A rotary pump, the rotational direction of which can preferably be switched, featuring: a housing including a pump space featuring an inlet into a low-pressure region of the pump space for a fluid to be pumped and an outlet from a high-pressure region of the pump space for the fluid to be pumped; at least one rotor which forms delivery cells in the pump space; a bearing; and a sealing stay which axially faces the at least one rotor and separates the low-pressure region from the high-pressure region in the rotational direction of the at least one rotor; and featuring at least one lubricant feed, in the sealing stay, which feeds a fluid, as a lubricant, from at least one of the delivery cells to the bearing.

A helical gear pump includes a casing including a body (11), a front cover (12), and a rear cover (13), a pair of helical gears (23) and (24) that are housed in a hole portion formed on the body (11) and mesh with each other, and a pair of bearing cases (25) and (26) that sandwich the helical gears (23) and (24) in the hole portion. Of the helical gears (23) and (24), the number of teeth of the helical gear (23) on the driving side is larger than the number of teeth of the helical gear (24) on the driven side.

A positive displacement rotary fluid pump assembly includes a pump housing and a rotor supported within the housing for rotation about an axis offset with respect to a housing axis and including a plurality of chambers of increasing volume on an low pressure side of the pump and of decreasing volume on a high pressure side of the pump. A fluid inlet communicates with the plurality of the chambers of increasing volume for admitting fluid into the pump under a first low pressure, and a fluid outlet communicates with a plurality of the chambers of decreasing volume for selectively expelling fluid from the pump under a second higher pressure. At least one fluid control valve is operative to selectively close one or more of the chambers of decreasing volume from communication with the fluid outlet when the fluid pressure in such chambers is below the predetermined value and to open one or more other chambers of decreasing volume when the fluid pressure in such chambers is at or above the predetermined value.

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 gear pump that selectively directs lubrication to certain components within the pump. A system and method of retrofitting existing pumps to improve their longevity in the field. The system and method provides a clean, simple, efficient, and elegant improvement to current gear pump fuel delivery systems.

An oil pump is configured to include a rotor, a drive shaft that drives the rotor to rotate, a rotor chamber in which the rotor is contained, an inlet port and an outlet port each provided in the vicinity of the rotor chamber, and a pump cover. The pump cover is made of a resin. On a portion of an outer surface side of the pump cover corresponding to an inner portion, in which oil circulates, of the pump cover, a rib that has an erecting wall shape is provided.

Lobe pumps have rings which can be located at least partially in at least one of cover plates and rotors, if not both to provide at least thrust bearings to space the rotors from the cover plates. Some rotors may have voids in ears to make the rotor lighter in weight with the voids potentially capped, symmetrically disposed, arcuately shaped and/or have other desirable features. Some rotors may have ears extending beyond cutouts which may extend beyond hubs, if not beyond hub extensions as well which may receive cover spigots thereabout. Some rings may act as radial bearings as well when located in the cover spigots.

A geared volumetric machine comprising: a first and a second door (91, 92); the second door (92) operating at a greater pressure than the first door (91); one from between the first and second door (91, 92) being an inlet door of a fluid into the volumetric machine (1) and the other door being an outlet door of the fluid from the volumetric machine (1); a first cogged wheel (11) in turn comprising a first and a second lateral flank (111, 112); a second cogged wheel (12) enmeshing with the first cogged wheel (11); the first wheel (11) comprising a plurality of teeth defining between them a plurality of compartments (9) suitable to house teeth of the second wheel (12); a first and the second abutment (3, 4) between which the first cogged wheel (11) is interposed and that respectively face the first and the second lateral flank (111, 112) of the first cogged wheel (11). a first grooved pathway (31) which at least in a first angular position of the first cogged wheel connects a first and a second zone (51, 52), the first zone (51) comprising at least one of the compartments (9) which is in communication with the second door (92), the second zone (52) being a locus of points interposed between the first abutment (3) and the first flank (111). The first grooved pathway (31) comprises at least one stretch having a passage section having a surface smaller than 1 mm.sup.2.

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.

A fluid transfer pump that has a housing, a body portion movable within the housing between a first position and a second position, a gear coupled to the housing, a body cavity defined partially between the body portion and the housing, and an aperture defined in the housing that selectively provides a fluid to the body cavity. When the fluid is applied to the body cavity at or above a pilot pressure, the body portion is in the first position adjacent to the gear and when the fluid is applied to the body cavity at a fluid pressure lower than the pilot pressure, the body portion is in the second position and spaced from the gear.