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.

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.

The present invention is directed to a hydraulic double-acting hand pump in which a high and low pressure side fluid supply grooves are formed in a top surface, a fluid inlet is formed in a bottom surface, a body in which the fluid outlet is formed in a side surface is provided, a piston is inserted into and coupled to the high and low pressure side fluid supply grooves, an upper end of the piston is connected and fixed to a handle rotatably installed in the low pressure side fluid supply groove of the body, the piston alternately and repeatedly ascends and descends to supply fluids to the high and low pressure side fluid supply grooves, and the fluids are discharged through the fluid outlet of the body by pushing the fluids inside the high and low pressure side fluid supply grooves.

The present invention is directed to a hydraulic double-acting hand pump in which a high and low pressure side fluid supply grooves are formed in a top surface, a fluid inlet is formed in a bottom surface, a body in which the fluid outlet is formed in a side surface is provided, a piston is inserted into and coupled to the high and low pressure side fluid supply grooves, an upper end of the piston is connected and fixed to a handle rotatably installed in the low pressure side fluid supply groove of the body, the piston alternately and repeatedly ascends and descends to supply fluids to the high and low pressure side fluid supply grooves, and the fluids are discharged through the fluid outlet of the body by pushing the fluids inside the high and low pressure side fluid supply grooves.

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).

Double acting positive displacement fluid pump Double acting positive displacement fluid pump having two or more housings (3A,20A), a first housing (3A) comprising a pump fluid inlet chamber (3) and a separate housing (20A) comprising a pump fluid outlet chamber (20), the pump fluid inlet chamber (3) being in fluid communication with the pump fluid outlet chamber (20) by means of a through passage (6A), said through passage (6A) having an inlet positioned within the pump fluid inlet chamber (3) and an outlet positioned within the pump fluid outlet chamber (20), the inlet portion (6) of the plunger having an effective displacement area which is larger than the effective displacement area of the outlet portion (21) of the plunger, said passage being further provided with a combined suction-discharge valve assembly (9) arranged in the through passage, wherein the pump fluid inlet chamber (3) comprises a central pump fluid inlet chamber axis and a fluid entry (1B) having an inlet suction valve assembly (2), the pump fluid outlet chamber (20) comprises a central pump fluid outlet chamber axis and the through passage comprises a through passage axis, wherein the central pump fluid inlet chamber axis, the central pump fluid outlet chamber axis and the through passage axis are coaxial and form a central double acting positive displacement fluid pump axis.

A control valve includes a valve body and a valve element disposed in the valve body. The valve body is provided with a large pump inlet-outlet opening, a small pump inlet-outlet opening, a colorant bucket inlet-outlet opening and a colorant dispensing outlet. The valve core, which is provided with a passage, is rotated to allow connection of the large pump inlet-outlet opening and the small pump inlet-outlet opening with a colorant bucket or dispensing thereof, with at least three connecting structures being involved. The control valve is compact in structure and ingenious in design, and may fully achieve the objective of dispensing of large amount colorant or a small amount colorant by rotating the valve core; moreover, the objectives of cleaning the pump and preventing colorant drying and hardening in a colorant circulating pipe and a colorant outlet may be achieved.

A control valve includes a valve body and a valve element disposed in the valve body. The valve body is provided with a large pump inlet-outlet opening, a small pump inlet-outlet opening, a colorant bucket inlet-outlet opening and a colorant dispensing outlet. The valve core, which is provided with a passage, is rotated to allow connection of the large pump inlet-outlet opening and the small pump inlet-outlet opening with a colorant bucket or dispensing thereof, with at least three connecting structures being involved. The control valve is compact in structure and ingenious in design, and may fully achieve the objective of dispensing of large amount colorant or a small amount colorant by rotating the valve core; moreover, the objectives of cleaning the pump and preventing colorant drying and hardening in a colorant circulating pipe and a colorant outlet may be achieved.

A piston pump for a traction-controlled hydraulic vehicle braking system includes a pump piston and an annular piston that is arranged as a second piston in a resiliently loaded manner on the pump piston. As the delivery pressure increases, a resilient element is compressed and a stroke of the second piston is shortened so as to reduce a delivery quantity. This configuration enables a higher delivery pressure to be achieved for a given driving force. With low delivery pressure, the pump piston and the second piston deliver together so as to achieve a rapid build-up of pressure.