US1125949A - Ore-roasting furnace. - Google Patents

Description

E. BRACQ. ORB BOASTING PUBNAGB.

APPLIOATION FILED MAY e, 1911.

Patented Jan. 26, 1915.

2 SHEETS-SHEET 1.

THE` NORRIS PETERS Co.. PHOTOALITHO, v/ASHINGIUN, n C

E. BRACQ.

ORE BOASTING'FURNAGB,

APPLICATION FILED MAY 6, 1911.

1,125,949.. Patented 53911.26, :m5,

2 SHBBTS-SHEBT 2.

THE MORRIS PETERS CoA. PHOTD-LITHO.. WASHING lON, D, C.

UNITED STATES PATENT OFFIC.

EMILE BRACQ, 01E' LENS, FRANCE.

ORE-ROASTING FUR/NACE.

Application led May 6, 1911.

.o all whom it may concern:

Be it known that I, EiurLn BRACQ, citizen of the French Republic, residing at Lens, Pas de Calais, France, have invented certain new and useful Improvements in Ore- Roasting Furnaces, of which the following is a specification.

This invention relates to furnaces for roasting ores and chiefly using mechanical means for manipulating` the material to be roasted.

In existing mechanical furnaces, the roasting is effected on parallel superposed floors comprising one or more arms which mix the material to be roasted and advance it. That device has serious drawbacks. The arms are always in contact with the material, at a very unequal temperature, according to the floors, they are always at the same temperature and very difficult to handle, the method of raking or stoking used frequently produces accumulations, and the arms moving (these accumulations) are soon damaged if the thing is not properly remedied, finally the fall from one floor to another produces dust which in certain cases, such as for instance that of roasting sulfurous ores for the manufacture of sulfuric acid, is very unpleasant and frequently necessitates dust exhausting installations of large size, which does not prevent the choking of the inlet conduits to the dust collecting apparatus, and moreover it is necessary to clean the latter very frequently.

The present invention does away with these important drawbacks by using a furnace with a continuous hearth of helical shape and an arm having a movement of rotation about itself, which, in moving on the hearth, mixes and advances the material being roasted. Its travel is such that it passes into the portion of the furnace which is not operative, where it is possible to watch its state and to replace it, if necessary, and it can remain in the latter portion for a suitable time for completing its cooling.

In order to make the invention better un- `derstood, an application of the same is -section through the central core on lines co-b of Fig. 1, Fig. 3 is a vertical section showing the emptying of the furnace, Fig.

Specification of Letters Patent.

Patented Jan. 26., 1915.

Serial No. 625,491.

4 a vertical section on line c-cZ of Fig. 3. Figs. 5 and 6 are sections of different forms of arms. Fig. 7 is a diagrammatic plan of a modified arrangement of the arm, and Fig. 8 is a diagram representing the developed path of the arm.

In the said figures A. is the helical hearth, B the metal band surrounding the hearth, U the charging hopper, D the ore distributer, E the conduit, for the combustion gases, F (Figs. 3 and 4) the discharge hopper, G a central core constituted by two concentric cylinders, the intermediate space between which is filled with a refractory or nonconducting material, the distance is maintained at the top and at the bottom by two rings cooled by a circulation of liquid, so as to avoid transmission of heat from the outside to the inside of the ring, the upper ring forms a toothed wheel for driving the core.

H H1 (Figs. l and 2) are uprights connected by cross-bars I I1 I2 and sliding in guides J and J1 secured to the central core, and a circulation of liquid constantly cools the uprights and the guides.

K is the arm circulating in the furnace and pivoted about a pin L, so as to enable its inclination to be changed relatively to the i,

upright H. The arm K rotates about itself by means of the toothed wheels O, M, N.

O is a toothed wheel with a ball and socket joint driving the arm K and enabling it to pivot about the pin L when the bracket e P is moved relatively to the upright H.

N are toothed wheels with a clutch sleeve for producing rotation in one or in the other direction of the spindle Q. The latter, by means of the spindle It causes the core G, and consequently the upright H and the arm K to rotate about the central axis. At the same time the spindle Q, by means of a screw-thread S and a nut T, produces a movement in the vertical direction of the upright H and of the arm K. The movement of rotation in the horizontal plane and the movement in the vertical direction, give to the arm K a resulting helical movement which moves it on the hearth.

U is a nut normally rotating with the spindle Q, and capable of being locked by means of a ratchet wheel V, which results in a movement in the vertical direction of the spindle Q, and consequently of the nut J t T, upright I-I and the arm K.

spindle X and capable of being locked by a ratchet wheel Y, which results ina movement in the vertical direction of the spindle X and of the ends of the arm K which 'pivots about the pin L.

V"Z are weights balancing the uprights H and H1, the cross bars I, Il, I2 as well as the brackets Xed above, the arm K, the spindle X and the toothed Wheels O.

The working of the apparatus is 'as follows: The driving movement is imparted by the pulley 1; the toothed lwheels N N1 M1 'rotate the core G and 'the parts driven by the latter, that is 4to say, the upright H and the arm K. The screw thread S brings Iabout a vertical movement o'f the arm VK `'which we assume to beat the bottom of the furnace on the hearth, the toothed wheels O rotate the arm K about itself. The latter on 'rising along the hearth, pushes back the .materiah the latter advances, at -the same time being miXed in ya perfect manner, a little before 'having arrived at the top, the nut U 'is locked 'by means `of the ratchet V, the

control offt'he pawl arranged on Vthe ratchet v"wheel V can be obtained by means of a tappet arranged on the cross bar I2 which, moving in 'the vertical direction, makes it veryeasy. The nut U produces then an upward movement of the spindle. Q and consequently 'of the upri,`ght H and of the arm 5K, but 'the vspindle Q on rising, disengages the sleeve 2 and engages it at the other side thus producing the reversing of'movement. The spindle K descends then again rotating about itself in the 'opposite direction, that is `'to say, ,having the tendency to raise the ma- .'te'rial beiiig'roasted but at that moment the Vspindle 7c is no longer in the material, the' nut U having raised it to a suiicient extent. On arrival at vthe bottom, the opposite manipulation takes place, so that the path described by the arm K can be represented by 3,4., 5,6, 3 `or Fig. s.

y.In order to make sure that the material situa't'edton'ard the bottom ring does not remainin the furnace less long than that at the circumference and comes out properly roasted, a vertical movement is given to the spindle X by the nut lV which for the purpose is locked by the pawl of the ratchet Y, this pawl can be controlled by a tappet arranged on the` cross bar 7 secured to the core G. This vertical movement of the spindle X takesplace toward the end of the travel of the arm K, and by causing the spindle X to descend, brings about a tipping of the arm .K `about the pin L, so that the upward movement of the spindle Q disengages the end of thearm, more `quickly thanthe inner portion which can remain in the material. During 12h@ `downward stroke, the arm will raise therefore the yquantity of material with vwhich it is still in engagement, so that the result will be a slackening of the advance movement of the material situated near the Center 4 The pivot movement of the arm K and the vertical movement can be easily adjusted and varied by the position and length of the tappets controlling the locking ratchet wheels. The latter having been adjusted, rthe working is entirely automatic. The movtement described can be obtained by other combinations than those given by way of example, and even electricity can be used as driving'agentvhich makes it possible to obtain easily the different Vmovements by the` use of contacts closing or breaking the clrcuit, lfor starting or stopping the movements and by use rof a reversing switch for reversing the movement. It is easy to do 4this in the vsame way as in apparatus such as planing machine, lifts 'and the like where the movement of one partrelatively to another, makes it'easy to producekor to break contacts. inthe present case the movable part is: (4l) the upright H relatively to the core, (2) the arm K relatively to the Vupright H and `(3) the core Gr relatively yto the furnace.

The ore coming fromithe hopper C is distributed by D. This distributer is constituted by two helical conveyers mounted on one and the same spindle and having screw threads of opposite directions ythe pitch of each being moreover `of a different value depending on'the distanceof the feed point from the centerof the furnace. tributing screws are controlled by means of R (this spindlel being moreover at about 90 l to the plane of Fig. l) by that of bevel wheels andof asystem of ratchetwheel and pawl 8 similarkto that used in forcing lubricators ofa well known type. The operating lever for the pawl having reciprocating ,.1

motion, the distributer always lrotates in the same direction whatever be the direction of rotationv of the spindle controlling it. Moreover', the adjustment of the output is very convenient and can be varied vwithin wide limits. The roasted mineral (Figs. 3 and-l) falls into a hopper F with trap doors 'normally closed, which are automatically opened. at each descent of the upright H, and in that way the continuous admission of air into the furnace is avoided.

Doors arranged at certain distances apart The dis-` and provided with air inlets, enable the furnace to be inspected and air to be supplied at the desired points. The fairly large pitch of the screw of the hearth aEoi-ds a wide passage to the gases.

The arm can shift a layer of ore of much greater thickness than the type of arm sliding without rotating, owingto its regular mixing which turns over the layer, the 4roa-s`tin, is more rational and more complete. The arm does not remain in the very active portion of lthe furnace, it merely passes through the same, and after having passed beyond the hopper F, it can be inspected, a removable trap door 9 gives access to it, and a shutter 10 on being raised enables the furnace to be closed. rlhis arm K is constituted by a hollow core 1l and a toothed easing 12, an inner pipe 13 supplies to it liquid, which cools the hollow core 11 and consequently the casing 12 by contact, there is no danger of swamping the furnace, for the core 11 being sufliciently cooled, can be considered as breakable. The effort to be produced by the arm, is moreover limited by the tension of the springs of the driving clutch, shown at la in Fig. 1. The circulating liquid in the arm is admitted through 15 and escapes through 16. lt is possible to establish communication between 15 and 17, escape of the liquid from the upright l-l, the inlet 1S into H takingplace through a pipe not shown, arranged near the center of the furnace and plunging into another fixed pipe. A calking prevents leakages.

A furnace 19 enables heat to be supplied in the cases where the combustion of ore requires it, the reheating can be effected on one or several turns, and in the same way the hearth can be provided with any number of turns. A helical rib arranged on the arm at the outlet from the core Gr, prevents the material from falling into the interior of the furnace.

Fig. 5 shows a section of the arm K with blades enabling the hearth to be scraped, if

it becomes raised. Fig. (i is another type of special arm for ores which easily cake together during the combustion, and this arm can also be provided with blades. Fig. 7 shows the device with a non-radial arm for avoiding, in case of ore easily sliding, the driving of the latter from the center toward the circumference, the Obliquity of the arm enables the material to be brought back to` ward the center. The installation shown is completed by a ball bearing 20 enabling the whole easily to turn. Lateral rollers not shown in the drawing guide moreover the ring G on its rolling track. Other ball bearings 21 and enable U and W to r0- tate with the spindles Q and X. The escape of gases at the ends of G is closed by sand joints 23 and 2i. The balance weights Z counteract any strain due to loads on the screwthread.

The toothed wheels 0 engaging with the arm l, are always in engagement to the same extent, in spite of the variable obliquity of the arm, owing to the mobility of the arm in its guide P owing to the ball and socket joint 25 mounted on the arm, the said joint forming by means of teeth the clutch, is connected to the toothed wheel U during the useful period, that is to say, during the upstroke of the arm in the installation in question. The aXis of the arm corresponds to the aXis of the bracket P, consequently everything takes place as if the ball and socket joint did not exist. lf the Obliquity is changed for the downward travel, there takes place a slipping at the driving teeth of 25, that is to say, during the unimportant period of working. rlhe hearth being a continuous one, the travel of the material in the furnace can be changed by a change of the direction of the advance movement of the arm, which would then describe the path 3, 6, 5, et, 3 of Fig. 8, and the supply would be effected from the bottom, the roasted ore escaping from the top. This arrangement can have advantages in certain cases, it makes it possible to reheat the hearth at the end of the roasting by means of the gases situated below, which are in contact with a much stronger furnace. It makes it unnecessary to raise the material for charging and to raise the furnace for the emptying truck. ln either case there is no fall of the ore during the combustion, consequently there is no, or very little, dust. llhe depression in the furnace can be very slight, as the different floors do not constitute baille plates, moreover there is no danger of choking of the conduits by dust.

l/That l claim as my invention and desire to secure by Letters Patent is 1. In an ore roasting furnace the combination with a central rotary hollow core, of a helical hearth arranged around said core, a hollow stirring arm mounted in said core and extending above the surface of the hearth, means for imparting to said arm a helical movement following the surface of the hearth, means for maintaining a circulation of'water through said arm, and means for rotating the arm about its axis.

2. In an ore roasting furnace, a central rotary hollow core, a helical hearth arranged around said core, a hollow stirring arm mounted in said core and extending above the surface of the hearth, means for rotating the arm about its axis, means for maintaining a circulation of water through said arm, means for imparting to said arm an upward helical movement following thc surface of the hearth, means for tilting the arm upward at the end of its travel, and means for then imparting to the arm a downward helical movement.

In testimony whereof I have signed my name to this speoication in the presence of two subscribing witnesses.

EMILE BRAGQ.

Witnesses Louis CAHON, Louis DHNIZ.

Copies of this patent may be obtained for rive cents each, by addressing the Commissioner of Patents, Washington, ID. C.

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