Unsteady and steady flow control on pumping systems

The possibility of reducing the severity of pressure transients produced during the starting and stopping of pumps by means of a gradual variation of the rotational speed of the pump driver is shown. Efficient regulation of the discharge supplied by the pump is also possible by varying the rotational speed instead of throttling. Both problems require knowing how to vary the speed; a simple PID (proportional-integral-derivative) control scheme is used to show the way rotational speed should be varied