A New or Improved Fire-alarm.
Year: 1890

page_text: Date of Application, 26th Mar., 1890
Complete Specification Left, 24th Dec., 1890-Accepted, 14th Feb., 1891
PROVISIONAL SPECIFICATION.
A New or Improved Fire-alarm.
I, EUGENE RAIKEM, Engineer, of 37, Rue Philippe-le-Bon, Bruxelles, Belgium,
do hereby declare the nature of my invention to be as follows:-
The present invention has for its object to automatically indicate in a given
locality the beginning of a conflagration, even if the fire has smouldered a long time
before the appearance of flames, and to effect this by means of an apparatus which
costs little and occupies a small space.
The invention consists in the combination with an air vessel arranged in such a
manner, that the enclosed air is in equilibrium with the external air:
1. Of a glass-pipe composed of two parallel branches (preferably a horse-shoe-
pipe) containing mercury and into which are introduced two platinum wires, the
first wire dipping into the mercury in one of the branches, while the second reaches
down to a short distance above the level of the mercury.
2. A rod connected at one end with an electric bell, and at the other end with
the second platinum wire mentioned above which communicates with one of the
battery poles, while the platinum wire dipping into the mercury communicates with
the other polc.
The air vessel or receiver has preferably the shape of an upright cylinder
provided with a porous bottom.
If there is no variation of temperature, or if it is so slow, that, owing to the
communication through the porous bottom, the air contained in the vessel has the
same temperature as the external atmosphere, the level of mercury is the same in
the two branches of the mercury tube.
But, if a fire breaks out, so as to cause a rapid increase of temperature, the air in
the vessel expands, acts on the mercury in the first branch and drives
up in the
second branch, until the mercury meets the platinum wire and thereby closes the
electric circuit, which controls the alarm bell.
If, however, a fire smoulders for some time before the outbreak of flames, there
is no sudden rise of temperature, or sufficient heat to set the apparatus in action at
the suitable moment. To avoid this drawback, the metallic walls or sides (preferably
of brass) may be internally coated with a material having a low melting point. As
soon as the normal temperature is exceeded, this material runs upon the porous
bottom, and covers the same, thereby preventing any further communication
between the air in the interior of the vessel, and the atmosphere. Consequently,
the air contained in the receiver expands continuously, and the alarm bell is rapidly
set in action.
Dated this 25th day of March 1800.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
A New or Improved Fire-alarm.
1, EUGENE RAIKEM, Engineer, of 37, Rue Philippe-le-Bon, Bruxelles, do
hereby declare the nature of my invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement —
The present invention has for its object, to automatically indicate in a given
locality the beginning of a conflagration, even if the fire has smouldered a long
time before the appearance of flames, and to effect this by means of an apparatus
which costs little and occupies a small space.
The invention chiefly consists in the combination with an air vessel arranged
in such a manner, that the enclosed air is in equilibrium with the external air:
1. Of a glass pipe composed of two parallel branches (preferably a horse-shoc
pipe) containing mercury and into which are introduced two platinum wires, the
first wire dipping into the mercury in one of the branches, while the second reaches
down to a short distance above the level of the mercury.
2. A rod connected at one end with an electric bell, and at the other end
with the second platinum wire mentioned above, the latter thus communicating
with one of the battery poles, while the platinum wire dipping into the mercury
communicates with the other pole.
In the accompanying drawings, Fig. 1 is a vertical section and Fig. 2 a front
elevation embodying my invention.
In these drawings
-
T represents an upright cylindrical receptacle made of brass and resting on a
porous base,
R is the Ushaped glass tube containing mercury,
X is a platinum wire reaching down to the bottom of the receptacle T,
B is a terminal or binding post through which an electric current may pass to
the wire X,
V is a metallic rod attached to the other terminal of the apparatus,
C is a platinum wire extending from the rod V to a short distance above the
level of the mercury.
If there is no variation of temperature, or if it is so slow that, owing to the
communication through the porous base, the air contained in the vessel has the
same temperature as the external atmosphere, the level of mercury is the same
in the two branches of the mercury tube.
But, if a fire broke out, so as to cause a rapid increase of temperature, the air in
the vessel expands, acts on the mercury in the first branch and drives it up in the
second branch, until the mercury meets the platinum wire and thereby closes the
electric circuit, which controls an alarm bell.
If, however, a fire smoulders for some time before the outbreak of flames,
there is no sudden rise of temperature, or sufficient heat to set the apparatus
in action at the suitable moment. To avoid this drawback, the metallic walls
or sides of the receptacle T may be provided with an internal lining S of a material
having a low melting point. As soon as the normal temperature is exceeded,
this material runs upon the porous bottom, and covers the same, thereby preventing
any further communication between the air in the interior of the vessel, and the
atmosphere. Consequently, the air contained in the receiver expands continuously
and the alarm bell is rapidly set in action.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is-
1. An automatic fire-alarm, comprising in its construction a U shaped tube R
partly filled with mercury, one branch of which tube terminates in an air chamber T

page_text: resting on a porous base, and an electric alarm bell circuit, adapted to be closed by
the mercury contained in the said tube, in case of any sudden expansion of the
air in the air chamber T, substantially as described.
2. In an automatic fire-alarm as aforesaid, the use of an easily fusible substance.
adapted to melt in case of a smouldering fire, and to plug the pores in the base cf
the air chamber, in order that the air thus prevented from escaping through the
pores, may act with greater force on the mercury and thereby close the electric
circuit, substantially as described.
Dated this 24th day of December 1890.
EUGENE RAIKEM.
By Fairfax & Wetter,
433, Strand, London, Agents.