A pump unit which has at least one high-pressure port and at least one low-pressure port, having a motor and a hydraulic pump which has at least one high-pressure outlet and at least one low-pressure outlet, wherein the high-pressure outlet is connected to the high-pressure port via at least one pressure-regulating valve.

An oil pump for an engine is disclosed. The oil pump may include a first pump mechanism configured to supply oil to a main lubrication gallery of the engine, and a second pump mechanism configured to supply oil to a piston cooling gallery of the engine. The first pump mechanism may be designed for a first type of engine and the second pump mechanism may be designed for a second type of engine. The first type of engine may have a greater quantity of cylinders than the second type of engine.

A composite piston machine has two moving assemblies of a rotor and a composite piston placed 180° out of phase with each other and linked to a shaft eccentrically placed inside the inner cavity of a main body that has ports for the inlet and outlet of fluids from it. This inner cavity is covered by two lids and divided in two working chambers by a separator. The composite pistons move following the rotation of the rotors while oscillating with respect of them and following the path of skid guides carved in separator and lids, dividing each working chamber in inlet and outlet chambers of variable volume, and intermittently obstructing the inlet and outlet of fluids from the inner cavity through the ports. The machine is designed for compressing gases or pumping liquids and can also operate as an engine driven by compressed gases or with pressurized liquids.

A medical system includes a medical instrument including an irrigation and aspiration channel to carry irrigation fluid to, and remove aspirated matter from, a distal end of the medical instrument, a reservoir to store the irrigation fluid, a receptacle to collect the aspirated matter, and a vane pump including a pump housing having an inner surface around a pumping chamber, the pump housing including irrigation inlet and outlet ports coupled to the pumping chamber and respectively connected to the reservoir and the irrigation channel, and aspiration inlet and outlet ports coupled to the pumping chamber and respectively connected to the aspiration channel and the receptacle, and wherein the vane pump is configured to simultaneously pump via the pumping chamber, at substantially the same flow rate, the irrigation fluid from the reservoir to the distal end and the aspirated matter from the distal end to the receptacle.

A structure of rotor connection of multi-axial multi-stage roots pump comprises a rotor body, a rotor shaft is arranged on one end face of the rotor body, a sub-shaft cavity is opened in the rotor shaft, and the locating keyways are symmetrically opened on both sides inside the sub-shaft cavity; a sub-shaft is arranged on the other end face of the rotor body, the sub-shafts and the sub-shaft cavities of two adjacent rotor bodies are matched, locating keyways are symmetrically opened on both sides of the sub-shaft, and the keyways are installed and fixed through sub-rotor shaft keys in the locating keyways. The invention overcomes the disadvantages of the prior art, and the first-stage rotor body is limited and fixed by the bearing, while the second-stage rotor body is only radially limited by the bearing in the first-stage rotor body. The rotor shaft on the other side is also fixed and limited by the bearing, so the thermal expansion displacement and thermal stress of the second-stage rotor body are completely independent during operation. The thermal expansion displacement of the first-stage rotor body does not affect the second-stage rotor body, and it can also synchronously drive the second-stage rotor body.

A screw spindle pump, comprising a pump housing having a lead screw received therein and at least one running spindle which meshes with said lead screw, as well as a connector housing which is placed onto the pump housing and has a suction connector and a pressure connector, the two latter fluidically communicating with a suction inlet and a pressure outlet of the pump housing, wherein the connector housing is composed of a first housing part and a second housing part, one of the two latter having the suction connector and the other having the pressure connector, both said housing parts being rotatable relative to the pump housing and both being rotatable relative to one another.

The present invention relates to a fixed displacement pump for use for conveying a hydraulic fluid in a closed hydraulic circuit, a closed hydraulic circuit, a construction machine and a method for operating a fixed displacement pump in a closed hydraulic circuit.

An electric compressor system for a vehicle includes: an electric motor having a rotor and a motor shaft which selectively rotate in a first rotation direction or a second rotation direction; an external rotation shaft extending from the motor shaft of the electric motor; a first compressor unit connected to the external rotation shaft and selectively compressing a first fluid according to the rotation direction of the external rotation shaft; and a second compressor unit connected to the external rotation shaft and selectively compressing a second fluid according to the rotation direction of the external rotation shaft, wherein the first compressor unit and the second compressor unit are sequentially arranged on the external rotation shaft, the first compressor unit is fluidly connected to a first fluid system, and the second compressor unit is fluidly connected to a second fluid system.

A gear pump that is used to pump fluid, such as oil, in a vehicle. The gear pump comprises a gear assembly having a drive shaft including a drive shaft key; a set of drive gears mounted on the drive shaft, with a drive gear of the set of drive gears being keyed with the drive shaft key; a driven shaft including a driven shaft key; a set of driven gears mounted on the driven shaft, with a driven gear of the driven gear set being keyed with the driven shaft key; and a torque drive feature associated with the drive shaft or the driven shaft, wherein the torque drive feature is configured to check keying with the driven shaft key.

Overheating of a process liquid retained in a reservoir of a multiphase pump during extended gas slugs is avoided by circulating a cooling liquid in thermal contact with a process liquid through an external cooling apparatus, which can include a heat exchanger. In some embodiments, process liquid from the reservoir is circulated through the cooling loop, while in other embodiments a separate cooling liquid is circulated between a reservoir heat exchanger and the external cooling apparatus. The liquid in the cooling loop can be circulated by a separate cooling pump, or process liquid can be circulated through the cooling loop due to a pressure differential between an inlet and an outlet of the cooling loop within the multiphase pump. The multiphase pump can be a twin screw pump, and the reservoir can be formed between outer and inner casings of the multiphase pump.