An Improved Automatic Electric Heat Alarm.
Year: 1892

page_text: complete promotio
COMPLETE SPECIFICATION.
An Improved Automatic Electric Heat Alarm.
We, FRED SUMNER PALMER, residing at 113 Devonshire Street Boston, in the
County of Suffolk, and Commonwealth of Massachusetts, United States of America,
Electrician, and LEONARD H. DESISLE, of Lamoine, County of Hancock, &
State of Maine, United States of America, 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 :-
Our invention consists of an automatic electric heat alarm, and is intended for
use chiefly in connection with journals, bearings, and other parts of machinery
where injury may occur through overheating by reason of friction or other causes,
it being designed automatically to give an alarm when the heating of the parts
begins to be so great as probably to cause damage.
It is fully illustrated in the accompanying drawings, in which-
Figure 1 is a vertical section. Figure 2 is a plan. Figure 3 is an elevation of
the whole device.
Similar letters refer to corresponding parts throughout the figures.
We provide a thin metallic cup or reservoir A. A plug B constructed of some
material which is a non-conductor of electricity, preferably hard rubber, vulcanite,
or laminated fibre, is fitted or screwed into said reservoir. From the centre of the
plug B is a downwardly-extending thermometric tube b, reaching nearly to the
bottom of the reservoir A, and the upper portion of the plug B is centrally and
vertically bored to receive a conductor-wire or spindle C, the spindle being
vertically adjustable in said plug by means of a nut F or other suitable device.
The plug B is also bored vertically near its outer edge to receive a second
conductor-wire or spindle D, the lower end of which extends nearly to the bottom
of the reservoir A. The spindle C is connected at its upper end with one of the
poles of an electric battery by means of the set-screw E, and the spindle D with
the other pole of the battery by any convenient device..
In operation the reservoir A is partially filled with mercury, the plug B and
reservoir A are fitted together, and the whole device set in or upon the journal-
box or bearing of the machine. As the parts become heated the mercury expands
and rises in the tube until it comes in contact with the spindle C, and having beeu
always in contact with the spindle D, an electric circuit is thus completed and an
alarm is given by means of a bell or other device. The spindle C being vertically
adjustable in the plug B, may be so set as to be brought in contact with the mercury
at any desired temperature.
Our device is constructed upon the general principle of the invention of
The Electric Heat Alarm Co. communicated to H. D. Fitzpatrick and for which
Letters Patent of Great Britain were issued on January 12, 1892, No. 576 and is
designed to overcome a possible practical difficulty in the operation thereof.
Our improvement, for which alone we make application for Letters Patent,
(hereby expressly disclaiming the special features claimed and allowed to said

page_text: H. D. Fitzpatrick,) consists of making the entire plug B of material which is not
a conductor of electricity, and in using the spindle D, extending downwardly
through the plug B to the reservoir A, as one of the battery connections, instead
of using a metallic plug and making direct connection with such plug.
The principal advantage of our improvement lies in the fact that with the
metallic plug and thermometric tube it is found in practice that globules of the
mercury may, under certain conditions, as by sudden jars, be thrown upward into
the metallic tube and chamber described in the Specification of said Patent No. 576
of 1892 and be left in contact with the spindle, thus making an electric connection
and giving an alarm needlessly, whereas with our device no alarm is given under
the same circumstances, because the whole plug and tube are of non-conducting
material and no, electric connection is established. The use of the plug constructed
entirely of non-conducting material also simplifies and cheapens the construction
and cost of construction of the device, as it obviates the necessity of the special
insulation of the spindle C, which is required when the metallic plug is employed.
It is obvious that the use of our spindle D becomes necessary as a consequence of
the adoption of the non-conducting plug.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
An automatic electric heat alarm consisting of the combination of a hollow
metallic reservoir, a quantity of mercury within said reservoir, a plug constructed
of material which is a non-conductor of electricity partially filling said reservoir
and having a small, downwardly-extending, tubular bore, a conductor-wire or
spindle supported within and surrounded by said non-conducting plug and extending
to such point as that it may be reached by said mercury when expanded and risen
in said tube, a second conductor-wire or spindle supported within said plug and in
contact with said mercury before said mercury is expanded, the whole in combination
with an electric battery having its poles connected with said spindles, respectively,
and a bell or other alarm or indicator connected with and operated by said electric
battery.
Dated this Eleventh day of June 1892.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.