Steam Heated Evaporators is designed to self adjusts the liquid chlorine level to prevent the build up of excessive pressure. An automatic or manual shut-off valve and pressure relief valve, cathodic protection, steam valve, condensate trap, drain valve, pressure gauge and temperature gauge are also included for safe operation. It is designed for reliability, safety and very little maintenance. It is fully automatic or partially automatic depending upon the level of automation and sophistication. It is fitted with a liquid injection system to prevent too high exit temperatures at low consumption conditions. In steam heated type the vaporizing medium is steam.