GB638287A - Improvements in or relating to boilers - Google Patents

Abstract

638,287. Return-tube steam boilers. DANKS OF NETHERTON. Ltd. Feb. 25, 1947, No. 5481. '[Class 123(ii)] [Also in Group XXVIII] In a shell type boiler A, Fig. 1, in which one or more furnaces C together with smoke and return tubes 7, 17 respectively are supported by end tube plates 1, 2, the furnaces open into a combination chamber D and communication between the latter and the rear ends of the tubes 7 is effected by extension tubes 5 which are preferably of Venturi shape internally and project from the tubes 7 into openings in the front wall 4 of said chamber. At their front ends individual tubes 7 are connected to the tubes 17 by U-tubes 18 which are housed within a cover 19 and are supported by a second tube plate 13 spaced from the plate 2. The tube ends 7 are jointed to the junction tubes 18 by fittings 27, Fig. 6, each having oppositely directed jet passages 28, 28<SP>1</SP> by means of which steam for cleaning purposes may be injected into the junctions and tubes 18, 7 respectively from a steam chest 26, the latter being defined by a pair of plates 24, 24<SP>1</SP> and a peripheral closing ring 25 and being located within the space 20 between the tube plates 2, 13. The lower ends of the junctions 18, Fig. 5, are jointed to the return tubes 17 by short tube lengths 21 in screw-threaded engagement at 22 with said junctions.