A pump particularly for pumping a liquid such as ink, paint, glue or the like, includes at least one rotating pumping member having a respective shaft. The at least one rotating pumping member being at least partially housed inside a pump body, the shaft being rotatably supported by at least one support associated with the pump body. The shaft has on its external cylindrical surface in contact with the liquid one, or more recesses, or the at least one support includes on its internal cylindrical surface in contact with the liquid, one or more recesses.

A pump particularly for pumping a liquid such as ink, paint, glue or the like, includes at least one rotating pumping member having a respective shaft. The at least one rotating pumping member being at least partially housed inside a pump body, the shaft being rotatably supported by at least one support associated with the pump body. The shaft has on its external cylindrical surface in contact with the liquid one, or more recesses, or the at least one support includes on its internal cylindrical surface in contact with the liquid, one or more recesses.

A compressor is provided and may include a shell and a stator. The shell includes an inner surface and an outer surface. The stator may be attached to the shell at the inner surface via a first stake. The first stake may be formed by deforming a portion of the shell into the stator.

A gear wheel for gear pumps/motors including a plurality of asymmetrical teeth, each tooth including a driving side with a convex shape and mating with a corresponding convex side of a counter-wheel and a discharge side defined, in most of its length, as a cavity of a convex profile. The discharge side is configured so that the radius passing through a tip of the teeth is substantially at least tangent to the discharge side, or intersects the discharge side.

A compressor is provided and may include a shell having an inner surface and an outer surface and a bearing housing disposed within the shell and having an engagement surface opposing the inner surface. The engagement surface may include a first channel formed substantially perpendicular to a longitudinal axis of the shell and a second channel formed substantially parallel to the longitudinal axis of the shell and in communication with the first channel. The first channel and the second channel may receive a deformed portion of the shell therein to fix a position of the bearing housing relative to the shell.

Disclosed are rotary positive displacement machines capable of acting as an engine and as a pump, serving to improve the profile of working members of helical rotary engines, compressors and pumps. An actuator is comprised of a pair of rotors having engaged helical teeth. The rotors are disposed in chambers which encircle both. The working areas of the profiles of the teeth in an engaged pair are delineated in cross-section by portions of a cycloidal curve for one rotor and by arcs of circumferences which are eccentrically offset from the axis of the second rotor. Such a profile of teeth produces an eccentrically cycloidal engagement capable to work efficiently at very high rotor rotation speeds. The presence of power contact and low sensitivity to gearwheel skews allow for working with nonhomogeneous media, including those containing solid inclusions.

Fluid delivery devices using a pair of meshed external gears, in spite of no reciprocating component for fluid delivery enabling low rotational vibration, the high noise due to the trapping phenomenon, and the teeth bouncing contact due to undesired large backlash heretofore afforded in the gear manufacturing process, restrict the employments in the industrial field requiring quiet environment such as electric motor vehicles or room services. Accordingly, a gear pump or motor or a gear refrigerating compressor comprising a shaft gear and a driven gear meshed rotatably within a gear chamber formed with a housing and opposite side walls, which delivers fluids from a inlet chamber to a outlet chamber; a backlash of the meshed gears having fluid-leak-tight clearance; a closed chamber provided in a internal portion of at least a side wall; an opening provided on a side wall from which a communication passage extends to a closed chamber; and at least a elastic disc capsule contained in the closed chamber, comprising a pair of concaved elastic disc plate abutted and sealed against each other with gas inside, of which occupying volume varies elastically subject to the fluid pressure therein enabling to absorb or expel the squeezed fluid in the trapped interstice during the trapping period of the interstice, whereby the fluid entrapped in the interstices isolated by the fluid-leak-tight backlash suppressing the pressure transmission inwardly or outwardly, whereof volumetric variation during the trapping period is compensated by the compression or expansion of the elastic disc capsule, suppressing pressure pulse and air bubble generation and eliminating the teeth bouncing contact, achieving a low noise, low vibration and high efficiency gear pump or motor or refrigerating compressor.

The invention provides a rotary device comprising a first rotor rotatable about a first axis and having at its periphery a recess bounded by a curved surface, and a second rotor counter-rotatable to said first rotor about a second axis, parallel to said first axis, and having a radial lobe bounded by a curved surface, the first and second rotors being coupled for intermeshing rotation, wherein the first and second rotors of each section intermesh in such a manner that on rotation thereof, a transient chamber of variable volume is defined, the transient chamber having a progressively increasing or decreasing volume between the recess and lobe surfaces, the transient chamber being at least in part defined by the surfaces of the lobe and the recess; the ratio of the maximum radius of the lobe rotor and the maximum radius of the recess rotor being greater than 1.

The present invention relates to a rotor for a vacuum pump 150 having a roots pumping mechanism, the rotor comprising at least two hollow lobes 160, 162, 164, 166, each lobe having an outer wall 208 which defines a lobe profile, a hollow cavity 210 generally inward of the outer wall, and at least one strengthening rib 226 located in the cavity to resist stress on the lobes generated during rotation.

A gerotor pump is provided with a pump housing defining a chamber and having an inlet and an outlet separated by a planar surface. The planar surface defines a notch connected to the outlet. An inner gear member is rotatably and eccentrically supported within an outer gear member. The inner gear member defines a series of external teeth with a first tooth defining a fluid passage therethrough and a second tooth independent of fluid passages. The fluid passage is defined by an aperture extending axially through the first tooth fluidly connected to a channel extending across the first tooth on an end face of the inner gear member. The passage and the notch cooperate to form a fluid pathway for pressure relief and reduced tonal noise in the pump by disrupting harmonics during operation.