The purpose of evaporation is to vaporize the solvent in order to enrich the solute in the solution.
At the end of the operation the substance recovered is known as the concentrate.
A conventional evaporator is heated by steam which condenses and transmits heat energy to the solution to be evaporated.
As this solution boils it in turn releases vapor which may
Either be condensed in a condenser, in which case the process is known as single effect evaporation.
Or be used to heat another evaporator, in which case it is known as multiple effect.
In theory an unlimited number of evaporators may be associated in series in this way.