Year: 1896

page_text: Date of Application, 29th Apr. 1893
2005
COLL
1807
I, THEOPHILUS DAVIES FARRALL of 82, Judd Street, Euston Road, Electrician,
do hereby declare the nature of this invention to be as follows:-
My invention relates to a new mode of producing heat by electricity which mode
consists in causing the fields of force surrounding two or more conductors, or the
adjacent convolutions of one conductor, to oppose or interfere with or "cut"
another.
one
The invention also relates to apparatus whereby the heat produced by such clash
of forces, as well as the heat produced by the mere resistance of the conductors, is
beneficially utilized, the production of heat by electricity with the use of a given
current being thereby so cheapened that such mode of producing heat shall be
economical and commercially valuable. A further object of my invention is to
provide means and apparatus by which heat generated electrically can be utilized for
heating buildings, cars, rooms, stoves, and culinary utensils.
I have discovered a process by which I am able to produce incandescence of the
heating wire with a reduction of the electrical energy now utilized to produce black
heat in such wire; have discovered how to use well known material so that the heat
thus produced can be retained for a long period of time; and have devised and
provided means and structures with which such heat can he successfully and
economically utilized.
It is well known that when an electric current flows through a conductor there is
produced around that conductor a field of force analogous to that existing between
the poles of a magnet. It is likewise well known that the field of force thus produced
is helical and. that it advances in the direction in which the current. is flowing
through such conductor with a rotary screw motion.
According to my invention I utilize the fields of force surrounding conductors for
the production of farther quantities of heat than are produced by the simple resistance
of the heating wire and 1 effect a great saving of current by carrying the heating
conductors to incandescence and there maintaining them at the point of their
highest resistance and at which the ratio of heat units to current strength is far
greater than at any other point.
If two or more parallel conductors which have flowing through them in the same
direction currents of substantially equal strength, or if the parallel convolutions of a
solenoid through which a current of electricity is passing be placed sufficiently close
together a very considerable interference results between the fields of force surrounding
these conductors or convolutions and heat is produced thereby. If the current or
currents be made to flow in opposite directions in the two conductors or the contiguous
sections of the same conductor there results even more violent disturbance of the
fields of force surrounding these conductors, the forces of these fields being brought
into greater conflict with each other and the amount of heat produced being thus
greater than when the currents flowed in the same direction.
I have discovered that the more intimately the convolutions are formed-thus
causing a greater interference between the lines of force the quicker the point of
incandescence is reached in the wire and the lesser becomes the consumption of current
necessary to produce and maintain the same. The reason for this will be apparent
when it is considered that this incandescence results from two components, the heat.

page_text: developed by the resistance of the wire and that produced by the clash of the fields
of force surrounding the conductors. These fields of force become rapidly more
dense the closer the approach is made to the wires which the said fields surround.
When the wires are brought close together the influence of this component to the
production of heat rapidly increases and less heat developed by the resistance of the
conductor is necessary to obtain the required incandescence.
In carrying out my invention I prefer to so arrange the conductor or conductors
composing my heater that the currents in any two adjacent convolutions shall flow in
opposite directions carrying the current first in one direction as through a solenoid
and discharging at the same end of the coil at which it entered. I thus utilize most
advantageously the new process in electric heating which I have discovered. So
perfect is the incandescence that I can obtain by utilizing such method of winding,
that the coronas surrounding the individual convolutions of wire blend and the
heater becomes one incandescent mass while the current required is less than that
required to produce black heat in the present heaters.
To retain the heat produced 1 partially embed in or surround the electric
conductors with substances that have great heat retentivity, where duration of heat
is desired, which substances should be non-conductors of electricity but reasonably
good conductors of heat. For this purpose I preferably use asbestos in the form of
paper cloth or packing, though other substances possessing like qualities may be used
if desired.
In the construction of heaters I find two general classes, namely:-
First. That in which it is desired to radiate from the heater into the air the
largest possible proportion of the heat produced. Of this class of heaters those used
in beating buildings, rooms, cars, and stoves, may be mentioned.
Second. Those in which it is desired to retain in the heater for the heating of
articles immediately adjacent thereto, as large a proportion of the heat as possible.
Of this class examples are leaters used in ovens, coffee-pots, chafing-dishes, and
the like.
For the first class of heaters, namely that where radiation of heat is desired, I
provide vacuous and air-tight heating chambers for the electric conductors and the
cartridges and cores made therewith, thus avoiding the loss of heat due to convection
of air currents.
In the second class of heaters, namely that where radiation into the air is not
desired but rather to be avoided, air is not pumped out as the convection currents
aid in confining the heat to the surface to be heated. The heating coils are confined
in air-tight chambers however as after the first heating all of the oxygen of the
confined air is used up and oxidation of the conductors is impossible.
The heaters may be variously constructed and generally consist of two or more
parallel conductors or the adjacent convolutions of one conductor in contiguous
sections of which the current flows in opposite directions and so arranged in relation
to each other that the fields of force surrounding said contiguous sections oppose
interfere with or "cut" each other, said conductors or conductor being enclosed in
an insulating and refractory substance such as asbestos paper or cloth wrapped around
a cylinder used as a core and upon which the wire is so wound that in adjacent turns
the current flows in opposite directions so as to enable the coils to be wound close
together without danger of short circuiting. The wires may be wound for ward and
then back or side by side, the result being the same in either case the wire being
wound tightly so as to embed itself in, and be retained in position by, the asbestos
covering of the core.
To prevent loosening of the coils by expansion plastic asbestos composition which
dries hard and refractory is pressed between the coils which may furthermore be
covered with a wrapping of asbestos or asbestos paper and enclosed in an outer
cylinder or shell, the joints between the core and shell being packed air-tight and the
shell exhausted of air.
The winding may be continuous froin end to end or divided in sections which inay
be placed in series or multiple for regulating the heat produced.

page_text: For certain purposes, as for heating cars and buildings, internal and external layers
of refractory material may be of considerable thickness in order to give the heater
such beat storing capacity as to prevent sudden fluctuations of temperature by the
temporary cessation of the current incidental to the various circumstances of working.
By exhausting the shell of air radiation of heat is facilitated and oxidation of the
coils is avoided so that they may be heated to incandescence without injury in order
to obtain from a given length of wire the maximum resistance and intensity of heat
with the minimum consumption of current.
In applying the heater to a vessel, a coffee-pot for instance, the beater would
surround the lower part of the vessel of reduced diameter and enclosed in an
air-tight asbestos-lined casing with a considerable space between it and the coils
which as radiation of heat is to be avoided would not be exhausted of air, the oxygen
in the contained air being soon used up and not renewed so that the oxidation is
very slight.
The heater for a chafing dish, a cooking or other stove, would be similarly or
otherwise arranged. A safety connecting plug of special form is provided on cooking
utensils and the like to prevent short circuiting or shocks. It consists of a plate
with an elliptical aperture having holes at the sides thereof in which the beating coil
terminals are countersunk, the leading in wires from the main circuit being connected
to spring contacts on an elliptical plug having a cam-shaped shank so formed as to
only permit its entrance into the elliptical aperture when so presented thereto that
their long diameters correspond when so inserted and turned a quarter round the
spring contacts enter the holes and complete the circuit.
It will be obvious that my invention is in no way confined to the particular forms
of heaters described but may be applied to other forms with equal advantage.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
I, THEOPHILUS DAVIES FARRALL of 82, Judd Street Euston Road, London N.W.
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:-
My invention relates to a new mode of producing heat by electricity which mode
consists in causing the fields of force surrounding two or more conductors, or
the adjacent convolutions of one conductor, to oppose or interfere with or "cut"
one another.
The invention also relates to apparatus whereby the heat produced by such clash
of forces, as well as the heat produced by the mere resistance of the conductors, is
beneficially utilized, the production of heat by electricity with the use of a given
current being thereby so cheapened that such mode of producing heat shall be
economical and commercially valuable. A further object of my invention is to
provide means and apparatus by which heat generated electrically can be utilized
for heating buildings, cars, rooms, stoves, and culinary utensils.
In the electrical heaters heretofore devised the heat obtained is the result of the
passage of an electric current through a substance which offers considerable
resistance to such passage. In heaters other than mine, the heat so produced is
simply the manifestation of the work performed in forcing the electric current through
this substance and varies in quantity directly with the capacity of the conductor and

page_text: the variation in resistance offered to the passage of a given current through such
resisting substance. The resisting substance is usually metallic and is ordinarily used
in the form of wire bent into convenient shapes so as to include within a small space
great length of wire. Former heaters have therefore depended simply on the
resistance of the heating wires for the generation of heat. This has necessitated the
use of coils of great length and with large heating surfaces, no portion of which
ever becomes very hot and the useful radiation of heat therefrom being very slow.
I have discovered a process by which I am able to produce incandescence of the
heating wire with a reduction of the electrical energy now utilized to produce black
heat in such wire; have discovered how to use well known materials so that the
heat thus produced can be retained for a long period of time; and have devised
and provided means and structures with which such heat can be successfully and
economically utilized.
It is well known that when an electric current flows through a conductor there is
produced around that conductor a field of force analogous to that existing between
the poles of a magnet. It is likewise well known that the field of force thus
produced is helical and that it advances in the direction in which the current is
flowing through such conductor with a rotary screw motion.
According to my invention I utilize the fields of force surrounding conductors for
the production of further quantities of heat than are produce by the simple
resistance of the heating wire and I effect a great saving of current by carrying the
heating conductors to incandescence and there maintaining them at the point of their
highest resistance and at which the ratio of heat units to current strength is far greater
than at any other point.
If two or more parallel conductors which have flowing through them in the same
direction currents of substantially equal strength, or if the parallel convolutions of a
solenoid through which a current of electricity is passing be placed sufficiently close
together a very considerable interference results between the fields of force surrounding
these conductors or convolutions and heat is produced thereby. If the current or
currents be made to flow in opposite directions in the two conductors or the contiguous
sections of the same conductor there results even more violent disturbance of the fields
of force surrounding these conductors, the forces of these fields being brought into
greater conflict with each other and the amount of heat produced being thus greater
than when the currents flowed in the same direction.
I have discovered that the more intimately the convolutions are formed-thus
causing a greater interference between the lines of force-the quicker the point of
incandescence is reached in the wire and the lesser becomes the consumption of current
necessary to produce and maintain the same. The reason for this will be apparent
when it is considered that this incandescence results from two components, the heat
developed by the resistance of the wire and that produced by the clash of the fields
of force surrounding the conductors. These fields of force become rapidly more
dense the closer the approach is made to the wires which the said fields surround.
When the wires are brought close together the influence of this component to
the production of heat rapidly increases and less heat developed by the resistance of
the conductor is necessary to obtain the required incandescence.
It is due to the influence of this component that the leading wires are not fused by
the current required for the use of the heater, for while the starting current is very
great and may bring the leading wires to red heat, as soon as the heater becomes hot,
the resistance of the same becomes so much greater that the current passing becomes
much smaller and, when luminosity is produced the leading wires are not heated above
black heat. This fact very much increases the durability and economic value of the
heater. As the wires are brought close together, however, the danger of short
circuiting becomes very great. To minimize this danger and to enable me to bring
the convolutions as close together as possible, I apply the well known principle that
parallel conductors or the adjacent convolutions of a single conductor with currents
or current passing in the opposite direction repel each other while with the current
flowing in the same direction they are attracted and more readily short circuited.

page_text: In carrying out my invention I prefer to so arrange the conductor or conductors
composing my heater that the currents in any two adjacent convolutions shall flow in
opposite directions carrying the current first in one direction as through a solenoid
and discharging at the same end of the coil at which it entered. I thus utilize most
advantageously the new process in electric heating which I have discovered. So
perfect is the incandescence that I can obtain by utilizing such method of winding,
that the coronas surrounding the individual convolutions of wire blend and the heater
becomes one incandescent mass while the current required is less than that required to
produce black heat in the present heaters.
To retain the heat produced I partially embed, or surround the electric conductors
with substances that have great heat retentivity, where duration of heat is desired.
which substances should be non-conductors of electricity but reasonably good
conductors of heat. For this purpose I preferably use asbestos in the form of
paper cloth or packing, though other substances possessing like qualities may be used
if desired.
In the construction of heaters I find two general classes, namely
First. That in which it is desired to radiate from the heater into the air the
largest possible proportion of the heat produced. Of this class of heaters those used
in heating buildings, rooms, cars, and stoves, may be mentioned.
Second. Those in which it is desired to retain in the heater for the heating of
articles immediately adjacent thereto, as large a proportion of the heat as possible.
Of this class examples are heaters used in ovens, coffee-pots, chafing-dishes, and
the like.
For the first class of heaters, namely that where radiation of heat is desired, I
enclose the coils in vacuous air-tight chambers thus avoiding the loss of heat due to
convection of air currents.
In the second class of heaters, namely that where radiation into the air is not
desired but rather to be avoided, air is not pumped out as the convection currents aid
in confining the heat to the surface to be heated. The heating coils are confined in
air-tight chambers however as after the first heating all of the oxygen of the confined
air is used up and oxidation of the conductors is impossible.
The heaters may be variously constructed and generally consist of two or more
parallel conductors or the adjacent convolutions of one conductor in contiguous
sections of which the current flows in opposite directions and so arranged in relation
to each other that the fields of force surrounding said contiguous sections oppose,
interfere with, or "cut" each other, said conductors or conductor being enclosed in
an insulating and refractory substance such as asbestos paper or cloth wrapped
around a cylinder used as a core and upon which the wire is so wound that in
adjacent turns the current flows in opposite directions so as to enable the coils to
be wound close together without danger of short circuiting. The wires may be wound
forward and then back or side by side the result being the same in either case, the
wire being wound tightly so as to embed itself in, and be retained in position by, the
asbestos covering of the core.
To prevent loosening of the coils by expansion plastic asbestos composition which
dries hard and refractory is pressed between the coils which may furthermore
be covered with a wrapping of asbestos or asbestos paper and enclosed in an outer
cylinder or shell, the joints between the core and shell being packed air-tight and
the shell exhausted of air.
The winding may be continuous from end to end or divided in sections which may
be placed in series or multiple for regulating the heat produced.
For certain purposes, as for heating cars and buildings, internal and external
layers of refractory material may be of considerable thickness in order to give the
heater such heat storing capacity as to prevent sudden fluctuations of temperature
by the temporary cessation of the current incidental to the various circumstances of
working. By exhausting the shell of air radiation of heat is facilitated and oxidation
of the coils is avoided so that they may be heated to incandescence without injury

page_text: in order to obtain from a given length of wire the maximum resistance and intensity
of heat with the minimum consumption of current.
In applying the heater to a vessel, a coffee-pot for instance, the heater would
surround the lower part of the vessel of reduced diameter and enclosed in an air-
tight asbestos-lined casing with a considerable space between it and the coils
which as radiation of heat is to be avoided would not be exhausted of air, the
oxygen in the contained air being soon used up and not renewed so that the
oxidation is very slight.
The heater for a chafing-dish, a cooking or other stove, would be similarly or
otherwise arranged. A safety connecting plug of special form is provided on cooking
utensils and the like to prevent short circuiting or shocks. It consists of a plate
with an elliptical aperture having holes at the sides thereof in which the heating
coil terminals are countersunk, the leading in wires from the main circuit being
connected to spring contacts on an elliptical plug having a cam-shaped shank so
formed as to only permit its entrance into the elliptical aperture when so presented
thereto that their long diameters correspond when so inserted and turned a quarter
round the spring contacts enter the holes and complete the circuit.
It will be obvious that my invention is in no way confined to the particular
forms of heaters described but may be applied to other forms with equal
advantage.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The production of heat by the passage of an electric current through two or more
conductors, or the adjacent convolutions of one conductor so arranged that the current
flows in opposite directions in contiguous sections thereof so that the fields of force
surrounding the same shall oppose or interfere with or "cut" one another substantially
as described.
LIOTO rave Auch lay
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.