The purpose of the present invention is to suppress the occurrence of unevenness in a rotor of an internal gear pump, suppress the formation of gaps between the end surfaces (side surfaces) of an inner rotor and an outer rotor, and to prevent a decline in volume efficiency. Thus, the pump device of the present invention includes an internal gear pump (10), in which an inner rotor (13) is inscribed to an outer rotor (12), and includes a plate member (7) which is provided to an end surface of the rotors. The plate member (7) is formed of a material having high hardness, has a shape that does not block a suction port (150), has a through-hole (73) formed therein, and has O-ring grooves (71,72), which each have a continuous shape and house an O-ring formed therein.

A pump includes a housings and a rotor capable of rotating within the housing. The rotor engages an interior surface of the housing in use, with at least two radially-inward shaped surfaces on the rotor forming respective chambers with the interior surface. In use, the chambers transport fluid from an inlet in the housing to an outlet in the housing as the rotor rotates. A seal provided between the inlet and the outlet will engage each of the shaped surfaces to prevent fluid passing from the outlet to the inlet as each shaped surface travels from the outlet to the inlet. The rotor includes a surface portion extending axially and circumferentially between respective edges of the shaped surfaces. On planes normal to an axis of rotation of the rotor, the surface portion of the rotor has a greater curvature than that of the interior surface of the housing.

A gear pump and gear pump housing are provided. The gear pump housing includes an inner wall and an outer wall. The inner wall defines an inner pumping cavity having a pumping cavity inlet and a pumping cavity outlet. The outer wall surrounds at least part of the inner wall. The outer wall being spaced apart from the outer wall defining a pressure cavity between the inner and outer walls. The pumping cavity outlet is in fluid communication with the pressure cavity. As such, the pressure cavity may be supplied with high pressure fluid that is pumped. The gear pump includes a pair of pumping gears between the pumping cavity inlet and pumping cavity outlet.

A sealing device includes a relatively dimensionally stable, elongated friction and/or wear element and an elastically-deformable elongated sealing element which rests lengthwise on the friction and/or wear element. The friction and/or wear element encompasses the sealing element at the ends of the friction and/or wear element.

A rotary pump (10) comprises a housing (20) having a first (21) and second fluid port (22) and an interior surface defining a cavity (24) in which a rotor (30; 230) is located, wherein the rotor comprises at least a surface recess (231a-231d) forming at least a fluid-conveying chamber (232a-232d) with the interior surface of the housing. The pump further comprises at least a resiliently deformable diaphragm (50; 226) providing part of the interior surface of the housing and being urged into contact with the surface of the rotor by the action of pressurising means acting on the rear surface of the resiliently deformable diaphragm. The pump further comprises one or a pair of flow channels (41a, 41b; 241a, 241b) associated with the resiliently deformable diaphragm extending longitudinally from opposite ends of the rotor. In embodiments where the pump comprises one flow channel (575), the flow channel is in fluid communication with the first fluid port and an aperture (595) opens from the interior surface of the housing to place the second fluid port in direct fluid flow communication with the fluid-conveying chamber. In embodiments where the pump comprises a pair of flow channels (241a, 241b), the pair of flow channels comprise a first flow channel in fluid communication with the first fluid port and closed to the second fluid port and a second flow channel closed to the first fluid port and in fluid communication with the second fluid port, with each flow channel being located at opposite sides of the diaphragm. Embodiments of the invention exhibit continuous fluid flow when in use.

A rotary pump comprising a housing having a first and second fluid port and an interior surface defining a cavity in which a rotor is located, wherein the rotor comprises a surface recess forming a fluid-conveying chamber with the interior surface of the housing, the pump further comprising a resiliently deformable diaphragm providing part of the interior surface of the housing and being urged into contact with the surface of the rotor by the action of pressurising means acting on the rear surface of the resiliently deformable diaphragm, the pump further comprising one or a pair of flow channels associated with the resiliently deformable diaphragm extending longitudinally from an end of the rotor. In embodiments where the pump comprises one flow channel, the flow channel is in fluid communication with the first fluid port and an aperture opens from the interior surface of the housing to place the second fluid port in direct fluid flow communication with the fluid-conveying chamber. In embodiments where the pump comprises a pair of flow channels, the pair of flow channels comprise a first flow channel in fluid communication with the first fluid port and closed to the second fluid port and a second flow channel closed to the first fluid port and in fluid communication with the second fluid port, with each flow channel being located at opposite sides of the diaphragm. Embodiments of the invention exhibit continuous fluid flow when in use.