Hydraulic rams are used to pump liquid from a low pressure source (i.e. at a low height) to a high pressure elevated target. Hydraulic rams operate using the principle of water hammer. The drag of water through a waste pipe closes a waste valve (against the force of a weight) A pressure wave bouces off the waste valve and forces water to flow uphill As the pressure wave dissipates, the waste valve opens (due to the descent of the weight) Water then flows through the waste valve, eventually closing the waste valve again The volumetric efficiency is the ratio of the volume water delivered to the target versus volume of water flowing through the waste pipe.
