A scroll vacuum pump has an axially extending drive shaft with an eccentric shaft portion, such that rotation of the drive shaft imparts an orbiting motion to an orbiting scroll relative to a fixed scroll. An axial adjustment mechanism has a plurality of adjustment members angularly spaced around the drive shaft and extending through the pump housing towards the orbiting scroll, the plurality of adjustment members each being configured to provide an independently adjustable axial position of the orbiting scroll. A plurality of sealing means isolate the plurality of adjustment members from a pump chamber, the plurality of sealing means extending around each of the plurality of adjustment members and comprising at least one flexible portion such that one end of the sealing means may orbit relative to a fixed other end of the sealing means.

A housing unit of a Roots pump includes a rotor housing, which includes a peripheral wall, and a cover member, which closes an opening of the rotor housing. At least one of a mating surface of the peripheral wall or a mating surface of the cover member includes an annular first groove accommodating a seal member. The rotor housing includes a bulging portion including a second groove. The seal member incudes first projections, which project from an annular seal body, and a second projection, which projects further radially inward from the seal body than the first projections. Each first projection includes a distal end that contacts a side surface on a radially inner side or on a radially outer side of the first groove. The second projection is arranged in the second groove to determine the position of the seal body in the first groove.

A housing unit of a Roots pump includes a rotor housing, which includes a peripheral wall, and a cover member, which closes an opening of the rotor housing. At least one of a mating surface of the peripheral wall or a mating surface of the cover member includes an annular first groove accommodating a seal member. The rotor housing includes a bulging portion including a second groove. The seal member incudes first projections, which project from an annular seal body, and a second projection, which projects further radially inward from the seal body than the first projections. Each first projection includes a distal end that contacts a side surface on a radially inner side or on a radially outer side of the first groove. The second projection is arranged in the second groove to determine the position of the seal body in the first groove.

A fluid-injected compressor installation (1) comprises a screw compressor (2) with a compression housing (4) in which a pair of compressor rotors (6a, 6b) are mounted. A drive motor (3) drives the compressor rotors. An inlet (7) and an outlet (8) on the screw compressor (2) supply a gas and discharge compressed gas. A gear transmission (20) between the shaft (16) of one of the compressor rotors and the motor shaft (11), includes a driven gear (18) and a driving gear (19); a motor bearing (21) on the motor shaft (11) next to the driving gear (19); and a dynamic seal (25) next to the motor bearing (21), on the drive motor (3) side, such that the motor bearing (21) is between the driving gear (19) and the seal (25).

A single-screw compressor includes a screw rotor with helical grooves, a gate rotor assembly including first and second gate rotors, and a casing housing the screw rotor and the gate rotor assembly. A rotor support member is attached to the first and second gate rotor rotors, and is rotatably supported by the casing. Each of the helical grooves of the screw rotor has a front sidewall surface and a rear sidewall surface. Each of the gates of the first gate rotor slides only on the front sidewall surface of the helical groove in which the gate has entered. Each of the gates of the second gate rotor slides only on the rear sidewall surface of the helical groove in which the gate has entered. The first and second gate rotors of the gate rotor assembly are coaxially arranged and relatively displaceable in a circumferential direction.

Fluid-injected compressor installation (1) which is provided with: a screw compressor (2) with a compression housing (4) in which a pair of compressor rotors (6a, 6b) are mounted; a drive motor (3) with a motor housing (9) in which a motor shaft (11) is mounted which drives the compressor rotors (6a, 6b); an inlet (7) and an outlet (8) on the screw compressor (2) for the supply of a gas and for the discharge of compressed gas;
with the compression housing (4) and the motor housing (9) being directly joined to each other; characterised in that the compressor installation (1) is provided with: a gear transmission (20) between the shaft (16) of one of the compressor rotors (6a, 6b) and the motor shaft (11), consisting of a driven gear (18) and a driving gear (19); a motor bearing (21) on the motor shaft (11) next to the driving gear (19), and a dynamic seal (25) next to the aforementioned motor bearing (21), on the drive motor (3) side, such that the motor bearing (21) is between the driving gear (19) and the seal (25).

A seal assembly configured for use with a high pressure single screw compressor includes a seal body and at least one attachment structure. The at least one attachment structure fixedly attaches the seal body to the rotor of the compressor, such that the seal body is rotatable along with the rotor. The seal body has a textured outer surface which creates a labyrinthine path between the compressor housing and the seal body.

A seal assembly configured for use with a high pressure single screw compressor includes a seal body and at least one attachment structure. The at least one attachment structure fixedly attaches the seal body to the rotor of the compressor, such that the seal body is rotatable along with the rotor. The seal body has a textured outer surface which creates a labyrinthine path between the compressor housing and the seal body.

A single-screw compressor includes a screw rotor with helical grooves, a gate rotor assembly including first and second gate rotors, and a casing housing the screw rotor and the gate rotor assembly. A rotor support member is attached to the first and second gate rotor rotors, and is rotatably supported by the casing. Each of the helical grooves of the screw rotor has a front sidewall surface and a rear sidewall surface. Each of the gates of the first gate rotor slides only on the front sidewall surface of the helical groove in which the gate has entered. Each of the gates of the second gate rotor slides only on the rear sidewall surface of the helical groove in which the gate has entered. The first and second gate rotors of the gate rotor assembly are coaxially arranged and relatively displaceable in a circumferential direction.

A scroll compressor including a housing, a motor in the housing, an orbiting scroll, and a fixed scroll. An injection valve assembly is provided between the fixed scroll and the housing and further includes a cover plate, a valve plate, a gasket retainer, and an injection valve. The compressor capable of increasing a surface pressure at a position at which the injection valve of the injection valve assembly needs to be supported, and preventing deformation of the gasket retainer by reducing a bead height of the gasket retainer.