A fluid pump includes an inlet plate with an inlet; an outlet plate, the outlet plate having an outlet plate outlet passage; an outlet; an electric motor having a shaft which rotates; a pumping element coupled to the shaft such that rotation of the pumping element by the shaft causes fluid to be pumped from the inlet to the outlet, the inlet plate interfacing with the pumping element in an inlet sealing surface interface and the outlet plate interfacing with the pumping element in an outlet sealing surface interface; a purge passage which receives fluid from the outlet plate outlet passage, the purge passage being in fluid communication with the inlet sealing surface interface and the outlet sealing surface interface; and a filter downstream of the outlet plate outlet passage which filters fluid that passes through the purge passage prior to reaching the inlet and outlet sealing surface interfaces.

A self-cleaning transfer gear pump for transferring molten metal includes the following features: a transfer conduit extends upward from an outlet of a base, two rotatable gears are formed of refractory material and disposed in the gear chamber and engage each other during rotation. A boss functioning as a bearing extends from the drive gear and is adapted to be received in an opening in the base. A shaft is fastened at a lower end to the drive gear. A filter is fastened to the base so as to cover the inlet and prevents particles and objects in the molten metal from entering the gear chamber. In operational mode, a motor rotates the shaft and the drive gear whereby the drive gear and the second gear engage each other while being rotated so as to positively displace molten metal from the inlet to the outlet and along the transfer conduit to the remote location. In self-cleaning mode, the motor rotates the shaft and the drive gear effectively to draw molten metal from the transfer conduit by positive displacement, through the outlet, and toward the inlet therefore cleaning the filter by removing the particles adhering to the filter. Also included are a system with optional filter and optional self-cleaning mode but including an inlet portion of a die casting machine, and a method for operating the gear pump. A flow sensor may be used to transmit pulses into and from the transfer conduit so as to enable determination of a volume of molten metal being charged. The control of the molten metal volume being charged is not solely controlled by the flow sensor.

A pump having at least two fluid drivers and a method of delivering fluid from an inlet of the pump to an outlet of the pump using the at least two fluid drivers. Each of the fluid drives includes a prime mover and a fluid displacement member. The prime mover drives the fluid displacement member to transfer fluid. The fluid drivers are independently operated. However, the fluid drivers are operated such that contact between the fluid drivers is synchronized. That is, operation of the fluid drivers is synchronized such that the fluid displacement member in each fluid driver makes contact with another fluid displacement member. The contact can include at least one contact point, contact line, or contact area.

A fluid system for a pump, which includes a downhole rotating shaft and bearings inside a housing, and where a fluid volume around shaft is circulated from outside housing through a filter, so that only clean non-abrasive fluid is permitted inside fluid volume pump to draw fluid around the shaft. A fluid expeller is included to expel fluid from the accumulated volume of fluid through the filter to purge the filter.

A fuel pump includes an inner rotor, an outer rotor, a casing, and a housing. The inner rotor includes outward teeth. The outer rotor includes inward teeth geared with the outward teeth. The casing houses the inner rotor and the outer rotor, and forms a variable capacity pump chamber between the inward teeth and the outward teeth. The housing is formed in a cylindrical shape and includes a cylindrical inner portion, the casing being press fit into the cylindrical inner portion. A recessed portion is formed at a predetermined position in a circumferential direction of an outer circumferential surface of the casing, the recessed portion being recessed toward a radial direction center of the outer circumferential surface.

An electrical submersible pump system include an electric submersible pump coupled to a lower end of a production conduit extending into a wellbore, the production conduit in fluid communication with a discharge of the electric submersible pump and with a well conduit extending to the surface. A bypass conduit is nested inside the production conduit and is in fluid communication with the discharge. The check valve is opened when flow is established in the annular space and is otherwise closed. The bypass conduit extends for a selected distance above the discharge. The bypass conduit has a plurality of selected diameter apertures through a wall of the bypass conduit to enable flow into the annular space.

A stator for a helical gear device includes a first section having first helically convoluted chamber with a set of radially inwardly extending lobes and a second section adjacent to the first section. The second section includes a stack of cutter disks. Each cutter disk includes a front surface, a rear surface, an interior surface defining a central opening extending from the front surface to the rear surface, a forward cutting edge, and a rearward cutting edge. The interior surface forms a same number of lobes for the central opening as the set of radially inwardly extending lobes in the first section. Each cutter disk is aligned along a common centerline, and each cutter disk is rotated slightly relative to each other to form a second helically convoluted chamber with a same pitch as the first helically convoluted chamber. The second helically convoluted chamber exposes, to materials passing through, portions of the forward cutting edge or the rearward cutting edge of each cutter disk.

A pump housing includes: a slide surface, along which inner and outer gears are slid; a suction guide passage, which is recessed from the slide surface and guides the fuel at a suction side; a discharge passage, which is recessed from the slide surface-and guides the fuel at a discharge side; and a communication groove, which is recessed from the slide surface and is shaped into an arcuate form that extends along a circumcircle of the inner gear. The communication groove is communicated with the suction groove and the discharge passage through two opposite groove end parts, respectively, of the communication groove.

A pump having at least two fluid drivers and a method of delivering fluid from an inlet of the pump to an outlet of the pump using the at least two fluid drivers. Each of the fluid drives includes a prime mover and a fluid displacement member. The prime mover drives the fluid displacement member to transfer fluid. The fluid drivers are independently operated. However, the fluid drivers are operated such that contact between the fluid drivers is synchronized. That is, operation of the fluid drivers is synchronized such that the fluid displacement member in each fluid driver makes contact with another fluid displacement member. The contact can include at least one contact point, contact line, or contact area.

A rotary pump may include a rotary cover and a rotary housing that may be engaged with one another during operation. A ring gear may be positioned within an internal portion of the rotary cover and rotary housing, and an inner gear may be positioned within a portion of the ring gear. The rotary pump may be configured with a pressure relief portion that may be in fluid communication with an outlet of the pump. The rotary pump may be configured such that pressurized fluid passing through the pressure relief portion is routed to an inlet of the rotary pump.