Improvements in Fire-alarms.
Year: 1891

page_text: Date of Application, 9th Apr., 1891
Complete Specification Left, 9th Jan., 1892-Accepted, 5th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in Fire-alarms.
I. BENJAMIN PRYOR STOCKMAN of 3 Poets' Corner Westminster, Civil
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to provide a certain and reliable means of giving
prompt alarm upon the outbreak of fire; and my invention consists of an automatic
apparatus, combining the known methods of pneumatic signalling with a system of.
electric and magnetic apparatus. As regards the pneumatic part of the system, I
adopt the usual tubing, or piping, such as is used for pneumatic bells or speaking
pipes and I construct a drum or air-box, of a special form, so as to render it most
sensitive to heat, that is, to receive the earliest impression from the heated air where
a fire breaks out, also the quickest transmission of heat from the outside to the
inside of the air-box, and the maximum impulse to be given to the column of air in
the pneumatic tubes.
To effect these results, I use, by preference, a parallel form of air-box, or of a
form to present the most effective surface of the thin metal covering, and, to prevent
the thin metal from bulging or expanding, by the force of the heated air, which
would otherwise prevent the utilisation of that force in the direction required, I tie
the thin surface metal at several points, thus causing the force to expend itself in the
direction of the column of air in the pneumatic tubes attached to the air-box.
The position of the air-box may be, on a ceiling, or in any overhead or vertical
position.
The apparatus, so far described, is similar to that described in my Patent Specifi-
cation No. 18,203 A..D. 1889.
I introduce a small instrument, which I call a "pulsator" and which is attached
to the end of the pneumatic tubing furthest from the air-box; but neither the
tubing nor the pulsator need be placed outside, or beyond, the walls of the room
containing the air-box.
The pulsator may be fixed on the face, or in any angle, of a wall, or in a cup-
board. It comprises a spreading india-rubber cap, or pulse-valve, connected with
the end of the pneumatic tubing; and there is a light piston-rod, sliding in a guide,
its lower end terminating in a button which rests on the india rubber cap, and above
it is a screw the turning of which up or down regulates the distance between its end
and the upper end of the piston rod.
The air in the air-box, being heated by the fire, expands and drives the column
of air before it in the pneumatic tube, till the pressure forces the india-rubber cap
of the pulsator into a convex surface lifting the piston-rod until its top end touches
the lower end of the screw, making contact.
This ends the pneumatic part of the operation; the rest being electrical and
electro-magnetical.
The pulsator can be adjusted for any degree of heat.
The alarm of "fire" is given by the "indicator" which is an instrument placed
at the remote end of the system. It indicates a fire by the dropping of a semaphore
arm (or it may contain any number of semaphores) but the indicator is not actuated
by direct pneumatic agency, as it was in my former Patent alluded to.
semaphore is held in its vertical position by a lever and a notch; and the other
end of the lever forms an armature to an electro-magnet, over which it hovers.
The
The indicator derives its action from the pulsator, which closes the electric circuit
of the electro-magnet under the indicator lever. The magnet draws down the tail
end of the lever, lifting the other end out of the notch, and the semaphore falls
instantly into a horizontal position; in doing which it also crosses or bridges two

page_text: horizontal parallel conductors; and, thereby, closes an electric circuit in which may
be any number of alarm-bells or gongs.
The situation in which the indicator is fixed, may be at any distance, even beyond
the premises if so required; in fact its distance is only limited by the length of the
electric wire between it and the pulsator.
My invention is applicable to buildings of every kind whether public or private ;
to ships collieries; and, in fact, in any situations where fire may occur.
Dated this 9th day of April 1891.
B. P. STOCKMAN, M. Inst. C.E.
COMPLETE SPECIFICATION.
Improvements in Fire-alarms.
I BENJAMIN PRYOR STOCKMAN of 3 Poets' Corner Westminster 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 my invention is to provide an automatic means of giving prompt
alarm upon the outbreak of fire; and my invention consists of an apparatus, partly
pneumatic and partly electric; the pneumatic part first coming into action auto-
matically, by the effect of heat; and the electrical part then giving the signal or
alarm, by the dropping of a semaphore arin and the ringing of an alarm-bell or
any number of alarm bells; also communicating, when required, with a fire
brigade station automatically or it may be attached to a street signal post of the
fire-brigade.
The apparatus, comprised by this invention, consists of three parts exclusive of
the electric batteries, alarm-bells, and the electric conducting wires; namely, first,
an "air-box"; second, an instrument called a "pulsator"; and third, the signalling
instrument, called an "indicator." The two first mentioned comprise the pneumatic
part of the action, the indicator being actuated solely by electricity.
Reference is to be had to the accompanying drawings, which form part of this
Specification.
First, the air-box:
Fig. 1 is a plan, and Fig. 2 is a section.
The air-box is made of metal in the form of a parallel box; the top and bottom
being constructed of very thin copper, or other good conductor of heat; and these
thin sheet covers are tied together, internally, by wires a, a .
to tie the surfaces at points in their centre of gravity; and, by
surfaces are prevented from bulging, or buckling during the
air-box.
arranged so as
this means, the
inflation of the
The air-box is soldered perfectly air-tight, except at a vent by a nozzle pipe, c,
projecting from its rim, for the purpose of attachment to a fine tube, connecting it
with the pulsator. The air-box is fixed to a ceiling, or to the internal part of a
roof, by means of the lugs, b, b, b, or it may be fixed in any suitable vertical
position and a space is left between its top surface and the ceiling, to allow the
heated air to strike the top thin plate as well as the under one.
The air-box may
also be enclosed in a circular moulded rim, or concealed within an ornamental
ceiling flower, with a perforated under side to admit the heated air.
Second, the pulsator:
Fig. 3 is a front view showing the outer case in section, and Fig. 4 is a sectional
plan.
_A
The pulsator is a small instrument, constructed in the following manner :-
small metallic disc, with a hole in its centre, and fixed on a tubular stem, d, is
covered over with sheet india-rubber, e, and tied down tightly around the neck or
tubular stem. This forms a pulse valve, and is fitted and embedded in the outer

page_text: framework, so that its upper surface only is seen. Above this is a netal frame
carrying a vertical rod, with a button shaped end, which rests in the centre of
the india-rubber cap, e; the vertical rod slides up and down in a hanging socket or
guide, g, and over the centre of the vertical rod, f, is a vertical screw, h, which, by
screwing up or down, recedes from, or approaches the top end off. Both the
points, and h, are tipped with platinum. The vertical rod, f, and its guide, g, are
insulated from the metal frame and screw, and fine covered wires from both are
attached to the terminals, 1, 1, from which the conducting wires of the electric
system proceed, communicating with the indicator. This instrument is enclosed,
for protection, in a metal cylinder, held in place and fastened down by the cap, o,
which is pressed by a hinged lever, n, and locked, by a lock and key, the bolt of
the lock passing under the tail end of the lever. A section of the cylindrical cover
is shown at m, m.
Third, the indicator:
Fig. 5 is a side elevation; Fig. 6 is a plan of same; Fig. 7 is an additional detail
to show that the magnet bobbins are sometimes placed in advance of each other, or
tandem fashion.
The indicator consists of a stand, base-plate, and other supports, made of wood,
vulcanite, or other convenient material, on which there are two metal pillars with
fulcrums or centres; on one of which is hinged a semaphore arm, p, and the other
pillar poises a lever, s, above it. The semaphore arm has a notch in its top edge;
and the lever above has a cranked end which rests in the notch; and thus holds the
semaphore in a vertical position; ready for action. The other end of the lever is
provided with an armature, u, made of thin soft iron; and immediately under it, is
fixed an electro-magnet, ; the distance between them being sufficient to allow the
cranked end of the lever to lift out of the notch in the semaphore, p, when the
armature end is drawn down by the magnet. The semaphore being thus released,
drops into a horizontal position (³). On the semaphore, p, there is a rocking
bridge, of conducting metal, (7) platinized in two places underneath; and, on the
base-plate, are two corresponding parallel conducting bars, a, a, platinized at y, y ;
across which the rocking bridge rests when the semaphore falls. There is no
pneumatic tubing in connexion with the indicator, as the pneumatic action ends
with the pulsator, which may be fixed in the same room or chamber containing the
air-box, or in any other convenient place in proximity thereto. The air-box and
pulsator are like one combined instrument, being connected by a fine tube between
them. The indicator may be placed at any remote distance from the premises to
be indicated, or at any fire-brigade station.
The action is as follows:-The heated air, caused by fire or other undue heat,
ascends to the air-box; and the heat passes, through the thin metal covers, to the
interior, expanding the enclosed air, which cannot escape; and the force, due to
the expansion, presses forward the column of air contained in the fine tube, between
air-box and pulsator, till it reaches the underside of the india-rubber cap e, which
it forces upwards in a convex form; and this dilation of the india-rubber lifts the
vertical rod f, till its point touches the point, h, of the screw. This contact causes
an electric current to How from the batteries to the indicator; and, first, renders
the magnet, r, active, when the armature, u, of the lever, is pulled down, and the
cranked end of the lever is lifted out of the notch in the semaphore, p, which
instantly falls horizontally; and its rocking bridge, , rests across the parallel
conductors,, ; and, in so doing, a shunt circuit is closed, which continues the
current, independently of the current through the coils of the magnet. While the
semaphore p, remains in this horizontal position, the current continues to flow,
ringing the alarm-bells. The semaphore may have, marked upon it, the number, or
other description of the room or chamber protected.
Although only one set of apparatus is described, there may be any number fixed;
sometimes may use several air-boxes and pulsators, with a less number of
indicators, or there may be an equal number of each; or, in fact, any combination,
according to circumstances.

page_text: The invention is used for every description of premises, or other places requiring
protection from fire, by giving, automatically timely warning of an outbreak.
The dimensions of the apparatus may be varied, as may also some of the details
of construction, depending upon the special requirements of the fitting and fixing
to be carried out.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is performed, I declare that what I
claim is -
1. The air-box, as described and illustrated, with the tension wires placed in the
centre of gravity of the surface, to prevent bulging or buckling.
2. The instrument called the pulsator, as shown and described.
3. The union, or joint action, of the air-box and pulsator as two branches of one
pneumatic system.
4. The indicator, as shown and described; being actuated solely by electricity ;
and the use of an electro-magnet, to draw down the end of a lever, to release a
semaphore arm, and thus cause it to drop and so close a shunt circuit; for the
purpose of giving the alarm of fire.
5. The whole combination comprising my invention for an automatic fire-alarm,
substantially as hereinbefore set forth, illustrated and described.
Dated this 9th day of January 1892.
B. P. STOCKMAN, M. Inst. C.E.