Achieving a Variable Flow Supply by Controlled Unloading of a Fixed-Displacement Pump

This paper addresses the operational performance of a fixed-displacement pump controlled by an unloading valve to provide a fluctuating flow source. This approach should be cheaper and more efficient than the use of a variable-displacement unit. Computer simulation is used to predict the performance of the system and act as a guide in optimizing the control system. An experimental rig has been constructed to examine the practicalities of these ideas. Some experimental results are presented. Future work will be concerned with noise and efficiency studies.