Abstract :
The subject matter of this paper is divided under the following headings: Introduction; Natural-circulation boilers; Directly-heated forced-circulation boilers; Indirectly-heated boilers; Special-effect boilers; Conclusion; Acknowledgments; References. Introduction. Some data are presented to show the rate of increase in cost with rising pressure for arrangements of boilers, superheaters, economizers, and air heaters, both stoker-fired and pulverized-fuel-fired, with increase in final steam temperature and, alternatively, with reheat. The effect of feed-water temperature on the extent of boiler, economizer, and air preheater surface is also discussed. The codes in force governing the thickness of boiler tubes and the methods adopted for fabrication of high-pressure steam drums, are referred to. Natural-Circulation Boilers. Boiler units installed for high-pressure service since 1920 have been listed according to the steam cycles on which they are operated. Some descriptions are given of some of the plants from each of the five tables which have been prepared. Directly-heated Forced-Circulation Boilers. Consideration is given to the Benson boiler and to the ¿Once Through¿ series boiler, as being the most advanced of this type. Indirectly-heated Boilers. Some particulars of the Schmidt and Loffler boilers are given. Special-effect Boilers. The majority of these are experimental only: the Atmos boiler is described.
