CLowes

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Clowes’ Hydrogen Oil Lamp

Although the Clowes’ Hydrogen Oil Lamp should probably be categorized in the Ashworth-Hepplewhite-Gray section, the uniqueness and ingenuity of this lamp calls for its own special section.

The need to be able to accurately measure levels of firedamp in minute concentrations became more and more of a necessity as ventilation  became more complicated in deepening mines.  The standard Davy lamp fell way short of being a useful instrument for measuring low levels of firedamp.  Towards the end of the 1800’s, several people in England and in Europe were working on the problem utilizing the basics of the Davy lamp.  The Pieler Lamp was introduced in Germany about 1885, and was probably the first commercially made device that could accurately measure small amounts of firedamp.  While used extensively in Europe, it had its drawbacks and didn’t see much use in England.

On March 29, 1892,  James Ashworth of Morely, and Frank Clowes of Nottingham filed a patent application (No. 6051) for “Improvements in Miner’s Safety Lamps”.  Basically, the patent was covering the idea of installing a hydrogen gas burning device in any ordinary safety lamp to be utilized in gas testing.  Ashworth and Clowes were capitalizing on the fact that a hydrogen flame gives a hot non-luminous flame, and therefore a large testing flame can be used and larger and plainer caps obtained for easy reading.  The patent covers two methods of delivering hydrogen to the burner: 1) Compressed hydrogen contained in a separate vessel or in a receptacle attached to the lamp, and 2) hydrogen directly from generating device.  It is interesting to note that while the patent drawings show these devices on Ashworth-Hepplewhite-Gray lamps, there is no mention of any particular lamp in the patent text.

What evolved into commercial use based on the patent was a modified Ashworth-Hepplewhite-Gray lamp with a detachable external cylinder for compressed hydrogen.  The lamp would use an oil flame for detecting methane down to 2 1/2%.  Below that, the hydrogen gas was turned on via the cylinder valve and the burner lit by the oil flame.  The oil flame would then be extinguished, and the hydrogen flame would be standardized to 0.4 inch tall.  The tips of the blue caps would be observed in comparison to the rungs on a vertical ladder scale.  Very accurate results could be obtained in atmospheres from 0.25% to 3% firedamp.  After the test was completed, the oil wick was ignited using the hydrogen flame, then the hydrogen gas was turned off and the cylinder detached.

The Clowes lamp was used from about 1892 to the 1920’s.  The lamp did not get approval to be used in “safety-lamp” mines when the approval system for mine lamps was in place. 

The lamp had many advantages over the Pieler lamp.  First, it could be used in atmospheres that contained above 2 1/2% firedamp.  Second, it could tolerate higher air current velocities safely.  Third, it could be used as a source of light.

To see two examples from my collection, click on the thumbnails below.