GB745231A - Improvements in water heaters and steam generators - Google Patents

Abstract

745,231. Forced flow steam boilers; hot-water boilers; tubular heat-exchange elements. WEBB, H. W. B. April 21, 1954 [May 14, 1953], No. 13498/53. Classes 64(1), 64(3) and 123(2). A forced flow, once through steam boiler or hot water heater has an oilfired combustion chamber D lined with banks of water tubes, the combustion gases flowing from the chamber to a stack G through two horizontal passes defined by baffle plates F and in which are disposed further banks of water tubes. The latter tube banks and those lining chamber D are built up from preformed units of the form shown in Fig. 1, each unit consisting of a continuous length of tube which is bent to form an elongated box-like structure wherein straight lengths X of the tube pass diagonally between opposite end return bends which are held in position by welded-on transverse members T. At intervals across the width of the structure some of the straight tube portions such as Y extend along in the plane of the side of the unit to form a support, for example for the baffle plates F. The ends A, B of the tube length protrude from one end of the unit whilst a stud C is welded to a return bend to project from the mid-point of the other end. The units M1, M2 are disposed around chamber D and in the horizontal passes as shown in Fig. 3 and are connected together by U-couplings L, a pump K supplying water from a feed tank FWT through pipes K2, K3 to the serially connected units M1, M2 respectively. The outlets N1, N2 from the units connect with a separator S whence steam is withdrawn through an outlet valve OV. The stud C on each unit engages in a socket C 1 in one end of the boiler casing to hold the unit in position whilst at the other end a removable inspection door E and removable panels such as H are provided to enable any unit to be removed and replaced without disturbing the others. To protect the apparatus against damage due to overheating the studs C projecting from the terminal units M 1 , M 2 bear against members C 2 slidably mounted in the respective sockets C1 and engaging members T1 connected by links to a switch SW, the increased expansion of units M1, M 2 when excessive temperatures occur therein causing the switch to operate to shut down the plant.