Patent GB-816744-A (GB)
Title: Improvements in or relating to steam generators
Inventor: OSTERGAARD PALLE CLIFFORD
IPC: F22B21/22
Filed: 1957-07-24
Abstract: 816,744. Water-tube steam boilers. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. July 24, 1957, No. 23417/57. Class 123(2) A transportable, water-tube steam generator is heated by a heat transfer liquid which is itself indirectly heated in a chamber in which are brought together exothermically reacting chemical products or by-products which may be highly corrosive, poisonous or which may react violently with the boiler water if the tubes should leak. The heat transfer liquid, for example, water, diphenyl oxide or liquid metals, is inert to the reaction products. The reactants may be fluorine and a hydroxide. In one form, the generator comprises a generally spherical outer pressure shell 10 of stainless steel or plain steel lined with a corrosion resistant alloy surmounted by a bolted-on dome-shaped cap 52. An upright, cylindrical reaction chamber 110 of less diameter than the cap is disposed centrally in the shell below the cap. Inlet pipes such as 118, 120 for the reactants and outlet pipes such as 122 for the reaction products lead from the chamber through the cap and pipes 116 for the flow of heat transfer liquid extend vertically through the chamber. Banks of steam generating tubes 18 extending between inlet and outlet headers 16, 14 are spaced at equal intervals around the chamber 110, the headers communicating respectively with downcomers 31 and steam and water risers 30. The downcomers and risers terminate in four steam and water separator drums 32 which are supported on brackets 34 above the shell 10 and which have steam offtakers 36. The heat transfer liquid with which the shell is filled is circulated through the tubes 116 and over the tubes 18 by four pump units which are mounted on the outer shell 10 above the upper headers 14. The impeller 70 of each pump is disposed in a casing 61 which is divided by a partition wall into an upper suction chamber 72 and a lower discharge chamber 74. The heat transfer liquid is drawn from the space above the reaction chamber into the suction chamber through a member 76 and discharged from the chamber 74 against an angled baffle 48 which diverts the flow over the banks of generating tubes. Baffles 98, 100, 102 divert the cooled liquid into the tubes 116. The headers 14, 16 are releasably secured into openings in the shell 10 for the easy repair or replacement of the tube banks 18, a fault bank being removed from the shell through the top opening after removal therethrough of the chamber 110. The banks can be isolated individually by valves 130, 132 in the downcomers and risers respectively to prevent complete shutdown if a fault occurs in one bank. To provide for natural circulation of the heat transfer liquid if a pump should fail, a swing check valve 94 attached to a pump discharge flap valve 92 which normally closes a pump by-pass opening 96 opens when the pump stops to allow the liquid to by-pass the pump. The check valve 92 closes simultaneously to prevent reverse flow through the pump. In a modification (Figs. 5 and 6, not shown), the steam generating tube banks are of pancake form with a central opening for the chamber 110 and the steam and water drums 32 may be omitted, the boiler then operating as a once-through type.