DESIGN OF HYDRAULIC RAM PUMP SYSTEMS

Automatic hydraulic ram pumps are environmentally friendly devices usi ng a renewable energy resource to pump water for domestic or agricultu ral use. Since being superseded by pumps using electrical or fossil fu el energy nearly a century ago, they are now coming back into favour i n many parts of the developing world. In the past, hydraulic ram pumps have been designed by rules-of-thumb having limited scientific basis. On-site adjustment has been used in the hope of rectifying the inevit able shortcomings of this process and ideal performance is rarely achi eved. The present proposal for optimum design allows relevant system p arameters (including the beat frequency) to be selected prior to insta llation.The paper shows how a ram pump system may be designed using tw o simple equations containing empirical factors dependent upon ram siz e, delivery head, material and wall thickness of the drive pipe and th e configuration of the impulse valve. The design method is illustrated with reference to a number of existing tests. New experimental result s for a 53 mm ram with five different impulse valve strokes are also p resented.