Improvements for Operating Electrio Smelting Furnaces.
Year: 1886

page_text: Improvements for Operating Electrio Smelting Furnaces.
I, HERBERT JOHN HADDAN, of 67 Strand, in the County of Middlesex, Civil
Engineer, do hereby declare the nature of this invention, a communication to ine
from abroad by Eugene Hutchinson Cowles and Alfred Hutchinson Cowles, both
of Cleveland, Ohio, United States of America, Manufacturers, 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 for operating electric smelting furnaces,
in which an ampere meter and resistance box are respectively connected in the
circuit between the dynamo and the furnace, to the end that, by means of the
ampere meter, the strength of the current, passing through the furnace, is indicated,
whereby is made known the resultant effect inside the furnace so that the latter
may be properly charged and the resistance increased or diminished to keep the
strength of the current at a suitable medium necessary, alike for the reduction in
the furnace and for the durability of the dynamo, the resistance box being used as
an auxiliary governor in regulating the current.
Heretofore in operating electrio smelting furnaces, the utter failure in many cases
and the want of entire success in others, may be accounted for, I think, by the
guess-work-system under which these furnaces have been operated. The electric
smelting furnace, as thus far developed, is necessarily a closed structure, and there
seem but two clues from which to determine the progress and the quality of
the reduction taking place inside of the furnace to wit-the character of the flame
issuing from the vents of the furnace and the force of the current passing through
the furnace. Heretofore the indications, of the flame seem to have been wholly
relied on. This, however, did not furnish data from which to satisfactorily operate
the furnace, for instance, if from the character of the flame it was found that little
or no reduction was taking place in the furnace there was nothing to indicate
whether it was from the want of ore, or other material in the furnace, or from the
want of sufficient power in the electric current passing through the furnace.
I discovered that an accurate indication of the electric current is indispensable
in operating the furnace, successfully, and have therefore devised the combination of

page_text: an ampere meter with the furnace, said ampere meter being connected in the circuit
between the dynamo and furnace. By means of the ampere meter and flame I was
enabled to determine what should be done to regulate the current and operate the
furnace successfully, but a difficulty still remained. With a knowledge of what
was to be done, there was not always the means at hand for doing it. The force
of the electric current had been controlled either by regulating the motive power
of the dynamo, or by moving the electrodes nearer together, or farther apart, in
the furnace. The former was not desirable, and was not practical if more than one
furnace was being operated by the same motive power. The current usually
could be controlled by more or less separating the electrodes, but these should be
regulated primarily to give the best results in the furnace rather than to control
the current for extraordinary occasions.
I have therefore devised the combination of a resistance box with the furnace
and ampere meter, the said resistance box being connected in the circuit, and
usually, but not necessarily, between the ampere meter and furnace.
The motive
power is of course regulated to give approximately the electric current desired.
The electrodes are regulated to give the best results in the furnace provided the
proper current is had, and the resistance box is utilized as an auxiliary governor,
to control the current when it could not otherwise be regulated by the normal
action of the electrodes.
The accompanying drawing is a diagramatic view with parts in section of the
furnace, ampere meter, resistance box and dynamo arranged in a convenient order
in the circuit.
A represents the furnace, through the end walls of which are introduced the
electrodes B and B¹. The furnace has a cover A¹ with one or more vent-holes a in
the top for the escape of the waste products of combustion, and through which
from time to time fresh material, fuel, ore, etc may be fed to the furnace.
The electrodes are connected respectively with the wire C, leading to and from
the dynamo, and the electrodes may be moved end wise to increase or diminish the
distance between the inner end of the same, according as more or less resistance is
required in the furnace to develop the necessary heat for reducing the ores,
metals etc, being treated. These electrodes are manipulated, or operated auto-
matically as the case may be, primarily for treating the ores and are to regulate
the current solely to this end, for extraordinary occasions, such as switching the
current, etc, a resistance box D is provided.
E is an ampere meter that is likewise inserted in the circuit, and through whose
helix the entire current flows, indicating by its suction of a plunger armature e,
attached to a spring balance and dial-faced indicator e¹ the total strength of the
current being used. This ampere meter is an important element in the manage-
ment of the furnace, as by the position of the finger on the dial the furnace
attendant can tell to a nicety what is being done by the current within the
furnace. It is placed upon a shelf in a good light, near to and in full view of a
person in any position about the furnace.
Between the ampere meter and the furnace in the furnace room, and forming
part of the circuit, is placed a large resistance coil of German silver immersed in
water, a heavy copper slide passing backwards or forwards as desired, throwing
more or less of this resistance into the circuit, and almost the entire energy of the
current may be thus applied to heating water.
The object of the resistance box is to serve as a safety appliance. It is used by
the furnace operator when it is desired to change the current from one furnace to
another, or if it be necessary to choke off the current almost entirely before
breaking it by a switch, thus preventing serious flashing at the commutator of the
dynamo or at the switch. It is likewise of value should any evidence of a short
circuit appear in the furnace or elsewhere.
The peculiar style or make either of the ampere meter or of the resistance box is
not essential. Various kinds of either are in use that would answer the purpose
well if made of sufficient capacity. Their precise location in the circuit is a matter

page_text: of no consequence, so that they be conveniently located for the operator is all that
is required.
The ampere meter or resistance box, both or either of them, are not necessary in
the main circuit, but may, if preferred, be placed one or both of them in a shunt
current of the main circuit or a shunt current of the dynamo that may pass around
the field magnets of the ordinary type of dynamos.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed, I declare that what
I claim is
1. The combination, with an electric furnace, of an ampere meter connected in
the same circuit, substantially as set forth.
2. The combination, with an electric furnace, of a resistance box connected in
the same circuit, substantially as set forth.
3. The combination, with an electric furnace, of an ampere meter and resistance
box connected in the same circuit, substantially as set forth.
DOLL
1000