page_title: Davy lamp
section_title: Design and theory
hierarchical_section_title: Davy lamp / Design and theory
caption_attribution_description: Deutsch: Replika einer Pielerlampe. Die Pielerlampe wurde zur genauen Bestimmung der Schlagwetterkonzentration in Steinkohlenbergwerken verwendet. Durch verwendeten Brennspiritus wird die Flamme erst bei Anwesenheit von Methan sichtbar und zudem ist die Methankonzentration exakter als mit einer Benzinwetterlampe bestimmbar. English: Replica of a Pieler lamp, a derivative of the Davy lamp. The Pieler lamp was used to measure fire damp (methane) concentration in coal mines. By using ethanol as a fuel, the flame only becomes visible in the presence of methane, and moreover, determines the concentration more accurately than a gasoline-fueled lamp. The calibrated apertures on the side are for gaging flame height. Polski: Replika spirytusowej lampy górniczej Pielera (rodzaj paliwa odróżnia ją od podobnej w konstrukcji benzynowej lampy Davy'ego) ze skalą w postaci poziomych wąskich otworów w osłonie, wyskalowanych (kolejno od dołu) liczbami: ¼ - ½ - ¾ - 1 - 1¼ - 1½
context_page_description: The Davy lamp is a safety lamp for use in flammable atmospheres, invented in 1815 by Sir Humphry Davy. It consists of a wick lamp with the flame enclosed inside a mesh screen. It was created for use in coal mines, to reduce the danger of explosions due to the presence of methane and other flammable gases, called firedamp or minedamp.
context_section_description: 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. It originally burned a heavy vegetable oil.
  The lamp also provided a test for the presence of gases. If flammable gas mixtures were present, the flame of the Davy lamp burned higher with a blue tinge. Lamps were equipped with a metal gauge to measure the height of the flame. Miners could place the 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). A methane-air flame is extinguished at about 17% oxygen content (which will still support life), so the lamp gave an early indication of an unhealthy atmosphere, allowing the miners to get out before they died of asphyxiation.
caption: A type of Davy lamp with apertures for gauging flame height
exif: {"Image Make": "Nokia", "Image Model": "6210 Navig", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "212", "Image CustomRendered": "Normal", "Image ExposureMode": "Auto Exposure", "Image WhiteBalance": "Auto", "Image DigitalZoomRatio": "1", "Image SceneCaptureType": "Standard", "Image GainControl": "None", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "EXIF ExposureTime": "1/250", "EXIF FNumber": "14/5", "EXIF ISOSpeedRatings": "74", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2009:12:18 11:59:22", "EXIF DateTimeDigitized": "2009:12:18 11:59:22", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "1593/200", "EXIF ApertureValue": "297/100", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, auto mode", "EXIF FocalLength": "37/10", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "520", "EXIF ExifImageLength": "1600"}