Improvements in heat exchangers for indirectly heating a fluid by means of a vapour and liquid mixture and to methods of indirectly heating a fluid by a vapour and liquid mixture

摘要

876,308. Heating steam boilers by steamwater mixture. BABCOCK & WILCOX CO. June 22, 1960 [June 25, 1959], No. 21861/60. Class 123(2) Steam and water primary heating mixture from a closed cycle boiling water reactor, entering a heat exchange chamber at 62 between the upper and lower tube plates 28, 34 of an annular bunch of secondary water tubes 44 in the lower steam generating section 30 of a pressure vessel 14, is separated into steam and water spaces 52, 54 respectively, the condensed steam, after it has been in heat exchange with the water tubes 44, mixing with the water in the space 52 for withdrawal, at a temperature below saturation temperature. from an outlet portion 70 through an outlet 64 connected to the water reactor, not shown. A ring 56, connected to the vessel 14, supports the centre of the tube bunch 44 and a cylindrical shroud 58 which extends around the lower portions of the tubes 44 and, in combination with an inclined annular baffle 66, forms an annular flow passage 60 for the upward flow of primary heating mixture, water plus condensate passing downward through the shroud 58 to the outlet portion 70. Secondary water, descending in a downcomer tube 84 located, with a surrounding space 86, within a sleeve 42 inter-connecting central openings 38, 40 in the plates 28, 34 rises, from a lower inlet chamber 36, through the tubes 44 to an annular riser passage 88 between a cup-shaped collector baffle 76 and the adjacent wall of an upper separator section 32 of the vessel 14. The passage 88 is closed at its upper end by an annular plate 90. Steam-water mixture from the passage 88 passes through six cyclone steam separators 91 disposed around the inner periphery of the collector baffle 76, steam from the upper distributer plates 92 of the separators being passed through a corrugated, tray-type, scrubber 94, accommodated in a secondary steam space 78, to an outlet 18. The lower extension ends 93 of the separators depend into a secondary water space 80 within the lower portion of the baffle 76 which communicates with the upper end of the downcomer 84. A pipe 100 feeds make-up water to the water space 80 adjacent the inlet to the downcomer 84. A vent 72 is provided below the plate 28 for the removal of non-condensible gases in the primary steam space 30 and primary and secondary water gauge connections 74, 98 are provided in the vessel 14 which also has an upper 'manhole 20, a number of lower handholes 24, and a lower drain connection 26. A blow down connection 96 communicates with the water space 80. The reactivity of the reactor can be regulated by adjusting the level 50 of water in the water space 54 to thereby vary the temperature of the cooled liquid leaving the outlet 64. The water reactor and the steam generating section 32 can be combined in a single pressure vessel, biological shielding being disposed between the steam generating tubes and the reactor core. A steam drum, located outside the reactor, could replace the separating section 32. In a further arrangement the generating and separating sections comprise separate vessels in vertical alignment and connected by a downcomer riser conduit, the separating section being heated outside the reactor.