The advances leading up to the carbide caplamp as we know it started as early as 1897. The first carbide lamps that resemble modern ones came on the scene in 1900. However, they did not have real popularity until the 1920's. Carbide caplamps were primarily used in mines, with other markets supported by farmers, hunters and other outdoors persons. Other larger carbide lamps were used as handlamps for mining foreman, motorcycle headlamps, bicycle lights, military searchlights, and other purposes. For decades the carbide lamp was the only headlamp considered suitable for caving. Its unmatched durability and economy made it the only logical choice for any caver who valued his or her hide. However, the carbide lamp was slowly abandoned for electric lights as they became more reliable and less expensive. Since the advent of LED lighting (which is admittedly lighter and far more economical) carbide lighting has become even more uncommon. Even in their waning popularity, carbide lamps are still a symbol of caving, and still have unmatched durability. Still, the market is giving way to the electric light. In 1984 the last Justrite was made, ending American production for 19 years. In 1995 Premier produced the last English carbide caplamp. New carbide lamps were completely unavailable in the U.S. for seven years until 2002 when the MINEX lamp began its brief distribution in the U.S. J. K. Dey & Sons began selling MINEX lamps to the United States especially for Inner Mountain Outfitters. In 2003, a new American made lamp, the Mike Lite, began distribution through Inner Mountain Outfitters and remains in production today. Though the MINEX is still in production, it is no longer available in the United States. However, Petzl is still producing an acetylene lamp with a generator. Other styles of generators are also available at caving vendors such as Inner Mountain Outfitters. The generator style acetylene lamps are much different from their cap-mounted counterparts. They operate on a brute force approach to lighting, and provide a brilliantly bright light, but consume a considerable amount of carbide.
The carbide lamp operates because of a chemical reaction between calcium carbide, and water:
CaC2 + H2O => C2H2 + CaO + heat
However, there is another chemical reaction that occurs within the lamp bottom between the lime (calcium oxide) and the water to produce calcium hydroxide.
CaO + H2O => Ca(OH)2
The water is stored in a reservoir above the carbide. Set at a rate determined by the user, the water will drip into the carbide chamber. When the water touches the carbide it will produce a hot, damp lime powder and acetylene gas. The gas passes through a filter, through a gas tube, and then through the tip where the gas can be ignited to produce a bright, gentle flame. The light produced by the flame is much different from that of the light produced by a incandescent bulb. Incandescent bulbs produce one very bright spot. Though the spot can be adjusted in many cases, there is a sharp contrast between what is in and out of the spot. Since the eye adjusts to the brightest light it detects, the user will experience a sort of tunnel vision. A carbide lamp will produce a soft diffuse. The light of a carbide will not penetrate as far, but the diffuse will be broader.
If you are going to use a carbide lamp you should first know how it works. The diagram to the right shows a cross section of your lamp.
There are other lamp parts which are not always necessary or do not come with all lamps. The first of which is a "cool grip" or "bumper grip" which appears on Premiers and many of the later Autolites and Justrites. In the chemical reaction between calcium carbide and water the bottom of the lamp will become quite hot. For the comfort of the user a rubber grip is provided on the bottoms of some lamps. The second part is the wind guard (featured left). This helps prevent gusts of wind from blowing out the lamp's flame. Some wind guards are part of the wing nut, and other will fit over the wing nut.
Flame protector credited to:
Rea, Thomas G. Caving Basics Third Edition, p.11.
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