| 摘要 |
1,125,423. Desalination of water; flash evaporators. WESTINGHOUSE ELECTRIC CORP. 22 Feb., 1967 [21 April, 1966], No. 8362/67. Heading B1B. Saline water which contains calcium sulphate in solution is purified by pumping the saline water through conduit 60 and the condenser tubes 66 of a multi-stage flash evaporator, passing the preheated water into a tank 76 where the water is held for a period in contact with anhydrite seed crystals thereby reducing the concentration of dissolved calcium sulphate in the water, and then conducting the treated water through a heater 80 into the first flash chamber of the evaporator. The flashed vapours condense on the outer surface of tubes 66, and the condensate (desalinated water) is withdrawn from the evaporator by pump 82. Brine is withdrawn from the last flash chamber, and a portion of the brine is recycled, with fresh feed, to condenser tubes 66, while the remainder of the brine is discharged through outlet 72. Tank 76 is provided with an agitator 84 and with an outlet 86 from which some of the smaller calcium sulphate crystals are pumped through conduit 88 to the feed inlet conduit 60. Also described is a multi-stage flash evaporator wherein an additional holding tank is disposed between two sections of the condenser tubes. This apparatus is operated without recirculation of brine.
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