Safety lamp

A safety lamp is any of several types of lamp, which are designed to be safe to use in coal mines. These lamps are designed to operate in air that may contain coal dust, methane, or firedamp, all of which are potentially flammable or explosive [Felling mine disaster] [Mining accident] .

First Safe Lamps

The first safety lamp was invented by William Reid Clanny, an Irish physician, who announced his discovery [ [http://www.minerslamps.net/homepage/safetylamphistory.htm Pictures] ] on May 20th, 1813 at the Royal Society of Arts in London, but it was not tried out in a colliery until 1815 [ [http://www.welshminerslamps.com/info_lamp_history.shtml Dates] ] . Within months of this demonstration, two improved designs had been announced: one by George Stephenson, which later became the Geordie lamp, and the Davy lamp, invented by Sir Humphry Davy. Most later lamps are constructed on the principle discovered by Davy, that a flame enveloped in wire gauze of a certain fineness does not ignite firedamp

Both the Davy and Stephenson lamps were fragile. The gauze in the Davy quickly rusted in the moist air of a coal pit, and so became unsafe, while the glass in the Stephenson was easily broken, and could then allow the flame to ignite firedamp in the atmosphere. Later designs, the Gray, Mueseler, Marsaut, and other lamps, tried to overcome these problems by using multiple gauze cylinders, but the glass remained a problem until toughened glass became available. [ [http://www.geopedia.fr/minelamps-us-p0.htm Mining lamp catalog] ] .

Also, the light that all these gave was poor and this was not solved until the introduction of electric lighting in mines around 1900. But it took until 1930 for the introduction of battery-powered helmet lamps to finally solve the problem.

Early Illumination

Prior to the invention of these safety lamps, miners used candles with open flames or phosphorescent sources of light (such as rotting fishFact|date=November 2007) and later flint or steel mills designed by 'Spedding.' Later, barometers were used to tell them if atmospheric pressure was low (in which case more methane seeped out of the mine into the air).

The use of small mammals or birds was used much later to warn of the presence of the deadly carbon monoxide present after underground fires or explosions, the so-called afterdamp. Such animals are much more susceptible to the gas, and will die before a human, so giving an early warning of the problem. An alternative method of removing the methane involved igniting the gas deliberately to cause explosions, thus evacuating the mines of the majority of explosive or easily flammable material present.

The lack of good lighting was a prime cause of a painful eye affliction (nystagmus).

Modern Lamps

Nowadays, safety lamps are mainly electric, and traditionally mounted on miners' helmets (such as the wheat lamp), sealed to prevent gas penetrating the casing and being ignited by electrical sparks.

Although its use as a light source was superseded by electric lighting, the flame safety lamp had continued to be used in mines into recent years to detect methane and blackdamp, though modern mines now use sophisticated gas detectors for this purpose.

References

ee also

*List of light sources
*Pellistor