A gear pump having a drive shaft and at least two gear wheel pairs which each include a drive gear wheel and a driven gear wheel. The two gear wheels of a gear wheel pair are in meshing engagement with one another, and the drive gear wheels are arranged on the drive shaft and in torque-transmissive engagement with the drive shaft. The gear pump has a freely rotatably mounted shaft on which the driven gear wheels of the gear wheel pair are arranged in torque-transmissive engagement, wherein the driven gear wheels are mounted on the freely rotatably mounted shaft by means of a clearance fit.

A pump includes a casing defining an interior volume. The pump casing includes at least one balancing plate that can be part of a wall of the pump casing with each balancing plate including a protruding portion having two recesses. Each recess is configured to accept one end of a fluid driver. The balancing plate aligns the fluid displacement members with respect to each other such that the fluid displacement members can pump the fluid when rotated. The balancing plates can include cooling grooves connecting the respective recesses. The cooling grooves ensure that some of the liquid being transferred in the internal volume is directed to bearings disposed in the recesses as the fluid drivers rotate.

A pump includes a casing defining an interior volume. The pump casing includes at least one balancing plate that can be part of a wall of the pump casing with each balancing plate including a protruding portion having two recesses. Each recess is configured to accept one end of a fluid driver. The balancing plate aligns the fluid displacement members with respect to each other such that the fluid displacement members can pump the fluid when rotated. The balancing plates can include cooling grooves connecting the respective recesses. The cooling grooves ensure that some of the liquid being transferred in the internal volume is directed to bearings disposed in the recesses as the fluid drivers rotate.

A pump assembly comprising a casing having a first pump chamber defining a first flow path and a second pump chamber or more defining a second flow path. A first pump stage includes a first shaft mounted to the casing for rotation about a rotation axis, a first pair of intermeshing gears disposed in the first flow path of the first pump chamber, the first pair of intermeshing gears interfacing each other in operative engagement, one intermeshing gear of the first pump stage mounted on the first shaft. A second pump stage includes a second shaft mounted to the casing for rotation about a rotation axis different than the rotation axis of the first shaft, a second pair of intermeshing gears disposed in the second flow path of the at least second pump chamber, the second pair of intermeshing gears interfacing each other in operative engagement, one intermeshing gear of the second pump stage mounted on the second shaft. A transmission drivingly engages the first shaft to the second shaft.

A pump assembly comprising a casing having a first pump chamber defining a first flow path and a second pump chamber or more defining a second flow path. A first pump stage includes a first shaft mounted to the casing for rotation about a rotation axis, a first pair of intermeshing gears disposed in the first flow path of the first pump chamber, the first pair of intermeshing gears interfacing each other in operative engagement, one intermeshing gear of the first pump stage mounted on the first shaft. A second pump stage includes a second shaft mounted to the casing for rotation about a rotation axis different than the rotation axis of the first shaft, a second pair of intermeshing gears disposed in the second flow path of the at least second pump chamber, the second pair of intermeshing gears interfacing each other in operative engagement, one intermeshing gear of the second pump stage mounted on the second shaft. A transmission drivingly engages the first shaft to the second shaft.

A pump and purge valve configuration may include an inlet, an outlet arranged downstream of the inlet and defining a portion of an operational fluid pathway, and a pump mechanism arranged along the operational fluid pathway between the inlet and the outlet. The pump and purge valve configuration may also include a purging fluid pathway having a purge inlet in fluid communication with the operational fluid pathway at a point downstream of the pump. The purging fluid pathway may extend from the purge inlet to a relief point. The pump and purge valve configuration may also include a purge valve arranged along the purging fluid pathway. The purge valve may be configured to remain open unless a triggering fluid pressure develops in the pump mechanism.

A pump and purge valve configuration may include an inlet, an outlet arranged downstream of the inlet and defining a portion of an operational fluid pathway, and a pump mechanism arranged along the operational fluid pathway between the inlet and the outlet. The pump and purge valve configuration may also include a purging fluid pathway having a purge inlet in fluid communication with the operational fluid pathway at a point downstream of the pump. The purging fluid pathway may extend from the purge inlet to a relief point. The pump and purge valve configuration may also include a purge valve arranged along the purging fluid pathway. The purge valve may be configured to remain open unless a triggering fluid pressure develops in the pump mechanism.

A fluid working system such as a pump for displacing a working fluid such as hydraulic fluid or a motor using a working fluid is provided. The system may have a positive displacement machine which includes one or more working chamber with displacement means such as a cylinder with a reciprocating piston. There are also two or more fluid ports to allow the working fluid to flow into and out of the working chamber. The working fluid flows from one fluid port means to another either being forced to do so when pumped or moving the piston when functioning as an engine. The fluid working system has associated therewith a non-dead compliance volume of a material such as syntactic foam. This compliance volume acts to smooth any pressure fluctuations within the working fluid system.

A fluid working system such as a pump for displacing a working fluid such as hydraulic fluid or a motor using a working fluid is provided. The system may have a positive displacement machine which includes one or more working chamber with displacement means such as a cylinder with a reciprocating piston. There are also two or more fluid ports to allow the working fluid to flow into and out of the working chamber. The working fluid flows from one fluid port means to another either being forced to do so when pumped or moving the piston when functioning as an engine. The fluid working system has associated therewith a non-dead compliance volume of a material such as syntactic foam. This compliance volume acts to smooth any pressure fluctuations within the working fluid system.

A pump stage assembly including at least two pump suction stages and at least one pump pressure stage. The pump suction stages and the pump pressure stage are arranged spaced apart from one another in a pump housing PG and have a common drive shaft. The pump suction stages are formed by a first assembly of intermeshing external gearwheels that lie in a first plane, and the pump pressure stage is formed by a second assembly of intermeshing external gearwheels that lie in a second plane. A first delivery volume flow can be drawn in from a first region of a dry sump by a first pump suction stage, and a second delivery volume flow can be drawn in from a second region of the dry sump by a second pump suction stage. The two delivery volume flows intermix in the pump housing before they reach an oil tank.