Improvements in Heat Indicators and Fire Alarms.
Year: 1890

page_text: Date of Application, 26th July, 1890
Complete Specification Left, 17th Apr., 1891-Accepted, 6th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in Heat Indicators and Fire Alarms.
I SIDNEY STUART WALKER of Woodside Knowle in the County of Warwick
Mechanical Engineer do hereby declare the nature of this invention to be as
follows:-
My invention consists of the construction and combination hereinafter described
of the parts of heat indicators and fire alarms.
In constructing a heat indicator according to my invention I take a strip of brass
and a strip of iron and bend each strip into a C shape or arc of a circle. I then
place the brass band within the iron band and fasten their ends together so as to
form a compound C shaped band composed of dissimilar metals which are expanded
unequally by equal increments of heat; that is the outer iron band is expanded less
than the inner brass band when they are exposed to equal increments of heat. Or
the compound C shaped band may be composed of other dissimilar metals or alloys
or materials which are expanded unequally by equal increments of heat.
I arrange this compound C shaped band around a metal case preferably circular
the external compound C shaped band being situated a short distance from the said
metal case.
The metal case contains a toothed quadrant gearing with a pinion on
the axis of a finger traversing a graduated dial. One end of the C shaped band is
fixed to the metal case and the other or free end is linked to the arm of the toothed
quadrant.
On the C shaped band of the apparatus being exposed to an increase of
temperature it expands and gives motion to the toothed quadrant linked to its free
end and through the pinion to the index finger which finger traversing the dial
indicates the temperature.
For the purpose of fitting the heat indicator described to act as a fire alarm or
to indicate when the temperature of the room or place in which the apparatus is
situated' has reached an arranged temperature I combine with the said indicator the
following appliances.
In the path of the finger traversing the dial I arrange a metallic stud which is
capable of adjustment on the dial for bringing the apparatus into action when the
room or place has attained the arranged temperature. This stud is connected by a
wire with the terminal of a voltaic battery or other source of electricity the said
stud wire and terminal being properly insulated. To the metal case of the
apparatus the other terminal of the voltaic battery or other source of electricity is
connected. On the finger in its traversing motion bearing against and making
electrical contact with the said adjusted stud the electrical circuit is closed and an
electrical bell or other signal or relay in the circuit is put into operation and an
alarm is thereby given.
The closing of the electrical circuit may be effected by the end of the C shaped
tube or the toothed quadrant or other moving part of the apparatus coming into
electrical contact with one of the terminals of the voltaic battery or other source of
electricity.
I also combine the parts I have described for closing the electrical circuit with
pyrometers generally in which the temperature is indicated by a finger traversing
a dial.
Dated this 26th der of Lul 1890
W. T. WHITEMAN,
Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in. Heat Indicators and Fire Alarms.
I SIDNEY STUART WALKER of Woodside, Knowle in the County of Warwick
Mechanical Engineer 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 :-
-
My invention consists of the construction and combination hereinafter described
of the parts of heat indicators and fire alarms.
In constructing a heat indicator according to my invention I take a strip of
brass and a strip of iron and bend each strip into a C shape or arc of a circle. I
then place the brass band within the iron band and fasten their ends together so as
to form a compound C shaped band composed of dissimilar metals or alloys which
are expanded unequally by equal increments of heat; that is, the outer iron band is
expanded less than the inner brass band when they are exposed to equal increments
of heat. Or the compound C shaped band may be composed of other dissimilar
metals or alloys or materials which are expanded unequally by equal increments
of heat.
I arrange this compound C shaped band around a metal case preferably circular,
the external compound C shaped band being situated a short distance from the
said metal case.
The metal case contains a toothed quadrant gearing with a pinion
on the axis of a finger traversing a graduated dial. One end of the C shaped
band is fixed to the metal case and the other or free end is linked to the arm of the
toothed quadrant.
On the C shaped band of the apparatus being exposed to an increase of
temperature it expands and gives motion to the toothed quadrant linked to its free
end and through the pinion to the index finger which finger traversing the dial
indicates the temperature.
For the purpose of fitting the heat indicator described to act as a fire alarm or
to indicate when the temperature of the room or place in which the apparatus is
situated has reached an arranged temperature 1 combine with the said indicator the
following appliances.
In the path of the finger traversing the dial I arrange a metallic stud which is
capable of adjustment on the dial for bringing the apparatus into action when the
room or place has attained the arranged temperature. This stud is connected by a
wire with the terminal of a voltaic battery or other source of electricity the said
stud, wire and terminal being properly insulated. To the metal case of the
apparatus the other terminal of the voltaic battery or other source of electricity is
connected. On the finger in its traversing motion bearing against and making
electrical contact with the said adjusted stud the electric circuit is closed and an
electric bell or other signal or relay in the circuit is put into operation and an alarm
is thereby given.
The closing of the electric circuit may be effected by the end of the C shaped
band or the toothed quadrant or other moving part of the apparatus coming into
electrical contact with one of the terminals of the voltaic battery or other source of
electricity. I also combine the parts I have described for closing the electric
circuit with pyrometers generally in which the temperature is indicated by a finger
traversing a dial.
I will now proceed to describe with reference to the accompanying drawing the
manner in which my invention is to be performed.
Figure I represents. in front elevation and Figure 2 in cross section a combined
heat indicator and fire alarm the parts of which are constructed and arranged
according to my invention;
Figure 3 represents in plan of underside partly in horizontal section the gearing
which I prefer to use for adjusting the position on the dial of the electric metallic
stud of the fire alarm.

page_text: Figure 4 represents a modification for adjusting the position of the electric
metallic stud.
The same letters of reference indicate the same parts in the several figures of
the drawing.
a is the metallic case around which the compound C shaped band b, bis arranged
the said band b, bas hereinbefore stated consisting of an inner brass band and an
outer iron band or composed of other dissimilar metals which are expanded
unequally by equal increments of heat. The two bands lie in close contact and
their ends are fastened together; or the said bands are brazed or soldered together
through their whole length, one end of the compound band being fitted in the
block e fixed to the side of the case and the other or free end of the band being
fitted in the block d to which the arme of the toothed quadrant f is jointed;
is the
graduated dial made of china or earthenware or other electrical insulating material
and is the index finger traversing the said dial for indicating the temperature.
The axis of the finger i carries the pinion which gears with the quadrant f
When the heat indicator is exposed to an increase of temperature the compound
band b, expands and its free end operating upon the arme the latter turns the
toothed quadrant on its centre, which quadrant gearing with the pinion gives
motion to the index finger i and the latter traversing the dial indicates thereon
the temperature, to which the instrument is exposed. As the heat of the room or
place in which the instrument is stationed diminishes the compound band b contracts
to its normal figure assisted by the spring at its fixed end and the index finger
returns to its normal position on the dial.
The heat indicator which I have described may be used alone for indicating
temperatures or may be fitted with the appliances which I will next describe
for enabling the indicator to act as a fire alarm or for indicating when the
temperature of the room or place in which the indicator is stationed has reached an
arranged temperature.
P
m is a metallic adjustable stud in the path of the finger i traversing the dial. The
said metallic stud is carried by the circular metallic disc a capable of rotation the said
disc working closely or in electric contact with the outer ring fixed to the non-
metallic or insulated dial h. The stud m is connected with one of the terminals
of a voltaic battery or other source of electricity by means of the wire g² secured
to the said terminal y and to the metallic ring p with which the disc carrying the
stud is in electrical communication. The terminal is fixed to but insulated from
the case a of the heat indicator. The other terminal of the voltaic battery
is connected to the case a of the heat indicator. As the index finger makes
its traversing motion, operated as hereinbefore described, it bears against and
makes electric contact with the stud m and the electric circuit is closed and an
electric bell or other signal or relay in the circuit is put into operation and an
alarm thereby given.
For the purpose of adjusting the position of the electric stud m on the dial
so as to cause the alarm to be given at any desired arranged temperature of
the room or place, the face of the disc carrying the stud is made into teeth s
with which a pinion t gears the axis of the said pinion projecting to the outside
of the case and being insulated from the case. By fitting a knob or key u on
the end of the pinion axis the disc n can be rotated and the stud m brought
opposite that part of the graduated dial which indicates the temperature at
which it is desired the alarin shall be brought into operation as will be understood
by an examination of the drawing,
When the index finger of the heat indicator traverses a graduated arc instead
of a circle or nearly a circle the electric metallic stud may travel in a rectilinear
path instead of a circular path.
This modification is represented in elevation in Figure 4 where the metallic
stud is marked m the said stud being carried by the screw box m² working on the
screw w turning in bearings in and being insulated from the case the said screw
having only a rotary motion.

page_text: The stem of the screw extends outside the case and by means of a knob or
key passed onto its end the screw may be rotated and the metallic stud moved
in one or other direction so as to bring it opposite that part of the graduated
arc which, indicates the temperature at which it is desired that the alarm should
be set in action. The screw box m² slides in the slot the sides of which
are electrically insulated from the case of the heat indicator. The sliding screw
box m² is connected by a wire q² soldered to its base to the insulated terminal
of the voltaic battery the other terminal of the battery being fixed electrically
to the case.
The index finger i on coming into contact with the adjusted metallic stud m
Figure 4 closes the electric circuit and puts the alarm into operation in the
manner herein before described.
By these arrangements the temperature at which the electric circuit is closed
and the alarm operated can be varied at pleasure by changing the position of
the stud m.
In place of closing the electric circuit by the action of the index finger upon a
metallic stud in communication with one of the terminals of the voltaic battery the
closing of the electric circuit may be effected by the free end of the C shaped
compound band coming into contact as it expands with a wire or rod capable of
adjustment in communication with the insulated terminal 7; or in like manner other
moving part of the instrument may be made to close the electric circuit; for example
the toothed quadrant for the arm e may by their motion be brought into contact
with an adjustable rod or wire in communication with the terminal 7 and thus close
the electric circuit.
I also combine the parts I have described for closing the electric circuit with
pyrometers generally in which the temperature is indicated by a finger traversing
a dial.
When the pyrometer is used in connection with hayricks silo-tanks ship-
holds and the like the case of the instrument is provided with a pointed rod which
is thrust into the haystack or silo or among the goods in the hold of a ship.
Although I have described and represented that part of my invention which has
for its object the closing of the electric circuit and the putting into operation of an
alarm when the instrument indicates an arranged temperature in combination with
a heat indicator having a compound band for operating the index finger yet this
part of my invention may be used in combination with heat indicators generally in
which compound metallic bars strips or tubes are used for operating the pointer or
index finger.
Having now particularly described and ascertained the nature of my inven-
tion and the manner in which the same is to be performed I declare that 1 claim
as my invention of "Improvements in heat indicators and fire alarms "
First The arrangement of parts hereinbefore described and illustrated in the
accompanying drawing for giving motion to the index finger or pointer of the heat
indicator; that is to say arranging around and at a short distance from the outside
of the case of the heat indicator a compound C shaped band of the kind described
one end of the said band being fixed to the case and the other or free end being
linked to the arm of a toothed quadrant or other equivalent mechanism for trans-
mitting the motion of the said band to the index finger or pointer substantially as
described and illustrated.
Secondly-The addition to or combination with heat indicators in which the
temperature is indicated by the action of heat on a compound metallic bar strip or
tube operating on an index finger or pointer traversing a graduated dial or are of
the parts of the mechanism herein before described and illustrated in the accom-
panying drawing for converting the heat indicator into a fire alarm that is to say
arranging in the path of the index finger or pointer traversing the graduated dial
or arc an adjustable metallic stud connected with one of the terminals of a voltaic
battery or other source of electricity the finger or pointer in its traversing motion
bearing against and making electric contact with the said adjustable metallic stud su

page_text: as to close the electric circuit and put into operation an electric or other signal
or relay substantially as described and illustrated.
Thirdly-The modifications described in which the closing of the electric circuit
is effected and the signal put into operation by means of the C shaped band referred
to in the first claim or the quadrant or other moving part of the heat indicator
coming into contact through an adjustable metallic rod or wire or metallic electric
conductor with one of the terminals of the voltaic battery or other source of
electricity as before described.
Dated the Sixteenth day of April 1891.