A seal arrangement for a vane cell pump of cartridge design which is configured such that it can be switched into multiple flows is described. The seal arrangement comprises a first seal which is arranged so as to run around the circumference of a side plate of the vane cell pump, and a second seal which is arranged so as to run around a shaft leadthrough which is provided in the side plate. The seal arrangement is distinguished by a third seal which, apart from at least one first fluid connection, shuts off at least a second fluid connection with respect to the at least one first fluid connection within a region which is configured between the first seal and the second seal.

A seal arrangement for a vane cell pump of cartridge design which is configured such that it can be switched into multiple flows is described. The seal arrangement comprises a first seal which is arranged so as to run around the circumference of a side plate of the vane cell pump, and a second seal which is arranged so as to run around a shaft leadthrough which is provided in the side plate. The seal arrangement is distinguished by a third seal which, apart from at least one first fluid connection, shuts off at least a second fluid connection with respect to the at least one first fluid connection within a region which is configured between the first seal and the second seal.

A hydraulic pump or motor includes a mounting flange that is disposed at the first end of the housing. The mounting flange defines a pair of bolt receiving slots that are disposed along the X-axis on either side of the shaft. The pair of bolt receiving slots each define a radius center that are spaced away from each other a X dimension, and a pilot projection extends longitudinally away from the mounting flange, defining a pilot projection diameter. A ratio of the X dimension to the pilot projection diameter ranges from 1.1 to 1.5.

A liquid pump capable of achieving pressure equilibrium includes a body, piston member, unidirectional input valve, unidirectional output valve, input inner-pipe, unidirectional gas-feeding hermetic-seal valve and input outer-pipe. The body has an input opening, output opening and piston opening. The piston member has a piston space communicating with the piston opening. The unidirectional input valve includes an input plug and input resilient element. The input plug abuts against the input opening. The unidirectional output valve includes an output plug and output resilient element. The output plug abuts against the output opening from outside. An input channel of the input inner-pipe communicates with the input opening. Direction of gas-flow between the unidirectional gas-feeding hermetic-seal valve and the input inner-pipe is opposite input direction of the input channel. The input outer-pipe has an input portion communicating with the input channel. A gas-feeding-channel is defined between a gas-feeding-portion and the input inner-pipe.

A liquid pump capable of achieving pressure equilibrium includes a body, piston member, unidirectional input valve, unidirectional output valve, input inner-pipe, unidirectional gas-feeding hermetic-seal valve and input outer-pipe. The body has an input opening, output opening and piston opening. The piston member has a piston space communicating with the piston opening. The unidirectional input valve includes an input plug and input resilient element. The input plug abuts against the input opening. The unidirectional output valve includes an output plug and output resilient element. The output plug abuts against the output opening from outside. An input channel of the input inner-pipe communicates with the input opening. Direction of gas-flow between the unidirectional gas-feeding hermetic-seal valve and the input inner-pipe is opposite input direction of the input channel. The input outer-pipe has an input portion communicating with the input channel. A gas-feeding-channel is defined between a gas-feeding-portion and the input inner-pipe.

A seal tube assembly of a pump system is provided. The seal tube assembly includes a single seal tube having a first axial end sealably coupled to a first vane pump and a second axial end sealably coupled to a second vane pump. The single seal tube includes transverse contact surfaces at the first axial end and transverse contact surfaces at the second axial end. The single seal tube is formed to define a first seal tube cavity at the first axial end and a second seal tube cavity at the second axial end.

A seal tube assembly of a pump system is provided. The seal tube assembly includes a single seal tube having a first axial end sealably coupled to a first vane pump and a second axial end sealably coupled to a second vane pump. The single seal tube includes transverse contact surfaces at the first axial end and transverse contact surfaces at the second axial end. The single seal tube is formed to define a first seal tube cavity at the first axial end and a second seal tube cavity at the second axial end.

A liquid pump capable of achieving pressure equilibrium includes a body, piston member, unidirectional input valve, unidirectional output valve, input inner-pipe, unidirectional gas-feeding hermetic-seal valve and input outer-pipe. The body has an input opening, output opening and piston opening. The piston member has a piston space communicating with the piston opening. The unidirectional input valve includes an input plug and input resilient element. The input plug abuts against the input opening. The unidirectional output valve includes an output plug and output resilient element. The output plug abuts against the output opening from outside. An input channel of the input inner-pipe communicates with the input opening. Direction of gas-flow between the unidirectional gas-feeding hermetic-seal valve and the input inner-pipe is opposite input direction of the input channel. The input outer-pipe has an input portion communicating with the input channel. A gas-feeding-channel is defined between a gas-feeding-portion and the input inner-pipe.

A liquid pump capable of achieving pressure equilibrium includes a body, piston member, unidirectional input valve, unidirectional output valve, input inner-pipe, unidirectional gas-feeding hermetic-seal valve and input outer-pipe. The body has an input opening, output opening and piston opening. The piston member has a piston space communicating with the piston opening. The unidirectional input valve includes an input plug and input resilient element. The input plug abuts against the input opening. The unidirectional output valve includes an output plug and output resilient element. The output plug abuts against the output opening from outside. An input channel of the input inner-pipe communicates with the input opening. Direction of gas-flow between the unidirectional gas-feeding hermetic-seal valve and the input inner-pipe is opposite input direction of the input channel. The input outer-pipe has an input portion communicating with the input channel. A gas-feeding-channel is defined between a gas-feeding-portion and the input inner-pipe.

Some embodiments are directed to a positive displacement pump having an eccentric piston, comprising a tube having a first end and a second end that is terminated by a cylinder secured to a delivery zone, the tube including an intake opening and a delivery opening, a drive shaft extending between the transmission zone and the tube, a piston arranged in the delivery zone and mounted in a sliding manner at the end of the shaft, being pressed against the cylinder by an elastic presser so as to prevent fluid displacement between the tube and the delivery zone when the pump is dry, and the elastic presser is provided to press the piston against the cylinder when the pump is running under load.