GB1020474A - Improvements in or relating to steam generators - Google Patents

Abstract

1,020,474. Water-tube steam boilers. HENSCHEL-WERKE A.G. March 11, 1963, No. 9588/63. Heading F4A. A steam generator has a lower annular water chamber and an upper annular evaporation chamber which are spaced apart and interconnected by vertical water tubes 3 which are arranged in contacting or close juxtaposed relationship around a combustion chamber 6 to form the walls of a flue for the combustion gases leaving the combustion chamber. In the form shown, the generator comprises annular water and evaporation chambers connected by three concentric rows of tubes 3 which are enclosed by an inner cylindrical casing 1. An outer casing 4 provides an annular space through which air flows to a burner, combustion gases discharging through a gap 7 in the inner row of water tubes, and flowing between the rows as indicated by the arrows, to an outlet 10. The flue crosssectional area may decrease in the latter part of the combustion gas path, so that there is no decrease in the combustion gas velocity as a result of the gas cooling. The boiler may have a circular or a rectangular horizontal crosssection and the water tubes may be arranged to form a spiral row inside the outer casing. In a further modification, the water tubes are reduced in diameter at their ends, which are welded to the upper and lower annular chambers, whilst this reduction may be extended some distance from the alternative tops and bottoms of adjacent walls to provide a vertical sinuous flue. A ceramic material may fill spaces between adjacent water tubes in any one wall.