (5) provided in a second-stage pump chamber (2), a single rotating shaft (7) to which the first-stage impeller (4) and the second-stage impeller (5) are fixed, and an exhaust port (Pd) of the first-stage pump chamber (1) and an intake port (Ps) of the second-stage pump chamber (2) which communicate with each other. An outer diameter of the first-stage impeller (4) is larger than an outer diameter of the second-stage impeller (5).

A pump, wherein a first pressure space and a second pressure space are formed between an end-facing wall of an accommodating housing and a second housing part of a pump insert, wherein an annular sealing element which is arranged between the end-facing wall and the second housing part encloses the second pressure space and seals it off in relation to the first pressure space, wherein the first pressure space is connected via a first outlet channel to a first delivery chamber which is formed between a rotor and a stroke ring of the pump insert, and the second pressure space is connected via a second outlet channel to a second delivery chamber which is formed between the rotor and the stroke ring.

A high suction pressure thrust load balance assembly configured for use with a single screw compressor includes comprises a sealing baffle that is keyed to, so as to be rotatable along with, a main rotor drive shaft of the single screw compressor. The sealing baffle is configured to create a force or load to counteract the axial force of the main rotor drive shaft created during rotation of the main rotor drive shaft using the pressurized oil used to lubricate the mechanical shaft seal of the compressor.

A rotary positive displacement pump comprising a pair of forwardly-positioned sealing arrangements and a pair of forwardly-positioned sleeves are received within a cavity providing for easy maintenance of the pump when the seals need to serviced. Each of the sealing arrangement includes a dynamic seal and a static seal. The dynamic seal abuts a corresponding sleeve and hub while a static seal is established between the corresponding sleeve and rotor.