US1484791A

US1484791A - Roasting furnace

Info

Publication number: US1484791A
Application number: US649382A
Authority: US
Inventors: Leggo Arthur Victor
Original assignee: Individual
Current assignee: Individual
Priority date: 1921-12-22
Filing date: 1923-07-03
Publication date: 1924-02-26
Anticipated expiration: 1941-02-26

Description

A. V. I ,EGGO

ROASTING FURNACE Original Filed Dec. 22. 19:21

l/vvf/VTOR ARN/0R V. 5660,

Feb. 26 1924. 1,484,79l

A. V. LEGGO ROASTING FURNACE Original Filed Dec 22 1921 v l 5 Sheets-Sheet 2 'l "13; ARTHURV. Laeeo Patented Feb. 25, i924.

Uhliif SFTES ARTHUR VICTGR LEGGO, OF IEELBOURNE, VICTORA, AUSTRALIA.

ROASTING FUBNACE.

Original application filed December 22, 1321, Serial No. 524,301.

Serial No. 649,382.

To all atomv vit may conce/m.'

Be it known that ARTHUR Vieron Lneeo, of 497 Collins Street7 Melbourne, in the State of Victoria, Commonwealth of Australia, metallurgist7 have invented certain new and usefr-.il lmprovements in Roasting Furnaces, of which the following is a specification.

This invention relates to improvements in the rabbling mechanism of ore roasting furnaces and refers especially to the arms and teeth on the rabble shafts for stirring and exposing the ore in its passage through the furnace. Y

The object of the invention is to provide certain improvements in the construction and arrangement of rabble teeth for attachment to a rabble arm whereby a tho-rough stirring and even distribution of the ore passing over the hearth of a furnacel and an eectual exposure of the ore being stirred to the action of the furnace gases is effected.

l accomplish the abovementioned object by providing the rear of a rabble arm with a row of detachable furrow forming teeth and the front of the arm with a row of stirring teeth having downwardly, forwardly and inwardly inclined narrow shanlrs terminating in broad feet set at an angle to the front of the arm and disposed to travel between the centres of the paths traversed by the furrow forming teeth.

The stirring teeth may be arranged with the front of the foot on the centre tooth set radially to the pivot point of the arm and with the feet of the teeth on the inner and the feet of the teeth on the outer parts of the arms set at opposite angles to the radial line whereby the said teeth in the act of stirring the ore will ensure the same being maintained at a uniform depth over the whole area of the furnace hearth.

ln order that the invention may be readil),7 understood reference will now be had to the accompanying sheets of explanatory drawings wherein Figure l is a view in sectional elevation of part of a straight line multiple hearth furnace showing a rabble shaft with arms fitted with teeth constructed in accordance with the present invention.

Figure 2 is a View in elevation of a rabble arm fitted with stirring and furrow forming teeth constructed and arranged in accordance with the present invention. In

Divided and this application filed July 3,

this view the inner end of the rabble arm and part of a rabble shaft are shown in section.

Figure 3 is a view in plan of Figure 2.

Figure -t is a view similar to Figure 3 showing a modified form of furrow forming tooth attached to the rear of the rabble arm.

Figure 5 is a view similar to Figures 3 and 4 showing combined stirring and rabbling teeth attached to the arm.

Figure 6 is a view in perspective of the outer end of a rabble arm fitted with stirring and furrow forming teeth and drawn to a larger scale than the other figures.

Figure 7 is a View in perspective of an oblique furrow forming tooth for attachment to the rear of the rabble arm.

Figure 8 is a view in perspective of a modified form of stirring tooth for attachment to the front of a rabble arm.

Figure 9 is a View in end elevation of a rabble arm showing a combined stirring and furrow forming tooth attached thereto'.

Figure l0 is a view similar to Figure 9 and showsl a slight modification in the construction o-f the combined stirring and furrow forming tooth.

In these drawings the numeral 13 designates a rabble shaft having rabble arms 36 projecting alternately from opposite sides thereof.

rlhe rabble arms are formed with longitudinally disposed

flanges

82 and 83 which project horizontally from both sides thereof and on the upper side of the leading flanges 82 and on the underside of the following flanges 83 are formed a plurality of tapered projections 84.

A plurality of stirring teeth 85 and a plurality of furrow forming teeth 86 are detachably secured to the flanges on the rabble arms by tapering jaws 87 which are adapted to be passed over the flanges and moved laterally thereon to engage with the tapered projections 84, and the said teeth van be locked securely on said flanges by means of locking bars 88 or other approved devices in the ordinary way.

Part only of a locking bar 88 is illustrated in Figure 6 of the drawings and it is shown ready to be dropped into position so that projections on the underside thereof will prevent the jaws of the teeth moving inward off the tapered projections 84.

`When the rabble teeth are aflixed to the V82 of the arms are formed with narrow shanks 89 which incline forwardly, inwardly and downwardly and terminate in broad feet 90 having bevelled lower edges (sce l 1 igure 6).

The upper surfaces of the broad feet oif the stirring teet-h are made horizontal as shown in Figure 27 or they can be thickened on one side sok as to give them a suitable lateral inclination (see Figure S) in either direction `to cause the ore to be moved inward or outward as desired during the stir n ring operation.. The inclination of the feet on the teeth (shown in Figure S) is arranged to cause the ore being rabbled to be moved outwardly and it will obvious that when an opposite inclination is given to the feet the ore will be moved inwardly.

The shanks 89 of the front teeth are inclined inwardly so as to lie more or less in line with the centre of the paths of movement of their lower ends when the arm is in operation.

All the front teeth. S5 with the exception of the innermost one are made uniform in size and shape and owing to the set of the slianks the front edges of the feet thereon are'disnosed at an an le to the front of thel labble arm. rlhe front of the feet on the teeth near the centre of the row is disposed in or approximately in a radial line (marked A in Figure 3) drawn from the centre of the rabble shaft and the front of the foot ci' the outermost tooth is so arranged that its outer side is in advance of the inner'side as clearly indicated by a radial line (marked B in Figure drawn from the centre of the rabble'shaft through the inner side of the said foot. rThe front of the foot 'on the innermost tooth is arranged so that its inner side is in advance of its outer side and may be in the same radial line (marked (l inV Figure 3) to that passing through the outer side of the leading edge of the neXt ad]a cent tooth.

ln most rabbling operations where rotatre there I employed to pass orc ver the hearth is a tendency for the ore to be distrilaited more or loss unerenlwr and with a greater depth toward the outer part of the paths traversed by the said arms, and for the dead oro on the hearth to be left exposed to the furnace gases atY the Ybottoni of the furrows formed by the lteeth. li/lany ores are likely to form cakes when left undisturbed and exposed to the furnace gases and more especially those ores containing zinc and lead. VThe construction and arrangement 'of the front teeth as above de' scribed tends to obviate the uneven distribution of the ore ast-he angles of the feet of thel outer teeth serve to counteract such tendenclos, and to keep a complete covering of rabbled ore evenly disposed over the bed so as to prevent the exposure of the unrabbled ore to the gases and so retard or prevent the dead ore forming into hard cakes. T he setV of the feet of the inner front teeth serves lto move outwardly any ore which may mount up adjacent to the rabble shaft and thereby prevents the said ore passing'down the sleeve 91 surroundingthe shaft, to the hearth beneath.

'.ll e feet 90 of the teethinay beY made sufficiently broad to ensure the sides of each tooth traversing a path which meets with o crei-laps the path traversed by the nearest si of the adjacent teeth as vshown by the concentric dotted lines 9:2 in Figure 3 of the drawings rlhe outer side of each front tooth is disposed in advance of the inner K side of the next outermostL toothV thereby leaving' openings 85" through which the ore passesV radially between the feetwhen the rabbling mechanism is in operation' thus facilitating thc passage of the teeth through the ore. Y

The construction and set of the lfront teeth arefsuch that theyV thoroughly stir the whole bed of ore well in advance of the rabble arm without causing it to Abank up unduly with the result that the load on the arm is kept smaller and the'teeth attachments kept cooler than when it is banked the ore so'as to ensure a fresh surface be-A ing exposedY andthe back teeth S6 (which are made shorter than the front teeth) leave the surface ot the ore toi-med into deep furrows and ridges thereby causing'a maximum of surface to beV exposed.Y @n the next revolution ol" the arm the Shanks 89V of the front teeth pass through'the ridges Y left between the .furrows and distribute the ore laterally sc that the bed of ore is flattened more or less before the oncoming rear teeth 86 again form it into furrowsf ln the present invention the j teeth are designed especially'V to' keep Vthe ore evenly distributed over the hearth of the furnace' and prevent any unrabbled ore from being exposed to the furnace gases at the bottom of the furrowsy formed by the back teeth.V

As the bottoni of the back teeth is higher than the bottoni of the front teeth it will be apparent that no exposure of unrabbled ore on the hearth can taire place which might cause a calring or setting of the saine.

The inner ends of the rabble arms are fitted with broad obliquely disposed teeth 93 which operate to inove the ore away from the rabble shaft and prevent the sa 'l ore banking up suiliciently to jews 'do-.m the sleeve surrounding the said shaft and falling to the hearth therebeneath.

The angle of the inner strirring teeth on each arin is greater than that ef the remaining stirring teeth with the result that they act to throw further outward the ore pushed baclr by the action of the oblique teeth and thereby effect a incre even distribution of the ore on the hearth.

The furrowY forming teeth 86 on the following flange 83 to traclr midway between the shanlrs of the front teeth and depend from the said following flange as shown in Figures 2 to 6 of the drawings.

rlhe faces of the rear teeth 86 for forining furrows and ridges in the ore are flat and may be set in line with the edge of the following flange as shown at D in Figure 6 or seine or all of the teeth rnay be set obliquely to the said flange as shown in Figures 3 to 5 and on the outer end of the arni shown in Figure 6 as desired. wiWhen the teeth S6 are set obliquely seine of theni can be arranged to move the ore radially in one direction and the remaining or some of the remaining teeth can be arranged to inove the ore radially in the opposite direction (see Figure e). The rear teeth can all be arranged at the sarne angle as shown in Figure 3 or some of the teeth can be i'orined with more or with less obliqueness than the others as desired.

'lhe arrangenient of the rear teeth as above described enables the ore being rabbled to be passed over a hearth in any direction at a desired rate of speed whilst keeping the sa ne at a more or less uniform depth throughout all parts of the hearth.

ln lieu of securing the stirring and furrow forming teeth detachably to the rabble arins either cr both can be cast integrally on the front and rear thereof and be Otherwise constructed and arranged as above described.

ln an alternate construction (see Figures E) and l0) the stirring and furrow forming teeth are formed integrally with each other and the furrow forming teeth are set obliquely to the axis of the arm7 and as shown in Figures 5 and l0 the furrow forming teeth can be formed of greater breadth than the furrow forining teeth illustrated in the ether figures of the drawings.

The combined stirring and furrow forniing teeth are formed with two jaws which engage both flanges of the rabble arins and the teeth are retained in correct spaced relationship by ineans of distance pieces 95 forined on the sides thereof and which abut against each other when the teeth are thrustover the ends of the arms and inte position thereon. yThe Obliquity and shape of the furrow forining teeth are shown in dotted lines in Figure 5 and this forni of furrow forming tooth is particularly adapted to facilitate the movement of the ore over the hearths of turret furnaces.

l claini:

l. ln roasting furnaces. rabble arin7 a row of stirring teeth on the front and a row of furrow forming teeth on the baclr of the rabble arin., and dowr ii'dly., ferwardly and inwardly inclined slianlis on the. stirring teeth having broad feet set an angle to the front of the rabble arn'i.

2. ln roasting furnaces, the combination with a rabble arni of a row of furrow forni-- ing teeth on the rear of the arin,l row cf stirring teeth on the front of the arn'i having narrow downwardly, forwardly, and inwardly inclined shanlis adapted to pass through the ridges of ore between the furrow formed by the rear teeth, and broad feet on the stirring teeth having their front faces set at an angle to the front of the arni whereby when the arin is in inotion the paths of the stirring teeth overlap and the ore being stirred will pass radially between the sides of the feet and between the front of one stirring tooth and the back of the neXt adjacent stirring tooth.

3. ln roasting furnaces, the combination with a rabble arin of a row of furrow forniing teeth on the rear of the arin, a row of stirring teeth on the front of the arm having downwardly, forwardly and inwardly inclined shanlrs, broad feet on the stirring teeth set at an angle to the front of the arin, the front of the foot of the centre stirring tooth being set approximately radially to the pivot point of the arin, and the feet of the teeth on the inner and the feet of the teeth on the outer parts of the arm being set at opposite angles to the radius of their path whereby the said teeth in the act of stirring thc ore will ensure the saine being maintained at a uiforin depth over the whole of the furnace hearth substantially as described.

4. ln roasting furnaces, a rabble arin having a row of stirring teeth on the front the-reof. and a row of furrow forining teeth depending froin the arni at the rear of the stirring teeth and having oblique faces arranged to niove the ore being rabbled in a radial direction.

5. ln roasting furnaces7 a rabble arni having a row of stirring teeth on the front thereofT and a row of furrow forming teeth on the rear of the arm, seine of the said furrow forn'iing teeth having iiaces set ebliqnely to the arm and the remaining furrow torming teeth having faces set in line with the sait arm.

6. In roasting furnaces, a rabble arm having stirring teeth on the front thereof provided with depending` narrow Shanks having broad shallow feet adapted to cover the whole path of the rabble, and furrow forming teeth en the rear of the arm having their lower ends disposed above the level ot the i'eet on the stirring teeth.

7. In roasting furnacese a rahble arnn having a row of teeth on the fear and a row of teeth on the front thereof, tapered projections on the front Yand rear ot' the arm, jaws on the upper ents et the front teeth engaging the projections en the :trent of the arm, narrow Shanks inclining inwardly, 'torwardly and downwardly from the said aws, broad feet on the lowerl parts of the said shanks set at an angle to the front of the rabble arm and adapted to track so that the sides et the path traversed by the edges of each tooth will overlap the paths ot the adjacent teeth on the arni. y

8. In roasting furnacesy a rabble arnn a row of stirring teeth on the front and a row offulrow forming teeth on the rear of the arm7 said stirring teeth having forwardly` and' inwardly inclining shanks7 broad feet on the Shanks having horiZent-al lov-Jer surfaces and inclined'npper surfaces whereby when the rabble is in action the inclination of the upper surfaces oi the said broad feet Vwill move the ore laterally.

9. In rabbling inechanisn'i of roasting ur- Y nace a rabhle'arm having combined stirring n ring and furrow orn'iing teeth comprising narrow forwardly, downwardly and inwardly inclining shanks having a broadioot at their lower ends obliquely disposed blades at the rear ot the Shanks said obliquely disposed blades being arranged to track at one side of the paths taken Vby the feet on theinclined shanks and having their lower ends above the bottoni oit the said feet, and means for attaching the combinedteeth to the ble arm.

ln testimony whereof l haveV alixedA my signature.

ARTHUR vieron Lneefo