How does it work?
The acetylene obtains by hydrolysis of the carbide of calcium (by bringing down gout with gout the water on the carbide), itself prepared by reaction the carbon enters (in the form of coke) and the lime, in very high temperature in an electric oven (2200°C)
3 C + CaO ® CaC2 + 2 CO
CaC2 + 2 H2O ® HC º CH + Ca(OH)2
The acetylene (Eb =-83°C) is gas in common temperature. The forming(training) of the acetylene according to the reaction
2C + H2® C2H2 is endothermique (DH = + 230 kJ.mol-1). The acetylene is, for that reason , unstable. It tends to decompose into carbon and dihydrogène, in a sometimes violent way, especially if it is compressed or liquefied. (1)
The advantage of this mode of lighting likes in its longevity
Where find lamps ?
Hypermarkets of the sport : Décathlon – Le vieux campeur :
count about 100 Euro Plastic most of the time to gain weight, but with the immense advantage of power hang on(collide) the beak and its reflector on the helmet, while the body of the lamp pend weakly in your belt.
The secondhand trades : if your region is one so much is little chalky and hollow, it would be very surprising not to find there . It is generally lamps which one carries(wears) in the hand and which dates the first half of the century. The price can vary from 10 Euro to 150 Euro even more for the details of collection. Verify before buying that the beak is not narrow-minded and that the lamp is not cracked or drilled. Please , also verify the state of the joint of the chamber with carbide. If this one is dry and stiff, please , distrust, the waterproofness will not be assured. If it is the only defect of the lamp, you can easily adapt a rubber for conjoint jars, that works well magnificently.
Barbes (at Paris) : Here is the equivalent of the Big General store of Istanbul, with its multicolored shops where everything piles up in a feigned disorder. Please , go from a military surplus to the other one, you will manage certainly to find a which(who) of it will sell you new of it for 23 Euro (with there premium, 2 extra beaks, rare foodstuff). There are enough young people in Paris visiting catacombs not to arouse the slightest interrogation on behalf of the salesman.
Where find some carbide ?
You can there find in the agricultural cooperatives for a modest price. About 21 Euro for 5 kg, what assures(insures) you several hundreds of hours of lighting. If you leave in expedition, do not however neglect the good hurdy-gurdy MAG-LIGHT, the light bulbs and the extra pile, 2 lighters and a quantity of sufficient(self-important) water. It is better two precautions that one, underground your life depends on it !!!