A proportional metering pump includes a hydraulic machine, a metering mechanism provided with a nozzle, and a unit for attaching the nozzle to the pipe for access to the cavity inside the hydraulic machine, including a securing ring mounted in rotation about one of the ends of the nozzle, a locking ring mounted so as to be able to translate along the longitudinal axis around the pipe for access to the mixing chamber and is pressed, in the direction of the metering mechanism, against a shoulder created on the access pipe by a spring, the securing ring and the pipe being able to engage following a screw connection at the end of which they are secured in rotation so as to prevent unscrewing of the securing ring. Also disclosed is a method for assembling and disassembling a metering mechanism on a hydraulic machine of such a pump.

A hydraulic pressure amplifier arrangement (1) is described comprising a supply port (A1), a pressure outlet (A2) connected to the supply port via check valve means (3), an intensifier section (5) having a high pressure piston (6) in a high pressure cylinder (7), a low pressure piston (8) in a low pressure cylinder (9) and connected to the high pressure piston (6), and a control valve (12) controlling a pressure in the low pressure cylinder (9), wherein the control valve (12) comprises a hydraulically actuated valve element (13). Such a pressure amplifier arrangement should have a good operational behavior in a cost effective manner. To this end the control valve (12) comprises spring means 16 acting on the valve element (1) in a direction towards a starting position of the control valve.

An displacement amplifying mechanism that enlarges an amount of displacement of an actuator includes an accommodation chamber in which a liquid is sealed, a first wall portion that forms a wall surface of the accommodation chamber and applies a pressure to the liquid in accordance with displacement of the actuator, and a second wall portion that forms the wall surface of the accommodation chamber and is displaced in a first direction which is a direction away from the accommodation chamber in a state where an elastic force acting in a second direction approaching the accommodation chamber is generated by a pressure of the liquid when the first wall portion applies the pressure to the liquid, in which an area of the second wall portion in contact with the liquid is smaller than an area of the first wall portion in contact with the liquid.

The invention provides an apparatus for compressing a first fluid. The apparatus comprises a compressor piston comprising a piston cylinder and a piston assembly slidably mounted therein. The piston assembly comprises first and second spaced apart piston members defining a space therebetween. The space is configured to contain a second fluid used to cause compression of the first fluid. The piston assembly further comprises means for feeding second fluid to the space between the first and second piston members.

The invention provides an apparatus for compressing a first fluid. The apparatus comprises a compressor piston comprising a piston cylinder and a piston assembly slidably mounted therein. The piston assembly comprises first and second spaced apart piston members defining a space therebetween. The space is configured to contain a second fluid used to cause compression of the first fluid. The piston assembly further comprises means for feeding second fluid to the space between the first and second piston members.

A downhole injection system in selective communication with a wellhead assembly and a wellbore, the downhole injection system including a pumping chamber in selective communication with the wellhead assembly, the pumping chamber defining a wellhead pressure portion defining a wellhead pressure inlet in selective communication with the wellhead assembly and a wellhead pressure outlet in selective communication with the wellhead assembly, where the wellhead pressure portion is maintained at a wellhead pressure, and a chemical portion in selective communication with the wellbore, and a movable plate positioned within the pumping chamber, where the chemical portion is separated from the wellhead pressure portion by the movable plate.

A lift apparatus and method for driving a downhole reciprocating pump is disclosed and includes a hydraulic cylinder having a piston and a hydraulic fluid port, the piston being coupled to a rod for driving the reciprocating pump, the piston being moveable between first and second ends of the cylinder in response to a flow of hydraulic fluid through the hydraulic fluid port. A variable displacement hydraulic pump is responsive to a displacement control signal to draw hydraulic fluid from a reservoir and to produce a controlled flow of hydraulic fluid at the outlet. The apparatus also includes a valve connected between the hydraulic fluid port and the reservoir, the valve being responsive to a valve control signal for controlling discharge of hydraulic fluid from the hydraulic fluid port of the cylinder back to the reservoir to facilitate movement of the piston through a downstroke away from the second end toward the first end of the cylinder. The apparatus further includes a first sensor located proximate the first end of the cylinder and operable to produce a first signal indicating a proximity of the piston to the first sensor, a second sensor located proximate the second end of the cylinder and operable to produce a second signal indicating a proximity of the piston to the second sensor, and a controller operably configured to generate the displacement control signal and the valve control signal in response to receiving the first signal and the second signal.

A lift apparatus and method for driving a downhole reciprocating pump is disclosed and includes a hydraulic cylinder having a piston and a hydraulic fluid port, the piston being coupled to a rod for driving the reciprocating pump, the piston being moveable between first and second ends of the cylinder in response to a flow of hydraulic fluid through the hydraulic fluid port. A variable displacement hydraulic pump is responsive to a displacement control signal to draw hydraulic fluid from a reservoir and to produce a controlled flow of hydraulic fluid at the outlet. The apparatus also includes a valve connected between the hydraulic fluid port and the reservoir, the valve being responsive to a valve control signal for controlling discharge of hydraulic fluid from the hydraulic fluid port of the cylinder back to the reservoir to facilitate movement of the piston through a downstroke away from the second end toward the first end of the cylinder. The apparatus further includes a first sensor located proximate the first end of the cylinder and operable to produce a first signal indicating a proximity of the piston to the first sensor, a second sensor located proximate the second end of the cylinder and operable to produce a second signal indicating a proximity of the piston to the second sensor, and a controller operably configured to generate the displacement control signal and the valve control signal in response to receiving the first signal and the second signal.

A pressure-driven metered treating chemistry dispensing pump for a laundry treating appliance having a housing having first, second and third chambers, with the first and second chambers each in fluid communication with the third chamber; a fluid inlet fluidly coupling a first fluid to the first chamber; an outlet fluidly coupled to the third chamber; a piston disposed in the housing; wherein, when the piston moves in a first direction in response to the first fluid entering the first chamber via the fluid inlet, the second chamber decreases in volume thereby ejecting at least some of the second fluid from the second chamber into the third chamber, and when the piston moves in a second direction, different from the first direction, the first chamber decreases in volume thereby ejecting at least some of the first fluid from the first chamber into the third chamber to mix the at least some of the first fluid and the at least some of the second fluid to form a mixture in the third chamber, which can be emitted through the outlet.

A pressure-driven metered treating chemistry dispensing pump for a laundry treating appliance having a housing having first, second and third chambers, with the first and second chambers each in fluid communication with the third chamber; a fluid inlet fluidly coupling a first fluid to the first chamber; an outlet fluidly coupled to the third chamber; a piston disposed in the housing; wherein, when the piston moves in a first direction in response to the first fluid entering the first chamber via the fluid inlet, the second chamber decreases in volume thereby ejecting at least some of the second fluid from the second chamber into the third chamber, and when the piston moves in a second direction, different from the first direction, the first chamber decreases in volume thereby ejecting at least some of the first fluid from the first chamber into the third chamber to mix the at least some of the first fluid and the at least some of the second fluid to form a mixture in the third chamber, which can be emitted through the outlet.