Fog machine

A fog machine, fog generator, or smoke machine is a device that emits a dense vapor that appears similar to fog or smoke. This artificial fog is most commonly used in professional entertainment applications, but smaller, more affordable fog machines are becoming common for personal use. Fog machines can also be found in use in a variety of industrial, training, and some military applications. Typically, fog is created by vaporizing proprietary water and glycol-based or glycerin-based fluids or through the atomization of mineral oil. This fluid (often referred to colloquially as fog juice) vaporizes or atomizes inside the fog machine. Upon exiting the fog machine and mixing with cooler outside air the vapor condenses, resulting in a thick visible fog.

Heated fog machines use either an inert gas or an electric pump to propel mineral oil, glycol, or glycerin and water mixture into a heat exchanger, where the solution is vaporized. The most commonly encountered form of heated fog machine is the pump machine. Very basic models of this type of machine consist of a fluid reservoir, an electric pump to move the fog fluid and heat exchanger which vaporizes the fluid. More complex models may include a variety of other features, including variable speed pumps to control the output of fog, timer modules, or components for remote operation and monitoring of the fog machines' status. Some manufacturers have produced accessories and fluids that when combined with an ordinary heated pump machine, create fog effects similar to chilled fog machines. Gas propelled fog machines use an inert gas (most commonly CO₂ or nitrogen) to propel either mineral oil or a glycol based fluid into a heat exchanger where it is vaporized into particles, creating a fog. Some models of gas propelled fog machine provide control over the output of fog by varying the volume of gas used to propel the fluid.

Chilled fog machines are designed to create thick clouds of fog that lie close to the ground and dissipate as they rise. They are typically created by using either dry ice, liquid nitrogen, or more recently liquid air.

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