GENERIC DESIGN OF RAM PUMPS

The hydraulic ram pump was invented over 200 years ago but became obso lete with the general availability of mains water. It is used for pump ing surface water and is powered by the potential energy of the supply . Ram pumps are particularly appropriate for use in remote regions of the developing world as their construction is basic and robust and the y are inexpensive and easy to install and maintain. A rational design procedure applicable to any ram pump is described in this paper. The m ethod is based on the three nondimensional relationships that have bee n found to govern ram pump behaviour. The relationships express beat f requency, quantity delivered and source capacity in terms of the indep endent variables. By assigning upper and lower bounds to the critical velocity in the drive pipe, it is possible to derive three characteris tic pump parameters from which the dependent variables may be determin ed directly. These parameters all take the same numerical values withi n a feasible design space. The design method has been confirmed using the results of existing experiments. A number of examples are given wh ich illustrate the ease and rapidity of the procedure.