An electric motor driven pump assembly configuration that includes an electric motor, a hydraulic pump driven by the electric motor is provided. The hydraulic pump is driven by the electric motor to convert electrical power into hydraulic power. A multi-inlet hydraulic pump enhances cooling flow through a pump case of the assembly and also enhances cooling flow for cooling the electric motor and corresponding drive/control components.

A submersible pumping system has an electric motor, a rotary hydraulic pump driven by the electric motor, and a linear hydraulic pump that is configured to move a production fluid. The rotary hydraulic pump produces a pressurized working fluid that drives the linear hydraulic pump. In another aspect, a method is disclosed for controlling the temperature of an electric motor within a submersible pumping system disposed in a wellbore. The method includes the steps of circulating motor lubricant through a hydraulically driven production pump to reduce the temperature of the motor lubricant.

The present invention provides an improved pump assembly incorporating a liquid pump and an air pump and which pump includes a flexible annular diaphragm member coaxially about a piston-forming element forming a component with the liquid pump.

The invention relates to a method of venting a synthetically commutated hydraulic pump (2). The connecting fluid conduits (8, 16), connecting said synthetically commutated hydraulic pump (2) with a fluid reservoir (7) is vented at least on start-up of the synthetically commutated hydraulic pump (2), using a fluid intake device (14, 17, 20) that connects to a fixed displacement pump (3).

A pump-regulator combination includes first and second pumps, a control valve, first orifice, and pilot valve. The first pump is configured to pump fluid from a tank to a first point. The control valve is configured to control pressure and/or delivery flow at the first point by adjusting a displacement volume of the first pump. The second pump is configured to pump fluid from the tank to a second point, through the first orifice, and back to the tank. A highest load pressure of the actuator is connected to a third point. The pilot valve includes an adjustable second orifice connected to the third point, via a fourth point, and the tank to pass fluid from the actuator to the tank. A pressure at the second point acts to close the second orifice. A pressure of the fourth point acts to adjust the control valve.

Metering device for introducing a liquid additive into a main liquid flowing along a pipe, includes a pump for withdrawing additive from a container and metering it, this pump including a first inlet for receiving a flow of main liquid which drives the pump, a second inlet for picking up additive and an outlet for the resulting mixture; a Venturi installed in the pipe, and connected in parallel with the pump, the first pump inlet connected by a first line to the Venturi inlet while the outlet connected by a second line to the Venturi throat; a first element for varying the restriction at the Venturi neck, and a second element sensitive to the pressure drop across the pump for controlling the first element to reduce the bore section when the pressure drop across the pump increases, and increase the bore section when the pressure drop across the pump decreases.

A hydraulic pump assembly having a main pump, a charge pump and an auxiliary pump driven by a single shaft is provided. A pair of hydraulic porting members cooperates to feed and distribute hydraulic fluid between the three pump units, and a single inlet may be used to provide hydraulic fluid to the charge pump and the auxiliary pump.

Lifting device (10) for vertically lifting liquids, where the lifting device (10) comprises: a lifting line arrangement (18) for guiding a liquid from an open lower reservoir (16) to an upper reservoir (14); a lowering line arrangement (20) for guiding the liquid from the upper reservoir (14) to the lower reservoir (16); a pressure converter (12) with an actuating member (36), the pressure converter (12) being configured to convert a liquid pressure in the lowering line arrangement (20) into a liquid pressure in the lifting line arrangement (18) by means of a substantially linear movement of the actuating member (36); and a pump member (38) for pumping the liquid in the lifting line arrangement (18) towards the upper reservoir (14) and/or for pumping the liquid in the lowering line arrangement (20) towards the pressure converter (12).

A Side-Intake piston water jet propulsor for marine vehicles employs a concept of Side-Intake of water and generates thrust through piston's reciprocating motion in cylinder. The concept of Side-Intake makes intake openings on the side and near the discharging end of the cylinder wall to achieve that the piston separates the cylinder into a dry and a wet compartment during its movement. The dry compartment is kept at atmospheric or ambient pressure. As a result, the piston confronts air or ambient pressure instead of water during its recovering stroke for water intake. From hydrodynamics point of view, this characteristic of piston's recovering stroke through air achieves the same function as an oarsman recovering his oar through air. However, said propulsor achieves that under water or a vessel's water line.

A connector plate, for mechanically and hydraulically connecting a hydraulic machine with a hydraulic attachment part, includes a plurality of hydrostatic connector recesses. Each recess has a first side that includes a first orifice opening to the hydraulic attachment part, and a second side with a second orifice opening to the hydraulic machine. The plurality of orifices are arranged so as to open in a substantially axially parallel manner with respect to a drive shaft of the hydraulic machine. A hydraulic machine includes such a connector plate, and a hydrostatic unit includes such a hydraulic machine and a hydraulic attachment part.