Presence of Explosive Gases in Mines or other Places.
Year: 1888

page_text: Date of Application, 27th Aug., 1888
Specification Accepted, 12th Oct., 1888
Presence of Explosive Gases in Mines or other Places.
I FERDINAND BOSSHARDT of the firm of F. Bosshardt & Co. of 4 Corporation
Street Manchester in the County of Lancaster Mechanical Engineer & Patent
Agent, do hereby declare the nature of this invention which has been communicated
to me from abroad by Jean Molas of Paris in the republic of France, Civil Engineer,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The object of this invention is to provide a simple and effective apparatus which
automatically detects and announces the presence of fire damp gases in mines or
other gases in other places.
And in order that this invention may be better understood I have caused to be
appended hereunto one sheet of drawings marked with letters of reference indicating
like parts in the various figures.
Fig. 1 is a vertical section at M-N Fig. 2 a side elevation and Fig. 3 a plan
of the apparatus. Fig. 4 is a detached view in perspective.
In carrying out this invention and referring to the figures generally the
apparatus consists of a chamber A, made round of very thin metal and of a capacity
of 2 litres & a half, tinned or galvanized according to the requirements of the
place in which the apparatus is to he employed. The lower part of the chamber A
is formed reduced in diameter and slightly conical, the shoulder between the two
being perforated as well as the surrounding portion of the envelope L into which
the chamber A is fitted, for the purpose of giving the gases access to the interior
of the sama.

page_text: The said lower part of the chamber A is filled with substances K such as pumice
stone or tripoli in small pieces, which serve to dry the entering gases, as well as
to prevent a current of air in the chamber A.
The upper part of the chamber A is also formed reduced in diameter and at
its bottom provided with a small grid which serves to protect a very thin and
sensitive skin diaphragm, fixed a little above the same. On this diaphragm which
is arranged to float up & down are arranged two small strips of silver weighing
with the diaphragm 3 centigrammes. Inside the upper portion 13 of the chamber A
near its top is fitted a wooden disc C formed concentrically with a hole near to
which are secured four electric terminals D D' which maintain the aforesaid silver
strips on the said diaphragm and form a contact between each other the moment it
rises, whereby simultaneously two electric currents are established one serving to ring
a peal of bells arranged severally and the other to maintain an incandescent lamp &
fixed below the apparatus.
The four electric terminals D D₁ are brought into connection with a suitably
arranged electric pile by means of the conducting threads F & E and the top part B
of the chamber A fitted hermetically into a hole formed in the wooden socket H;
which serves to suitably secure the apparatus to the ceiling or other place and when
employing the same in mines the ornamental envelope L into which the chamber A
is fitted hermetically by means of an india rubber packing I can be dispensed
with.
The application and working of the apparatus is as follows:-
The ceiling or other part of the locality to which the apparatus is to be applied,
is formed with a recess into which is secured tightly the socket H so as to cause a
small volume of atmospheric air to remain between the said recess and skin diaphragm,
the density and weight of which is different from that of the undue accumulated gases
in the room. Under ordinary circumstances the aforementioned silver strips on the
said diaphragm are positioned a little below the said electric terminals D. D', and as
soon as an undue accumulation of gases in the room takes place, they cause the
diaphragm to ascend and bring thereby the silver strips into contact with the electric
terminals D, D', which causes the peal of bells to ring and the incandescent lamp G
to illuminate the locality where the gases are unduly accumulating, without risk of
exploding the same.
As soon as the undue accumulation of gases has ceased and fresh air has entered
the locality, the skin diaphragm descends and breaks the electric contact between the
incandescent lamp G and peal of bells so that the latter cease simultaneously.
It will be understood that the sensitiveness of the apparatus may be increased or
reduced according to circumstances by simply increasing or decreasing the weight of
the silver strips and skin diaphragm respectively, so as to compensate for more or
less inflammable or explosive gases.
The apparatus described being sensitive to a mixture of 6% gas to 94% atmo-
spheric air.
When the apparatus is employed in mines where atmospheric air is pure, the
envelope L is dispensed with, and a volume of air conducted between the afore-
mentioned recess and the top of the skin diaphragm by means of a pipe O, see Fig. 4,
reaching to the bottom into an earthenware receptacle, which has also for its object
to vary the pressure, density or weight of the atmospheric air above the skin diaphragm
from that of the fire damp gases below the same.
When an accumulation of undue gases or fire damp exists, the miner is at once
warned by the light produced by the incandescent lamp G, at the same time the
engineer is warned by the bells arranged in his vicinity to which other bells in other
parts of the mine are connected by electric contact. The bells in the engineers place
will be so arranged as to always indicate the part of the mine, i.e,. the apparatus
which has been actuated by the fire damp gases.

page_text: Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
1) The general arrangement and combination of parts constituting my invention
and various applications thereof, substantially as and for the purpose specified.
2) The combination of a diaphragm furnished with silver strips insiden chamber A,
with a suitable number of terminals D, D', in such a manner that on undue accumu-
lated gases entering the chamber A, the same will lift the diaphragm & form a
contact between the silver strips and the terminals D, D', and cause simultaneously
and automatically the ringing of alarm bells & lighting of the incandescont lamp Ğ
through suitable electric connections, substantially as and for the purpose specified.
Dated this Twenty fourth day of August 1888.