Abstract: 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.

Abstract: 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.