UNA CONSTRUCCION DE HOGAR COMPLETAMENTE SOLDADA.

摘要

1,265,741. Once-through vapour generators. FOSTER WHEELER CORP. 21 April, 1969 [1 May, 1968], No. 20317/69. Heading F4A. An all-welded furnace construction for a oncethrough vapour generator comprises a rectangular furnace enclosure including two oppositely facing walls and side walls therebetween; each wall comprising a number of substantially parallel upright finned tubes welded together to define each wall including the lower parts of the walls; headers connected to the tubes so that the tubes are divided into a number of flow passes connected in series; the headers and their connections to the tubes being arranged so that the tubes adjacent to and on either side of the enclosure corners and defining each corner are of the same flow pass. The flow from the economizer is passed equally to two vertical headers 26, 261, Fig. 1, each feeding the tubes of one half of a vertical division wall 24 (pass A). From the division wall, the flow is taken via a downcomer to a single header 28 and thence through the central tubes 22a of the flat floor 22, these tubes being bent upward to form the central tubes 14a of the front wall 14 (pass 1). From the tubes 14a, the flow is taken to inlet headers 30, 32, 34, 36, 38, 40 and thence through pass 2, comprising the entire side walls 18, 20, the side portions 16b and 16c of the rear wall 16, and the side portions 22b and 22c of the floor 22, the side portions 22b and 22c being bent upwardly to form the side portions 14b and 14c of the front wall. Finally, the flow passes to header 42 to flow through the central portion 16a (pass 3) of the rear wall 16. Thus, the three sides of each of the four bottom corners of the furnace enclosure are formed by tubes of the same pass (pass 2), whereby temperature differences producing thermal stresses in the welded connection between these tubes are avoided. As shown in Fig. 2, the tubes of each pass are welded together through fins. Where the tubes of pass 1 of the floor 22 pass through pass 3 of the rear wall 16 to join the header 28, they are bent as shown so that each group of four tubes is aligned in a vertical plane. The resultant gap in the floor is bridged by a seal plate 50 welded to the tubes. In a modification, the flat floor is replaced by a hopper bottom. For this purpose, the tubes which would have constituted a flat floor are bent downwardly to form one side of the hopper, while the other side of the hopper is formed by a continuation of the rear wall.