Improvements in Signalling Apparatus for Indicating the Presence of Explosive Gases in the Atmosphere.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Signalling Apparatus for Indicating the Presence
of Explosive Gases in the Atmosphere.
We EDUARD STERN and MORITZ KAUFMANN Manufacturers of Cologne in the
Kingdom of Prussia and German Empire do hereby declare the nature of this
invention and in what manner the same to be performed to be particularly described
and ascertained in and by the following statement :-
This invention has for its object a very simple and reliable apparatus which will
indicate by an electric bell signal when a certain excess of explosive gases particularly
hydrocarbons are present in closed localities especially in coal-carrying ships.
This invention is illustrated in the accompanying drawings in which
Figure 1 is a sectional elevation of the apparatus.
Figure 2 horizontal section on line a, a Figure 1.
The apparatus consists in a brass cylinder composed of two parts b and c into
which is fitted a metal bottom f by a clamping-ring e and screws &². The said metal
bottom is not entirely closed but has four segmental apertures f².
The lower projecting part of the brass cylinder is adapted for the reception of a
porous clay receptacle a.
Between the outer edge of the bottom and the ring e is clamped a metal
diaphragm e consisting of very thin corrugated sheet metal somewhat like the bellows
of a concertina.
The diaphragm or "membrane" d is closed at the top and open at the bottom
and is, by reason of its shape and the thinness of the metal of which it consists,
extremely sensitive and susceptable to the slightest variations in atmospheric
pressure.
The upper end of the brass cylinder is closed by a wooden disc g secured by four
screws and carrying on its upper surface the terminal screws kk¹ and at its centre a
contact screw ; the screws 1, l' at the edge serving for the attachment of the loop or
ring n for carrying the apparatus.
The terminal is electrically connected with the cylinder c and through it with the
diaphragm d the terminal k being electrically connected with the contact screw i,
the terminals kk¹ are moreover connected with an electric signalling bell.
The operation of the apparatus is as follows:-
When light gases, for instance hydrocarbon gases, accumulate say in the hold of a
coal steamer, they will penetrate into the apparatus set up in such locality passing
through the porous clay cell a and reach the diaphragm d; as the pressure increases
the diaphragm is expanded upwards until the top of the diaphragm touches the
contact screw i closing the line and sounding the bell.
To permit observation of the contact screw for the purposes of adjustment it is
advisable to provide two holes facing one another in the walls of the cylinder which
holes can be hermetically closed by screws.
Upon the bottom fitted into the brass cylinder, a central boss m is provided into
which a screw pin h is inserted so as to allow the height of the diaphragm to be
adjusted.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
A
A signalling apparatus for indicating the presence in the atmosphere of explosive
gases consisting of a diaphragm d made of thin sheet metal and in bellows-shape,
closed at top but open at the bottom combined with a porous clay cell or vessel a
closing the bottom the diaphragm being connected with one pole of an electric signal
17

page_text: apparatus, contact devices i, k³ being connected with the other pole so that expansion
of the diaphragm closes the line, the metal pin h in the perforated bottom f serving to
adjust the diaphragm, all substantially as set forth and shewn.
Dated this 29th day of August 1889.
POPPLEWELL & CO.,
Agents for the Applicants.