A disc pump includes a pump body having a cavity for containing a fluid. The disc pump also includes an actuator adapted to hold an electrostatic charge to cause an oscillatory motion at a drive frequency. The disc pump further includes a conductive plate positioned to face the actuator outside of the cavity and adapted to provide an electric field of reversible polarity, the conductive plate being electrically associated with the actuator to cause the actuator to oscillate at the drive frequency in response to reversing the polarity of the electric field. The disc pump further includes a valve disposed in at least one of a first aperture and a second aperture in the pump body. The oscillation of the actuator at the drive frequency causes fluid flow through the first aperture and the second aperture when in use.

A disc pump includes a pump body having a cavity for containing a fluid. The disc pump also includes an actuator adapted to hold an electrostatic charge to cause an oscillatory motion at a drive frequency. The disc pump further includes a conductive plate positioned to face the actuator outside of the cavity and adapted to provide an electric field of reversible polarity, the conductive plate being electrically associated with the actuator to cause the actuator to oscillate at the drive frequency in response to reversing the polarity of the electric field. The disc pump further includes a valve disposed in at least one of a first aperture and a second aperture in the pump body. The oscillation of the actuator at the drive frequency causes fluid flow through the first aperture and the second aperture when in use.

A liquid suction pump comprising: a drive pipe to receive a liquid drive flow for the pump; a liquid conduit with first and second liquid delivery arms to provide pumped liquid, and a connecting valve arrangement between the arms. First and second pump inlets to the arms have respective first and second one-way inlet valves. The valve arrangement has a valve inlet coupled to the drive pipe and valve outlets coupled to the arms to alternately close off a liquid connection between the valve inlet and respective arms. A compliant element is coupled to the drive pipe. The drive flow oscillates in pressure/flow rate due to alternate switching of the valves. A compliance of the compliant element is such that a geometry of the suction pump in combination with the compliance defines a resonant condition, and the oscillation is at a resonant frequency of the pump.

A disc pump includes a pump body having a cavity for containing a fluid. The disc pump also includes an actuator adapted to hold an electrostatic charge to cause an oscillatory motion at a drive frequency. The disc pump further includes a conductive plate positioned to face the actuator outside of the cavity and adapted to provide an electric field of reversible polarity, the conductive plate being electrically associated with the actuator to cause the actuator to oscillate at the drive frequency in response to reversing the polarity of the electric field. The disc pump further includes a valve disposed in at least one of a first aperture and a second aperture in the pump body. The oscillation of the actuator at the drive frequency causes fluid flow through the first aperture and the second aperture when in use.

A disc pump includes a pump body having a cavity for containing a fluid. The disc pump also includes an actuator adapted to hold an electrostatic charge to cause an oscillatory motion at a drive frequency. The disc pump further includes a conductive plate positioned to face the actuator outside of the cavity and adapted to provide an electric field of reversible polarity, the conductive plate being electrically associated with the actuator to cause the actuator to oscillate at the drive frequency in response to reversing the polarity of the electric field. The disc pump further includes a valve disposed in at least one of a first aperture and a second aperture in the pump body. The oscillation of the actuator at the drive frequency causes fluid flow through the first aperture and the second aperture when in use.

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.

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 hydropneumatic device having pressure a working part with a working piston guided in the working part and an intensifier part with an intensifier piston guided in the intensifier part. A connecting section for a hydraulic connection of the working part and of the intensifier part provides a connecting line for passage of hydraulic fluid between the working part and the intensifier part. The connecting section includes an adapter component which can be mounted on the working part and the intensifier part, and in the interior of which the connecting line is formed. In the mounted state of the adapter component, an opening, which is provided at the side on the working part, of a hydraulic chamber of the working part is connected, via the connecting line, to an opening, which is provided at the side on the intensifier part, of a hydraulic chamber of the intensifier part.

A hydropneumatic device having pressure a working part with a working piston guided in the working part and an intensifier part with an intensifier piston guided in the intensifier part. A connecting section for a hydraulic connection of the working part and of the intensifier part provides a connecting line for passage of hydraulic fluid between the working part and the intensifier part. The connecting section includes an adapter component which can be mounted on the working part and the intensifier part, and in the interior of which the connecting line is formed. In the mounted state of the adapter component, an opening, which is provided at the side on the working part, of a hydraulic chamber of the working part is connected, via the connecting line, to an opening, which is provided at the side on the intensifier part, of a hydraulic chamber of the intensifier part.

A disc pump includes a pump body having a cavity for containing a fluid. The disc pump also includes an actuator adapted to hold an electrostatic charge to cause an oscillatory motion at a drive frequency. The disc pump further includes a conductive plate positioned to face the actuator outside of the cavity and adapted to provide an electric field of reversible polarity, the conductive plate being electrically associated with the actuator to cause the actuator to oscillate at the drive frequency in response to reversing the polarity of the electric field. The disc pump further includes a valve disposed in at least one of a first aperture and a second aperture in the pump body. The oscillation of the actuator at the drive frequency causes fluid flow through the first aperture and the second aperture when in use.