GB254575A - Improvements in control arrangements for superheaters and re-heaters in water tube boilers - Google Patents

Abstract

254,575. Yarrow, H. E. Oct. 15, 1925. Water-tube boilers provided with superheaters and interstage reheaters have transverse division plates within the furnace casing and uptake, dividing the path for the furnace gases into three sections, each being controlled at the uptake end by a damper. Superheating and reheating elements are accommodated respectively in two sections and steam generating elements in all three sections. At each side of a Yarrow boiler a superheater F or F<1> and a reheater G or G<1> are provided, interposed between the upper and lower banks of steam generating tubes D, E, or D<1>, E<1>, which extend the full length of the furnace. An intermediate space or section occupied by steam generating tubes only is defined by division plates H, I, extending from the combustion chamber to the uptake, their upper parts H<1>, I' starting from the upper end plates of air preheaters and extending to dampers K, L, M, &c., which control the flow of gases through the sections. A single set of dampers extending across the full width of the uptake may replace the three dampers on each side, and the control may be thermostatic. The steam generating tubes enclosed between the plates H. I are arranged in deeper tanks than the corresponding elements in the other sections. A feedwater heater or economizer provided with the requisite division plates may occupy the whole or part of the space shown as taken up by the air preheaters.