A NEW OR IMPROVED APPARATUS OR INSTRUMENT FOR DETECTING THE PRESENCE AND INDICATING THE PER-CENTAGE OF FIRE-DAMP OR LIGHT CARBURETTED HYDROGEN GAS IN THE ATMOSPHERE OF MINES
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Arthur Hill Maurice at the Office of
the Commissioners of Patents on the 4th October 1878.
ARTHUR HILL MAURICE, of Cold Norton, near Stone, in the County of Stafford,
Mining Engineer. "A NEW OR IMPROVED APPARATUS OR INSTRUMENT FOR
DETECTING THE PRESENCE AND INDICATING THE PER-CENTAGE OF FIRE-DAMP OR
LIGHT CARBURETTED HYDROGEN GAS IN THE ATMOSPHERE OF MINES."
This Invention relates to a new or improved apparatus or instrument for detecting
the presence of fire-damp or light carburetted hydrogen gas in mines, and deter-
mining and indicating at any time the per-centage of gas existing in the atmosphere
of any portion of a mine, being in fact a fire-damp indicator.
The apparatus consists of an air vessel of any convenient size or shape made of
wood or metal, with a lid or cap to screw or otherwise fasten on, so that when
closed the vessel shall be air-tight. Attached to this vessel is a gauge so arranged
that any rarefaction of the air or formation of partial vacuum in the interior of the
vessel is indicated by it. The gauge may be a water or mercury gauge, an ordinary
pressure gauge, or an aneroid or mercurial barometer, and it is intended to show
the difference between the pressure or density of the atmosphere on the outside of
the vessel and that on the inside of the vessel after the action of the apparatus for
the detection of gas has been completed.
The other portion of the apparatus consists of a mass of spongy platinum or of
finely divided metallic platinum (or any other form of platinum or metal which will
answer the same purpose), which is placed in an air-tight box or cap, having been
first thoroughly dried by ignition or by being kept in a dessicator. This box or cap
containing the platinum is so arranged that on being placed in the air vessel,
and the latter closed, it may be opened from the outside of the air vessel by
means of a rod, lever, screw, or other contrivance (so that the platinum becomes
exposed to the atmosphere inside the vessel), and may be closed again in like manner
when desired. This is done in such a way that the air vessel continues perfectly
air-tight during the opening and closing of the platinum box. The action of the
instrument or apparatus is as follows:-The air vessel being taken into the mine
Paving D,17

page_text: with the cap or lid off becomes filled with the atmosphere which it is intended to
test, the platinum box is placed in it, and it is then closed air-tight. The gauge or
aneroid is now read off, the platinum box is opened so as to expose the platinum
to the interior atmosphere, and at the end of five minutes is closed again. The gauge
or aneroid is now read a second time.
The platinum on being uncovered immediately acts upon any fire-damp which
may be mixed with the air, inducing slow combustion, the product being carbonic
acid gas and water vapour, and the consequence being a rarefaction or reduction in
the volume of the atmosphere in the interior of the air vessel, varying exactly as
the per-centage of fire-damp present.
The gauge or aneroid shows the amount of rarefaction or reduction of bulk in
the air vessel, and also by means of a table made for the purpose the exact per-
centage of fire-damp in the air.