Improvements in Electric Fire Alarms.
Year: 1889

page_text: Date of Application, 17th Aug., 1889
Complete Specification Left. 10th May, 1890-Accepted, 5th July, 1890
PROVISIONAL SPECIFICATION.
Improvements in Electric Fire Alarms.
I, HENRI DE POULPIQUET of 87 rue de Richelieu, Paris, in the Republic of
France, Civil Engineer, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is a system for an electric conductor which permits of
a fire being automatically announced as soon as it breaks out on the route of the said
conductor the wires of which are connected to an electric bell.
This conductor is furnished ;-
1st, with a metallic wire in the form of a spiral, which constitutes one of the wires
of an electric circuit and
2nd, with an ordinary wire or even a second spiral.
These wires are encased in a tube or polished case of some insulating or non-
conducting matter or material which can be destroyed by fire or is ignitable or simply
becomes soft through heat.
Under the ordinary conditions of temperature the sheaths or cases oppose one
another by contact with the two wires; but if the fire destroy these tubes at any
point of the conductor the spiral wire immediately establishes a close contact between
the two wires by interrupting in some way the melted insulating or non-conducting
matter.
One of the conductors can for example be provided with a non-conductor.
1 1000
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electric Fire Alarms.
I, HENRI DE POULPIQUET, of 87 rue de Richelieu, Paris, in the Republic of.
France, Civil Engineer, 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:—
The object of this invention is a system for an electric conductor which permits of
a fire being automatically announced as soon as it breaks out on the route of the said
conductor or as soon as the temperature at any point of the line rises above its normal
degree; the wires of each conductor are connected with an electric bell or with any
suitable signalling station.
This conductor is furnished first with a metallic wire wound spirally and forming
part of an electric circuit and second with an ordinary wire or if desired with another
spiral wire which latter however is coated with some, ordinary insulating material.
The first wire is wound upon this insulating sheath of the second wire in a coil of
greater or less length as required.
By thus connecting the two wires one of which forms as it were a spring over the
other enveloped in insulating material an excellent fire alarm is obtained for as soon
as the heat softens the coating of insulating material the spiral wire will by virtue of
its spring action make. cuts into the said coating and on cutting it through join the
second wire whereby an instantaneous contact is made between the two wires which

page_text: before that moment had been insulated from each other; and as soon as an electric
circuit is thus established the alarm bell is sounded.
In the accompanying drawing is represented an example of a fire alarm conductor
device constructed in accordance with my invention.
One of the wires b viz. that coated with the insulating material 61 is attached to one
of the pole pieces B of an electric alarm or of any convenient signalling apparatus.
The other wire a wound spirally upon the first is connected with the other pole
piece A of the alarm or signalling apparatus. The conductor is extended over the
whole of the building that it is desired to protect from fire and as soon as the
temperature rises above the normal degree in any part of the line or path of the con-
ductor it will soften the insulating material and the outer spiral wire will by virtue of
its elasticity pass through such insulating material and come in contact with the inner
wire thus making a circuit.
The conductor formed by the combination of the two wires may be coated with
an envelope or sheath of some light fabric such as tarlatan, silk, gauze or the
like harmonizing in color with the furniture of the apartments in which it is fitted
up
or it may be covered with some insulating material such as gutta-percha, " Chatterton
or the like.
Should the conductor be situated in a place containing either fermentable or easily
ignitable matters such as hay, wool, waste of textile materials etc. it may be enclosed
in any suitable tube such as brass, iron, lead etc., the great conductibility of which
will accelerate the softening of the insulating envelope if the temperature should in
consequence of an abnormal fermentation rise to an excessive degree. When the
circuit is closed in the manner indicated above the alarm bell will notify that the
fermentable or inflammable materials in question should be seen to, to avert danger
from fire.
The coating or sheath with which my improved alarm conductor is covered also enables
the degree of sensitiveness of the conductor to be controlled according to the various
influences of heat that are likely to make themselves felt in its proximity. A silk
sheath for instance is the best insulator from heat and burns slowest.
The thinner the wire wound spirally upon the inner conductor the more flexible
and sharp it will obviously be, hence it will, with proportionately greater facility,
effect the cut through the insulating material covering the inner wire, so that the
formation of the circuit may be made almost instantaneous.
It will be understood that by varying the diameter of the spiral wire and the
nature of the onter envelope or sheath covering both wires that compose this
improved alarm conductor, the temperature at which the same will act may be pre-
determined at will.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is ;-
1. An automatic electric alarm or signalling device adapted to announce a fire or
an abnormal increase of temperature consisting of a conductor composed of two metal
wires one of which is unprovided with any insulating coating and is in the shape of a
spiral while the other is coated with a suitable insulating material and has the first or
spiral wire wound upon it in such a manner that the softening of the insulating
material will allow the two wires to make contact thus closing the electric circuit
whereof both these wires are the conductors substantially as described and illustrated
in the accompanying drawing.
2. An automatic electric alarm adapted to announce a fire or an abnormal increase
of temperature consisting of a conductor composed of two metal wires in the shape
of spirals one only of which is coated with insulating material substantially as
described.

page_text: 3. In an automatic electric alarm adapted to announce a fire or an abnormal increase
of temperature consisting of two metal wires arranged substantially as described and
shown in the accompanying drawing the employment as a cover or sheath enclosing
both wires of a material being a more or less good conductor of heat for the purpose
of enabling the sensitiveness of the apparatus to be controlled substantially as
described.
Dated this 10th dose of Mar 1900
W. P. THOMPSON & BOULT,
Agents for the Applicant.