Improvements in Processes and Apparatus for Testing Miners' Safety Lamps.
Year: 1886

page_text: THUVIDIONAL SPECIFICATION.
Improvements in Processes and Apparatus for Testing Miners'
Safety Lamps.
We, ARCHIBALD REID ORMISTON, of 33 Burnbank Gardens, Glasgow, in the County
of Lanark, North Britain, and JAMES ORMISTON of Mount Vernon, Glasgow aforesaid,
both Mining Engineers, do hereby declare the nature of this Invention to be as follows,
that is to say :-
Our said Invention has for its object the practical testing of miners' safety lamps in
a better, more reliable, and satisfactory manner than heretofore.
By the processes in use for testing safety lamps an attempt is made to ascertain
whether flame will communicate from the interior of a lamp to a combustible gaseous
mixture surrounding the lamp; but we believe this mode of testing to be unreliable
and unsatisfactory, and we have satisfied ourselves that a much more searching test is
made by arranging matters so that it can be ascertained whether flame on the outside
of the lamp will ignite a combustible mixture inside of the lamp. Whether the testing
is to be by the communication of flame outwards or inwards, it is desirable to have a
suitable combustible mixture with which to make the test, and a part of our Invention
relates to a mode of obtaining such a mixture in a simple and reliable manner so as to
be practically uniform in its results in all cases.
In carrying out our Invention we produce a combustible gaseous mixture by passing
a stream of coal gas, or of vapor of shale or petroleum spirit, and air, at a slight
pressure, through a closed cylinder of strong sheet iron, or other suitable vessel of
sufficient size to insure a thorough mixing of the gases before they reach the exit end.
In both the inlet and outlet pipes we place wire-gauze checks to prevent the mixture
from being ignited in the vessel; and on the outlet pipe we fix a small testing nozzle
fitted with a wire-gauze cap to serve as a safety burner. The gaseous mixture when
sufficiently combustible, is ignited at this burner, and from the appearance of the flame
the operator judges whether the mixture is of a suitable composition and regulates the
supplies of gas or vapor and air accordingly. The flame should be of a blue color and
without any whiteness, whilst the combustion should be vigorous and close to the
gauze.

page_text: The safety lamp to be tested has the oil vessel unscrewed and detached from it;
and there is screwed into its place a tightly fitting inetal plate through which there
passes into the interior of the lamp a pipe having a safety burner of the kind
hereinbefore described. The pipe is fitted with a tap and is connected to the outlet
pipe of the mixing vessel; and when about to test the lamp the combustible mixture,
which has itself been tested as hereinbefore described, is admitted in the interior of
the lamp. The mixture fills the lamp and passing through the wire gauze, forms a
combustible atmosphere surrounding it. A light is applied externally and igniting the
mixture causes thic lamp to be enveloped in a searching flame which at once reveals
any defective part in the wire gauze or other part of the lamp by igniting the mixture
in the interior. But if the lamp is perfect the flame will simply play upon the
outside without causing ignition internally.
This Thrantee fifth day of June 1886
EDMUND HUNT,
Applicants' Agent.
We, ARCHIBALD REID ORMISTON, of 33 Burnbank Gardens, Glasgow, in the County
of Lanark, North Britain, and JAMES ORMISTON, of Mount Vernon, Glasgow, aforesaid,
Doth Mining Engineers, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement, that is to say :-
Our said Invention has for its object the practical testing of miners' safety lamps
in a better, more reliable, and satisfactory manner than heretofore.
By the processes in use for testing safety lamps an attempt is made to ascertain
whether flame will communicate from the interior of a lamp to a combustible gaseous
mixture surrounding the lamp; but we believe this mode of testing to be unreliable,
and we have satisfied ourselves that a much more searching test is made by arranging
matters so that it can be ascertained whether flame on the outside of the lamp will
ignite a combustible mixture inside of the lamp.-Whether the testing is to be by the
communication of flame outwards or inwards, it is desirable to have a suitable
combustible mixture with which to make the test, and a part of our Invention consists
of a mode of obtaining such a mixture in a simple and reliable manner so as to be
practically uniform in its results in all cases.

page_text: The accompanying explanatory drawing is a perspective view of a convenient
arrangement of apparatus for carrying out our Invention.
We produce a suitable combustible gaseous mixture by passing a stream of coal gas,
or vapor of shale or petroleum spirit, and air at a slight pressure, through a closed
cylinder of strong sheet iron or other suitable vessel of sufficient size to insure a
thorough mixing of the gases before they reach the exit end. The apparatus shown
in the drawing is suitable for using vapor from petroleum spirit or other volatile
hydrocarbon, and comprises a strong closed vessel divided internally by a partition
indicated by dotted lines into two compartments, A, B, whilst one, A, of these com-
partments has in it a partition indicated by dotted lines and extending from the front
end to within a short distance of the back end. The petroleum spirit is filled into the
compartment, A, through a screw plug, C, but only to a depth which will allow ample
space for the passage of air over its surface. The air is supplied by means of bellows,
1, (or it might be in any other convenient way) and proceeds through a pipe, E, made
with two branches, F, G, one, F, of which is connected through a stopcock, H, to the
carburetting compartment, A. The air enters the front end of the compartiment, A at
one side of its partition and proceeding over the surface of the petroleum to the back
end returns at the other side of the partition, being richly charged with the hydro-
carbon in its passage, and passing from the compartment, A, by a pipe, J, to the
compartment, B. The second branch air supply pipe, G, communicates through a
stopcock, K, with the compartiment, B, and proceeds along with the charged or
carburetted air from the compartment, A, from the front to the back end of the
compartment, B, becoming thoroughly intermixed in the passage, and leaving the back
end by a pipe, L, fitted with a stopcock, M. At the entrance to the pipe, L, "wire
gauze is fixed to render it impossible for flame to pass by the pipe, L, into the
compartment, B. A small testing burner, N, with a stopcock is connected to tho
pipe, L, near the compartment, B, and is also provided with wire gauze to prevent
flame from penetrating inwards. Similarly all the inlets into the vessel, A, B, are
protected with wire gauze to prevent the mixture from being ignited within the vessel.
The gaseous mixture when sufficiently combustible, is ignited at the testing
burner, N, and from the appearance of the flame the operator judges whether the-
mixture is of a suitable composition and adjusts the stopcocks, H, and K, accordingly.
By partly closing the stopcock, H, admitting the air into the compartament, A,
containing the petroleum spirit, and partly opening the stopcock, K, admitting unmixed
air into the compartment, B, the richness of the ultimate mixture is diminished and
vice versa. The flame at the burner, N, should be of a blue color and without any
whiteness, whilst the combustion should be vigorous and close to the burner.
A safety lamp P, to be tested has its oil vessel unscrewed and detached from it;
and there is screwed into its place a tightly fitting metal plate or testing bottom Q,
fitted with a stopcock, R, and with an internal nozzle or safety burner protected with
wire gauze. The testing bottom, Q, may be easily constructed by taking an ordinary
safety-lamp oil vessel, removing the wick and pricker fittings, soldering into it the
stopcocks, R, and covering over the wick opening in the top with wire gauze. Each
testing bottom, Q, is connected by a flexible tube, S, to the pipe, L, by which the
combustible gaseous mixture is supplied. The testing is done by admitting the
combustible gaseous mixture into the testing bottom, Q, and thence into the lamp
chamber, and applying a flame to ignite the mixture as it escapes through the lamp
gauze to the outside. If there be any hole or defect in the lamp top, P, the flame
which at once envelops the lamp when the light is applied will strike through and
the mixture will burn inside upon the gauze cap of the testing bottom, Q. To
render the test extremely searching the lamp may be moved about and turned upside
down so as to make sure that the external flame plays over every part of it. And for
detecting small holes which are scarcely large enough to be dangerous, it will be found
that sudden checkings of the current of combustible mixture while the flame is
playing round the outside of the lamp will be effective. For this purpose the current
may be checked by pinching the flexible supply tube, S, and when there is a hole
large enough to require attention or repair the flame will penetrate into the lamp.

page_text: All the time required for testing a lamp by our improved method is only a few
seconds, so that there is no fear of injuring the lamp by the flame when the testing is
properly done.
In order to render the testing operation quite complete we proceed as follows after
doing what has already been described. We remove the testing bottom, Q, and screw
the proper oil vessel to the lamp top, P, and light the lamp. We then dip the lighted
lamp into a small open topped cylinder, T, supplied with some of the combustible
mixture through a flexible tube, U, and stopcock, V. The cylinder, T, is provided
with wire gauze at its bottom to prevent ignition of the mixture in the supply pipe.
This dipping serves for testing the condition of the lanip bottom and will show if
flame can communicate from the interior through any aperture or space, as for
example at the attaching screw, or at the pricker tube. The cylinder, T, is made so
shallow that the explosive mixture in it is never likely to put out the lamp flaine,
thereby saving time and trouble for relighting.
Having now particularly described and ascertained the nature of our said Invention
and in what manner the same is to be performed we declare that what we claim is :-
1. The testing of miners' safety lamps by means of a combination of processes and
apparatus substantially such as hereinbefore described.
2. The testing of a miner's safety lamp by admitting a suitable combustible mixture
into the interior of the lamp and igniting it on the outside of the lamp gauze substan-
tially as hereinbefore described.
3. The preparing of a combustible gaseous mixture for testing miners' safety lamps
in the manner and by means of the apparatus substantially as hereinbefore described.
Dated this Ninth day of March 1887.
EDMUND HUNT,
Applicants' Agent.