Improvements in Fire Alarms.
Year: 1893

page_text: Date of Application, 26th May, 1893
Complete Specification Left, 26th Feb., 1894-Accepted, 31st Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Fire Alarms.
I, LOUIS JOSEPH TIRARD, Chemist of 48B Rue St. Auge, Caen, in the
Republic of France, do hereby declare the nature of this invention to be as
follows:-
This invention for improvements in fire alarms has for its object to provide an
automatic fire alarm adapted to give an alarm at any desired place on the
occurrence of a fire at a certain other place and which shall not be liable to get
out of order and shall be thoroughly reliable; and consists essentially in
supporting a weight by means of thermometric tubes arranged to break at about
45 degrees centigrade; in connecting the said weight to a lever which on the
falling of the weight on the breaking of the thermometric tubes, breaks a glass
tube or otherwise opens a closed tube to atmospheric pressure, the said tube leading
to a desired spot at which it is desired to give the alarm; and in arranging the
said tube at the said spot in connection with an apparatus containing a liquid in
such manner that when the tube is open to the atinosphere a flow of liquid takes
place from the said apparatus to operate an alarm. In one arrangement the pipe
leads to the top of a vessel containing a liquid and having an outlet at the bottom
leading to a counterweighted receptacle so that when the tube is open the liquid
flows into the counterweighted receptacle which then falls over and is arranged to
start a clockwork-bell or other signal.
Dated this o6th day of May 1802
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Fire Alarms.
1, LOUIS JOSEPH TIRARD, Chemist of 48" Rue St. Auge, Cuen, in the
Republic of France, 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 :-
This invention for improvements in fire alarms has for its object to provide an
automatic fire alarm adapted to give an alarm at any desired place on the
occurrence of a fire at a certain other place and which shall not be liable to get
out of order and shall be thoroughly reliable; and consists essentially in
supporting a weight by means of thermometric tubes arranged to break at about
45 degrees centigrade, in connecting the said weight to a lever which on the
falling of the weight on the breaking of the thermometric tubes breaks a glass
tube or otherwise opens a closed tube to atmospheric pressure the said tube leading
to a desired spot at which it is desired to give the alarm, and in arranging the
said tube at the said spot in connection with an apparatus containing a liquid in
such manner that when the tube is open to the atmosphere a flow of liquid takes
place from the said apparatus to operate an alarm. In one arrangement the pipe
leads to the top of a vessel containing a liquid and having an outlet at the bottom
leading to a counterweighted receptacle so that when the tube is open the liquid
flows into the counterweighted receptacle which then falls over and is arranged to
start a clockwork-bell or other signal.

page_text: --
In the accompanying sheet of illustrative drawings:
Fig. 1 is an elevation of the controlling mechanism of a fire alarm constructed
according to this invention and Fig. 2 is a plan.of the same.
Fig. 3 is a front sectional elevation of the temperature compensating and alarm
starting apparatus constructed according to this invention and Fig. 4 is a side
sectional elevation of the temperature compensating mechanism.
The controlling apparatus mounted on a wooden plate with holes for the two
fixing screws a and b consists of a counterweighted lever A free to rotate on its
axis B and formed with brackets C and D bored with two holes lined with cork in
which slide easily the rods of the two thermometric tubes E F.
These two tubes
rest at the extremity of their bulbs on a movable piece G of horn or box wood or
other suitable material free to turn on its axis secured in the bracket H by a nut I.
The counterweighted lever A is provided at the back with a sharp projection J.
A copper or lead tube K communicates at L with the stuffing box M having fixed
in its centre a glass tube N provided with a ring stopper and closed at its extremity
which projects several centimetres.
:
The apparatus being fixed at any point and with the thermometric tubes closed
at 40° C. If a fire commences the temperature will rise progressively near the
point being of course greater at the ceiling than at the floor level. At 40° the
expansion of the liquid will be complete in the tubes and the liquid will begin to
effect the compression of the air in the air chamber but no movement will
take place. The tabes are constructed with the rods very thick and the
bulbs very thin. Being then at 40° and the temperature continuing to rise, the
compression of the liquid continues; at exactly 45° the expansion of the glass
being at its maximum, the tubes will break and they will invariably break at the
bulb which is the weakest part. The counterweight A having then no support
will fall sharply to X and the projection J by its displacement will break the glass
tube N and admit air to the tube K and to the top of a receptacle containing a
column of liquid such as glycerine and open at the bottom so that the liquid flows
out into a receptacle T held in equilibrium by a counterweight so that as soon as
the weight of the liquid falling into the receptacle is sufficient the receptacle will
swing over and start either a clockwork bell or a whistle, horn, syren, or other
means of alarm.
It is easily understood that this alarm may be made to sound at any desired place
and to indicate also on a dial or indicator in an hotel the apartment in danger since
the communication is made by a tube of a few millimetres in diameter and almost
invisible, that may be led where required.
It will also be easily understood that the starting at the temperature indicated
may be varied since by taking account of the 5° for compression the thermometric
tubes may be closed at any desired degree, say at 20° 40° or 50°. To avoid any
fear of oxidation all our bearing parts are of glass.
A single thermometric tube would be sufficient for the action of the apparatus
but as a precautionary measure two are used. In case one of these tubes break the
support G turns at once and the counterweighted lever is released. In order to
avoid a false alarm due to rise of atmospheric temperature the alarm starting
mechanism is arranged also to act as a compensator. Supposing for example that
in a factory it were necessary to have 600 meters of tube containing about 7.5 litres
of air, and the increase of temperature vary by 50° that is from 10° up to 40°
this variation would inevitably give rise to a false alarm by effecting the outflow
of all the liquid contained in the bulb c¹ (Fig. 3) into the counterweighted
receptacle T.
―
This apparatus is composed of a receptacle P' containing as much glycerine as the
air contained in the conducting tube K can increase in volume; the height of this
receptacle is equal to the distance comprised between the two bulbs c and c¹ of the
tube O.
Let us suppose that the expansion of the
liquid contained in the receptacle P will
air is at its maximum temperature the
flow into the receptacle S through

page_text: the tube Q down to R consequently only the glycerine contained between the two
bulbs c c will flow from the tube O.
C
As the receptacle T is mounted on a swinging lever provided at its other end
with a counterweight the quantity of glycerine which has flowed cannot effect the
starting of the alarm which only takes place when the tube O and bulb c¹ by
emptying themselves completely have overbalanced the counterweight. It is the
swinging over of this receptacle which starts the clockwork of the bell alarm.
V is the communicating tube between the top of the receptacle and the pipe K.
As shown in Fig. 3 the tube O dips at its lower end into the liquid the joint
of which with the copper tube i which rises to its upper end is perfect.
The closing tube N may be a metallic tube of a somewhat brittle alloy and
provided with a groove to facilitate its rupture, this tube being soldered to the
conducting pipe.
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. A fire alarm in which the alarm is controlled by a thermometric tube
constructed to break at a certain temperature and thus determine the admittance of
air to a closed tube and in which the alarm mechanism is started by the flow of
liquid from a vessel on air being admitted to the vessel through the said closed tube
substantially as described.
2. A fire alarm controlled by means of a counterweighted lever held in its
raised position by thermometric tubes constructed to break at a certain temperature
substantially as described.
3. A fire alarm consisting of a counterweighted lever arranged to fall at a certain
temperature, a closed tube opened on the fall of the lever, and a receptacle
containing liquid free to flow from the said receptacle on the opening of the closed
tube substantially as described.
4. A fire alarm consisting of a counterweighted controlling lever held in its
raised position by means of thermometric tubes constructed to break at a certain
temperature, of a closed tube leading from the controlling mechanism to a
receptacle containing a liquid and arranged to be broken or opened on the fall of
the counterweighted lever, and of a receptacle containing a liquid free to flow from
the said receptacle on the admittance of air substantially as described.
5. A fire alarm starter consisting of a receptacle containing a liquid free to flow
from the said receptacle on the admittance of air and of a counterweighted
container arranged to receive liquid flowing from the said receptacle substantially
as described.
6. In a fire alarm in which the alarm is started on the opening of a closed tube,
a compensator for changes of atmospheric temperature constructed and arranged in
conjunction with the closed tube substantially as described.
7. The improvements in fire alarms substantially as described with reference to
the drawings.
Dated this 26th day of February 1894.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.