The Davy Safety Lamp
المؤلف:
GEORGE A. HOADLEY
المصدر:
ESSENTIALS OF PHYSICS
الجزء والصفحة:
P-249
2025-11-22
423
It frequently happens that an explosive mixture of gases accumulates in some part of a mine. An ordinary lamp brought in contact with this mixture would cause an explosion. To prevent this, and still make it possible to use a light, Sir Humphry Davy devised a form of lamp in which, as the illustration shows, the flame is entirely surrounded with wire gauze. Whenever the lamp is brought into an inflammable mixture of gases, some of the mixed gas will enter the lamp and burn there. But so great is the heat conductivity of the gauze that the gas outside the lamp does not receive heat enough to take fire until the gauze becomes red hot.
An experiment that shows this conductivity can be made by placing a piece of wire gauze upon a tripod with a Bunsen burner beneath it. The gas may be lighted either above or below the gauze, and the flame will not pass through (Fig. 1).
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