US806690A - Electrical ring-furnace. - Google Patents

Description

PATENTEB DEG. 5, 19057 E. MESBRn BLEGTRIAL RING FURNGE.

APPLICATION FILED APE. 26. 1904.

5 SHEETS-SHEET PATENTBD DEC. 5, 1905.

K. MEISBR. ELECTRICAL RING PURNCFt APPLICATION FILED APR. 26. 1004.

5 SHEETS-SHEET 2.

Z'nss 66 gg? M r u we f No. 806,690. PATENTED DEG. 5, 1905. K. MEISBR.

ELECTRICAL RING FURNAGE.

APPLICATION FILED APR.26,1904.

5 SHEETS-SHEET 3.

5 SHEETS-SHEET PTENTBD DEC. 5, 1905.

v L7-nem @75%967 APPLICATION I www5@ PATBNTBD DBG. 5, 1905.

APPLICATION FILED APR.26, 1904.

K MEISER ELECTRICAL RING FURNAGE.

UNITED STATES KARL MEISER, vOF NUREMBERG, GERMANY.

ELECTRICAL RING-FURNACE.

Specification of Letters Patent.

Fatented Dec. 5, 1905.

Application fried April ze, 1904. serai No. 205,006.

To all whom', t may concern.-

Beit known that I, KARL MEISER, engineer, residing in Nuremberg, Germany, have invented certain new and useful Improvements in Electrical Ring-Furnaces, of which the following is a clear description.

The chief advantages otiered by the ordinary electric furnaces are that the latter allow high temperatures to be obtained and that they are very ecient and can be easily regulated. .Notwithstanding these distinguishing features, cases occur sometimes in practice where the use of an ordinary electric furnace would not be advantageous, either from an industrial or from a technical point of view. In such cases the new electric ring-furnace renders excellent services. It consists of a ringconduit in which several electric ring-furnaces are arranged. Of the latter but one isalways in operation, while the other furnaces are being cooled down or subjected to a preliminary heating. This is eifected by causing a current of air or of certain gases to circulate in the ring-conduit and to transmit the heat, a similar eti'ect being thus produced, like that obtained in the ordinary gas-heated ring-furnace, based upon the utilization of heated products of combustion. A

The new electric ring-furnace can be used in all those cases where good results are realized only when the material to be operated upon is heated very slowly-for example, in the manufacture of incandescent-lamp filaments. rIhe new electric ring-furnace will also iind application in the case of all those substances which are not capable ot' conducting electricity at an ordinary temperature, but become conductive in the presence of higher temperatures. It', for example, raw pressed electrodes for primary batteries were to be burned in an ordinary electric furnace, considerable difficulties would have to be overcome, the unburned electrode mass being nearly a non-conducting substance. In the present electric ring-furnace these difficulties are entirely avoided by subjecting the electrodes to a preliminary heating eiiect before they are used for conducting the electric current.

The invention is illustrated in the accompanying drawings, in which- Figure l is a plan view. Figs. 2 and 3 are sections on the lines A B and C D of Fig. 1. Fig. 4 is a plan view of a modiiication. Figs. 5 and 6 are sections on the lines E F and G I-I of Fig. 4L. Fig. 7 is a plan view of a still further modification. Fig. 8 is a section on line I K of Fig. 7, and Figs. 9 and l0 show a further modification.

Referring first to Figs. 1 to 3, the electrodes p and n, which convey the current, are arranged at the top and bottom of each chamber l 2 3, &c. The bottom electrodes remain always in position, while a top electrode is introduced only into that compartment which is just at work-vl. e., in the drawings into chamber 2. Chamber 2 is heated by electricity, chambers 8 and 1 are cooled down, chambers 3 t 5 are subjected to a preliminary heating, chamber 6 is recharged, and chamber 7 is emptied. The heat from chambers 8 l 2 is conveyed into chambers 3 4 5 by the circulating air, which enters into chamber 8, flows through chambers 1 2 3 L 5, and when slide t is open escapes from chamber 5 into conduit The latter can be connected with the chimney by means of a similar arrangement like that used in gas-heated ring-furnaces. However, the represented figures show a complete air circulation. It being a fact that while, on the one hand, a gas-heated ring-furnace requires a continuous supply of gas and oxygen, for which products ot' combustion are let ofi3 therefrom in corresponding quantities, the electric ring-furnace allows, on the other hand, a circuitous circulation of the air, which serves here only for conveying heat. In this manner any loss of heat in the chimney is avoided. A further advantage which the described construction has over gas-heated ring-furnaces is that there exists no longer any necessity to draw oftl the air from the last chamber at the lowest possible temperature. The new furnace allows the air to be drawn oi from the last chamber at as high atemperature as 50()D and even at higher temperatures, the entire heat which said air contains being passed into the first chamber without waste. The height of the temperature to be used for drawing ot'f depends solely upon what highest temperature the new charge can stand without disastrous etfect. In this case the electric ring-furnace with circulatory action has the advantage that only a small number of chambers is required, so that it can be constructed at a small expense. The circulation is obtained through a ventilator provided at e, which when slide a is open draws off the air from chamber 5 into conduit and forces it from here into conduit f. When slide g is IOO open, the air'passes from conduitf into chamber 8 and flows thereupon in the above-described manner through chambers 8 l 2 3 4 5. Chambers 5 and 8 are separated from the opened chambers 6 and 7 by slides c and (il. As soon as the heating of the charge contained in chamber 2 is completed top electrode p is withdrawn and introduced into chamber 3. The further operations of shifting slides c and d, of closing chamber 6, and of opening chamber 8 cause chamber 6 to be inserted in the circuit and chamber 8 to be put out of circuit, and so on.

In the electric ring-furnace represented in Figs. 4, 5, and 6 the electrodes are arranged horizontally, chambers 6 and 7 are again open, and chambers 8 1 2 3 4L 5 are inserted in the circuit. When slide /t is open, the air-current is drawn by the ventilator from cham ber 5 into cond uitz' and then pressed toward chamber 8, the slide v of which is also opened. In Figs. l, 2, 3 a stationary ventilator is used. However, the one required for the construction shown in the followingfigure is a movable electroventilator capable of being shifted according as the fire progresses. If, for example, chambers 7 8 are opened, the electroventilator is inserted into conduit f through aperture Z, which had been previously closed by a cover, the air being thus drawn 0H from cham ber 6 and passed toward chamber l.

In order to have the heat effectively transmitted by the air, the walls inclosing the material to be operated upon must of course be as thin as possible. In this connection the fact should also be mentioned that in the electric ring-furnace the material to be treated becomes the hottest part, while in a gasheated ring-furnace the products of combustion constitute the hottest substance. The circulating air acts, therefore, in the furnacechamber as a cooling and at the same time also as preserving mediuml upon the walls. This cooling action canbe regulated by means of adjusting the number of revolutions made by the ventilator.

While I have used the term air in the foregoing description, any other suitable gas can be used as a bearer of heat. rIhe use of air would of course represent the simplest method. However, it is almost as easy to work with mixtures of nitrogen and carbonicoxid gas or carbonio acid. rI`hese gases may be readily produced my means of throwing some live coal into the new chamber to be inserted. If other gases have to be used for the work, the chamber in question, which is closed at first by a cover and slide, must of course be filled with gas in order to expel all air before said chamber is inserted in the circuit. 'Ihe joints of the cover and the slide are made close, as usually, by means of clay or the like.

In many cases it is possiblel by the use of special gases to cause the material to be treated to be burned in the electric 'ring-furnace directly without being surrounded by a fireproof casing. An example which proves this assertion are the electrodes, which when nitrogen and carbonic-oxid are used for obtaining the circulating gas can be burned and treated with graphite without any protecting-case.

Figs. 7 and 8 showacombination of the new electric ring-furnace with the well-known gasheating ring-furnace. Such combination has the economical advantage that electricity, which is usually expensive, has only to be used for bringing about such increased temperature that can no longer be obtained with the aid of gas. In the figures, fm, is the gas-conduit, whence the gas enters into the furnacechamber-/. e., into chamber .Lof the figure; when the slides are accordingly opened. The gas is burned in said chamber with the heated air in the same manner as it is done in ordinary gas-heated ring-furnaces. On reaching the highest gas temperature the gas is cut off and the electric current inserted. When heated by electricity, the furnace can work with circuitous air or gas circulation exactly as it has been described heretofore, so that no heat at all is lost hereby in the chimney. To this purpose chimney-slide r1. is closed and ventilator 0 is set to work. Willen the slides are properly opened, said ventilator draws ofi' the gas from chamber 8 and passes it through conduit 71 into chamber 11. In order that this gas fiowing from chamber 8 to chamber 1l may pass over the shortest course, slides c in the wind-conduit m are closed. In the described combined furnace all thc advantages of the electric ring-furnaces are also realized, except that no indifferent gases are used, the latter being' provided by the gases of combustion. Attention may finally be called to the arrangement of the electrodes shown in Figs. 7 and 8, which diifers from that represented in the other figures. In this case two furnace-chambers are provided for each compartment. They are connected in the bottom by means of a conductor t, both electrodes being thus placed above the furnace.

A modified execution is also represented in Figs. 9 and l0, allowing the furnace-chambers themselves to be combined to a ring-conduit. In the latter the material to be treated is arranged alternately with electrodes p. Two particular electrodes are connected with the circuit, so that the current circulates between them. The air circulation is as before described.

Having thus described my invention, what I claim isl. An electric ring-furnace comprising' a ring-conduit, a series of chambers therein, means for electrically heating said chambers, a second conduit, connections between the ring-conduit and said second conduit, slides controlling said connections, a passage leading from the second cond uit, connections from IOO IOS

IIO

10 second conduit, connections from said passage to the chambers and slides controlling said connections and a Ventilator for producing a circulation of air and gas.

ln witness whereof I have hereunto set my hand in presence of two witnesses.

KARL MEISER.

Witnesses:

ANDREAS STIcI-I, HENRY B. MEIsER.

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