Improvements in Electro-heating Apparatus.
Year: 1891

page_text: Late of Application (in United Kingdom), 8th Apr., 1891
Complete Specification Left, 8th Apr., 1891-Accepted, 16th May, 1891
COMPLETE SPECIFICATION.
Improvements in Electro-heating Apparatus.
I, CHARLES EDWIN CARPENTER, of the City of Minneapolis, in the County
of Hennepin, and State of Minnesota, in the United States of America, Electrician,
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:-
This invention relates to improvements in that class of electro-heating apparatus
in which the heating effects of passing a current of electricity through a conductor
of high resistance and small capacity is utilized for heating by conduction the
surface plate of the apparatus for use.
Prior to this invention the conductor, or as it is more commonly designated, the
resistance which must be insulated from the surface plate has usually been held in
place either by being imbedded in pulverized clay or a similar material, or
attached to an asbestos card and confined against the plate under pressure, as in
several patents heretofore granted to me," the object being to prevent short
circuiting and consequently fusion of the resistance, to confine the heat as much as
possible to the plate to be heated and to conduct the maximum quantity of heat to
the plate.
In all these prior forms of apparatus, in carrying them in stock, it is necessary
to make the complete apparatus, because on account of their construction the parts
are liable to displacement or loss.
The prime object of this invention is to have the resistance permanently attached
to but insulated from the plate to be heated, by an adhesive material, which will
also withstand the heat to which it will be subjected in use, without deterioration.
Another object is to have the adhesive material of such character that its
coefficient of expansion will be substantially the same as both the plate and
resistance, whereby fracture thereof, due to uneven expansion, will be avoided, and
the resistance will at all times be held against displacement, either by accident or
otherwise.
These objects are attained by the devices illustrated in the accompanying
drawings, in which
Fig. 1 represents a plan view of a surface plate of a shape adapted for use as
sad iron, showing the disposition thereon of a resistance of the reflex type;
Fig. 2. a central longitudinal section therethrough, showing the relative dis-
position of the resistance and the adhesive insulating material;
Figs. 3, 4, and 5, detail plan views of different forms of heated plates and
resistances; and
Figs. 6, 7 and 8, enlarged detail views more clearly illustrating the disposition
and arrangement of the resistance and the adhesive insulating material.
Similar letters of reference indicate the saine parts in the several figures of the
rawing.
Referring by letter to the accompanying drawings, A. indicates the plate to be
eated, B the resistance, and C the adhesive insulating material for attaching the

page_text: resistance to, and at the same time insulating it from, the plate. This adhesive
insulating material prefer should be the ordinary enamel, such as is applied to
the surface of various metals, generally in a plastic condition, which, after being
fused and cooled, coats the metal with a hard glazed surface similar in its nature
to glass.
There are many different methods of manufacturing and applying this enamel,
glazing or coating, now known and practiced in the arts, and my invention is
intended to comprehend all of them, by which an enameled or enamel-like surface
or coating can be obtained, and which will withstand the heat to which it
will be subjected in the use of the apparatus, my invention not being limited in this
respect to what may be commercially known as enamel, or to any particular metal
or substance, of which the plate to be heated shall be composed, for this must be
regulated by the character of the metal to which the different enamels may be
applied, and by the relative coefficients of expansion of the enamel and the metal
of which the heated plate is composed.
In practice I have found the best results produced by first enameling the back
of the plate and then laying the resistance upon this enamel and applying a second
or as many additional coats of enamel over the resistance as may be desirable, the
first coat applied to the plate serving to insulate the resistance therefrom, and also
as a base for the application of the remaining coats, which secure the resistance to
the plate. If the additional coats over the resistance be thin, the finished surface
will present a corrugated appearance, as illustrated in Fig. 7, but, if a thick coating
be applied, or a number of coats, exceeding the height or thickness of the resistance,
then the finished surface will be flat and smooth, as illustrated in Fig. 8, these
details being a matter of choice in the manufacture, and not affecting the
operativeness of the apparatus.
When completed these plates may be stored or kept in stock in any convenient
number, and the apparatus in which they are to be used, need not be completed
until it is desired for delivery or use. These plates may have any desirable form,
either circular, square, rectangular, or of a shape suitable for a sad iron, and may
be of any suitable dimensions consistent with the character and uses of the
apparatus and so also may the resistance be of any of the usual types, such as
the reflexed illustrated in Fig. 1, the spiral, illustrated in Fig. 3, or the transverse
or longitudinal, as illustrated in Figs. 4 and 5 respectively. The dotted lines in
Fig. 2 illustrate the additional elements which I prefer to employ in completing the
apparatus as a sad iron, but which form no part of the present invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. In an electro-heating apparatus, the combination with the heated surface-plate
and the resistance, of a coating enamel or its equivalent, securing the resistance
to, but insulating it from, said plate, substantially as and for the purpose
described.
2. In an electro-heating apparatus, the combination with the plate to be heated
and the resistance, of a coating of adhesive enamel or its equivalent, for securing
the resistance to, but insulating it from, said plate, substantially as described.
Dated this 59.1 1 f M
1001
Witnesses:
:-
G. A. EASTMAN.
M. E. M'SHAIN.
CHARLES E. CARPENTER.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.