GB1078494A - Improvements relating to heat exchangers - Google Patents

Abstract

1,078,494. Steam generators, tube supports. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. March 17, 1964 [March 25, 1963], No. 11798/63. Headings F4A and F4S. A steam generator comprises parallel-connected sheath ducts 24 each lapped back to form spaced legs and each containing a cluster of tubes (not shown in Fig. 1) extending along the length of the duct. The steam generator has evaporating, superheating and reheating sections. In Fig. 1 the sheath ducts 24 are arranged in upper and lower horizontally extending batteries. The ducts are each formed from two converging straight legs and a connecting piece 26 and each extend in a vertical plane. The heating medium, e.g. liquid sodium, passes from inlet header 20, through pipes 27, upper sheath ducts 24, joining pieces 25, lower sheath ducts 24, pipes 28 to outlet header 21. The tubes of each cluster are arranged in concentric circles about an axial tube, each circle of tubes being supported in indentations in a respective ring (34), and the rings (34) being axially spaced. The ends of the tubes of each cluster are welded into respective tube plates in fittings 31. Water from inlet header 15 passes through pipes 42 through the inner tubes of the lower ducts forming the low temperature section, and pipes 43 to mixing header 16. Steam from header 16 passes through inner tubes of alternate upper ducts forming the high temperature section to outlet header 17. Reheating inlet header 18 feeds pipes 45 and the inner tubes of the other alternate upper ducts from where the steam passes to outlet header 19. Pressure relief devices (Fig. 4, not shown) comprise chambers separated from the interior of piece 26 by a bursting disc (37) and connected to a common vent. In a further embodiment (Fig. 6, not shown) the duets are arranged with both legs vertical and a pressure relief device (51) at the upper ends, the membrane being separated from the sodium liquid by gas.