Control of Feed Water Pump

Abstract

This report introduces a control method of the feed water pump. As the kind of the control of the feed water pump, there are 1) control of pump speed, 2) pump delivery pressure, 3) the pressure difference between pump delivery and boiler drum, 4) the difference pressure between outlet and inlet of the feed water control valve, and 5) direct control of feed water pump by feed water control signal. This last control method is early used in practice for the control of auxiliary boiler and weir's type feed water pump. In spite of the fact that the plant efficiency should be improved by the adoption of this control system, it has been not adopted to main boiler. It may be considered that the reason for this is that there was an anxiety in the stability of feed water control signl or response of pneumatic governor. We chose best machinery in cooperation with each manufacture by the careful study on the said points, and fitted a feed water control valve and a constant discharge pressure governor on the pump side for an emergency use. As the results there was no trouble of hunting of the feed pump governor and the response of feed water control system about which we were anxious and it was proved that this control system can be sufficiently reliable.