GB670644A - Heating boiler with heating surface reduced by improved convection - Google Patents

Abstract

670,644. Boiler furnaces. AKTIEBOLAGET GUSTAVSBERGS FABRIKER. Jan. 31, 1949 [Jan. 30, 1948], No. 2664/49. Class 51 (i). [Also in Group XIII] A heating boiler comprises a fuel compartment 4 defined by water spaces as at 5, 6 and 26 and water-cooled grate bars 1, separated by a secondary combustion space 41 from a convection pass formed as a zig-zag gas passage by water spaces 40, 49, 80, 56 and 77 having vertical fins on their outer walls and tapered ends 83, 53, 78 and 61, and a final flue 62 connected to an exhaust fan 68 and to a chimney flue 73, said flue 62 being provided with dampers 64 and 75 before and after the fan outlet respectively. A water way 27 formed as a fuel bridge fixes a fuel line 29 and horizontal water ways 36, 38 provide a tortuous path to the secondary combustion chamber, preheated secondary air being supplied through slits 34 at the top of a duct 32. The secondary air enters at 59 beneath a top-plate 45, passes down side flues 39 to the duct 32 which is provided with a damper 33 operated by a thermostat 42 in the combustion space 41. A removable cover 14 for the fuel compartment 4 seating on the top edge 9 thereof by a groove 13 may be raised by a lever system 12, 21 on to wheels 22 disposed on tracks 23 on the boiler top, and an opening 15 formed in said cover 14 is closed by a small lid 16 with a bayonet catch. The cover 14 and smaller covers 46, 50 disposed over the flue passages of the convection pass are lagged with insulating material such as glass wool or asbestos. The boiler is said to be operated at economical flue gas speeds of 3-10 cubic metres per square metre of flue area per second. Specification 670,645 is referred to.