GB807658A - Forced-flow once-through steam generators - Google Patents

Abstract

807,658. Forced-flow steam boilers. SULZER FRERES S.A. Aug. 10, 1956 [Sept. 9, 1955], No. 24601/56. Class 123(2) A forced-flow, once-through boiler has twin parallel combustion chambers and flues A, B, each containing a vaporizing section 1, a wall-mounted superheater 2, a platen type superheater 3, an intermediate reheater section 4, convection-heated final and pre-superheaters 5, 6 and an economiser 7, the reheater section 4 in flue A being mounted in a highly-heated region between surperheaiters 3 and 5 whilst the section in flue B is disposed in a comparatively cool region located after the superheater 6. As indicated by the arrows in full line, the working medium entering at 8 flows through the economisers 7, evaporating sections 1 and superheaters 2, 3 and 5, 6 in the respective flues in parallel, the steam from the final superheaters 5 combining for flow to a turbine (not shown). Partially expanded steam returns from the turbine and is reheated by series flow through the reheater section 4 in flue B and the reheater section 4 in flue A as indicated in broken line. The series connection of the reheater sections avoids the necessity of dividing the reheating steam flow whilst the disposition of one of the reheater sections in a cool zone facilitates boiler starting, the combustion chamber B being fired first and, when sufficient steam is flowing in the reheater, firing the chamber A.