The present invention relates to a device (1, 30) for the recirculation of an at least partially gaseous composition containing hydrogen, wherein the device (1, 30) is a dry rotary pump comprising a first rotating shaft (13) and a second rotating shaft (14) driving respectively a first piston with claws (8) and a second piston with claws (9) in rotation in a pumping chamber (2) comprising an inlet orifice (11) and an outlet orifice (10) for the gaseous composition, the first rotating shaft (13) and the second rotating shaft (14) being configured to be driven in rotation by a drive system (17,18) situated in a gear chamber (4), wherein the device (1, 30) comprises a first pair of seals (19) and a second pair of seals (20), each comprising a first shaft seal (19a, 20a) and a second shaft seal (19b, 20b), the first pair of seals (19) being provided around the first rotating shaft (13) and the second pair of seals (20) being provided around the second rotating shaft (14) between the pumping chamber (2) and the gear chamber (4), wherein the device (1, 30) comprises a pressure equalization chamber (25) which is in fluid connection with a gap (24) present between the first shaft seal (19a, 20a) and the second shaft seal (19b, 20b) of the first and of the second pair of seals (19, 20) to regulate the pressure in the gap (24), wherein the gear chamber (4) is in fluid connection with the gap (24), and wherein the pumping chamber (2) is in fluid connection with the first shaft seal (19a) of the first pair of seals (19) and with the first shaft seal (20a) of the second pair of seals (20) by means of a pulsation attenuation chamber (22). The present invention also relates to a fuel cell system (40, 50, 60, 70, 80, 90) comprising a device for recirculation according to the present invention.

A rotary positive displacement pump includes a main body rotationally supporting two parallel, axially extending, shafts with gears in constant mesh condition, such that the shafts rotate in opposite directions. A rotor case body is connected to a front side of the main body and has a stationary interior pumping cavity, fluid product inlet and outlet openings, and two cylindrical rotor case hubs each receiving internally one of the shafts. A pair of rotors each have a rotor wing and a rotor drive element that is mounted torque proof on a rotor seat at an end region of one of the shafts. Each rotor seat pair has an axial abutment surface and a mounting surface. The pump also includes fasteners each engaging a mating section of one of the shafts and exerting an axial clamping force on one of the rotor drive elements against one of the axial abutment surfaces.

An object of the present invention is to provide a transfer device capable of stably transferring a food material transferred by a pump device in accordance with the physical properties of the food material. A transfer device (3,5), wherein a pump device (17) includes a housing unit (31) in which a pump chamber (36) in which a pair of Roots-type rotors (32A, 32B) are disposed and a downstream channel (37) communicating with the pump chamber are formed, and a pump driving unit (39) that drives the pair of Roots-type rotors to rotate in mutually opposite directions, the housing unit includes a casing (34) that houses the pair of Roots-type rotors, and the pair of Roots-type rotors have lobes (32AP, 32BP) each having a V-shaped profile and being meshable with each other, and are attached to the casing interchangeably left and right.

A screw spindle pump, including a spindle housing, in which a drive spindle and a running spindle meshing therewith are received in spindle bores. The drive spindle has a cylindrical spindle core and at least two circumferential spindle profiles, and, on an end face, in a depression axially delimited by a planar bottom surface and in which the two profile valleys open out between the two spindle profiles offset by 180°, there is a disk-shaped coupling element, which has an insertion receptacle for a drive shaft of a drive motor and which is coupled to the drive spindle for conjoint rotation therewith via a form-fitting engagement with axially protruding projections that laterally delimit the depression and engage in lateral receptacles of the coupling element. The bottom surface is delimited by the spindle core in the region of the openings of the two profile valleys, and the coupling element has a rounded configuration, corresponding to the shape of the spindle core, in the element regions that adjoin the regions of the opening. The diameter of the coupling element, in the region of the rounded element regions, is no greater than the diameter of the spindle core.

A positive displacement pump has a casing with a central body and two closing lids, the central body being provided with two cylindrical communicating chambers, one suction pipe and one discharge pipe, and two rotors revolvingly mounted in the chambers of the central body and supported by shafts revolvingly mounted in the closing lids. The two rotors include a male rotor having only protuberances, not cavities, and a female rotor having only cavities, not teeth or protuberances.

A pump apparatus (1) for use in mobile means of transport (100) such as semitrailers, tank trailers, tank semitrailers (101), tank trucks and trucks (102), has a drive motor (40) and a rotary piston pump (2) having two rotor units (10, 20) on rotatably mounted rotor shafts (11, 21), connected to rotor gear wheels (12, 22). A drive pinion (32) of a drive shaft (31) coupled to one of the rotor gear wheels (12) and is received in a recess (81) of the motor shaft (41).

A screw spindle pump, including a spindle housing, in which a drive spindle and a running spindle meshing therewith are received in spindle bores. The drive spindle has a cylindrical spindle core and at least two circumferential spindle profiles, and, on an end face, in a depression axially delimited by a planar bottom surface and in which the two profile valleys open out between the two spindle profiles offset by 180°, there is a disk-shaped coupling element, which has an insertion receptacle for a drive shaft of a drive motor and which is coupled to the drive spindle for conjoint rotation therewith via a form-fitting engagement with axially protruding projections that laterally delimit the depression and engage in lateral receptacles of the coupling element. The bottom surface is delimited by the spindle core in the region of the openings of the two profile valleys, and the coupling element has a rounded configuration, corresponding to the shape of the spindle core, in the element regions that adjoin the regions of the opening. The diameter of the coupling element, in the region of the rounded element regions, is no greater than the diameter of the spindle core.

A rotor is shown with an asymmetrical structure for a pump, wherein the rotor includes at least one cutting edge and at least one rounded edge, as well as the pump as such including one or more rotor(s). The rotor (1) has a first circular element (4) where a material-moving cavity (5) is provided in the first circular element (4).

A gear pump could be said to include a first gear and a second gear intermeshed with the first gear. An inlet side is configured to have an inlet connection connected thereto. A discharge side is configured to have a first discharge connection connected thereto. At least one shaft is in operable communication with each of the first and second gears. A bearing is configured to support at least one of the shafts via an inner bore and having an outer peripheral surface. A valve bore is formed into bearing between the inner bore and the outer peripheral surface. A second discharge connection is formed into the bearing. A tap provides fluidic communication between the valve bore and a pad defined in the inner bore. A valve is positioned in the valve bore. The valve includes a moving valve member. A spring biases the moving valve member in a direction toward the second discharge connection. A fuel pump system is also disclosed.

A rotary piston engine comprises a housing (10), which forms an interior space (11), and at least two rotary pistons (20, 30), which are arranged in the interior space (11). Formed on the interior space (11) are an inlet opening (13) and an outlet opening (15) to guide a fluid through the interior space (11). The rotary pistons (20, 30) are thereby driven by fluid flowing through. Each rotary piston (20, 30) has on its outer circumference at least two sealing strips (21, 31). According to the invention each rotary piston (20, 30) comprises at least two cavities (27, 37), in each of which a tube (38B) or an elastic solid rod is arranged. The sealing strips (21, 31) project into the cavities and against the tube (38B) received therein or the elastic solid rod. Through the tube (38B) or the rod, the sealing strips (21, 31) are pushed radially outwards.