CARBIDE LAMP

'Carbide lamps' also known as 'Acetylene Gas lamps' are simple lamps that produce and burn acetylene gas (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 the 1892 (not to be confused with the oil powered Davy lamp). Large domestic settings, veteran cars, lighthouses, bicyclists; all used Acetylene Gas powered lighting and they are still used by cavers, hunters, and cataphiles.

Contents

Mechanism

Use in caving

History

References

See also

External links

Mechanism

The conventional format of producing Acetylene Gas 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

In cave survey, 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 non-toxic 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. If a permanent magnet is not attracted to a lamp part, then that part is suitable for use in cave survey (the body of the lamp may be brass, but the reflector made of ordinary steel, so both must be checked. Austenitic stainless steel reflectors are suitable.)
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 (carbide versus batteries), but this advantage is less significant or reversed 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 gasses to flow under a shirt pulled out from the body: such a configuration is referred to as a "Palmer furnace" for SUNY Oneonta 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, (). Domestic lighting was introdused in circa 1894 and bicycle lamps from 1896.
Another early lamp design is shown in a patent from Duluth, Minnesota on October 21, 1902 ().
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.
'The Re-Invention of Carbide of Calcium and its use with Acetylene Gas lamps.'
Acetylene gas lighting was successfully developed and introduced by many manufacturers for various uses from circa 1894. Fuller in America is credited with its introduction in 1895. Often described as artificial daylight, Willson and Moorehead re-discovered the properties of acetylene gas in 1892. They demonstrated that by dripping water onto carbide of calcium, acetylene gas was produced which, when ignited under about 5lbs of pressure, gave a brilliant white light. Carbide of calcium is manufactured from coke and lime in an electric furnace with an achievable heat of approximately 4000 degrees Fahrenheit. The chemical action converts the coke and lime into carbide calcium and carbon monoxide gas. The chemical action which takes place when the water is brought into contact with the carbide of calcium was discovered by Friedrich Wohler in 1862:^[1]
CaC₂ + 2 H₂O → Ca(OH)₂ + C₂H₂
Acetylene gas as properly generated will produce 95.6% of pure gas per volume. The remainder is made up of sulphuretted hydrogen, ammonia, hydrocarbons and phosphoresced hydrogen (Ref 5). This latter impurity is perhaps the most dangerous, as it forms a highly explosive compound when brought into contact with copper (Ref 14). Owners of bicycle lamps should not fear as the hydrogen gas generated in a bicycle lamp is so minuscule that it will have no effect. On the other hand, it was a problem with very large domestic acetylene gas generators where substantial amounts of gas were produced. It also helped if the generator was kept cool, which in the most part was true when using your lamp on an evening ride. Some means of filtering the impurities was certainly needed as if they were allowed to pass along with the gas they would very quickly block the small burner tip. In consequence most manufacturers after 1900 used a horse-hair filter sandwiched behind a plate in the upper part of the generator. Modern users often remove this, not realizing the damaging effect at the burner. If the filter needs replacing then cotton wool is a good alternative.

References

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

See also

★ List of light sources

External links

★ acethylene.com A comprehensive guide to the care and maintenance of acetylene gas lamps

★ A Guide to Carbide Miner's Lamps. Has many good pictures & videos.

★ Carbide lamp Demonstration experiment: Instruction and video

★ ['Early Vehicle Lighting'] A guide to vehicle lighting; oil, candle and acetylene gas. Shire Publications UK.