A Ripple — Free Gear Pump Using Controlled Leakage

The major source of all types of noise in hydraulic systems is usually the positive displacement pump. Fluidborne noise (pulsations) produced by the pump are particularly troublesome because almost all system components convert it into airborne noise. The most straightforward means of reducing fluidborne noise is to use a quiet pump.

This paper reports the development of an external gear pump which utilizes controlled leakage to drastically reduce its flow ripple output. The theoretical basis for the technique is presented, along with an example of pump design using controlled leakage. An experimental evaluation is presented demonstrating the effectiveness of the technique.