A forced circulation evaporator includes a shell and tube calandria as the heat exchanger, a flash separator (Vapour liquid separator) and a circulation pump to facilitate the circulation. The flash separator is connected at the bottom, or the top of the calendria, as per the geometrical arrangement based on the no. of passes.
The liquid in the tube is heated with the steam, which increases the temperature and pressure. The pressure inside the flash separator is lower than that of the entering liquid. Due to this difference in pressure, the liquid gets flash evaporated within the separator. Therefore, this type of evaporator is also called Suppressed boiling evaporator / para-flash.
