Image Number 2 for United States Patent #4018209.
An air heater comprising a pipe assembly having an intake opening and an outlet opening which is horizontally supported by a stand and protected by a removable, open-topped sleeving. The pipe assembly is a series of internally interconnected pipes which provides a continuous air flow passageway from the intake opening to the outlet opening. The pipe assembly is heated by a small fire inside the sleeving while a pump forces cold air into the intake opening. As the pumped, cold air circulates through the heated pipe assembly, the air becomes heated, and hot air is expelled at the outlet opening.