A system comprises a variable displacement pump, a metering valve, a bypass line, a pressure regulating valve, a position sensor, and a control system. At least one fuel nozzle can be in fluid communication with the output line downstream of the metering valve, wherein the variable displacement pump is configured to supply fuel to the at least one fuel nozzle. The metering valve can be disposed in the output line for controlling outlet flow from the variable displacement pump. The system can also include an actuator line parallel to the variable displacement pump and connected to the output line to provide actuation pressure from pump output of the variable displacement pump.

A pump, which generally includes a pump housing and a pump piston. The pump housing defines a central longitudinal bore, a transverse bore communicating with the central bore for conveying a liquid through the pump housing, a liquid reservoir communicating with the central bore and the transverse bore for retaining an amount of the liquid conveyed through the transverse bore and a pressure relief slot extending from the transverse bore to the liquid reservoir. The pump piston is axially and rotatably slidable within the central longitudinal bore for pumping the liquid through the transverse bore.

A pump, which generally includes a pump housing and a pump piston. The pump housing defines a central longitudinal bore, a transverse bore communicating with the central bore for conveying a liquid through the pump housing, a liquid reservoir communicating with the central bore and the transverse bore for retaining an amount of the liquid conveyed through the transverse bore and a pressure relief slot extending from the transverse bore to the liquid reservoir. The pump piston is axially and rotatably slidable within the central longitudinal bore for pumping the liquid through the transverse bore.

The present invention refers to a peristaltic pump, especially refers to a linear peristaltic pump for precise and quantitative delivery of fluid, comprising a base, wherein, a lateral seat for fixing a flexible tube is provided on the base, a linear reciprocating movement mechanism is provided below the flexible tube; a sliding block is provided on the linear reciprocating movement mechanism, adapted for releasing and squeezing a flexible tube to moves up and down; a backflow preventing device is fixed on the base arranged close to the linear reciprocating movement mechanism. By adopting the above structure, a new operational principle of linear type is formed, and the structure of traditional rotary peristaltic pump is improved. The flexible tube is rarely abraded; it is easy to disassemble and assemble the flexible tube; and the feed liquid does not contact with the device.

The present invention refers to a peristaltic pump, especially refers to a linear peristaltic pump for precise and quantitative delivery of fluid, comprising a base, wherein, a lateral seat for fixing a flexible tube is provided on the base, a linear reciprocating movement mechanism is provided below the flexible tube; a sliding block is provided on the linear reciprocating movement mechanism, adapted for releasing and squeezing a flexible tube to moves up and down; a backflow preventing device is fixed on the base arranged close to the linear reciprocating movement mechanism. By adopting the above structure, a new operational principle of linear type is formed, and the structure of traditional rotary peristaltic pump is improved. The flexible tube is rarely abraded; it is easy to disassemble and assemble the flexible tube; and the feed liquid does not contact with the device.

A diaphragm pump (10), in particular for use as a detergent dosage pump, comprises a pump housing (12) with at least a first check valve (14) and a second check valve (16), a fluid chamber (18), a diaphragm (20) defining a wall of the fluid chamber (18) and reciprocatingly movable, a stepping motor (28) as driving means for reciprocating said diaphragm (20), wherein the stepping motor (28) comprises a controller (34) for actuating the stepping motor (28), and an external control unit (36) for operating the controller (34) of the stepping motor (28), wherein the external control unit (36) is connected to the controller (34) by a power supply line (38) for transmitting an operating signal (42, 46) to the controller (34), wherein the operating signal (42, 46) is a start signal for operating the diaphragm pump (10), in particular the stepping motor (28), at preset parameters. The diaphragm pump (10) according to the invention offers increased cost efficiency of the diaphragm pump (10) by integrating the power supply and the transfer of operating signals from the control unit (36) to the controller (34).

A diaphragm pump (10), in particular for use as a detergent dosage pump, comprises a pump housing (12) with at least a first check valve (14) and a second check valve (16), a fluid chamber (18), a diaphragm (20) defining a wall of the fluid chamber (18) and reciprocatingly movable, a stepping motor (28) as driving means for reciprocating said diaphragm (20), wherein the stepping motor (28) comprises a controller (34) for actuating the stepping motor (28), and an external control unit (36) for operating the controller (34) of the stepping motor (28), wherein the external control unit (36) is connected to the controller (34) by a power supply line (38) for transmitting an operating signal (42, 46) to the controller (34), wherein the operating signal (42, 46) is a start signal for operating the diaphragm pump (10), in particular the stepping motor (28), at preset parameters. The diaphragm pump (10) according to the invention offers increased cost efficiency of the diaphragm pump (10) by integrating the power supply and the transfer of operating signals from the control unit (36) to the controller (34).

Processes of and apparatus for supplying to an operation a liquid that is applied at the operation comprise delivering to the operation from a holding vessel a liquid of a prescribed composition comprising more than one constituent, whereby a spent liquid having a composition different from the prescribed composition can be formed at the operation. The spent liquid is returned to the holding vessel for redelivery to the operation. The composition of the liquid at the holding vessel can be continuously analyzed and the amount of each constituent of the liquid required to be added to the liquid at the holding vessel to provide a liquid of the prescribed composition determined and that amount of each constituent delivered to the holding vessel. A plurality of operations and respective holding vessels can be involved. The operations can comprise metalworking operations and the liquid of a prescribed composition can comprise a coolant.

Processes of and apparatus for supplying to an operation a liquid that is applied at the operation comprise delivering to the operation from a holding vessel a liquid of a prescribed composition comprising more than one constituent, whereby a spent liquid having a composition different from the prescribed composition can be formed at the operation. The spent liquid is returned to the holding vessel for redelivery to the operation. The composition of the liquid at the holding vessel can be continuously analyzed and the amount of each constituent of the liquid required to be added to the liquid at the holding vessel to provide a liquid of the prescribed composition determined and that amount of each constituent delivered to the holding vessel. A plurality of operations and respective holding vessels can be involved. The operations can comprise metalworking operations and the liquid of a prescribed composition can comprise a coolant.

A drive includes an inverter power circuit that applies power to an electric motor of a compressor from a direct current (DC) voltage bus. A power factor correction (PFC) circuit outputs power to the DC voltage bus based on input alternating current (AC) power. The PFC circuit includes: (i) a switch having a first terminal, a second terminal, and a control terminal; (ii) a driver that switches the switch between open and closed states based on a control signal; (iii) an inductor that charges and discharges based on switching of the switch; and (iv) a circuit that outputs a signal indicating whether the switch is in the open state or the closed state based on a voltage across the first and second terminals of the switch.