ES334662A1 - Vapor generator construction - Google Patents

Abstract

A once through or forced recirculation supercritical vapour generator has its furnace walls lined with tangent or finned tubes 40, backed by furnace insulation 42 and horizontally extending stiffener members 44 all supported by the furnace tubes. A cage of vertically extending I beams 50 supported independently of the furnace walls from structural steel work 46, surrounds the furnace walls in sliding contact with the stiffener members 44, which I-beams 50 are inter-connected at several horizontal levels by buckstays, such as 58, 60, 62, 64 extending along the furnace walls and welded to the vertical I beams 50. Opposed buckstays e.g. 58 and 60, or 62 and 64 are inter-connected at their ends by fluid carrying members 80 and 82, or 76 and 78, which pass through holes in the vertical I beams 50, in such a way as to allow for expansion and contraction on heating and cooling of the furnace walls. Thus each buckstay e.g. 58 is secured to its respective fluid carrying member e.g. 80 by a pair of rods 84 which pass through openings 85 in the buckstay, and openings in a collar 86 secured to the fluid carrying member. Rockers 88 and nuts 90 are then threaded on to the ends of the rods 84. The fluid carrying members 76, 78, 80 and 82 form part of downcomer circuit, in parallel with main downcomer 22 extending between the upper outlet headers of the tubes of a furnace division wall 20, and lower inlet headers of the furnace wall tubes 40. In this way the expansion of the fluid carrying members on heating is kept at the same order as that of the tube walls.