High-Pressure Steam Boilers: A Study of the Principles Underlying Their Design and Construction

Abstract

Abstract After briefly referring to the work of Münzinger, Hartmann, and Mellanby and Kerr, the author proceeds to discuss the lines of further investigation which to him seem to offer the most promise. In so doing he discusses the effect of tube inclination; the circulation problem; releasing surface and steam space; safety in operation; increase in capacity; boiler materials; temperature margins; and stresses in superheater tubes, riveted drums, and headers. Among other things, it is brought out by this discussion that (1) a high-pressure boiler must consist largely of banks of tubes; (2) that headers in great variety are available up to at least 1400 lb. pressure; (3) that drums must be of small diameter and should not contain over 10 per cent of the water content of the boiler; (4) that below 1000 lb. there is no need of employing alloy steels, but above that pressure such steels are available and should be used if the temperature margins so require; (5) that for superheats higher than 800 deg., alloy steels are indicated; (6) that 20 or more different designs of boilers are successfully operating at pressures of 500 lb. and over, six at 1000 lb., and one at 2000 and over; and (7) that enough work has been done to show that their efficiencies are comparable to those obtained with boilers of lower pressure. In closing, the author states his conclusions as to the type of high-pressure boiler best suited to present limitations.