A Practical Manual On Sea Water Distillation
With A Description Of The Necessary Machinery For The Process

THE EVAPORATOR. 133 from the evaporator casing is necessary when it has to be pumped away. There are several methods for arrang- ing the supply of the cooling and dilution water. It is usual to take such water from the circulation water, either from the pipe leading the circulation water to the distiller, or from the lower part of the distiller casing before the water has become warm, and for this dilution water to be led into the brine receiver, and there mixed with the hot brine coming into the receiver, or to the valve box of the pump, or any other means that are suitable. Different evaporator makers have their own method of discharging the brine, as also of cooling and diluting it. Information on these points may be gained by reading their descriptive pamphlets. (6) Quantity of Dilution Water. 151. The quantity of cooling and dilution water is usually that which reduces the brine to about half its density—that is, from ./I to 1/^ —and cooled down to 150° or lower. Therefore, if the quantity of the cooling water is made equal to the evaporation, that will be equal to double the quantity of the brine, and the above requirements will be satisfied. If the evaporation fluctu- ates, so as to be lowered much below half its maximum, then the feed (if not automatically regulated to suit the lowered production) will be increased. The pump will then have more to do, and should therefore be made amply large. If, however, the feed is regulated to suit the evaporation, however much it may fluctuate, then the brine will be proportionately lower, and the dilution water unchanged in rate of supply. 152. The least complicated way of dealing with the