Everything about The Davy Lamp totally explained
The
Davy lamp is a
safety lamp containing a candle, devised in
1815 by
Sir Humphry Davy. It was created for use in
coal mines, allowing deep seams to be mined despite the presence of
methane and other
flammable gases, called
firedamp or
minedamp.
Davy had discovered that, to
explode, the gas must be heated to its
ignition temperature and that if such heating is prevented, combustion can't occur. If the flame in a lamp is surrounded by metal
gauze to distribute the heat over a large area, the maximum temperature of the screen is below the ignition temperature of the gas. The first trial of a Davy lamp with a wire sieve was at
Hebburn Colliery on
9 January 1816.
Gas Detector
The lamp also provided a crude test for the presence of gases. If flammable gas mixtures were present, the flame of the Davy lamp burned higher with a blue tinge. Miners could also place a safety lamp close to the ground to detect gases, such as
carbon dioxide, that are denser than air and so could collect in depressions in the mine; if the mine air was oxygen-poor (
asphyxiant gas), the lamp flame would be extinguished (
black damp or
chokedamp).
Comparison with Geordie lamp
There was some controversy, since
George Stephenson also produced a similar safety lamp in
1816 called the
Geordie lamp.
How far the difference was appreciated at the time is hard to say; supporters of both men seem to have regarded the other as having plagiarised their man's idea and copied it wrongly. The Geordie lamp (with no gauze around the
flame) gave a brighter light and was popular with the
miners. The Davy lamp was simpler and cheaper to make and was popular with the mine owners.
There were safety arguments on both sides: in principle, a poorly maintained (or badly designed) Davy lamp could overheat the gauze if it met a high concentration of methane. The gauze rusted very easily in the damp conditions of mines, making the lamp hazardous. A serious objection to the Geordie lamp was that it stopped being a safety lamp if the glass was broken. Both original lamps were faulty, and led to numerous attempts to improve the design, by using multiple gauzes placed above the flame, and with a glass surround to improve illumination. However, they were still poor sources of light and matters didn't improve until the widespread introduction of small electric hand lamps later, in the Victorian period.
Accident rate
The introduction of the Davy lamp actually led to an increase in accidents in mines as the availability of the lamp encouraged the working of mines that had previously been closed for safety reasons
Modern Lamps
The modern day equivalent of the Davy lamp is the
Protector GR6S Garforth lamp which is used for firedamp testing in all
UK coal mines. A modified version of this lamp is used to transport the
Olympic Flame for the torch relays. They have recently been used for the
Sydney,
Athens, and
Turin torch relays and will be used for the
Special Olympics Beijing relay. The lamps are still made in
Eccles.
Further Information
Get more info on 'Davy Lamp'.
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