Control of Boilers Fired by Solid Fuels in Suspension

Abstract

In this paper are discussed those characteristics of boiler design and performance which have favoured the parallel development of automatic control of boiler auxiliaries. Consideration is given to those temporary conditions which arise during periods of load change, and which, if not accurately estimated and followed by the necessary corrective action, may lead to over-regulation of firing rate or feed-water supply. Instruments are provided to determine and inform the operator of the necessary action to be taken, and manual remote-control eliminates the laborious duties of routine readjustments necessary to maintain efficiency. In this field automatic control has many advantages and is quicker and more accurate in response than the human operator. The theory of elementary forms of automatic control devices is dealt with simply, and the mechanical means, employing pneumatically operated devices, by which these theoretical requirements are met are described. Examples are given of the use of standard apparatus in building up a composite control system, and the more complicated installations of boilers fired by spreader stokers, pulverized fuel and cyclone furnaces are dealt with.