GB754996A - Improvements in or relating to a steam generating and heating unit - Google Patents

Abstract

754,996. Steam superheaters; water-tube boilers. COMBUSTION ENGINEERING, Inc. Oct. 21, 1954 [Nov. 3, 1953], No. 30324/54. Classes 123(2) and 123(3). A water-tube boiler has a furnace 1 lined with steam generating tubes extending between a water drum 14 and a steam and water drum 10 and is fired by burners 18 in the roof arch 19 of an offset furnace portion 1a, combustion gases passing downwardly in the offset portion and upwardly through the-furnace 1 to discharge through an offtake 20 into a lateral pass locating a superheater or reheater 21 and thence into a downpass locating further steam-heating surfaces or an economizer 23. The lining tubes 6, 7 of the front and rear furnace walls 2, 3 are bent outwardly to form two arches 24, 25, projecting into the furnace above portion 1a and below offtake 20 respectively. Spaced rows 30 of steam-heating tubes 27 are disposed across the furnace chamber, the tubes of each row extending from a header 29, across the offtake 20, through arch 25, across the furnace, through arch 24 and across the furnace again to a header 28, adjoining headers 28 being interconnected whilst the headers 29 are connected alternately to drum 10 and an outlet header 36 to provide a number of parallel double-pass flows for the steam. As shown in Fig. 4, the rows 30 are held at the correct spacing by the steam generating tubes 6 of arch 24, the tubes 6 also serving to maintain the alignment and prevent excessive vibration and warping of the individual tubes in each row. The same support is provided by the tubes 7 of arch 25. To protect the outermost steam-heating tubes 27 in each row from uneven or excessive heating, steam generating tubes 31 are provided to form the end tubes of the row.