An Improved Thermometric Electrical Circuit-closer.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
An Improved Thermometric Electrical Circuit-closer.
I, GILES HENRY ZEAL of 118 & 119 Great Saffron Hill, London, E.C. Thermometer
Maker; do hereby declare the nature of this Invention to be as follows:-
My Invention relates to an improved thermometric electrical circuit-closer for
causing an alarm to be sounded or a thermostatic regulator to be operated on the
attainment of a predetermined temperature, and the Invention has for its object to
enable the circuit-closer to be set for action at any temperature within its range
without the employment of movable terminals such as have heretofore been used for
the purpose.
The Invention consists of a mercurial thermometer, of U or other shape, having
two tubes somewhat wide apart connected with a single bulb the one terminal of the
electrical circuit being usually in permanent electrical connection with the mercury
and the other entering the bore of one of the tubes at a point above the normal
height of the murcurial column. The thermometer mount is pivoted to a suitable
support in order that by inclining the thermometer the one tube may be raised and
the other lowered so as to cause the relative lengths of the mercurial columns therein
contained to be varied (by reason of the fact that the mercury always has common
absolute level in both) thus varying more or less the distance separating the one
column from the terminal in its bore and consequently varying more or less the height
through which the mercury must rise and the increase of temperature which must
occur before the circuit is closed.
In adjusting the instrument the degree of inclination to be given, in order that
the alarm shall be sounded, or the thermometric regulator be operated, on the
attainment of a given temperature, is ascertained by setting it with reference to an
index and scale of temperatures corresponding to different inclinations and marked
upon the fixed and movable parts of the instrument.
Dated this 20th day of January 1897
An Improved Thermometric Electrical Circuit-closer.
I, GILES HENRY ZEAL of 118 and 119 Great Saffron Hill, London, Thermometer
Maker, 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 :-
My invention relates to an improved thermometric electrical circuit-closer for
causing an alarm to be sounded or a thermostatic regulator to be operated on the

page_text: attainment of a predetermined temperature, or for other uses, and the invention has
for its object to enable the circuit-closer to be set for action at any temperature
within its range without the employment of movable terminals such as have heretofore
been used for the purpose.
My invention is illustrated in the accompanying drawings in which Fig. I is a face
view of the improved thermometric electrical circuit closer and Fig. 2 is a detail view
of part thereof. The invention consists of a mercurial thermometer, of U or other
shape, having two tubes a a¹ somewhat wide apart connected with a single bulb b,
the one terminal c of the electric circuit being usually in permanent electrical
connection with the mercury as shown and the other c¹ entering the bore of one of
the tubes, (the tube a¹) at a point above the normal height of the mercurial
column.
The thermometer mount d is pivoted at d¹ to a suitable fixed support or back
board e in order that by inclining the thermometer one tube a or a¹ may be raised
and the other lowered so as to cause the relative lengths of the mercurial column
therein contained to be varied (by reason of the fact that the mercury always has
common absolute level in both) thus varying more or less the distance separating
the one column (the column a¹) from the terininal c¹ in its bore and consequently
varying more or less the height through which the mercury must rise and the
increase of temperature which must occur before the circuit is closed.
The pivot d is screw threaded and is fixed in the mount or back board e whilst a
milled headed nut d' acts in connection with such screw threaded pivot d¹ to clamp
the thermometer mount d to the fixed support or back board e in any desired
position.
In adjusting the instrument, the degree of inclination to be given in order that the
alarm shall be sounded, or the thermostatic regulator be operated on the attainment
of a given temperature, is ascertained by setting it with reference to an index and
scale of temperatures corresponding to different inclinations and marked upon the
fixed and movable parts of the instrument.
In the instrument represented in the drawings the thermometer mount & is
provided with a scale d³ and a central index d, and the fixed support or back board e
has an index e¹ thereon. The mount d has also a scale d5 thereon.
Thus when the central index d of the mount d is in line with the index e¹ of the
mount e the thermometer is in its normal position and the approximate temperature
can be ascertained by reference to the position of the mercurial column in relation to
the scale do but by inclining the thermometer mount d in either direction from such
position in a plane parallel with the plane of the tubes the instrument can be set to
close the electric circuit at any temperature within the range of the scale d³.
In order to prevent as far as possible, the terminal c¹ from retaining a globule of
mercury around it, I encase such terminal c¹ as shown at Fig. 2 with a thin coating c²
of glass leaving only a very small portion of the terminal c¹ extending beyond the
glass coating.
It will be evident that the scale d³ might be applied to the mount or back board e
instead of to the thermometric mount d.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. A thermometric electrical circuit-closer, comprising a two-tube thermometer and
circuit terminals applied thereto, a mount carrying said thermometer, a fixed support
or back board to which the mount is pivoted and upon which it is adapted to be
turned on its pivot, in a plane parallel with the plane of the tubes, to vary the
heights of the mercury in the tubes, and thereby vary the distance between the
mercurial column and one of the circuit terminals, whereby the circuit may be closed
at varying temperatures, substantially as described.
2. In a thermometric electrical circuit-closer the combination of a two-tube
thermometer provided with electrical contacts, a mount carrying such thermometer

page_text: and pivoted to a fixed support or back board, a scale on one of such parts, an index
on the other part, and means for clamping the thermometer mount to the fixed
support or back board in the required position to close the electric circuit or any
given temperature being attained substantially as herein set forth.
3. In a thermometric electrical circuit-closer, the combination therewith of an
electrical contact permanently in contact with the mercury, and a terminal extending in
the bore of the tube of the thermometer, and provided therein with a glass coating
surrounding said terminal to within a short distance of its end substantially as and
for the purpose described.
HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.
HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.