COST MINIMIZATION APPROACH TO THE DESIGN OF FLUID POWER CIRCUITS.

A technique is described for selecting the operating pressure and pipe sizes in fluid power circuits. The method is based upon the formulation and minimization of a cost function which quantifies the capital and running costs of the circuit. (The running costs are broadly defined in order to include the cost penalty due to the weight of the system, as well as the cost of lost power). The limitation imposed upon design by the commercial availability of only a limited range of stock sizes of pipe is taken into account to ensure that the design is realizable from stock components. An example is given which compares the results of a design based upon the cost criterion with a design arising from the use of empirical flow velocities to select pipe sizes.