Improvements in or relating to the Electric Treatment of Metal or other Bodies.
Year: 1892

page_text: Date of Application, 14th Apr. 1892
Complete Specification Left, 26th May, 1892-Accepted, 14th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Electric Treatment of Metal or
other Bodies.
We, CARL HUBERT AUGUSTE HOно, Engineer, of 138 Rue Belliard Brussels
and EUGENE AUGUSTE CLEMENT LAGRANGE Professor at the Military School,
Brussels, in the Kingdom of Belgium, do hereby declare the nature of this inven-
tion to be as follows:-
When, in an electrical circuit, the current passes directly from a body which is
a good conductor of electricity, into one that is not so good a conductor, heat will
develop at and near the contact surfaces of the two bodies, the magnitude of which
mainly depends on the nature, form and extent of such contact surfaces, i.e. is
proportionate to the electric resistance which the circuit meets with at that point,
and to the square of the intensity of current. This heat may become very intense
especially if the contact surfaces are comparatively small.
Advantage may be taken in a general manner from the heat generated by the
electrical current under those circumstances in assisting various chemical, physical
and mechanical operations to which the bodies may be submitted, especially when
it is required to raise the temperature of the metals to a given degree at a pre-
determined point for the purpose of subjecting it to a given chemical, physical or
mechanical operation.
Our object consists in the industrial application of this principle in the way we
will now proceed further to explain.
The fact that there exists in an electrical circuit, a greater or less electrical
resistance at the point of contact of one body, being a good conductor, and another
body which is not so good a conductor, and that this resistance gives rise to the
generation of a more or less considerable amount of heat, whenever an electric
current passes that point, will be observed especially when a metal bar is immersed
more or less in a conducting liquid, and if the contact surface of this bar with the
liquid is small in proportion to the size of the bath in section, taken normally in the
direction of the current. In this case, contact being produced between a good
conductor of electricity and a conducting liquid, the generation of heat at the point
of contact becomes very energetic under certain circumstances and presents certain
peculiarities which we shall now point out. Suppose we form an electrical circuit
the two extreme poles of which are the poles of a source of electricity, those two
poles communicating respectively, the one with a conducting liquid contained in a
suitable basin or vessel, the other with an electrode consisting, say of a metal bar
any desired description, and suppose we then close the circuit by a more or less
deep immersion of the bar into the bath. During the passage of the current there
will form upon the parts or surfaces of the metal plunged in the bath a layer of gas
enveloping like a sheath, as it were, the part of the metal bar thus immersed, this
varying on certain conditions depending on the size of the contact surface, the
nature of the liquid, and the electro-motive force of the current. The electrical
current, in issuing from the metal and entering the liquid has to pass through this
gaseous film, by which the electrical resistance at the contact surface is increased
far beyond its normal extent. Thus by this contact an additional resistance of a
peculiar kind is created, and one that may in certain cases be exceedingly powerful,
so that the current in passing this point undergoes a rather considerable fall of
potential and a great part of the energy of the current transforms into heat.
of
The current to be employed, in order to produce this action, depends necessarily
upon the nature and size of the bodies and of the liquids in contact; in general the
electro-motive force has a rather considerable value, whilst the intensity has a

page_text: relatively feeble value; this circumstance distinguishes clearly our method of
electrical heating froin all others now known.
It should be observed that if the solid body constitutes the negative electrode it
will undergo, as an effect of this passing current, a chemical reducing action, or an
action which will favour or promote its chemical combination with the positive
elements of the electrolyte. If on the contrary this body forms the positive
electrode, it will be subjected to a chemical oxidising action or to an action which
will assist its combination with the negative elements of the electrolyte.
As the heat producing action takes place at the point of contact between the
electrode and the electrolyte and in immediate vicinity to this point of contact, the
heat may at this point promote or produce chemical action either upon the body
constituting the electrode, or upon and between several bodies forming this electrode,
or again between such bodies and the electrolyte, or the bodies which could be
added to the electrolyte, no matter whether the electrolytic action of the current is
made use of or not.
It will be found that, under the same circumstances at the contact between the
electrode and the electrolyte, particles of the metal at the surface of the electrode,
or particles of foreign matter which may adhere thereto, will be separated from the
electrode. These facts are important occurring as they do in connection with both
alternate and continuous currents; with alternate current however, the chemical
actions are different.
The contact between the solid body and the liquid may be established in any
suitable manner, by immersion (total or partial), by surfaces or by tangency, by
the liquid being poured or sprinkled over the other body, (in the condition of vapour
or steam if required) etc. The liquid may also be introduced into the solid body.
But at all events it is necessary that the solid body and the liquid should each
be connected with one of the poles of the source of electricity.
To localize the calorific action upon and in the solid body at the given point, the
surface of contact with the liquid may be limited by enveloping the other parts of
that body in, or covering it with, a suitable insulator, or by making provision for
the current to start at a point calculated to favour localization of heat. This
insulator of the solid body may at the same time contain the liquid, for example it
may consist of clay, or like plastic, or any other, material. The insulator may in
this case be extended and assume the shape of a basin, ladle or other receptacle,
containing the liquid in which the action is to take place.
All that has above been said in reference to electrical contact between one solid
body and a conducting liquid will also apply to those cases where two or more solid
bodies are brought into contact with liquid.
bodies
Let it be pointed out that the liquid to be employed may be of any nature,
provided that it be more or less conducting, and also that it
in solution in suspension or otherwise.
may contain any
Let it also he pointed out that instead of liquid, moist or soaked bodies, consistent
or not, such as porous bodies capable of absorbing large quantities of liquid,
i.e. sponges, may be employed, and it will frequently be found easier to make
contact precisely at a given point between a solid body and a substance of this
class, than between a solid body and a liquid.
The liquid, which may be of any desired or suitable description, may contain any
solid or other foreign substances that may be required.
From the foregoing it will be understood that the arrangements or methods
described will advantageously and particularly apply to the treatment of metals by
electricity, where it is required that a high temperature should be attained at certain
points, as in soldering, forging, hammering and other similar operations. It will
also be understood that by this process the welding and cementing of various bodies
by electricity may be most rationally carried out, as may also be the electrical
heating of bodies for tempering or hardening purposes. The same may be said of
those operations which require the bodies to be melted such as casting, moulding
and the like.

page_text: It is to be observed that the bodies to be submitted to the calorific action of
the current may be acted upon indirectly. They may for example, be enclosed for
the purpose in a casing or mould which is then submitted to the heat producing-
action.
And lastly it should be observed that the fact, that a calorific action and a
chemical (electrolytic) action take place simultaneously upon the contact surfaces
between an electrode and a liquid, when a current is sent through them under certain
conditions, and also a mechanical action which consists in the separation of particles
of the bodies themselves or of foreign materials, may be put to advantage in
cleaning metal surfaces of all kinds.
This invention, then, consists upon the whole in the industrial application of the
phenomenon observable under certain conditions and with the results indicated,
when a solid body and a conducting or appropriated liquid are brought into electrical
contact, for heating bodies rapidly and economically to the desired degree, which
may be very high, while operating in a medium which according to the nature of
the bath, may be neuter, reducing, oxidising or favouring any chemical action,
which from a practical point of view is very important.
The principle of this invention may be carried into effect in connection with
processes and by means of apparatus of any usual or well-known description both
as regards the generation and control of the electric currents and the appliances to
be used in the particular work it is desired to perform.
Dated this 14th day of Annil 1800
W. P. THOMPSON & BOULT,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or relating to the Electric Treatment of Metal or
other Bodies.
We, CARL HUBERT AUGUSTE HOHO, Engineer of 138 Rue Belliard Brussels,
and EUGENE AUGUSTE CLEMENT LAGRANGE, Professor at the Military School,
Brussels, in the Kingdom of Belgium, 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:-
The present application for a patent has for object to claim the principle and
its different industrial applications of a new method of production of heat by means
of the electrical current.
Let us first explain the principle and the considerations which are connected
with it.
In a given body submitted to the calorific action of a current, the quantity of
heat which is produced in it by the passage of the electrical current in a given
time, is proportional to the electrical resistance of this body and to the square
of the intensity of the current. If this resistance of the body is relatively small,
as is the case with metals, the intensity of the current has to be relatively very
large with a very small electromotive force in order to produce the quantity of
heat necessary to render it incandescent.
The many difficulties resulting in practice from the effects of this fundamental
law are easily understood and it is to this circumstance that must be attributed
the little importance which was hitherto taken by the electrical production of heat
in its different applications to industry in general.
It is important for the practicability and the economy of the system that the
intensity of the current should be as small as possible with a rather large electro-
motive force. This is precisely the problem we have solved, by creating at the
passage of the current a natural resistance having a rather considerable value and
localized to the parts of the bodies to be heated. To obtain those effects by inter-
calating a liquid body in the electrical circuit, so that the part of the solid body to

page_text: be heated be in contact with the liquid, and the greatest resistance to the current
may be on the surface of this contact.
In order to show this fact, suppose as an example we form an electrical circuit
as in Figure 1 the two extremes poles of which are the poles of a source of
electricity d those two poles communicating respectively, the one c with an electrode
of large surface in a conducting liquid b contained in a suitable basin or vessel a,
the other with an electrode which shall be the body to be heated consisting say of
a metal bar of any desired description e and suppose we then close the circuit by a
more or less deep immersion of the bar into the bath. During the passage of the
current if the electromotive force is high enough there will form upon parts or
surfaces of the metal e plunged in the bath b a layer of gas, enveloping like a sheath
the part of the metal bar thus immersed. The electrical current passing from one
electrode to the other, through the liquid, preferably from c toe has to pass through
this gaseous film, by which the electrical resistance of the electrode e at the contact
surface is increased far beyond its normal extent. Thus at this contact an
additional resistance of a peculiar kind is created, which we will name a gazo-
electrical resistance, and which may in certain cases and according to the nature of
the liquid be exceedingly great, so that the current in passing this point undergoes
a rather considerable fall of potential, and the greatest part of the energy of the
current transforms into heat.
Different interesting properties result from the phenomenon produced by the
formation of this gaseous sheath.
1. The localization of the additional resistance, created at the surface of contact
between the electrode and the electrolyte causes the calorific action to carry itself
only at those points of contact and in their immediate vicinity, and this action to
be localized at those points.
2. The heat which is produced may be regulated at will, by the composition of
the liquid, or by electrical or mechanical means, and may reach the highest
temperatures such as have not yet been obtained in industry.
3. If the solid body constitutes the negative electrode it will undergo, as an
effect of this passing current a chemical reducing action, or an action which will
favour or promote its chemical combination with the positive elements of the
electrolyte. If on the contrary this body forms the positive electrode, it will be
subjected to a chemical oxidizing action, or to an action which will assist its
combination with the negative elements of the electrolyte.
4. As the heat-producing action takes place at the points of contact between the
electrode and the electrolyte and in immediate vicinity to these points of contact,
the heat may at these points promote or produce chemical actions either upon the
body constituting the electrode or upon and between several bodies forming this
electrode as for example in the arrangement shown in Figure 2, or again between
such bodies and the electrolyte, or the bodies which could be added to the
electrolyte, no matter whether the electrolytic action of the current is made use
of or not.
5. It will be found that under the same circumstances at the contact between
the electrode and the electrolyte particles of the metal at the surface of the
electrode, or particles of foreign matter which may adhere thereto will be separated
from the electrode.
6. The gaseous sheath enveloping the electrode becomes luminous, and this
electrode becomes rapidly incandescent thus producing a strong light in the liquid.
These different facts are important; we desire in a general way to utilize them
for the chemical, physical and mechanical treatments of the bodies and for the
calorific actions to which the bodies may be submitted, for instance in the following
ways:
A. When it is desired to carry those bodies, more particularly metals, to a
rather high temperature in a given part, or in given points of their mass, for
instance, for welding (Figure 4) soldering, forging, hammering, laminating and
similar operations.

page_text: B. When it is desired to carry metallic or other bodies to incandescence, for
instance for the production of electric light (Figure 10).
C. In the operations for the purpose of melting or softening solid bodies and
in those for the purpose of cementing annealing, casting, moulding etc. bodies.
D. When it is desired to heat bodies in order to temper or to harden them
especially metals.
E. For the cleaning of metallic surfaces, by the separation of superficial particles,
or of foreign matter which may adhere to them.
F. For the treatment of ninerals (Figures 7 and 8).
G. For the melting of certain bodies which require very high temperatures,
which cannot now be reached in industry.
H. For the operations of the industrial chemistry.
Those applications of the described process are only given as examples, this
process being essentially applicable to all operations in which the bodies are to be
submitted to calorific actions, in order to produce or favour chemical, physical or
mechanical actions of any kind.
The quantity of current to be employed in the applications of the described
process, depends necessarily upon the nature and size of the bodies and of the
liquids in contact, but in principle, the electromotive force has to be relatively high,
whilst the intensity is small, and this constitutes a characteristic, and one of the
great advantages of the system.
Although the continuous current may seem to be preferable to the alternating
current, this latter may be employed, but the chemical actions, caused by the
electrolytic action of the current, are different.
The contact between the solid body and the liquid may be established in any
suitable manner;-by immersion (total or partial) (Figure 1) by surfaces or by
tangency, by the liquid being poured or sprinkled over the other body (in the
condition of vapour or steam if required) (Figure 5) etc. The liquid may also be
introduced into the solid body. But at all events it is necessary that the solid
body and the liquid should each be connected with one of the poles of the source of
electricity.
To localize the calorific action upon and in the solid body at the given points,
the surface of contact with the liquid may be limited by enveloping the adjacent
part of that body in, or covering it with a suitable insulator, or by making
provision for the current to start at a point calculated to favour localization of
heat. This insulator of the solid body may at the same time contain the liquid, for
example it may consist of glass, of amianth, of clay, (Figure 3) or like plastic, or
any other material. The insulator may in this case be extended and assume the
shape of a basin, ladle, or other receptacle containing the liquid in which the
action is to take place.
All that has been said above in reference to electrical contact between one solid
body and a conducting liquid, will also apply to those cases where two or more solid
bodies are brought into contact with suitable liquid (Figure 2) when those bodies
are connected to the same pole.
Let it be pointed out that the liquid to be employed may be of any nature, pro-
vided that it be more or less conducting and also that it may contain any solid or
foreign substances in solution, in suspension or otherwise, and this in order to
appropriate it to the circumstances and nature of the applications.
Let it also be pointed out that instead of liquid, moist or soaked bodies, consistent
or not, and also porous bodies capable of absorbing large quantities of liquid, such
as sponges, amianth, sand, stones, the piled coal and other may be employed. It
will frequently be found casier to make contact precisely at given points between
a solid body and a substance of this class, than between a solid body and a liquid
(Figure 6).
It is to be observed that the bodies to be submitted to the calorific action of the
current may be acted upon indirectly. They may for instance, be enclosed for the

page_text: purpose in a casing or mould, which is then submitted to the heat-producing action
(Figures 7 and 9).
Lastly it should be observed that if, instead of being put in contact with a liquid,
the solid body was put in contact with another solid body less conducting, for
instance, by putting it (totally or partially) in an ore such as the pyrolusite a more
or less considerable resistance will also appear, localized at the points of contact
and in their immediate vicinity, and the calorific action of the current will also be
localized in these points; indeed in this case, the bodies which are in presence,
disengage generally; under the action of the heat, a sufficient quantity of gas or
gaseous liquid, to constitute a gascous film which shall be, more or less accentuated,
according to the nature and the compositions of those bodies.
This invention, then, consists upon the whole in the industrial application of the
phenomenon observable under certain conditions, and with the results indicated,
when a solid body and a conducting or appropriated liquid are brought into elec-
trical contact, for heating bodies rapidly and economically to the desired degree,
which may be very high, while operating in a medium, which, according to the
nature of the bath and the electrolytic action may be neuter, reducing, oxidizing,
or favouring any chemical action, which from a practical point of view is very
important.
The principle of the invention may be carried into effect in connection with
processes and by means of apparatus of any usual or well-known description both
as regards the electric currents and the appliances to be used in the particular work
it is desired to perform.
To carry out this invention it is sufficient to establish within the circuit of a
sufficiently powerful source of electricity, a switch or contact-breaker, a rheostat, a
voltmeter and an ampèremeter, and also a reservoir filled with the liquid suitable
for the particular work to be performed. Into this liquid will be immersed on the
one hand a large stationary electrode and on the other hand a movable electrode,
being the body to be heated, the portion which it is intended to heat only being
immersed. When this arrangement is completed, it is only necessary to turn on
the switch and properly to adjust the power and tension of the current by means of
the rheostat. Generally speaking it is preferable that the body to be heated
should constitute the negative electrode. The liquid containing reservoir in this
arrangement may be regarded as a substitute of the apparatus now employed in
most industries in heating bodies, such as the furnaces of forges and the like.
The above description will be best understood by reference to the accompanying
drawings in which,
Figure 1 is a longitudinal section in which a designates any suitable receptacle
or chamber such as a wooden box for example, adapted to contain liquid (b).
c is a metal electrode preferably of lead or copper, but which may be made of any
suitable conducting substance such as carbon. This electrode is connected by a
conductor to the source of electricity d which may be an electrical machine, a
primary or secondary battery, or the like. e is a metal piece partly immersed in
the liquid b and connected to the source of electricity d.
Assuming the circuit to be closed, it will be seen from the figure that an electro
gaseous envelope forms around the immersed portion of the piece e.
Figure 2 is a plan of the same arrangement as that shown in Figure 1, though in
this case the electrode e consists of two parts connected to the same pole.
Figure 3 illustrates the localization of beat at a given point of a bar e.
The basin may be of
a represents a basin containing liquid 6 and the electrode c.
any suitable material, but plastic clay is that which we would suggest in preference.
Figure 4 is a plan illustrating the employment of the process in connection with
the soldering together of two metal bars e e, the portions to be heated for this
purpose being immersed in the conducting liquid both bars being connected to the
same pole. The portion of the bars to be soldered are compressed by hand or by
any suitable device or mechanism,

page_text: Figure 5 illustrated a case where the liquid is replaced by a moist body such as
water or steam jet bissuing from a conducting pipe c and localizing the action
of heat upon an electrode bar, the circuit being formed by the parts debe and d.
Figure 6 shows an example of localization of heat at one single point of a metal
piece e by applying to that point a moist body such as an asbestos sponge 6 soaked
with liquid, the current being sent into the sponge by a contact piece c.
Figure 7 illustrates an instance where the heat is transmitted to the bodies to be
heated through the medium of a receptacle. e is the receptacle or crucible made
of conducting material such as carbon, graphite, or any other material capable of
resisting high temperatures. is the body to be heated or melted, such for example
as an ore.
Figure 8 shows the manner in which the process may be applied to the treatment
of ores or the melting of bodies by the heat developed through contact with an
electrode or electrolyte. b is the ore or body placed in the liquid contained in the
receptacle a in which the electrode e is immersed which is the seat of the calorific
action produced upon the mass.
Figure 9 illustrated an instance of the employment of the process for hardening
or tempering heated bodies either by simple conductibility or by radiation. In
the figure the body to be tempered or hardened, say a glass, is contained within a
conducting envelope or case e directly heated by the action of the current, either
throughout or partly, and retained for this purpose more or less deeply immersed
in the liquid b. When the body to be hardened has been sufficiently heated, the
current is cut off and the heated body is immersed into the liquid with or without
the above mentioned envelope.
Figure 10 illustrates the application of the process, to incandescent lighting. In
an open globe, containing conducting liquid b, a carbon "pencil" or point e is
plunged, or e may be of platinum or any other suitable material if preferred.
It penetrates to the required extent into the liquid and the portion thus immersed
is heated to incandescence. The globe is closed at its base by a metal piece C
forming an electrode.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is;
1. A method for the electrical production of heat caused in a circuit by the
creation and utilization of an additional gaso-electrical resistance, appearing and
localizing itself at the passage of the current at the points of contact of a solid
body with an appropriated liquid, or with a moist or soaked body, consistent
or not.
2. The method described for the electrical production of heat obtained at the
points of contact of a solid with a liquid or moist body, sufficiently well conducting,
interposed in an electrical circuit, this liquid or moist body being appropriated with
or without the electrolytic action of the current, so as, at will, to be neuter oxidizing,
reducing or favouring any chemical action.
3. A method for the electrical production of heat caused in a circuit by the
utilization of the particular resistance, which appears and localizes itself, when a
current passes at the points of contact between a well conducting body and a less
well conducting body, when this latter may produce gases or vapours which interfere
in the circuit, between the two bodies.
4. The methods described for the electrical production of heat applied to two or
more bodies, forming electrodes of the same name, in contact with an appropriated
liquid or moist body.
5. The application of those methods to the electrical treatment of metals for
welding, soldering, forging, hammering, laminating and other similar operations, by
the localized beating of the pieces to be submitted to those operations and forming
5 electrode in an appropriated liquid or moist medium.
6. The application of those methods for melting, softening, annealing, cementing

page_text: of metals and other bodies, by the heating of the pieces to be submitted to
those operations and forming electrode in an appropriate liquid or moist medium.
7. The application of those methods for tempering and hardening by the electrical
heating of the pieces to be submitted to those operations and forming electrode in
an appropriated liquid or moist medium.
8. The application of those methods to the treatment of minerals either by
melting or direct heating of the materials forming electrode in an appropriated
liquid or moist medium, or by melting or heating of those materials obtained
by the heating of the crucible which contained them, this crucible forming electrode
in an electrolyte.
9. The application of those methods for cleaning of metallic surfaces, by the
simultaneous combination of the calorific chemical and mechanical action in an
appropriated liquid or moist medium where the current produces the separation of
the foreign matters from the metallic surfaces.
10. The application of those methods for carrying a body to incandescence, in
order to produce light in a liquid or moist body.
11. The application of those methods to all the preceding operations by the
localized heating of the bodies to submit to those operations and simply put in
contact with an appropriate liquid or moist body.
12. In the preceding application, the heat being transmitted to the bodies to be
submitted to its action, by the medium of a casing or mould which is heated by the
methods described.
13. In the preceding applications the system described of an insulation on those
parts of the bodies which are to be withheld from the action of the current, this
system of insulation being or not extended so as to assume the shape of a receptacle,
in which the action is to take place.
14. In all these applications, the appropriation of the liquid or of the moist
body, by the addition, in solution, in suspension, or otherwise, of all foreign matters,
solid or not, in order to favour the chemical physical or mechanical actions,
according to the circumstances and the nature of the applications.
15. In all these applications, the combination of the claimed methods with all
other processes.
Dated thin oath day of May 1800
W. P. THOMPSON & BOULT,
Agents for the Applicants.