A cooling circuit comprises a refrigerant compressor incorporating a suction port and a pressure chamber incorporating a pressure port, a condenser arranged downstream of the pressure port, a fluid collecting chamber in which a reservoir of refrigerant is formed, an evaporator which is located between the condenser and the suction port, a feed unit which is connected at one side to the refrigerant reservoir and to the pressure chamber at the other side and which serves for supplying refrigerant from the refrigerant reservoir to the pressure chamber which incorporates a pumping unit for the refrigerant. It is proposed that in order improve this cooling circuit, the pumping unit comprise a pressure-tight closed housing which is provided with only one inlet and one outlet as access points and a pumping element which is movable for pumping the refrigerant be arranged in the pumping chamber thereof.

Automatic electric actuation of the pumping mechanism of a liquid dispenser apparatus is provided by configuring a hollow tube to cooperate with an electromagnetically driven actuator and further configuring the hollow tube to inter-fit with a stem of a liquid dispensing pump. Actuation of the actuator may, for example, drive the pump stem downwardly to cause a pumping action. Suitable actuators include, for example, solenoids, voice coil actuators and stepping motors.

A linear-acting electric pump unit and method for operating said unit. A linear-acting electric pump unit comprises an electromagnet and a pump unit. It is to be suitable for delivering gas/liquid mixtures. In order that it may be compactly assembled with other devices, it is to have a central inlet. The fluid delivered by the pump unit flows through the electromagnet and enters the pump unit on one side and leaves it on the other through the non-return valves, each arranged on the same centre line as the electromagnet. The pump unit can be used for delivery of gas/liquid mixtures, preferably in the sphere of combustion engines and their fuel supply systems and exhaust emission control systems.

A fuel pump, including a case, including a first section including a hub and a hole, a second section circumferentially arranged around the first section, wherein a radial space is arranged between the first section and the second section, an inlet in fluid communication with the radial space, a housing chamber arranged adjacent to the first section, and an outlet in fluid communication with the hole, a filter bowl removably connected to the second section, the filter bowl fluidly connecting the radial space with the hole, a valve assembly arranged at least partially in the first section and at least partially in the housing chamber, and a coil operatively arranged to apply a magnetic field to the valve assembly to selectively displace fluid therethrough.

An oscillating piston pump including: a first hollow tubular body in which a piston moves; a second hollow tubular body extending around the first hollow tubular body, carrying a solenoid that controls the movement of the piston, the first tubular body and the second tubular body forming a one-piece structural element.

Automatic electric actuation of the pump of a liquid dispenser apparatus is provided by a stepper motor having a threaded hollow liquid-conducting tube positioned therein and configured such that motor drives the hollow tube up and down in response to supply of a plurality of electrical pulses thereto. A lower end of the hollow tube is constructed to inter-fit with a stem of the pump such that driving the hollow tube up and down creates a pumping action.

A downhole magnetic pump system includes a tube positioned within a wellbore at least partially filled with a fluid. A conductive wire coil is helically wrapped around the tube and is configured to generate a magnetic field in response to an electrical current passing through the coil. A standing valve assembly including a one-way valve and a travelling valve assembly also including a one-way valve are both positioned in the tube, with the travelling valve assembly positioned uphole of the standing valve assembly. The traveling valve is configured to repetitively cycle between a first position uphole of the standing valve assembly and a second position uphole of the first position in response to the electrical current repetitively switching between a first state to a second state. In this way, a portion of the fluid is displaced in an uphole direction.

A control unit for a solenoid pump, the solenoid pump including: an inlet port, an outlet port, and a first through-bore connecting the inlet and outlet ports; a plunger disposed within the first through-bore and including a second through-bore; a spring arranged to urge the plunger toward the outlet port; a solenoid coil disposed about a portion of the plunger and arranged to displace the plunger toward the inlet port in response to direct current coil power applied to the solenoid coil, the control unit including a microcontroller operatively arranged to control the solenoid coil, a first transistor operatively arranged to receive an external signal and communicate the signal to the microcontroller to control the solenoid coil, and a second transistor, arranged between the microcontroller and the solenoid coil, the second transistor operatively arranged to energize and de-energize the solenoid coil in response to the microcontroller.

First and second pistons are mounted to a common shaft which reciprocates during compression and suction strokes. During each of the strokes, fluid is pumped out at an outlet, via a one-way valve on the second piston. The one-way valve is opened or closed depending on whether the first and second pistons are in the compression or suction stroke. Additionally, pressure from the outlet assists in traversing the first and second pistons in the compression stroke. During the suction stroke, the fluid pressure applies a force on the first piston to counteract the fluid pressure on the second piston so that a smaller spring may be used. The size requirements of the solenoid and spring are reduced. Additionally, the fluid pump provides lower pressure spikes, since fluid is pumped out during both the compression and suction strokes and also provides a more even flow of fluid.

The present invention relates to a fuel pump (1) which comprises a pump housing (2), a delivery element (3) for delivering fuel, a heat-generating actuator (4) for actuating the delivery element (3), a first fuel path (5) which leads from an inlet (20) to a delivery space (7), and a second fuel path (6) which leads from the inlet (20) past the heat-generating actuator (4) to a first housing opening (21), wherein the first housing opening (21) is arranged above the inlet (20) in the vertical direction (V). The present invention also relates to a fuel pump arrangement which comprises a fuel pump (1) according to the invention and a fuel tank (10) in which the fuel pump (1) is at least partially and preferably entirely arranged. The present invention also relates to a method for operating a fuel pump (1).