The invention relates to a device for generating a pulsating hydraulic fluid pressure in a working chamber (1) filled with hydraulic fluid, comprising a driveable working piston (4) movably guided in a hollow working cylinder, wherein a working chamber (1) that is in fluid communication with the working piston (4) is provided, such that, by means of the movement of the working piston (4) within the hollow working cylinder, a pulsating hydraulic fluid pressure can be generated in the working chamber (1). In order to provide a device for generating a pulsating hydraulic fluid pressure and in particular a diaphragm metering pump comprising such a device, which has small dimensions and in addition a rapid passage through the phase between closing the suction valve and opening the pressure valve, according to the invention, an auxiliary piston (20) is movably guided in a hollow auxiliary cylinder and is in fluid communication with an additional chamber (18, 21), wherein a closeable auxiliary channel (22), which connects the additional chamber (18, 21) and the working chamber (1), is provided, wherein the auxiliary piston (20) and the hollow auxiliary cylinder are formed and arranged in such a way that, by moving the auxiliary piston (20) within the hollow auxiliary cylinder, a hydraulic fluid arranged in the additional chamber (18, 21) can at least partly be forced out of the additional chamber (18, 21) into the auxiliary channel (22) and from the auxiliary channel (22) into the working chamber (1).

The invention relates to a device for generating a pulsating hydraulic fluid pressure in a working chamber (1) filled with hydraulic fluid, comprising a driveable working piston (4) movably guided in a hollow working cylinder, wherein a working chamber (1) that is in fluid communication with the working piston (4) is provided, such that, by means of the movement of the working piston (4) within the hollow working cylinder, a pulsating hydraulic fluid pressure can be generated in the working chamber (1). In order to provide a device for generating a pulsating hydraulic fluid pressure and in particular a diaphragm metering pump comprising such a device, which has small dimensions and in addition a rapid passage through the phase between closing the suction valve and opening the pressure valve, according to the invention, an auxiliary piston (20) is movably guided in a hollow auxiliary cylinder and is in fluid communication with an additional chamber (18, 21), wherein a closeable auxiliary channel (22), which connects the additional chamber (18, 21) and the working chamber (1), is provided, wherein the auxiliary piston (20) and the hollow auxiliary cylinder are formed and arranged in such a way that, by moving the auxiliary piston (20) within the hollow auxiliary cylinder, a hydraulic fluid arranged in the additional chamber (18, 21) can at least partly be forced out of the additional chamber (18, 21) into the auxiliary channel (22) and from the auxiliary channel (22) into the working chamber (1).

A fluid treatment system, for example a membrane filtration system, utilizing means to mechanically vary fluid recovery and energy recovery to optimize fluid production for a given energy input, based on the total dissolved solids concentration in the fluid feed stream.

An intensifier pump includes a piston including at least two selectable piston diameters. Additionally, the intensifier pump includes a plunger that in operation interacts with the piston. The plunger includes a plunger diameter that is smaller than each of the at least two selectable piston diameters.

An intensifier pump includes a piston including at least two selectable piston diameters. Additionally, the intensifier pump includes a plunger that in operation interacts with the piston. The plunger includes a plunger diameter that is smaller than each of the at least two selectable piston diameters.

This compression device is provided with a reciprocating compressor which compresses a gas, and a heat exchanger which cools gas compressed by the compressor. The heat exchanger is provided with a cooling unit for cooling the gas and with a connection unit which abuts against the outside surface of the compressor and has a gas inlet passage to allow gas discharged from the compression chamber of the compressor to flow into the cooling unit.

This compression device is provided with a reciprocating compressor which compresses a gas, and a heat exchanger which cools gas compressed by the compressor. The heat exchanger is provided with a cooling unit for cooling the gas and with a connection unit which abuts against the outside surface of the compressor and has a gas inlet passage to allow gas discharged from the compression chamber of the compressor to flow into the cooling unit.

A pump capable of dispensing both a large volume and a small volume of colorant comprises a large reciprocating positive displacement pump having a large reciprocating part, a large pump body and a large pump inlet-outlet opening, characterized in that: a small reciprocating part fixed to the large reciprocating part is disposed in the large pump body; a small pump body is disposed on a base of the large pump body, and provided with a small pump inlet-outlet opening; and the small reciprocating part, the small pump body and the small pump inlet-outlet opening constitute a small reciprocating positive displacement pump.

A pump capable of dispensing both a large volume and a small volume of colorant comprises a large reciprocating positive displacement pump having a large reciprocating part, a large pump body and a large pump inlet-outlet opening, characterized in that: a small reciprocating part fixed to the large reciprocating part is disposed in the large pump body; a small pump body is disposed on a base of the large pump body, and provided with a small pump inlet-outlet opening; and the small reciprocating part, the small pump body and the small pump inlet-outlet opening constitute a small reciprocating positive displacement pump.

A reciprocating pump, in particular a hydraulic pump of a slip-controlled vehicle braking system, includes a step piston, a differential pressure valve, and a pump outlet. The step piston includes a piston step that delimits a stepped space which is in communication with the pump outlet via the differential pressure valve. The piston step is configured such that the step space undergoes suction and displacement in a direction opposite to a displacement space, and in smaller quantities than suction and displacement in the displacement space, such that brake fluid volume flow in the pump outlet is evened out, and such that pressure pulsations are inhibited.