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

THE EVAPORATOR. 109 (e) Lagging. 90. Finally, the evaporator casing should be covered or lagged with a good non-conductor, so as to avoid waste of heat by radiation. (/) Construction Generally. 91. Generally, the evaporator in all its parts and in all its fittings should be supplied with everything of the best materials and workmanship. The wear and tear of an evaporator is very great, and if cheap and faulty, or inefficient work is used, the probability is that in a short time the evaporator will be put out of use by some trivial breakdown, necessitating repair. (E) Feed. 1. Quantity. 92. After many years of trials, the best quantity of feed has been found to be one and a-half times the evaporation, which gives a brine salinity of From this it will be seen that if the gained distilled water is measured against the brine discharged, its quan- tity will be twice the brine, or the brine one-half the gained water, whichever way it is taken. In official trials, the brine is measured so as to be one-half the evap- oration ; then it is known that the specified salinity of the brine is correct, and that the feed is what it should be in quantity. 93. The above, of course, applies only to ocean water of the usual strength of about 3’5 per cent, of saline matter. If the water is exceptionally strong, or the reverse (as mentioned in the Chapter on “ Sea Water ’ ), allowance must be made for this, by increasing the feed if it is over