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

126 SEA WATER DISTILLATION. comparatively soft and crumbly, so as to be easily re- movable with the fingers. This is an advantage for double distillation where one evaporator is used, but in multiple distillation, when several evaporators are linked together, pressure steam must be used. 132. Scaling tools, for removing the scale from the coils, are usually supplied with the evaporator. These are of various forms and shapes, suited to the form and design of coil that is fitted in the evaporator. But a good deal of the scale can be removed by the expansion and con- traction of the coils. A good plan is to empty out the boiling brine, then fill up quickly with cold sea water, and allow the water to stay in some little time. This will be found to very much loosen the scale, and make it more easy to remove when the coils are taken out to be cleaned. (3) Brine Area. 133. Before dealing with the brine level, or the brine discharge, it is more convenient to deal with the brine area—that is, the area of its surface or steam delivery area. This is a very important matter in connection with the subject of priming, for if the steam delivery area is insufficient for the amount of steam that has to be evap- orated from the sea water, frothing up will commence, and accumulate till it reaches the evaporator cover, and be carried over with the steam into the distiller, causing the fresh water to be salted so as to be quite useless, at anyrate, for such purposes as feeding water-tube boilers. When dealing with the size of the steam-room this sub- ject was touched upon, but it is necessary to say a few words more here.