The invention relates to a metering pump (1) made of plastic, with two rotors (10) coupled to one another via gears (11) and drivable in opposite directions, which are seated in a pump housing (5) equipped with suction ports (6) and outlet ports (7), wherein each rotor (10) has a rotor shaft (12), the rotor shaft ends (15) of which are seated in the walls (8, 4) of the pump housing (5). Each rotor (10) has two rotor blade walls (13) arranged diametrically on the rotor shaft (12), a partially cylindrical rotor blade shoe (14) being formed at each of the peripheral ends of said rotor blade walls, wherein the rotor blade shoes (14) on the one hand contact the cylindrical inside wall regions of the pump housing (5) and on the other contact the rotor blade shafts (13) of the adjacent rotor (10) in a sliding and sealing manner.

A high speed, rotary lobe gear pump assembly is provided which combines a positive displacement lobe gear pump having wipers with a centrifugal pump utilizing an impeller. The centrifugal pump feeds high pressure fluid flow directly into the lobe gear pump allowing the gear pump to rotate at high speeds without cavitation. The high speed capability of the pump assembly allows the lobe gear pump to operate without speed reduction gearing for the motor shaft.

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.

A fluid working system such as a pump for displacing a working fluid such as hydraulic fluid or a motor using a working fluid is provided. The system may have a positive displacement machine which includes one or more working chamber with displacement means such as a cylinder with a reciprocating piston. There are also two or more fluid ports to allow the working fluid to flow into and out of the working chamber. The working fluid flows from one fluid port means to another either being forced to do so when pumped or moving the piston when functioning as an engine. The fluid working system has associated therewith a non-dead compliance volume of a material such as syntactic foam. This compliance volume acts to smooth any pressure fluctuations within the working fluid system.

A system for delivering an additive into a fluid stream is disclosed that addresses the issues of delivering a pressurized stream of a shear thickening or dilatant material which is commonly used for fire suppression. The system uses a positive displacement pump that is controlled to deliver the additive to a fluid stream in the correct ratio according to fluid flow rates. The system also incorporates an injection quill for delivering the additive to the fluid stream within a dispensing line. The injection quill includes an internal extension within its valve chamber, and the internal extension provides ports that allow for improved fluid flow of dilatant material.

Method for increasing the smoothness of the free surface area of a PFA film, provided on a component by sequentially exposing it to a temperature higher than its melting temperature so as to melt at least the free surface area, lowering the temperature to solidify the melted portion, remelting the free surface area by exposing it to a temperature of at least the PFA melting temperature and again lowering the temperature. The PFA film may be provided on Al.sub.2O.sub.3, Ni or NiF.sub.2 film.

An internal combustion engine having at least one crankcase for defining a guide housing in which at least one crankshaft is guided in rotation about an axis of rotation and lubricated by a lubricating fluid, the at least one crankcase being of the dry-sump type. Such an internal combustion engine has at least two pumps forming a pump train of pumps on a common axis, the pump train being fitted in a cylindrical bore of the at least one crankcase.

A rotary positive displacement device comprises a housing having low and high pressure ports; first and second rotors each having a frusto-spherical outer surface, an axial surface, a shaft and a rotational axis. The axial surfaces comprise a teardrop surface and an involute surface together defining a lobe and a corresponding valley. High and low pressure openings each extend between the first and second rotors and the corresponding high and low pressure ports. The first and second rotors intermesh so that the at least two chambers are separated by the axial surfaces of the first and second rotors, each chamber having a variable volume as the first and second rotors rotate about their respective rotational axes. A lower edge of the high pressure opening is positioned along an outer diameter of the outer surface of the second rotor and between the second rotor shaft and the first rotor valley.

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.

The present disclosure relates to a method and system for manufacturing a multi-lobed helical rotor. The method for manufacturing a multi-lobed helical rotor may comprise mixing one or more powdered metals, compacting a mixture of one or more powdered metals to form a solid metal piece, sintering the solid metal piece, and polishing the solid metal piece. The system may comprise a positive displacement pump, which may comprise a casing, a multi-lobed helical rotor disposed in the casing, wherein the multi-lobed helical rotor comprise sintered powdered metals, an inlet to the casing, and an outlet leading from the casing.