A frac pump valve seat assembly includes a seat body and a wiper seal. The seat assembly is configured to mitigate the risk of fluid end erosion in the valve seating area by automatically clearing or wiping the mating surface of the fluid end at the time of installation. The wiper seal is located at a lower portion of the seat body and is designed to interface therewith the mating surface of the fluid end. Upon installation, the wiper seal scrapes or cleans the mating surface of propellants, sand, and other contaminants that may remain after initial cleaning. The contact surface of the seat body is optionally further reinforced with material implants with greater hardness than the material of the seat body.

A pump with a reservoir of a lubricant, including a hollow body in which a piston, loaded by a pressing element, sealingly slides, at least a port for loading the lubricant in a compartment defined by the inner wall of the hollow body and by the piston, and at least a valve for exhausting air trapped in the compartment together with the lubricant during a loading step.

An earphone test system (20) includes a plurality of test stations (22) each operative to perform a function during testing of an earphone device (12) coupled thereto. During testing of earphone devices (12) coupled to the plurality of test stations (22) the earphone test system (20) is operative to expose each of the plurality of test stations (22) to a noise field generated by a common noise field source (29).

The invention relates to a pump device comprising a pump piston (12) which is longitudinally movable in a pump housing (10) and which, controlled by a magnetic actuation apparatus (14), acts on an inlet valve (16) and an outlet valve (18), the inlet valve (16) opening during the intake stroke of the pump piston (12), and the outlet valve (18) opening during the delivery stroke thereof. The inlet valve (16) has an annular valve piston (20) which encompasses the pump housing (10) which has an entry point (22) and an exit point (24) for fluid. The valve piston (20) has a pressure-sensing surface (26) which is controlled by the pump piston (12) in such a way that, during the intake stroke, the pressure-sensing surface (26) of the valve piston (20) is moved counter to the action of an energy store (28) in the movement direction of the pump piston (12) and in the process vacates a fluid path into a pump chamber (30) of the pump housing (10) by means of the pump piston (12) and, during the delivery stroke, the valve piston (20) of the inlet valve (16), under the action of the energy store (28) and the pressure-sensing surface (26), blocks this fluid path and opens the outlet valve (18).

A wave energy converter includes a buoyant body and an acceleration tube with a working cylinder and working piston movable therein, a mooring system, and at least one energy collecting device including a differential cylinder having an internal pump piston connected to the working piston via a piston rod. The differential cylinder includes a pumping chamber and an annular pumping chamber. When decreasing volume of the annular gap-shaped pumping chamber, the pump piston expels hydraulic fluid from the pumping chamber toward the pressure accumulator and draws hydraulic fluid from the fluid tank into the substantially cylindrical pumping chamber. During a working stroke causing a decrease in volume of the substantially cylindrical pumping chamber, the pump piston causes hydraulic fluid to bypass the pump piston through a fluid connection from the substantially cylindrical pumping chamber into the annular gap-shaped pumping chamber and further in a direction toward the pressure accumulator.

An apparatus for dosing a fluid flow system with treatment fluid/chemicals is described. The apparatus includes a vessel; an inlet pipe or hose and an outlet pipe for coupling to the system so that fluid from the system may flow into the vessel and return into the system to flush chemicals from within the vessel and into the system. The vessel has a piston within it and the vessel wall defines a cylinder in which the piston moves under pressure of incoming fluid from a first position at which the vessel contains fluid to be dispensed into the system to a second position corresponding to substantially complete emptying of the vessel. The piston has a bypass passage through or around it that opens when the piston substantially reaches the second position so that fluid from the system may flow passed the piston when the piston is at the second position.

Apparatus for dispensing a dose of fluid, the apparatus comprising a dispensing vessel with a dispensing outlet, the vessel having a piston and a vessel wall defining a cylinder in which the piston may move under pressure from a first position to a second position, wherein the apparatus has a bypass passage that extends through the first piston and has a valve member that is opened by a valve actuating plunger in the piston that moves within the piston to push the valve open when the valve actuating plunger abuts a shoulder at or near the second position in the vessel; wherein the shoulder at the second position is an annular shoulder and the apparatus is adapted to dispense fluid in a sequence of stages comprising a mixing stage and a dispensing stage.

A fluid pump apparatus for an artificial lift system has a barrel, a standing valve positioned at a lower end of the barrel, a plunger reciprocatingly mounted within the barrel, and a traveling valve positioned in an interior of the plunger so as to control fluid flow through the plunger. The barrel has an opening at a top thereof and an opening at a lower end thereof. The standing valve is movable between an open position and a closed position. The plunger has a first aperture at an upper portion of the plunger and a second aperture extending through a wall of the plunger so as to open to a channel extending longitudinally through the plunger. The traveling valve has a head portion of the body extending downwardly from the head portion. The body is slidably movable within an interior of the plunger. The body has a fluid-passing channel therein that opens to an exterior of the body.

An earphone test system (20) includes a plurality of test stations (22) each operative to perform a function during testing of an earphone device (12) coupled thereto. During testing of earphone devices (12) coupled to the plurality of test stations (22) the earphone test system (20) is operative to expose each of the plurality of test stations (22) to a noise field generated by a common noise field source (29).

A fluid pump has a housing, a chamber having an inlet and an outlet, an inlet valve, an outlet valve, and a plunger. The plunger has a plunger tube extending into the chamber and supported for movement, on a suction stroke, to introduce a fluid into the chamber via the inlet, and, on a discharge stroke, to displace the fluid from the chamber via the outlet. An electromagnetic driving unit moves the plunger in two opposite directions. A magnetic core is located adjacent the plunger for establishing a magnetic path across the electromagnetic driving unit and the plunger. The core is located in the path of movement of the plunger on the suction stroke, and is protected or covered by a material against contact with the fluid in the housing.