An oil pump, in particular an electric or electromotive auxiliary pump for a motor vehicle, having a housing having an inlet on the admission side and an outlet on the pressure side, in addition to a pump rotor which is inserted in the housing such that it can rotate about an axis, and having at least one rotor part, a flexible housing component which is in the form of an elastic press plate and which extends over the cross-sectional surface of the pump rotor. The flexible pressure plate is maintained, in an advantageous manner, in the edge area of the second housing parts.

A rotary positive displacement pump comprises a housing rotationally supporting first and second parallel and axially extending drive shafts having constantly meshing gears such that the drive shafts rotate in opposite directions. A rotor casing is connected to a front side of the housing and has axial rear and front walls and a circumferential side wall jointly defining a pumping cavity. The casing houses first and second rotors drivingly connected to the first and second drive shafts respectively. The rotors rotate in opposite directions and mutually interact to provide a positive pumping effect on fluid product entering the cavity. First and second sealing arrangements prevent leakage of fluid product from the cavity towards the rear side of the casing along the first/second drive shafts. A heating device is detachably fastened to the rear casing wall to heat the casing, the first/second sealing arrangements and/or any fluid product within the casing.

A rotary, self-priming, positive displacement pump is described. The pump may include a pump housing having a fluid inlet and outlet, first and second rotary impellers having vanes, an input shaft and drive gears synchronizing the impellers to avoid clash, and a dividing wall separating a pumping chamber from a chamber containing the drive gears. The dividing wall separates the pumping chamber from the gear chamber, partially supports impeller shafts, and is formed in a plurality of abutting manually separable sections. When manually pulled apart, the separable sections free the impeller shafts for manual removal, to facilitate manual service to the pump.

An arrangement (100) for specifying the pressure (64), produced by a pump (30) driven by an electric motor (31), includes a processor (116) which derives a target pressure value (62, 118) from an internal torque value (114) and a loss torque (108). The arrangement (100) further derives (112) the internal torque value (114) from a motor current value (110) and a motor constant k.sub.e.

A pump for conveying a fluid includes a casing with a casing inner wall, a pump interior, an inlet opening, an outlet opening, a displacement assembly, and a radial protective element arranged in the pump interior in order to line at least one radial section of the pump interior, the radial protective element bearing against a radial section of the casing inner wall. A fastening element is provided which can be arranged in a fastening position in which the fastening element bears against an edge of the radial protective element and in the process fastens the radial protective element in the pump interior, wherein the fastening element has a longitudinal extent which extends from a first axial end of the pump interior along a recess arranged in the casing inner wall.

A rotary lobe pump having a pump housing with a pump room, an inlet opening and an outlet opening, a first multi-lobe rotary piston, which is arranged in the pump room and is rotatably mounted about a first axis of rotation, a second multi-lobe rotary piston, which is arranged in the pump room and is rotatably mounted about a second axis of rotation spaced apart from the first axis of rotation and meshingly engages in the first rotary piston, wherein the first and second rotary pistons are drivable in opposite directions and are designed to generate a flow of a conveyed medium from the inlet opening through the pump room to the outlet opening by counter-rotation about the first and second axis of rotation, respectively, and a drive device, which is mechanically coupled to the rotary pistons for driving the rotary pistons.

A rotary, self-priming, positive displacement pump is described. The pump may include a pump housing including an inlet and an outlet, a pump chamber including an upper wall, a lateral wall, and a floor, first and second rotary impellers in the pump chamber, and a pair of gears each secured to the first and second rotary impellers, and a pressure relief feature operable to relieve pressure developing in a relatively high pressure zone of the pump chamber. The gears mesh with each other to ensure that the vanes do not contact one another during rotation. The pressure relief feature may comprise one or more channels formed in the pump housing and/or the first and second rotary impellers. The channels connect the high pressure zone with another zone to redistribute pressure. The channels may include one continuous channel or alternatively, a plurality of unconnected channels.

An improvement to surface marking devices for pumping and circulating melted thermoplastic material to various surfaces including roads, parking lots and the like is provided. The pump for melted thermoplastic is comprised of a cold section and a hot section. The hot section is connected to a fluid or electric motor, or alternatively, an internal combustion engine for providing rotation to the pump. The connection to provide rotation to the hot section is through the cold section, which is spaced away from the hot section and connected with shafting to provide rotation to the hot section. A heating jacket is secured to the hot section for transferring heat from an external source to the hot section. The spacing between the hot and cold sections provides the ability to rebuild the hot section of the pump without removal from the cold section and without removal from the vehicle to which it is attached.

A rotor-chamber wall of a motor-driven Roots pump has a suction port and a discharge port. The side on which the discharge port is located with respect to a plane that includes both the rotational axis of a drive shaft and the rotational axis of a driven shaft is a first side. A first partition wall defines a gear chamber and has a first recess on the first side. A second partition wall defines the gear chamber and has a second recess. The first partition wall has a first oil supply passage that is configured to supply oil from the first recess to a first seal accommodating recess. The second partition wall has a second and a third oil supply passages. The second and the third oil supply passages are configured to supply oil from the second recess to a second and a third seal accommodating recesses, respectively.

An oil box device of a roots vacuum pump with a crossed cooling water tube set includes an oil box; two root vacuum pump transfer gears placed within the oil box; each gear being axially connected to a respective one of shafts of rotors of a roots vacuum pump; one shaft of the rotors being driven by another one shaft of the rotors; a multiple channel crossed cooling water tube set enclosing the two roots vacuum pump gears; two distal ends of the water tube set being crossed over one another; two water boxes installed at two ends of the water tube set; after assembly, the water tube set enclosing the two gears and two ends of the water tube set being crossed over each other at a lateral side of the two gears; and two joints being installed at a bottom side of the rear cover.