Smudge pot

In 1907, a young inventor, Willis Frederick Charles “W.C.” Scheu (Dec 1st, 1868 – April 11th, 1942), at that time in Grand Junction, Colorado, developed an oil-burning stack heater that was more effective than open fires in heating orchards and vineyards.

The Redlands district had 462,000 orchard heaters for the winter of 1932–33, reported P. E. Simpson, of the supply department of the California Fruit Growers Exchange, requiring 3,693,000 gallons of oil for a single refilling, or about 330 tank car loads.

[6] Smudge pot use in Redlands, California groves continued into the 1970s, but fell out of favor as oil prices rose and environmental concerns increased.

[7] Pots came in two major styles: a single louvered stack above a fuel-oil–filled base, and a slightly taller version that featured a cambered, louvered neck and a galvanized re-breather feed pipe out of the side of the chimney that siphoned stack gas back into the burn chamber and produced more complete combustion.

Pots are ignited when the air temperature reaches 29 °F (−2 °C), and for each additional degree of drop, another hole is opened on the control cap ("draft regulator").

Prior to the development of battery-powered safety blinkers on saw-horses, many highway departments used small oil-burning safety pot markers to denote work zones, and many railroad systems still rely on oil-fired switch heaters, long tubs of fuel with a wicks, that fit between the ties and keeps snow and ice from fouling the points of a switch.

The smudge pot was also used at construction sites and other cold places to take the chill out of buildings so workers would be comfortable, and for several decades (1920s–1970s) they were used as emergency night landing illumination at remote airfields without electric runway lights, acting as a series of small bonfires.

[13] The oily black clouds of smoke produced from these smudge pots was intended to limit the ability to locate a target.