Evaporators are used to increase the solid content in the liquids containing low solids, by evaporationg water or solvent from the liquid Evaporators basically consist of shell and tube heat exchanger columns called as calandrias. The product to be concentrated is passed through the tubes and the heating media, usually steam, is passed through the shell. The calandria tube side is under vacuum causing the liquid boiling at lower temperature, Thus making the operation economical and safe for heat sensitive products. Following are the types of evaporators depending upon the feed circulation configuration.