Due to high boiling temperature of sea water, scales are formed on the heating surface. The higher the boiling temperature required the more the formation of scales takes place. Other factors on which the formation of scale depends are flow rate and the density of brine formed.
Due to excessive scale deposits on heating surfaces, greater requirement of boiling temperature arises. Excessive scales will lead to low quality of fresh water and also reduction in the quantity of water produced. It will also prevent higher reduction of pressure inside the chamber from taking place.
Scale formation can be prevented by using a technique known as cold shocking. In this method the heating surface is alternatively heated and cooled, which reduces the formation of scales.
Also a routine maintenance of the generator should be carried out by shutting down the plant and removing the scale manually or by chemical treatments. The internal walls of the chamber or the shell should also be cleaned when the overall cleaning is done.
Air ejectors and educators should also be checked for holes or leakages, which can prevent the formation of desired vacuum.
The distiller, feed and brine pumps should also be properly maintained to prevent any interruption in the flow of fresh and sea water. The processes and the phenomena used in both plate and tube type FWGs are the same.
A constant check should be kept on the flow meter to prevent excessive or very less flow.
The salinometer alarm should be precisely set and given a constant watch. This is to prevent the degrading of the quality of fresh water produced.
