GB1101311A - Improvements in forced flow tubulous vapour generators - Google Patents

Abstract

1,101,311. Tube walls for furnaces; steam generators. BABCOCK & WILCOX Ltd. 7 Aug., 1964 [9 Aug., 1963], No. 31515/63. Headings F4A and F4B. In a forced flow vapour generator having walls lined with horizontal tubes supported by heated vertical means and in inwardly-extend - ing hollow arch above which is an entry to a lateral gas pass, a beam is disposed within the arch and supports the wall below the arch, the beam being heated so that differential expansion between the beam and the wall is largely avoided. The frame of the arch may be constructed so that differences of thermal expansion of the frame members can be accommodated. A header 4 which is fed with fluid from an economizer supplies fluid to downcomers 5 which are in heat exchange with the wall support members 7 which may be of the form described in Specification 877,116. An arch of tubes 3 surrounds a beam 9 from which the rear wall supports 7A are suspended. The beam 9 is supported through rocking devices on transoms mounted between pairs of side wall support members 7. The arch 3 has a framework comprising members 60, 105, 89 which is supported by the beam 9 through members 61 and rockers 63 and which is attached to rear tubes 133 through blocks 129. The tubes of the arch are attached to the frame by pivotal devices 139 to permit relative longitudinal movement and are rigidly attached to blocks 135, on the members 60, to the ends 109 of the members 105 and to blocks 99 on the members 89. The beam 9 is attached to the rear wall support members 7A by a linkage 73 which permits swinging of the wall, and the members 7A are attached to the frame of the arch by a pin 93 housed in a slot 95 in the member 89. The various members of the frame are connected together by pins housed in slots. The pinned joints of the frame and the rocking connections between the tubes or the arch, the frame, and the beam 9 accommodate differences in thermal expansion of these parts. Tubes 167 and 153 from the economizer extend horizontally along the beam 9 before passing vertically down the members 7A. The beam 9 is heated by these tubes largely avoiding differential thermal expansion of the beam and the rear walls. The support members 7 and 7A are similarly heated by the adjacent tubes. In another embodiment, Fig. 6 (not shown), the linkage 73 supports a block (197) which is attached to the member 89 by the pin 93 and which supports a rear wall comprising vertical tubes. In another embodiment, Fig. 7 (not shown), the tubes are interconnected to form a membrane wall and the wall below the arch is resiliently supported to accommodate different vertical expansions between different parts of the beam and the wall.