GB803555A - Improvements in the method of controlling the operation of steam generating plant - Google Patents

Abstract

803,555. Combustion apparatus. RITCHIE, E. G. Oct. 25, 1956 [Oct. 27, 1955], No. 30835/55. Class 51 (1). [Also in Group XIII] The water feed and the firing rate of a boiler 1, Fig. 5, are controlled automatically in dependence on variations in the steam pressure consequent upon variations in the steam demand so that, when the demand increases above the average, a regulator 10 closes the feed water valve and, on further demand increase, a regulator 13 increases the rate of firing The process is reversed during decrease in the steam demand to average, the regulator 13 returning the firing rate to normal, then the regulator 10 opening the feed water valve, and this condition remains until, with a further reduction in steam demand to a predetermined below average level, the regulator 13 reduces the firing rate below normal. When the steam demand again rises the process is again reversed, the regulator 13 increasing the firing rate to normal and, above average steam demand, the regulator 10 closing the feed water valve. Overfeeding or underfeeding is prevented by high and low water level regulators 11 master-controlling the regulator 10 and a reducing valve 14 may be supplied to maintain constant consumer steam pressure. In a modification. Fig. 6 (not shown), the regulator 13 can only operate when the feed water valve is fully closed or fully open. The control system may be applied to a battery of boilers. Specification 551,089, [Group XIII], is referred to.