An improved screw pump such as, for example, a twin screw pump, includes a casing including an internal chamber, and first and second rotors rotatably positioned within the chamber of the casing. The first and second rotors have an intermeshing threaded-shape profiling. A plurality of bearing seal assemblies are provided at each end of the first and second rotors. Each bearing seal assembly includes a bearing positioned about an end portion of a rotor to facilitate rotation of the rotor, and a seal positioned about an end portion of a rotor to seal passage of the rotor through the casing. The bearing is coupled to the seal so that the seal may be secured to the casing via the coupling of the bearing to the casing.

A rotary compressor is provided that may include a rotation preventing key between a roller and a rotary shaft, the roller being a separable-type roller assembled into the rotary shaft. The rotation preventing unit may constrain rotation of the roller and allow axial movement of the roller with respect to the rotary shaft. Thus, axial movement of the roller along the rotary shaft may be suppressed or prevented, and thus, friction loss and abrasion between the roller and a main bearing or between the roller or a sub bearing may be suppressed or prevented.

An element for compressing or expanding a gas including a rigid housing (2) containing an internal chamber; a rotor (3a, 3b) situated in the internal chamber and comprising a rotor shaft (4a, 4b); one or more bearings (7) in which the rotor shaft (4a, 4b) is bearing-supported, wherein the rotor (3a, 3b) with its rotor shaft (4a, 4b) is rotatably mounted with respect to the housing (2) by means of these bearings (7), wherein the rotor (3a, 3b) is mounted with one or more clearances with respect to a wall (5) of the internal chamber, and the element (1) is provided with a separate yielding component (10) which is positionally adjustable with respect to the housing (2) in such a way that at least one of the clearances can be acted upon, wherein the separate yielding component (10) is not directly attached to the rotor (3a, 3b).

A gear pump includes: an inner rotor having external teeth; an outer rotor having a tubular inner housing portion in which the inner rotor is rotatably housed in an eccentric state, and internal teeth meshing with the external teeth; a first core having a tubular rotor housing portion in which the inner and outer rotors are housed, and a flange portion projecting radially outward from a tube wall of the rotor housing portion; a board-shaped second core having a contact portion in contact with the flange portion in an axial direction, and closing an opening of the rotor housing portion; and a housing opposing the second core and made of a resin. A gap is formed between opposing surfaces of the second core and the housing in a state where the flange portion is in contact with the contact portion and the housing opposes the second core.

Technologies are generally described for clearance adjustments in twin-screw pump assemblies. A twin-screw pump assembly may include a conically shaped portion of a drive shaft enveloped by a bushing. For clearance adjustment, both clamping nuts of the drive shaft, which provide pretention to the bushing and secure an axial position of a threaded screw to the drive shaft, may be removed on the flow side of the pump assembly and the bushing loosened to adjust the angularity between bushing and drive shaft. The bushing may then be pushed over the conically shaped portion and both clamping nuts re-assembled. In some examples, a clamping nut of the driven shaft may be designed and used as removal/loosening tool for the drive shaft bushing.

Systems and methods are provided for pumps that deliver optimized torque characteristics and volumetric efficiency. A system includes a housing defining a surface and a rotor defining a face. A face clearance is defined between the face and the surface. The face clearance is variable in magnitude and determinative of target performance characteristics of the pump system. The housing is made of a material selected to have a thermal expansion characteristic and the rotor is made of a second material selected to have another thermal expansion characteristic. The thermal expansion characteristics deliver the target performance characteristics of the pump system.

Systems and methods are provided for pumps that deliver optimized torque characteristics and volumetric efficiency. A system includes a housing defining a surface and a rotor defining a face. A face clearance is defined between the face and the surface. The face clearance is variable in magnitude and determinative of target performance characteristics of the pump system. The housing is made of a material selected to have a thermal expansion characteristic and the rotor is made of a second material selected to have another thermal expansion characteristic. The thermal expansion characteristics deliver the target performance characteristics of the pump system.

A vane rotary compressor includes a roller rotatably supported in a cylinder and including a plurality of vane slots formed along a circumferential direction with back pressure chambers formed at one end of each of the vane slots. A plurality of vanes are slidably supported in the vane slots protruding toward an inner circumferential surface of the cylinder. A compression space formed by the vanes between the roller and the cylinder includes an inlet port and an outlet port formed at both sides of a contact point between the roller and the cylinder. A vane positioned between the inlet port and the outlet port is configured such that a front gap between a front surface of the vane and the inner circumferential surface of the cylinder is smaller than a rear gap between a rear surface of the vane and an inner surface of the back pressure chamber.

One of a pair of a fixed scroll and an orbiting scroll is the scroll including a step portion provided only at a predetermined position along a spiral direction on a blade bottom surface of a spiral wrap, and the other one of the scrolls is the scroll including a step portion provided only at a predetermined position along a spiral direction on a blade tip surface of a spiral wrap. A blade bottom surface of an end plate of the fixed scroll is set as a reference surface for setting a chip gap between both the scrolls. When a wrap height of the spiral wrap of the orbiting scroll is represented by (L) (Lo, Li) and a wrap height of the spiral wrap of the fixed scroll is represented by (lo, li), L (Lo, Li)>1 (lo, li) is satisfied.

A scroll compressor includes fixed and movable scrolls having a fixed and movable side plates and fixed and movable side laps to form first and second compression chambers. The fixed-side plate includes a discharge port and a relief hole extending from the front face through to the back face. The relief hole communicates for a predetermined amount of time with each of the first and second compression chambers and is shared by the first and second compression chambers. The front face of the movable-side plate includes a recessed part allowing the second compression chamber and the discharge port to communicate. The second compression chamber, during a latter stage of compression, and the discharge port communicating via a gap formed between a tip of the fixed-side lap and the recessed part before communicating via a side face gap formed between the fixed-side lap and the movable-side lap.