Improvements in Electric Heating Apparatus
Year: 1897

page_text: Date of Application, 29th June, 1897-Accepted, 9th Oct., 1897
Improvements in Electric Heating Apparatus,
I, GEORGE BRINTON FRALEY, of 147 North 12th Street, Philadelphia, United States
of America, Electrical 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:-
This invention relates to Electric Heaters, and has for its object to simplify their
construction, increase their effectiveness and at the same time adapt thein for use
with either a direct or alternating current as may be desired, the heater being
cheaply and effectively manufactured, and readily assembled and disconnected
according to requirements.
In the accompanying drawings:
Figure 1 is a longitudinal vertical sectional view of a core for direct current, and
attachments; the position of the insulating and protecting cover, being shown in
dotted lines.
"
Figure 2 is a similar view of the saine parts with two reflectors in position inside
of the tubular core.
Figure 3 is a similar view of the same parts in a modified form; the reflectors being
mounted beyond the ends of the tubular core.
Figures 4 and 5 are views in opposite side elevations of a modified form of core for
use with an alternating current.
Figure 6 is a view in side elevation of the lower portion of a core and attachments,
and the base on which it is to be mounted and through which the connections with
core and coils are made.
Figure 7 is a top plan view of the base.
Figure 8 is a central vertical sectional view of the same.
Figure 9 represents a side elevation of another form of an electric heater embodying
my invention.
Figure 10 represents a longitudinal sectional view of Figure 9.
Figure 11 represents a sectional view of the heater showing the manner of
assembling and insulating the parts.
Figure 12 represents a section on line y, y, Figure 10.
1 designates a tubular core of copper or other suitable material. There are
illustrated in the drawings three forms of cores, one being intended for use with a
direct current and illustrated in detail in Figures 1, 2 and 3 and two for use with
an alternating current and illustrated in Figures 4 and 5.
The cores are covered with a sheet of mica as at 2 and a sheet 3 of asbestos or other
non-conductor, around which is coiled any desired number of wires 4. In all the
figures which illustrate the wires, but one wire is shown except in Figure 1, in which
two are shown. The black line next to the core is intended to illustrate the mica
and where two or more coiled wires are used as in Figure 1, the separate coils may
be separated by sheets of asbestos as shown at 5 in Figure 1.
6 is a metal cap made at 6 at a sufficient diameter to embrace the lower end of
the core for which purpose the core extends slightly below its covering. The cap 6
is of reduced diameter below the part 6 and formed with a screw thread as at 7, the

page_text: lower end being closed by a perforated head 8 of porcelain or other insulating
material.
Through the perforation of the head 8 is passed a screw 9, which is provided with a
large head (or a washer under the head) 10. The screw thread 7 of the cap 6
engages in a similarly threaded metal thimble 11 in a base 12 formed of porcelain or
other insulating material (see Figures 7 and 8), which engages a metal plate 13
extending out through an opening 14 in said base 12 and provided at its outer end
with a suitable binding screw 15. The head 10 of screw 9 comes in contact with
another plate 17 which extends through an opening 18 in the opposite side of base 12
and having at its outer end a suitable binding screw 19.
The inner end of the screw 9 inside of the porcelain head 8 is formed as a binding
Bcrew to engage the lower end of the coiled wire 4, in this instance (Figures 1 and 2)
being provided with a washer 20 and nut 21 between which the wire is clamped.
By means of the construction described, a complete circuit is formed, the wire from
the electric supply being engaged by binding screw 19, the current passing through
plate 17, screw 9 into and through conductors 4, which are continuous and extend in
Figure 1, first upwardly then downwardly around the exterior insulation 5, contact
being made with the cap 6 at the point 22 thence by the binding screw 15.
In Figure 2 but one coil of wire is shown, here the upper end of the wire is connected
at 23 to the upper end of the core 1.
The core, wires, etc., are covered with any suitable coating of a good heat conducting
but insulating substance, as shewn by dotted lines at 24 Figure 1. The composition
employed for this purpose consists of the following ingredients in substantially the
proportions specified, viz. :-

page_text: apparent that if the tube had an unobstructed passage therethrough the larger
quantity of air flowing therethrough acting as a heat vehicle will carry away so many
units of heat as to reduce the temperature of the resistance to such an extent as to
impair its efficiency. The above conditions are avoided by retarding the flow of air
through the core, so as to prevent the maximum number of heat units from being
carried away by convection, this retardation being effected by the employment of one
or more reflectors suitably supported upon said core. The detention of the air within
the tube prevents the fall of temperature in the resistance itself and thereby reduces
the current but the temperature of the resistance is not liable to rise to an undesirable
degree since the hotter the air becomes the greater will be its buoyancy and velocity
and the greater the number of heat units removed from the interior of the heater.
The reflectors employed being preferably of metal become highly heated and serve as
baffle plates for the purpose of retaining the heated air within the core as long as
possible.
It will of course be evident that any suitable material may be employed in the
construction of the core and that if desired the reflectors 28 may be concaved and'
polished as well as the interior of the core, but I do not desire to be restricted
thereto in every instance.
Referring to the forms shewn in Figures 9, 10, 11 and 12:
29 designates a heater, the same being composed of the shell 30, which latter is
preferably a sheet of copper or other suitable conductive material, which is wrapped
upon itself in substantially the manner indicated in Figure 11 forming a core, said
core having between its convolutions the insulation 31, which may be asbestos or
other suitable material, it being noted that the free ends or edges 32, 33 of said
shell terminate preferably substantially opposite to each other and that the
intermediate portion of the shell has an opening 34 therein, through which passes a
fastening 35 which also serves as an electrical conductor between the inner and
outer portions of the shells, there being a fastening device at top and bottom.
:
36 designates the lower portion of the heater, the same being devoid of insulation
and having the extremity of the wire or conductor 37 in contact therewith, and with
the clip, clamp or bracket 36 to support the lower portion of the heater, said clamp
having the extension 39 on which the nut 40 is mounted, said extension 39 serving
as a support for the conductor 41, which is insulated therefrom by means of the
insulation 42 and is held in position between the shoulder 43 and said nut.
44 designates asbestos or other non-conducting material which encases the shell 30
extending from a point above the clamp 38 to the top of said shell, the clamp 45
being thus insulated from contact with the shell, and the wire or conductor 37 being
wound on said non-conducting material forming a primary coil 46, and having its
upper portion 47 communicating with said clamp 45, the current being thus taken
from the extremity 47 of the conductor to the clamp 45 and thence through the
conductor 41 to the terminal 48, which is adapted to serve as a binding post.
49 designates a series of reflectors which are placed within the shell 30 and are
secured therein in any suitable inanner as by the fastening device 50.
The operation is as follows:
The current entering at the point 39 passes into the clamp 38 and thence by
means of the primary coil 46 around the insulation-44 and into the clamp 45.at the
upper portion of the heater, it being remembered that said clamp is insulated from
the shell 30 by means of the non-conductor 44, the current passing from the
clamp 45 through the portion 41 to the terminal 48 and tbence out of the heater.
The passage of the current through the primary coil 46 in the manner described,
causes an induced or secondary current to be set up through the shell or core B,
which latter has its ends connected electrically as indicated at 35, and by reason of
the low resistance causes a large amperage of current to flow around itself, this
amperage is produced by the primary or heating coil 46, which perform two
functions, first, acting as a heating coil in itself and secondly, inducing a secondary
current which in its turn produces additional heat.
By increasing the convolutions of the core, we get more voltage in the secondary

page_text: circuit, which latter acts as a support for the primary coil, it being evident that the
voltage and amperage of the induced current is in proportion to the number of
ampere turns in the primary coil, and also to the convolutions of said core.
It will thus be seen from the foregoing that an effective heater is thus produced
due to the number of parts reduced to a minimum and the construction greatly
simplified.
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. In an electrio heater, the combination of a slotted core and a resistance coil
wound around said core.
2. In an electric heater the combination of a metallic core slotted for a portion
of its length and an insulated resistance coil wound around said core.
3. In an electric heater, a core, having a plurality of slots therein beginning
alternately at opposite ends, the lengths of said slots being less than the length of
said core, the latter forming a secondary circuit and an insulated primary coil
surrounding said core.
4. In an electric heater, a core having a plurality of slots therein, beginning
alternately at opposite ends, the length of said slots being less than the length of
said core, the latter forming a second circuit, and a primary resistance coil
surrounding said core.
5. In an electric heater, the combination of a core, a resistance coil wound around
said core, and a reflector suitably supported, adjacent to an end of said core.
6. In an electric heater the combination of a core, a resistance coil wound around
said core and a reflector located adjacent to each end of said core.
7. In an electric heater the combination of a core, a resistance coil wound around
Baid core and a reflector located within said core intermediate of the ends thereof.
8. In an electric heater the combination of a core, a resistance coil wound around
said core, and a concave reflector located near each end of said core, the concave
surface of said reflectors facing each other.
9. In an electric heater, a core formed of convoluted conducting material suitably
insulated, and having its ends electrically connected, a primary coil surrounding
said core and insulated therefrom, and means for conducting electricity to and from
said primary coil:
10. In an alternating current electric heater, a core formed of a sheet of suitable
conducting material, having suitable insulation therebetween, the inner and outer
portions of said core near the ends thereof being electrically connected, a primary
coil surrounding a portion of said core, insulation between said coil and core, and
means for conducting electricity to and from said coil.
11. In an electric heater, a sheet of conductive material wrapped upon itself and
having insulation therebetween, forming a core, a primary coil enclosing a portion
of said core, and insulated therefrom, a clamp or supporting device engaging the
lower portion of said core and in electrical connection therewith, a connection from
said clamp to said primary coil, a clamping device engaging the upper portion of said
core and insulated therefrom, a connection from said last mentioned clamp to suid
primary coil, and means for conveying electricity to and from said clamps.
12. In an electric heater, a sheet of suitable conducting material wrapped upon
itself forming a core and electrically connected at the ends thereof, iusulation
between the convolutions of said core, a primary coil surrounding the latter and
insulated therefrom, a support engaging the lower portion of said core and having
n connection to said primary coil, a support for the upper portion of said shell
but insulated therefrom, said support having also a connection to said primary
coil, a connection extending from the upper support and sustained upon a portion
of said lower clamp but insulated therefrom and means for conveying electricity
to and from said supports.
18. In an electric heater, a core consisting of suitable conductive material

page_text: wrapped upon itself and having insulation between the convolutions thereof, a
primary coil supported upon said core and insulated therefrom, a clamp engaging
the lower portions of said core and having connections to said primary coil, a clamp
insulated from the upper portion of said core and having connection to said.coil, and
reflectors located within said core.
14. In an electric heater, a core formed of convoluted conductive material, suitably
insulated and having its ends electrically connected, a primary coil surrounding
said core and insulated. therefrom, and means for conducting electricity to and from
said primary coil, in combination with a reflector located at or near an end of said
core,
15. In an electric heater the employment of a heat conducting and insulating
covering consisting of talc, silicate of soda, carbonate of soda and water, taken in
substantially the proportions specified.
Dated this 22nd day of June 1897.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.