A pump fluid driving apparatus includes a housing having a chamber, with two gears mounted within the chamber. The housing includes a first rounded wall section and a second rounded wall section, the first and second rounded wall sections defining at least a portion of the chamber. The gears have teeth located about their respective peripheries and operatively positioned with the teeth of the first gear and the teeth of the second gear intermeshed. The teeth include slotted teeth and solid teeth arranged with uniform spacing in a repeating pattern about the periphery of each of the gears, with each of the slotted teeth having a vane slot and a radially extending vane extending from the vane slot, and each radially extending vane being movable within the respective vane slot and being configured to contact the respective first or second rounded wall sections.

A mutual rotating scroll compressor includes: a first frame fixed to a casing; a second frame provided with an interval between the first frame and the second frame, a compression space being provided between the first frame and the second frame; a first scroll rotatably supported by the first frame and coupled to a driving motor to rotate in the compression space; a second scroll engaged with the first scroll to rotate about the second frame, the second scroll and the first scroll forming a compression chamber in the compression space; and a bearing housing including a housing part, including a boss accommodation part to which the second scroll is rotatably coupled, and a hinge lug which extends from the housing part and is movably coupled to the second frame.

A scroll compressor is provided which is capable of supplying oil stored in an oil storage chamber upward through a rotary shaft to lubricate a bearing portion. The scroll compressor may include a casing in which oil is stored in an oil storage chamber formed at a lower portion of the casing, a drive motor provided in an inner space of the casing, a rotary shaft coupled to the drive motor and including an oil supply path configured to guide the oil stored in the oil storage chamber and at least one oil hole that passes from the oil supply path to an outer circumferential surface of the rotary shall a main frame coupled to the rotary shaft and provided under the drive motor, a fixed scroll coupled to the rotary shaft and provided under the main frame, and an orbiting scroll provided between the main frame and the fixed scroll, into which the rotary shaft is inserted and to which the rotary shaft is eccentrically coupled, the orbiting scroll performing an orbiting movement to form a compression chamber with the fixed scroll. The oil guided upward through the oil supply path may be discharged through the at least one oil hole and supplied to the outer circumferential surface of the rotary shaft.

A screw compressor includes a compressor housing which has a screw rotor chamber arranged therein. Two screw rotors are arranged in the screw rotor chamber. At least one control slider is arranged in a slider channel of the compressor housing and is adjacent to both screw rotors by means of slider compression wall surfaces. The control slider is moveable in a direction of displacement parallel to the screw rotor axes. There is a position determining device for the at least one control slider. The position determining device has a position indicator that is coupled to the at least one control slider. The position indicator cooperates with a detector that extends parallel to the direction of displacement of the at least one control slider and along which the position indicator is moveable. The detector element is coupled to an evaluation device that determines the positions of the position indicator along the detector.

A method of casting a rotor using a cavity and core mold allows a longitudinal slot oriented transversely to the axis of rotation to be finish ground to high precision and tight tolerances by casting the slot to have a wider section which extends from the axis to a radius greater than the radii of the hubs of the rotor, and a narrower section which extends from the wider section to the outer surface of the rotor. The geometrical relation of the slot sections to the hubs as cast permits the grinding step to be performed without forming a leak path in either of the hubs.

A pump housing for an eccentric screw pump, with a longitudinal axis and a hollow space constituted running axially between a drive-side opening and a pump-side opening, wherein the pump-side opening is enclosed by a main housing body and a lid fastened removably thereto, wherein the main housing body includes a ring segment-shaped axial guiding surface lying opposite the lid.

A compressor element of a screw compressor inlet side and an outlet side and two helical rotors, respectively a male rotor with a drive for the male rotor and a female rotor that is driven by the male rotor by means of synchronisation gearwheels with at least one synchronisation gearwheel on the male rotor, wherein the drive and synchronisation gearwheels of the male rotor are chosen such that, upon being driven with acceleration of the rotors without gas forces, the resulting mechanical drive force that is exerted by this drive and by this synchronisation gearwheel on the male rotor has an axial component that is directed from the outlet side to the inlet side and that the movement of the male rotor in the axial direction from the outlet side to the inlet side is fixed by means of a single axial single-acting or double-acting bearing.

A pump, such as a vacuum pump, includes at least one housing and a motor and oil reservoir disposed within the housing. The pump housing can include a bottom exterior surface and one or more side and/or front exterior surfaces that extend generally up from the bottom exterior surface. An oil drain port can be positioned at or near the intersection of the bottom exterior surface and the side or front exterior surface. The housing can include an interior bottom surface that defines at least a portion of a drain passageway for the pump and can be fluidicly coupled to the oil reservoir. At least a portion of the interior bottom surface can be angled downward at an acute angle to the horizontal towards the oil drain port to improve the draining and replacement of oil in the pump.

A pump, such as a vacuum pump, includes at least one housing and a motor and oil reservoir disposed within the housing. The pump housing can include a bottom exterior surface and one or more side and/or front exterior surfaces that extend generally up from the bottom exterior surface. An oil drain port can be positioned at or near the intersection of the bottom exterior surface and the side or front exterior surface. The housing can include an interior bottom surface that defines at least a portion of a drain passageway for the pump and can be fluidicly coupled to the oil reservoir. At least a portion of the interior bottom surface can be angled downward at an acute angle to the horizontal towards the oil drain port to improve the draining and replacement of oil in the pump.

A compressor includes a compression mechanism having a ring-shaped first cylinder, a first piston eccentrically rotatable in an interior of the first cylinder, a first cylinder head member disposed adjacent to one axial end of the first cylinder, a second cylinder head member disposed adjacent to an other axial end of the first cylinder, and a fastening bolt. The fastening bolt fastens the first cylinder head member, the first cylinder, and the second cylinder head member together. An end face of the first cylinder head member contacts the first cylinder, and the end face is provided with a protecting groove. The protecting groove is formed closer to a center of the first cylinder than the fastening bolt, and has a groove width smaller than a groove depth of the protecting groove.