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

2O6 SEA AV ATER DISTILLATION. heaters, which it will be convenient to deal with next, before dealing with the filter, the feed regulator, and the pump. (d) FEED HEATERS. 80. In multiple distillation apparatus on land (where there is plenty of space available, including head-room over the apparatus), it is convenient to place the feed- water heaters over the centre line of the apparatus. There are, of course, various ways of placing the heaters. A convenient method of fitting them is as follows :— The first heater (nearest to the boiler) is the boiler feed heater. In close succession usually follow—the second heater, which heats the feed-water for the first evaporator, the third heater, which heats the feed to the second evaporator, and so on, for as many evaporators as are linked together. The arrangement of feed-water heaters for a treble distilling apparatus is shown in Fig. 22. 81. These heaters are connected together at top and at bottom by common pipes. The top pipe (A) is for steam and the bottom pipe (B) for the water resulting from the condensation of the steam. The feed-water is pumped into each heater casing at the lower part, at (F), (F), (F), in each of the three heaters. After circulating between the tubes within each heater, the feed-water passes out from the first heater to the boiler, from the second heater to the first evaporator, and from the third heater to the second evaporator. 82. The temperature of these three feed-waters is raised by the heat derived from three sources, (1) the exhaust steam from the pump, which can impart its latent heat; (2) the vapour or steam from the final evaporator, in which the latent heat of the steam is also used ; and (3)