| 摘要 |
1,103,452. Evaporators; multi-stage flashtype; desalination of water. AMERICAN MACHINE & FOUNDRY CO. 15, March, 1965 [20, March, 1964], No. 11954/64. Heading B1B. Water is desalinated by distillation in a series of flash evaporator stages 11 . . 18 each housing a condenser coil in which the feed water is heated, the water being further heated, before being introduced into the flash stage of highest temperature, by using it as cooling medium in the coil of a condenser 48 in which is condensed the vapour of a fluid, such as dichlorodifluoromethane, which circulates around a secondary system comprising the condenser 48, evaporator 29, compressor 60, expansion valve 63 and automatic control 65. Salt water is introduced into the system through pipe 19 and enters open tank 21, which may contain Rasching rings. The water is pumped from tank 21 through condenser coils 25, 26, 27 of stages 18, 17, 16. The salt water then flows through pipe 28 which passes through evaporator 29 where it causes the evaporation of the secondary heat transfer liquid. The water is returned to tank 21 through eductor 31 which aspirates air and carbon dioxide from the condenser section of stage 18. Excess water is discharged through pipe 34. Some of the circulating water is drawn off through pipe 36 and valve 35 into the flash evaporator section of stage 18, where it mixes with brine. Water is drawn from this flash stage through pipe 39 into surge tank 40, from which the water flows through pipe 41 to the condenser coils 42 . . 46 in stages 15, 14, 13, 12, 11. From coil 46, the water flows through pipe 47 in condenser 48 where it is heated to at least 140‹F. in heat exchange with the condensing heat transfer vapour. The temperature of the water is controlled by automatic valve 50 which admits it to flash stage 11. The steam evolved in the flash stages passes through wire mesh droplet separators and condenses on the adjacent condenser coil. The condensate, i.e. desalinated water, is withdrawn by pump 53. A suction pressure control 68 regulates the amount of feed water introduced into tank 21 through pipe 19 and valve 20. At intervals, sediment such as CaSO 4 is discharged from tank 40. In a plant suitable for the distillation of water from a deep well under pressure, the evaporator of the secondary heat transfer system is heated by the brine leaving the last flash stage. The brine then flows through a gas-eductor and returns to the open feed tank. In a third embodiment, the distillate and plant are deaerated by an eductor operated by a stream of cooled distillate. The concentration of radioactive wastes is referred to.
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