US665704A - Electric furnace. - Google Patents

Description

No. 665,704. Patented m. 8, mm. a. s. srnouc.

ELEOTBIGxFURNAGE.

(Applimtion flhd Apr. 4, 1896.)

(,llo Model.)

Inventor.

Witnesses.

Attorney.

No. 665,704. Patented Ian. 8, l90l. G. '8. STRONG.

ELECTRIC FURNACE.

(Application and Apr. 4, 1896.)'

3 Sheets-Sheet 2.

(No Model.)

Inventor. 6 58 Witnesses.

Attorney.

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Nu. 665,704. Patented Ian. 8. 'I90l.

G. S. STRONG.

ELECTRIC FURNACE.

(Application ma Apr. 4, 1300.) (lo Iodol.) 3 Shasta-She 3.

Witnesses. Inventor.

a v Zea .6, Attorney.

Tm: uonms Perms co. PHOTO-LUNG. vusmucrcn. a. c.

UNITED STATES PATENT OFFICE.

GEORGE S. STRONG, OF NEW YORK, N. Y.

ELECTRIC FURNACE.

3PEGIFICA'1ION forming part of Letters Patent No. 665,704, dated January 8, 1901.

Application filed April 4, 1896. Serial No. 586,182. \No model.)

To all whom it may concern.-

Be it known that I, GEORGE S. STRONG, a citizen of the United States, residing in the city of New York, in the county and State of New York, have invented a certain new and useful Improvement in Electric Furnaces, of which the following is a true and exact description, reference being bad to the accompanying drawings, which form a part of this specification.

My invention relates to electric furnaces, and has for its object primarily to provide for the attainment of an exceedingly high temperature in such furnaces. Particularly my invention relates to furnaces intended for the manufacturing of compounds such, for instance, as calcium carbid and in which some or all of the ingredients of the furnace charge are fed to the furnace in the form of electrodes, preferably formed and fed to the furnace from a plastic mass of the material, my present invention being in part an improvement upon the invention described and shown in my former Letters Patent, No. 587,343, of August 3, 1897.

The nature of myimprovements Will be best understood as described in connection with the drawings, which illustrate a furnace and devices used in connection therewith, which embody my improvements, and in which Figure 1 is a sectional elevation; Fig. 2, a plan view of a detail of the feeding mechanism; Fig; 3, an end view of the furnace, showing a certain portion of the feeding mechanism in section. Fig. 4is a cross-sectional view taken on the line 1 1 of Fig. 3. Fig. 5 is an elevation, partly in section, of the governing mechanism. Fig. 6 a plan, partly in section, of the valve and. valve actuating devices forming part of the governing mechanism; and Fig. 7 is a detail of the device for throwing fuel and air into the enveloping multiple A A is the furnace proper, which is of a type adapted to be heated by means of the electric are. As shown, the top' of the furnace (indicated at A) is arched, so that the heat will be reverberated from it to the part of the furnace where the greatest intensity of heat is required. The lower part A of the furnace is intended to serve as a receptacle for the calcium carbid or other material resulting from the treatment of the charge in the upper part of the furnace. The bottom A of the furnace is made movable, so that the accumulation upon it can be removed from time to time into the receiving-chamber A. It is important for the best results that air should be excluded or substantially excluded from the furnace A, and at the same time it is necessary to provide means for drawing off the gas generated in the furnace, and this I do in the plan shown by means of the flared-mouthed passage A in the crown of the furnace, this passage leading to a chamber A, from which chamber leads a pipe A having, as shown, branches A and A", controlled, respectively, by valves a and a. The branch A may lead to the atmosphere or into any convenient device for storing or utilizing the gases. The branch A, however, leads, as shown, through an open-ended pipe A to a nozzle or nozzles A, which in turn lead to an enveloping muffle A which last-mentioned muflie incloses as much of the furnace A as is practically convenient, A representing the escape pipe or stack of the muffle A and a indicating extensions of the muffle A the function of which will be hereinafter described.

B is a pipe through which liquid fuel is led to a nozzle B B being a pipe by which con1- pressed air is forced to the nozzle B lying within the nozzle B The nozzle B is entered into a flared extension a of the nozzle A and this flared extension a as well as the nozzle B lies in a conduit B, into which conduit open the pipes A and A It will be understood that oil or gas introduced through the conduit B and mixed with air from the conduit B will be thrown into the muffle A and ignited therein, thus heating this 111 uffle and through the inner walls thereof heating the furnace A, which furnace A is at the same time internally heated by the electrio arc. Obviously an exceedingly high temperature is obtainable in the furnace A by this means, and this is the prime object of my invention. Obviously also the valve a being closed and the valve a being open, the gases generated in the furnace A will pass, through the conduit A the chamber A, and the conduits A and A to the conduit B and thence through the nozzles A into the muffle A where they may serve as fuel for the said muffle, and at the same time the air neclOO essary to support combustion in the m uffie is drawn in through pipe A preheated by contact with the pipe A and passed thence through the conduit B and nozzles A to the muffle A cl indicates a sight-hole leading into the furnace opposite to the point where the arc is formed.

0 indicates a receptacle having a hoppershaped bottom 0, the opening of which lies directly above the flared mouth of the opening A 0 representing a conical valve by which this opening is closed or regulated, and C a valve-regulating wheel. Material to be treated is supplied to the receptacle C and fed at any desired rate of speed into the furnace A. I believe this device for feeding the furnace will be found convenient at times; but I contemplate its use principally as an adjunct to the method of feeding the furnace to be hereinafter described.

D D are electrode-guides, which should be made of material sufficiently refractory to resist the intense heatof the furnace and a material which is a good conductor of electricity. Preferably they are made of hard carbon.

E E are metal sockets in which the electrode-guides D are secured. As shown, these sockets are made hollow, and I preferably form them of iron. E and E are pipes connecting with the hollow sockets E at top and bottom and in communication with a watertank E Water is forced through one pipe through the socket E and back through the other pipe by any convenient pump or equivalent device, and the sockets are thus kept cool. lhe pipes E and E serve also as cond uctors for the electric current, which passes, for instance, from a connection F through both pipes to the socket E and from the socket E to the guide D. The current delivered to the one guide is positive and the current to the other guide negative.

G Gr are conduits or guides for the electrodes, made up of some highly-refractory material, such as brick, communicating, as shown, with the electrode-guides D D and preferably surrounded by the m uffies A a, which are preferably in communication with and form a part of the muffle A H H indicate metallic electrode-guides lying flush with the outer ends of the guides G G and flaring outward, so that their outer ends lie flush with a cylinder 1, with which they are in communication.

H H are feeding and pressing rollers which project into the narrower part of the flared portion H and are geared together by means of the pinions 7L2 h driven by the worm-wheel H which is seen red on the end of the shaft U 1 I are hoppers through which material is fed to the outer end of the cylinder 1.

J is a feed-screw working in the cylinder I and acting to force the material from the hopper 1 into the said cylinder and thence through the flared mouthpiece H into the guide H and thence through the guides G and D into the furnace A, the rollers ll" acting to compress and solidify the material as it passes from the cylinder to the electrodeguide.

J is the shaft of the feed-screw J, to which is secured the worm-wheel J driven by a worm J secured to the shaft .1, to which shaft is also secured the pinion J". This pinion is driven by a pinion K journaled on the shaft K, which in turn is driven by a mo tor, an electric motor being indicated, one at K and the other at and these motors, I will state, are arranged to run at different speeds corresponding with the consumption of the positive and negative electrodes in the furnace and so as to feed each electrode with a speed corresponding to its consumption.

K indicates a projecting hub of the pinion K upon which hub is secured an annular friction-surface K L is a clutch-supporting block having projecting arms L L, (see Figs. 3 and 4-,) L being a cylindrical jacket around the clutch, the clutch being keyed to the shaft K, as indicated at L L is a clutch-band lying in the cylindrical hollow of the clutch-block L and around the friction-surface K". The two ends of this clutch-band or friction-band are engaged by clutches L L each pivotally secured to setscrews Z and actuated by the wedge-shaped end of the pivot-lever L, said lever being pivoted at L and the link end L actuated by a link L with a sliding collar L the movement of this clutch along the shaft K being effected by its engagement with the arm L with a lever pivoted at L and the other arm L of which is actuated through the bellcrank lever M M, pivoted at M by the rod M. Each of the rods M is connected with the arms N of the bell-crank levers N N,pivoted at N N and normally forced outward by the action of the springs N N (See Fig.5.) The arms N N of the levers are connected by links 0 O with the pivot-pin O of a piston O",working in the cylinder P and connected through a port P with the valve-box Q. (Best shown in Fig. 6.) The valve-box Q is provided with an entrance-port Q for fluid under pressure, communicating with a chamber Q of the box, provided in addition with a chamber Q, communicating with the chamber Q through passage q", chamber Q communicating through passage Q with the port P, and the chamber Q communicating through port g with the chamber which chamber is in communication with the exhaust-passage Q Q Q indicate spring-boxes screwing into the valve-box, as indicated.

B and R are valves adapted normally to close the ports g and By means of pro jections R R on the valve-stems they are acted upon by the springs R R so as normally to keep them closed, and the valvestems (indicated at It It") project from the other end of the valve-box and are provided ITO with heads R R which heads rest upon or in close proximity to the oppositely-projecting arms S and S, which are secured to a sleeve S and journaled on a shaft S the sleeve S being also connected with a long lever-arm S which is connected, by means of the links S S, with the pivot-pin T of a rod T,the outer end of which, T is supported by a rigid slide and which carries a solenoidcore Tithe solenoid-coilbeingindicated at T as secured to a rigid part of the framing (indicated at T '1 being an adjustable thimble screwing into the framing T and carrying the spring T which acts to thrust the solenoidcore T out of the coils T and to hold the arms S and S, normally in the position indicated in Fig. 6. It is obvious, of course, that by passing a current through the solenoid-coil T the core will be attracted and acting on the rods and levers connected therewith will raise the arm S and depress the arm S, thus permitting fluid under pressure to enter through port Q, pass through chamber Q port g chamber and ports Q and P to the cylinder P, where it will depress the piston O and acting through the bell-crank levers N N and the connecting system described will move the sleeve L outward and by its means acting through the lever L L regulates the pressure which keeps the friction-band L' in action, and thus disconnect the pinion K from operative connection with the shaft K, stopping the feeding mechanism. On the other hand, the diminution or cessation of current through the solenoid-coils will permit the spring T to force the core T out of the coil, this action involving the closing of the valve R and the opening of the valve R, whereupon the fluid is permitted to escape from piston P through ports P and Q chamber port g chamber Q, and exhaustpassage Q whereupon the springs N N will at once cause the arms N N of the levers N N to move outward and acting through the described connections will reengage the clutch, coup-ling the pinion K to the shaft K and setting the feeding mechanism into operation.

It will be understood that the current which actuates the solenoid-coil T will be regulated in any of the well-known ways by the resistance developed to the passage of the are between the electrodes in the furnace A.

The material fed to the hopper I may be made up of a mixture comprising all the ingredients of the charge to be treated in the furnace or of only some of these ingredients, the other ingredients being fed or supplied to the furnace in some other way. The mass is to be of such a character that it will be aggregated or solidified by pressure or by the action of pressure and heat, to both of which it is subjected before reaching the furnace. It is fed continuously through the cylinder 1 through the flared mouthpiece H, passing the rollers H and then passing through the guides H, G, and D into the furnace, being suojected while passing through the guides G to a very high temperature derived from the muflie a and thus reaching the furnace already heated and very highly heated, so that the additional heat developed by the are springing from one electrode to the other will be sufficient to effect the desired chem ical combination with great rapidity.

VVhileI desire to make my electrodes proper as highly conducting as possible, it will be apparent that theircondnctivity will necessarily be much lower than that of carbon electrodes, and therefore it is that I find it advisable to use the electrode -guides D, made of some highly-conducting material, such as carbon, and projecting into the furnace, so as to give free way to the ends of the electrodes when in proper position for the formation of the arc. By this means I diminish very greatly the distance through which the electric cur rent must traverse to the-electrodes proper.

It is of course apparent from what has already been said that the heat to which the furnaces and the electrodes made up of the material of the charge are subjected is by my arrangement of the utmost possible intensity, the electrodes not only being highly heated before entering the furnace, but the furnace being heated not only by the intense heat of the electric are, but by the great heat developed in the enveloping muffle A and comm unicated through its walls to the inner furnace.

Having now described my invention, what i claim as new, and desire to secure by Letters Patent, is-

l. A furnace as A, in combination with a conduitor conduits, as G, leading into the furnace adapted for the feeding in of the material to be treated in the form of an electrode or electrodes, one or more m uffles, as a surrounding said electrode conduit or conduits, independent means for heating said muffles and means for heating the furnace A by the electric are including an electric circuit or circuits whereby current is conveyed to the electrodes in the conduits G.

2. A furnace as A in combination with means for heating the furnace internally by the electric are, a conduit or conduits as G leading into the furnace adapted for the feeding of the material to be treated, one or more muffles as A a surrounding said furnace A and said conduit or conduits G and independent means for heating the same.

3. A furnace as A in combination with means-for heating the furnace internally by the electric are, an enveloping muflie as A, means forheating said muffie independently and by combustion and a conduit leading from the interior to the enveloping muffle whereby gases generated in the electrically-heated furnace are led to the enveloping furnace and used for heating the same.

a. A furnace as A so constructed as to eX- clude air therefrom when in operation in combination with means for heating the furnace internally by the electric arc, an enveloping muffle as A means for heating said muffle independently and by combustion and a conduit leading from the interior to the enveloping muffle whereby gases generated in the electrically-heated furnace are led to the enveloping furnace and used for heating the same.

5. A furnace in combination with electrodeguides as D D formed of refractory and conducting material and extending into the furnace,electrical connections to each said guide, means for forcing into the furnace electrodes made up of an aggregated mass of some or all of the ingredients of the furnace charge and independent means for raising said electrodes to a high temperature situated adjacent to the furnace.

6. A furnace in combination with electrodeguides as D D formed of refractory and conducting material and extending into the furnace,electrical connections to each said guide, means for forming and forcing into the furnace electrodes made up of an aggregated mass of some or all of the ingredients of the furnace charge and means for raising the said electrodes to a high temperature situated between the forming mechanism and the furnace.

7. A furnace in combination with means for forcing into the furnace electrodes made up of an aggregated mass of some or all of the ingredients of the furnace charge, hollow sockets E at the end of the conduit through which the electrodes enter the furnace, Waterpipes leading to and from said sockets and carscarce bon electrode-guides D seated in said sockets and projecting into the furnace.

S. A furnace in combination with means for forming and forcing into the furnace electrodes made up of an aggregated mass of some or all of the ingredients of the furnace charge, hollow sockets E at the end of the conduit through which the electrodes enter the furnace, Water-pipes leading to and from said sockets and carbon electrode-guides D sealed in said sockets and projecting into the furnace.

9. The combination with an electricallyheated furnace as A, of an inclosing muffle as A a conduit leading from the electricallyheated furnace to the inclosing muffle whereby the gases generated are led into the outer muffle, an air-supply pipe for the outer muffle arranged to inclose a portion of the said conduit and means for injecting fluid fuel and air into the enveloping or outer muffle.

10. In combination with an electric furnace, means for forming and feeding electrodes made up of a mass of plastic material into the furnace, independent mechanism for actuating said forming and feeding devices so that the electrodes can be supplied to the furnace at a speed proportioned to their consumption therein and governing mechanism for the forming and feedingmechanism whereby the independent mechanisms are stopped and started simultaneously.

GEO. S. STRONG.

Witnesses:

CHARLES F. ZIEGLER, D. STEWART.

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