OTSO Indirect Fired Heaters / Water Bath Heaters consist of a pressure vessel with a heating section that contains plates, and does not allow the process fluid to come into direct contact with the firetube. The free water separates immediately and, therefore, does not need to be heated. This saves fuel, while increasing heater efficiency. These heaters are ideal for oil dehydration facilities, with oil gravity of 21° (and higher). We can also custom design your heater to accommodate various temperatures and lower API gravity oils, depending on your application.