Improvements in Pyrometers.
Year: 1895

page_text: Date of Application, 9th Apr., 1895-Accepted, 24th May, 1895
Improvements in Pyrometers.
I, ALVAN AUGUSTUS SIMONDS of Dayton, in the County of Montgomery, and
State of Ohio, one of the United States of America, Manufacturer, 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 pyrometers and more particularly to those pyrometers in
which a thermo-electrical current is employed and it consists in certain new
constructions and combinations of parts.
The best form in which I have contemplated embodying my invention is
illustrated in the accompanying drawing and the same is fully disclosed in the
following description and claims.
The drawing is a view partly in elevation, partly in section of my improved
pyrometer.
In this drawing A indicates the thermo-electrical elements, and B the indicator
which indicates the degree of activity of the thermo-electrical elements and
consequently the degree of heat applied thereto. cc are the conductors connecting
the thermo-electrical elements with the indicator. These conductors on leaving
the elements pass into a tube filled with plaster of Paris or like material in which
they are embedded and surrounded and by which they are insulated from each other
and from the tube d.
The thermo-electrical elements which I prefer to use are platinum and an alloy
of platinum and rhodium. The short conductors a leading from these elements into
the tube d are of platinum or of the same material as the elements themselves. In
most cases where such pyrometers have heretofore been employed, platinum
conductors have to be used for a considerable distance from the elements as the
heat is so great as to melt or rapidly destroy them if formed of other materials.
This has rendered such pyrometers less efficient than desirable inasmuch as platinum
possesses but a small conducting capacity, and as the heat to which such conductors
are subjected increases their resistance, the electric action of the thermo-electrical
elements is able to exert but little influence upon the indicator. To avoid the
effect of the heat upon the conductors, I employ the plaster of Paris as before
stated which prevents the conduction of the heat along the wires through the
insulating material and further maintain these conductors at a low temperature by
a water jacket E which surrounds the tube d. This water jacket is shown as
extending to within a short distance of the tube d adjacent to the thermo-electrical
elements, but it may be made to extend towards the elements as far as the tube d,
or to the end of that tube if so desired. I prefer to make the inlet pipe el extend
to near the end of the jacket nearest the thermo-electrical elements and to have
the same discharge near the top of the jacket. The outlet pipe e leads from the
upper side of the jacket at its opposite end. By this means the coldest water is
conducted to the end of the jacket nearest the heat or source of heat and as its
gravity is greater than the water within the jacket, passes downward at that point
around the tube d, thereby maintaining that part of the tube d at the lowest
possible temperature.
While this construction greatly improves the action of the pyrometer in cases
where the platinum conductors are employed for a considerable distance from the
elements by reason of maintaining the conductors at a low temperature or at

page_text: approximately their greatest conductivity, I am by this construction enabled to use
the best possible conductors for nearly the entire distance between the thermo-
electrical elements and the indicator.
This is also illustrated in the drawing in which the conductors a a extend but a
short distance into the piped, and at the point a' a¹ are joined to copper conductors cc
which extend from this point to the indicator.
A pyrometer constructed in this manner possesses a far greater sensitiveness, and
range of movement and has been found to give the most satisfactory results where
the prior forms of this device have been found impracticable.
I do not desire to limit myself to any particular form of indicator but prefer to
employ one formed on the well known principles of the volto-meter. The length
of the tube d and of the water jacket E should be such as to carry the conductors
without the injurious action of the source of heat which it is desired to measure.
Having now particularly described and ascertained the nature of my inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :
1. In an electrical pyrometer, the combination with thermo-electrical elements
and an indicator, of electrical connections between said elements and the indicator
and means for maintaining the said connections at a low temperature from a point
near the said elements to a point substantially without the influence of the source
of heat which it is desired to measure whereby the connections are maintained at
their normal conductive efficiency, substantially as described.
2. In an electrical pyrometer the combination with the thermo-electrical elements,
and an indicator, of electrical conductors connecting the said elements and indicator,
a heat and electrical insulating material surrounding said conductors from a point
neur the said elements to a point without the influence of the source of heat and a
water jacket for said insulation whereby a rise in the temperature of the conductors
to effect their conductive capacity is avoided, substantially as described.
3. In an electrical pyrometer the combination with thermo-electrical elements
and an indicator, of electric rounections between them, a casing filled with plaster
of Paris, said connections being embedded in said plaster of Paris, and insulated
thereby, and a water jacket surrounding said casing whereby the injurious heating
of the conductors is prevented, substantially as described.
4. In an electrical pyrometer the combination with the thermo-electrical elements,
and an indicator, of electric conductors extending from said elements to said
indicator, each conductor being composed of a main portion consisting of copper or
other good conductor, extending to within a short distance of the elements, and a
short portion of platinum or like conductor connecting the main portion and the
elements, and means for maintaining a comparatively low temperature at the point
of junction and outward from the said elements, substantially as described.
5. In an electrical pyrometer, the combination with the thermo-electrical elements,
and an indicator, of electric conductors extending from said elements to the indicator
each consisting of a short portion of platinum or like material adjacent to said
elements and the balance of copper, a heat and electric non-conducting insulating
material surrounding said conductors at the point of junction of their parts and a
water jacket for said material, substantially as described.
Dated this Eighteenth day of February 1895.
ALVAN AUGUSTUS SIMONDS.
Marks & Clerk,
18, Southampton Buildings, London, W.C., Agents.