IMPROVEMENTS IN OR APPLICABLE TO GAUGES FOR INDICATING STEAM, HYDRAULIC, OR OTHER PRESSURES, TO GIVE ALARM BY ELECTRICAL CONNECTION ON THE ATTAINMENT OF ANY EXCESS OR INCREASING PRESSURE OVER THAT TO WHICH THE GAUGE MAY BE ELECTRICALLY SET."
Year: 1879

page_text: LETTERS PATENT to John Roger Arnoldi, of the City of Ottawa, in the
County of Carleton, in the Province of Ontario, in the Dominion of Canada,
for the Invention of "IMPROVEMENTS IN OR APPLICABLE TO GAUGES FOR
INDICATING STEAM, HYDRAULIC, OR OTHER PRESSURES, TO GIVE ALARM BY
ELECTRICAL CONNECTION ON THE ATTAINMENT OF ANY EXCESS OR INCREASING
PRESSURE OVER THAT TO WHICH THE GAUGE MAY BE ELECTRICALLY SET."
PROVISIONAL SPECIFICATION left by the said John Roger Arnoldi at the
Office of the Commissioners of Patents on the 6th August 1879.
JOHN ROGER ARNOLDI, of the City of Ottawa, in the County of Carleton, in the
Province of Ontario, in the Dominion of Canada. "JMPROVEMENTS IN OR APPLI-.
CABLE TO GAUGES FOR INDICATING STEAM, HYDRAULIC, OR OTHER PRESSURES, TO
GIVE ALARM BY ELECTRICAL CONNECTION ON THE ATTAINMENT OF ANY EXCESS OR
INCREASING PRESSURE OVER THAT TO WHICH THE GAUGE MAY BE ELECTRICALLY
SET."
The object of this Invention is to furnish a simple, cheap, and convenient
electrical alarm attachment to steam or other pressure gauges most generally
manufactured to sound instant warning of excessive pressure, and also to act as a
check or tell-tale on attendants who are confined to limited pressures by instruc-
tions.
screw,
The Invention consists of a flat or spiral spring attached to a binding screw
passing through and insulated from the gauge case in connection with electric
wires, and a gong for sounding an alarm, said spring regulated by an adjusting
and is arranged with respect to the expansion tube or diaphragmn of a gauge, so
that by the expansion of the tube or diaphragm in contact with the spring the
electric circuit is closed or opened, according to whichever system is adopted, which
causes the ringing of a bell or other alarm in connection with the circuit, the
audible alarm continuing until the pressure is reduced.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Roger Arnoldi in the Great Seal Patent Office on the 6th
February 1880.
JOHN ROGER ARNOLDI, of the City of Ottawa, in the County of Carleton, in the
Province of Ontario, in the Dominion of Canada. "IMPROVEMENTS IN OR APPLI-
CABLE TO GAUGES FOR INDICATING STEAM, HYDRAULIC, OR OTHER PRESSURES, TO
GIVE ALARM BY ELECTRICAL CONNECTION ON THE ATTAINMENT OF ANY EXCESS OR
INCREASING PRESSURE OVER THAT TO WHICH THE GAUGE MAY BE ELECTRICALLY
SET."
The object of this Invention is to furnish a simple, cheap, convenient, and
effective electrical alarm attachment to steam or other pressure gauges, most
generally manufactured to sound instant warning of excessive pressure, and also to
act as a check or tell tale on attendants who are confined to limited pressures by
instructions. My Invention consists in a delicate spring adjustable to produce
electrical contact by or with an adjustable set screw or its equivalent working in
the gauge case or in a fixed attachment thereto, arranged as hereinafter described,
to produce an electrical alarm.
.
Figure 1 represents an ordinary electrical gong; Figure 2 represents an ordinary
annunciator or indicator; Figure 3 represents a nest of three steam boilers
electrically connected by their pressure gauges with Figures 1 and 2; Figures 4, 5,
and 6 represent front views of an ordinary expanding tube pressure gauge with a
portion of the dial removed.
A is a light metallic spring of a nearly straight form in Figures 4 and 5, and
spiral in Figure 6, which in Figure 4 is attached to the binding screw B insulated
from the gauge case by the collar of vulcanite or other suitable insulating substance,
to which one of the electric wires later described is attached; C is a simple binding
screw, to which the other electric wire is attached; D is an adjusting screw for
regulating the spring A by the insulating point D₁ formed of vulcanite or other
suitable insulating substance; E is a jam nut for keeping the screw D secured
at any desired point; F is the ordinary expansion tube in an expanding tube
pressure gauge, G being point of contact for closing and opening the circuit. In
Figure 5 the spring A is shown attached to the tube F, and the adjusting screw D
insulated from the gauge case by the insulating collar, and without any insulating
point D' is directly connected with the binding screw B (insulated from the gauge
case by the insulated collar). In this case the circuit is broken or completed at the
point G when the pressure to which the gauge is adjusted by the set screw D is
reached. In Figure 6 the spring is shown in a spiral form attached to or working
loose on a moveable metallic adjustable screwed end, and pointed pin or plunger D,
and arranged in a socket or bar J, which is insulated from the gauge case by the
insulating collar (this socket or box J receives one of the electric wires at binding
screw B). The pin or plunger D in the box J being adjusted by the jam nut E
sufficiently to make electric contact between its point and the tube F at G when
the tube through pressure reaches the point at which it is desired an alarm shall
be given, and. the spiral spring A will yield and allow the pin or plunger D to
recede as the tube F expands, still maintaining the alarm. Figure 6 A shows the
construction of this form of attachment and spiral spring on a larger scale. In
Figure 7 is represented one mode of applying to a diaphragm pressure gauge the
same combination, and of obtaining similar results as have been described for
Figure 4. Proper electrical conducting wires from the points B and C on the
gauge case H are carried in the usual electrical manner through an ordinary
battery in connection with one or more electric gongs or their equivalent, and also
in cases where a number of boilers or machines are employed, and separate gauges
are used with an annunciator the dials of which are to correspond with the gauges

page_text: of the respective boilers or machines as Nos. 1, 2, and 3, in Figures 2 and 3.
With the foregoing brief description of my Invention to which I have given the
name of "Arnoldi's Excessive Pressure Signal " I will now proceed to describe more.
particularly the mode in which it is employed. Assuming either of the gauges
Figures 4 or 7, to be attached to a steam boiler, heating apparatus, hydraulic or
other pressure system where a maximum pressure is allowed of, say 35 lbs., the
adjusting screw D is set up against the spring A until the latter or the pointed pin
or plunger D connected there with as in Figure 6, comes in contact with the gauge
tube or diaphragm F while the gauge indicates 35 lbs. By this arrangement
assuming the boiler or other vessel to be limited to 35 lbs pressure and set as above,
the electrical spring A and gauge tube F will connect when the pressure rises to
35 lbs, giving the alarm on the gong and operating the annunciator, and keeping the
gong sounding until the pressure is reduced. The gong or gongs and annunciator
may be placed in electric circuit at any distance from the vessel in which the
pressure is generated, and in order that the party in charge may be always certain
that the electric circuit is perfect, a switch or its equivalent may be placed in the
line of wires by which the circuit can be tested at any moment such as upon officers
changing watch on a steamship, or engineers in a factory, &c. It is obvious that
the spring A and adjustable screw D may be used on either open or closed circuit
electrically for alarm, and it is obvious that the spring may be brought into contact
with the needle arbor or pinion tooth quadrant on connecting rod to expansion
tube of an expanding tube gauge instead of with the expanding tube as described,
and that in a diaphragm gauge it may be brought into contact with the diaphragm
or with the levers, rack, or connecting rod of a diaphragm gauge. I consider the
direct application of the spring to the prime moving part of a gauge, such as the
tube or diaphram to be preferable, but I do not wish to be limited to the point at
which the spring is to be applied further than by the disclaimers hereafter following
nor to the method of attaching the spring to the gauge case, as it can perhaps
equally well be permanently attached to the prime or other moving parts of the
gauge above mentioned, and from contact with an insulated set screw pin or other
suitable attachment to form the circuit. The advantages of the above described
device over any existing application of electric alarms to diaphragın or expanding
tube pressure gauges, are mainly the following:-1st. The extreme simplicity,
facility, and inexpensiveness of its application to all forms of diaphragm or
expanding tube pressure gauges already constructed. 2nd. The extreme simplicity
of the combination dispensing with the intermediate parts which intervene in the
forms hitherto applied to diaphragm recording gauges between the diaphragm and
the point of electrical contact, this simplicity rendering the instrument not liable to
get out of order and its operation certain. 3rd. By the substitution of a delicate
direct acting spring adjusted as described for a set screw working in a post or stand,
and set upon a pivotted or yielding base (as heretofore applied to diaphragm
recording gauges) this part of the instrument is more reliable and rendered much
less liable to get out of order, it can also be adjusted with greater precision owing
to there being no intermediate points to produce backlash, and as long as the
expanding pressure tube or diaphragm alone retains its usefulness, the alarm will be
given at the set point. 4th. By the position of the spring in relation to the
expansion tube or other moving part the friction or disturbance to the action of the
gauge is reduced to a minimum, a continuous alarm is secured without danger of
the electrical contact ceasing until the pressure has been reduced below the point to
which the alarm is set. 5th. The danger of deranging the hand and the delicate
machinery of the gauge which exists where the hand is made the means of producing
the contact, is avoided as well as the danger of the electrical contact failing to be
made through the slipping or other derangement of the hand (or needle on its arbor)
and the resistance to the operation of the gauge is reduced to an inappreciable
minimum by the direct application of the spring to the prime moving part in the
manner described.

page_text: I claim as my Invevention ;-1st. In an expanding tube pressuse gauge the light
metallic spring A when exerting its resistance at a tangent with the tube or other
moving part substantially as described. 2nd. The light metallic spring A. and the
insulated set screw D in combination with the prime moving part or with the lever,
rack, tooth, quadrant, pin, or needle arbor, or connecting rod of an expanding tube
or diaphragm pressure gauge all arranged and operated substantially as above
described, to open or close an electrical circuit for the purpose of producing an alarm
or signal.
In witness whereof, I, the said John Roger Arnoldi, have heretofore set my
hand and seal, this Eighth day of January, A.D. 1880.
TATTY
תAAAND