This invention relates to apparatus and methods for pumping liquids, in particular using hydraulic ram pump techniques. The techniques we describe can advantageously be used, for example, for drawing water from a deep well in a developing country. We describe a hydraulic ram liquid pump, the pump comprising: a liquid conduit having first and second arms and a connecting portion to connect said arms; first and second one-way inlet valves to said liquid conduit; first and second internal shockwave generating devices within said liquid conduit between said first and second inlets; at least one one-way exit valve from said liquid conduit; wherein, in use, when said second shockwave generating device is sealed a column of liquid in said first arm is in fluid communication with a said exit valve and when said first shockwave generating device is sealed a column of liquid in said second arm is in fluid communication with a said exit valve.

A method for controlling a stroke velocity in a pump includes using a sensor to detect a start of a pump stroke and an end of the pump stroke. A stroke time is calculated, the stroke time being a time period between the start of the pump stroke and the end of the pump stroke. The stroke velocity is calculated based on a stroke length and the stroke time. The stroke velocity is compared to a reference stroke velocity. A hydraulic supply pressure to the pump is increased if the calculated stroke velocity is less than the reference stroke velocity, and the hydraulic supply pressure is decreased if the calculated stroke velocity is more than the reference stroke velocity.

A diaphragm pump includes a housing having a pumping chamber containing fluid. The pump has a transfer chamber containing hydraulic fluid, and a hydraulic fluid reservoir in fluid communication with the transfer chamber. The pump housing forms a cylinder with a piston defining a piston inner chamber and sliding in the cylinder. A valve leads to the piston inner chamber with a valve spool slidably mounted in the piston inner chamber to cover the valve and uncover the valve. A diaphragm connects to the valve spool by a plunger. An overfill limiter includes a spacer slidably mounted in the piston inner chamber. A first spring is intermediate the valve spool and the spacer and a second spring is intermediate the end of the piston inner chamber and the spacer, the second spring having a second spring constant greater than the spring constant of the first spring.

A diaphragm pump includes a housing having a pumping chamber containing fluid. The pump has a transfer chamber containing hydraulic fluid, and a hydraulic fluid reservoir in fluid communication with the transfer chamber. The pump housing forms a cylinder with a piston defining a piston inner chamber and sliding in the cylinder. A valve leads to the piston inner chamber with a valve spool slidably mounted in the piston inner chamber to cover the valve and uncover the valve. A diaphragm connects to the valve spool by a plunger. An overfill limiter includes a spacer slidably mounted in the piston inner chamber. A first spring is intermediate the valve spool and the spacer and a second spring is intermediate the end of the piston inner chamber and the spacer, the second spring having a second spring constant greater than the spring constant of the first spring.

A hydraulic pumping system can include an actuator including a piston rod that displaces in response to pressure in the actuator, a seal assembly that seals about the piston rod and is exposed to the pressure in the actuator, and another seal assembly that seals about the piston rod, is exposed to pressure in a well and includes multiple separate seal cartridges, each of the seal cartridges including a dynamic seal that slidingly and sealingly engages the piston rod. Another hydraulic pumping system can include an actuator including a piston rod that displaces in response to pressure in the actuator, a seal assembly that seals about the piston rod and is exposed to the pressure in the actuator, and another seal assembly that seals about the piston rod, is exposed to pressure in a well and includes a labyrinth ring comprising multiple ring layers.

The travel end expansion valve (1) for a piston type pressure converter (2) whose master cylinder (3) and slave cylinder (4) define a master chamber (9) and a slave chamber (10), respectively, includes an expansion master cylinder (12) which communicates with the slave chamber (10) and in which there can move an expansion main master piston (14) which is mechanically connected by a lever type transmission (11) with progressive effect to an expansion slave pump piston (15) which can move in an expansion slave cylinder (13), the transmission (11) being provided in such a manner that, when the expansion main master piston (14) is at the top dead center, the expansion slave pump piston (15) is at the bottom dead center, and vice versa, while an expansion release actuator (30) can cause the transmission (11) to move.

The travel end expansion valve (1) for a piston type pressure converter (2) whose master cylinder (3) and slave cylinder (4) define a master chamber (9) and a slave chamber (10), respectively, includes an expansion master cylinder (12) which communicates with the slave chamber (10) and in which there can move an expansion main master piston (14) which is mechanically connected by a lever type transmission (11) with progressive effect to an expansion slave pump piston (15) which can move in an expansion slave cylinder (13), the transmission (11) being provided in such a manner that, when the expansion main master piston (14) is at the top dead center, the expansion slave pump piston (15) is at the bottom dead center, and vice versa, while an expansion release actuator (30) can cause the transmission (11) to move.

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.

Illustrative embodiments of pump systems and methods are disclosed. In at least one embodiment, an apparatus comprises a piston pump including a motor and a plunger, where the motor is configured to drive linear reciprocating motion of the plunger in response to being supplied with a flow of compressed fluid, a metering valve fluidly coupled to the motor, the metering valve being configured to control the flow of compressed fluid to the motor, a purge valve fluidly coupled between the metering valve and the motor, a linear encoder coupled to the piston pump, the linear encoder configured to generate sensor data indicative of a position of the plunger, and an electronic controller operatively coupled to the metering valve, the purge valve, and the linear encoder, where the electronic controller is configured to receive sensor data from the linear encoder and to control the metering valve and the purge valve.