A steam generator is a device in which feed water is first heated to boiling temperature and then evaporated.
The generated saturated steam is collected in the steam drum above the water level and discharged in a controlled manner. Heating is usually provided by a U-tube bundle inserted in the lower part of the jacket and connected to the heat source. The steam generator has all the connections necessary for safe operation to accommodate the safety valve, vacuum breaker, level probe, conductivity electrode, pressure and temperature indicators and limiters, desalination and blowdown. Usually, at least one inspection hatch is also used, through which one can visually inspect the interior of the shell and the tube bundle.