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A type of Davy lamp with apertures for gauging flame height. The lamp consists of a wick lamp with the flame enclosed inside a mesh screen. The screen acts as a flame arrestor; air (and any firedamp present) can pass through the mesh freely enough to support combustion, but the holes are too fine to allow a flame to propagate through them and ignite any firedamp outside the mesh.
Both the Davy and Stephenson lamps were fragile. The gauze in the Davy lamp rusted in the damp air of a coal pit and became unsafe, while the glass in the Stephenson lamp was easily broken, and allowed the flame to ignite firedamp in the mine; later Stephenson designs also incorporated a gauze screen as a protection against glass breakage. [18]
Firedamp (1889) by Constantin Meunier depicts the aftermath of a mining disaster Stephenson's safety lamp shown with Davy's lamp on the left. Firedamp is explosive at concentrations between 4% and 16%, with most explosions occurring at around 10%. It caused many deaths in coal mines before the invention of the Geordie lamp and Davy lamp. [4]
The Davey Safety Lamp was made in London by Humphry Davy. George Stephenson invented a similar lamp but Davys invention was safer due to it having a fine wire gauze that surrounded the flame. This enabled the light to pass through and reduced the risk of explosion by stopping the "firedamp" methane gas coming in contact with the flame.
A Davy lamp, an early example of a safety lamp The tragedy inspired Hodgson to raise public concern about the hazards of mining. Public interest was fed by a short (16-page) pamphlet written by him and published prior to the second disaster in late 1813.
A lampman had responsibility for maintaining lamps and for issuing them from the lamp room at the start of a shift. Level. A level is a roadway along the strike of the strata, i.e. at right angles to the dip. [17] Longwall face. A longwall face is a coal face of considerable length between the gates from which the coal is removed. [1]
The mine was not "more than ordinarily gassy", but there is some evidence that the identified points of leakage might have been points of accumulation from leaks elsewhere. The lamps in use were Davy pattern [2] and naked lights called "midgies" in some areas. The coroner found no evidence that the midgies were connected with the explosion.
In 1812 the Felling mine disaster and the explosion at Mill Pit in Herrington near Sunderland focussed attention on the issue of the safe provision of lighting in mines. In the same year Clanny completed his first lamp consisting of a candle in a glass surround.