Carbide lamp

Carbide lamps, also known as acetylene gas lamps, are simple lamps that produce and burn acetylene (C₂H₂) which is created by the reaction of calcium carbide (CaC₂) with water.

These lamps were used in mines after the re-invention of the medium in 1892 (not to be confused with the oil powered Davy lamp). Carbide lamps were also used to illuminate buildings, as lighthouse beacons, and as headlights on cars and bicycles. They are still employed by cavers, hunters, and cataphiles.

Mechanism

The conventional format of producing acetylene in a lamp is by putting the calcium carbide in the lower chamber (the generator). The upper reservoir is then filled with water. A threaded valve or other mechanism is used to control the rate at which the water is allowed to drip onto the chamber containing the calcium carbide. By controlling the rate of water flow, the production of acetylene gas is controlled. This, in turn, controls the flow rate of the gas and the size of the flame at the burner, (and thus the amount of light it produces).

This type of lamp generally has a reflector behind the flame to help project the light forward. An Acetylene Gas powered lamp produces a surprisingly bright, broad light. Many cavers prefer this type of unfocused light as it improves peripheral vision in the completely dark environment. The reaction of carbide of calcium with water produces a fair amount of heat independent of the flame. In cold cave environments, carbide lamp users can use this heat to help stave off hypothermia.

When all of the carbide in a lamp has been reacted, the carbide chamber contains a wet paste of caustic lime (calcium hydroxide). This is emptied into a waste bag and the chamber can be refilled. The residue is toxic to animals and should not be deposited in locations where animals may consume it. However, over time the hydroxide will react with atmospheric carbon dioxide to form calcium carbonate, which is non-toxic.

Small carbide lamps called "Carbide Candles" are used for blackening rifle sights to reduce glare. These "candles" are used due to the sooty flame produced by acetylene.

Use in caving

Early caving enthusiasts, not yet having the advantage of light-weight electrical illumination, introduced the carbide lamp to their hobby. [ [http://www.teara.govt.nz/TheBush/BushAndMountainRecreation/Caving/4/en Caving equipment and culture] (from Te Ara Encyclopedia of New Zealand)] While increasingly replaced by more modern choices, a substantial percentage of cavers still use this method.

In cave surveys, carbide lamps are favored for the lead or "point" surveyor, who must identify suitable points in the cave to designate as survey stations. The sooty carbide flame may be used to harmlessly mark cave walls with a nontoxic and removable station label. Especially favored for this purpose are all-brass lamps or lamps made with no ferromagnetic metals, as these lamps do not deflect the needles of the magnetic compass, which is typically read while brightly illuminated from above using the caver's lamp.

Apart from their use as cave surveying tools, many cavers favor carbide lamps for their durability and quality of illumination. They were once favored for their relative illumination per mass of fuel compared to battery powered devices, but this advantage was largely negated with the advent of high-intensity LED illumination.

The acetylene producing reaction is exothermic, which means that the lamp's reactor vessel will become quite warm to the touch; this can be used to warm the hands. The heat from the flame can also be used to warm the body by allowing the exhaust gases to flow under a shirt pulled out from the body: such a configuration is referred to as a "Palmer furnace", after geologist Arthur N. Palmer.

History

The first carbide of calcium lamp (mining lamp?) developed in the United States was patented in New York on August 28, 1900 by Frederick Baldwin. [US patent|656874] Domestic lighting was introduced in circa 1894 and bicycle lamps from 1896. Another early lamp design is shown in a patent from Duluth, Minnesota on October 21, 1902. [US patent|711871] In the late 1900s, Gustaf Dalén invented the Dalén light. This combined two of Dalén's previous inventions: the substrate Agamassan and the Sun valve.

ee also

*List of light sources

References

* Clemmer, Gregg. "American Miners' Carbide Lamps: A Collectors Guide to American Carbide Mine Lighting". Westernlore Publications, 1987.

External links

* [http://www.acethylene.com/ acethylene.com] A comprehensive guide to the care and maintenance of acetylene gas lamps
* [http://www.ironminers.com/mineforum/viewtopic.php?t=633 A Guide to Carbide Miner's Lamps.] Has many good pictures & videos.
* [http://www.job-stiftung.de/index.php?id=31,140,0,0,1,0 Carbide lamp] Demonstration experiment: Instruction and video
* [Early Vehicle Lighting] A guide to vehicle lighting; oil, candle and acetylene gas. Shire Publications UK.
* [http://www.caves.org/member/mfraley/ The Carbide Caver] A website on the history, restoration, and use of carbide lamps for caving.