Pressure Change due to Blowing-off of Bailer Water

Abstract

The blowling-off of the steam boiler is a necessary measure in the boiler operation. Although the present author has published a paper on the concentration and blowing-off the boiler water, he discusses the pressure change due to the blowing-off in the present paper. First, the relation of the boiler water quantity and the pressure change is introduced basing on the material and heat energy balance in the boiler. From these, the pressure change due to the blowing-off in general case is expressed by an equation. The change of the pressure and water quantity due to the water feeding and blowing-off on the constant firing of boiler are described, using the steam qualities : specific volume, enthalpy and so on, assumed the logaritymic changes under 20 kg/cm² abs. pressure.Second, assuming that the feed water, blowing-off, steam generation and heat sbsorbed under the constant boiler water quantity are continuously, the pressure change by blowing-off may be determined. By the comparison between the first and second cases, its difference obsereved is about 20∼30%. It will be found in this paper that the self-evaporation or condensation is largely effected by the pressure change in the boiler.