Gas mantle

The name refers to its original heat source in gas lights which illuminated the streets of Europe and North America in the late 19th century.

[2] The combination of these properties yields a mantle that, when heated by a kerosene or liquified petroleum gas flame, emits intense radiation that is mostly visible light, with relatively little energy in the unwanted infrared, increasing the luminous efficiency.

The mantle aids the combustion process by keeping the flame small and contained at higher fuel flow rates than in a simple lamp.

In the late 19th century, several inventors tried to develop an effective alternative based on heating a material to a lower temperature but using the emission of discrete spectral lines to simulate white light.

Many early attempts used platinum-iridium gauze soaked in metal nitrates, but these were not successful because of the high cost of these materials and their poor reliability.

The modern gas mantle was one of the many inventions of Carl Auer von Welsbach, a chemist who studied rare-earth elements in the 1880s and who had been Robert Bunsen's student.

[3] To produce a mantle, cotton is woven or knit into a net bag, impregnated with soluble nitrates of the chosen metals, and then transported to its destination.

The user installs the mantle and then burns it to remove the cotton bag and convert the metal nitrates to nitrites which fuse together to form a solid mesh.

Early mantles were sold in the unheated cotton mesh condition, since the post heating oxide structure was too fragile to transport easily.

Originally, unused mantles could not be stored for very long because the cotton quickly rotted due to the corrosive nature of the acidic metal nitrates.

[7] One potential cause for concern is that particles from thorium gas mantles "fall out" over time and get into the air, where they may be ingested in food or drink.

[6][8] In June 2001, the U.S. Nuclear Regulatory Commission published a study about the Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials,[9] stating that radioactive gas mantles are explicitly legal in the US.