US2527309A

US2527309A - Gravity flow sintering machine

Info

Publication number: US2527309A
Application number: US736487A
Authority: US
Inventors: Kelsey Walter
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-03-22
Filing date: 1947-03-22
Publication date: 1950-10-24
Anticipated expiration: 1967-10-24

Description

Oct. 24, 1950 w. KELsEY 2,527,309

f GRAVITY FLOW SINTERING MACHINE Fild March 22, 1947 s sheets-sheet 1 ff f FREE ,van/R4L smPE L//vf o ,n l.

/m 47m/Mfr 0ct. 24, 1950 w. KELsEY 2,527,309

GRAVITY FLOW SINTERING MACHINE Filed March 22, 1947 5 Sheets-Sheet 2 HHIHHHIIIIHHIIIIIIIIHHHIHIIILL Oct. 24, 1950 W KELSEY 2,527,309

GRAVITY FLOW SINTERING MACHINE Filed March 22, 1947 5 Sheets-Sheet 5 STOCK SUPPL Patented Oct. 24, `1950 rUNITED STATESY PATENT OFFICE Walter Kelsey, New York, N. Y. Application March 22, 1947, serial No. 736,487

This invention relatesto sintering machines.

The invention contemplates a gravity iiow sintering machine, the function of which is to sinter ores; in general, to sinter or agglomerate any materials that will sinter, and for any use. l In the steel industry alone this machine is valuable in making usable, in the blast furnace for instance, low Igrade and crude iron ores, and waste from steel mills and shops The sintering machines at present in use are elaborate and costly to build and limited in their scope of use. The present invention is simple in design and construction, less costly and has a wide scope of use, and the operation is continuous. The stock supplied to the machine, is, in general, a mixture of the material to be sintered and a fuel, as well known.

The invention consists more particularly of an inclined sintering pass, in which the iiow of stock 'and sinter is regulated in consonance with the sintering action, with its body portion subjected to an induced iiow of air, and having its upper end provided with a feeding chute. At the lower end of the feeding chute, the stock is ignited continuously and brought to incandescence, by action of a iiame on the stock, which ignited stock is transposed to enable Ythe `transposed incandescent stock to sinter in the sintering pass under the action of the induced air flow. The fire line is dis- 8 Claims. (Cl. 26S-20) ,posed between the stock and the sinter, and the sintered stock is subjectedto controlling rollers or crushing means operating in consonance with the amount of stock sintered. The action throughout isA continuous,

v"Ihe invention will be further described, em,- `bodiments thereof shown in the drawings, and the invention will be nally pointed out in the claims.

In the accompanying drawings,

Fig. 1 is a vertical sectional side view taken on line I-I of Fig. 3;

Fig. 2 is a diagrammatic partial view of two .suction chambers, one for sintering and one for cooling;

Fig. 3 is an inclined section taken on line3-3 of Fig.,1;

Fig. 4 is an inclined section taken of Fig. l;

Fig. 5 is an inclined section taken on line 5-5 of Fig. 1; Y Y

Fig. 6 is a vertical section taken on line 6-6 of Fig. 1;

Fig. 7 is a side View of the air lock plates;

Fig. 8 is a partial front view of the air lock plates;

on line 4-4 Fig. 9 is a diagrammatical view of the operation of certain of the essential features ofthe invention, and

Figs. l0 and 11 are diagrammatical partial views Vof different positions of the i'lre `line..

Similar characters of reference indicate ncorresponding parts throughout the various views.

Referring to the drawings, the inclosed feeding chute I0 is either vertical or sloping in such a manner that there is a gravity flow of the stock. The length of the feeding chute I0 between a gate II and an ignition chamber I'I is such that there is no appreciable loss of air suction through the stock held in the feeding chute IIJ.

As a means of preventing excessive compacting in the feeding chute having a stock guide, sections I3 forming pockets I3a filled with stock are provided in the feeding chute. The stock iiowing ,oif of the stock body held in the pockets I3a moves with less force than if the stock had an unimpeded flow. Also each pocket takes practically all of the weight of the stock within the chute vertically above the pocket.

To prevent the lower layer or part of Stock` in the bottom of the feedingchute I0 from iowing ahead of the upper layer or part of stock in the chute, a row of chains I4 is hung in the feeding chute. These chains I4 are so hung that they will lay in the lower layer of owing stock or in the bottom |021 of the feeding chute and furnish enough resistance to retard the flow of this lower At the bottom VI2 of the feeding chuteY Il) the top surface of the stock is not restrained and takes its natural slope as it passes below an ignitor or ignition ame I'Ia either in the open or in an ignition chamber I'I, and then as an ignited stock or newly made sinter 52 the top surface of which 53 (see Fig. 9) passes below an air cooling intake I9 with a iiow adjusting damper ISa, and thence below the plunger 2I or other transposing means.

The ignition chamber I1 is so. made as to burn the fuel used to a flame. The flame is impinged y upon the exposed surface of the stock descending in the feeding chute throughout its width so as to properly ignite the stock while it passes below thechamber Il. suction aids to draw tinuity of the ignited stock or sinter.

l and l1. bulk of the stock pushes the` inclined fire line Ia ltowards the yfront side of the sintering pass into 3 rier is adjustable by a slide 20a clearing the sintering stock as it ows underneath.

Instead of the ignition chamber an open flame may be used impinging on the stock, and disposed above the barrier 20 with its slide 20a.

The air blast intake I9 is made to force a blast of air directly upon the hot surface of the ignited stock or sinter 52 with the object of cooling its surface 53 under retention of a fire line 5I, so it will not adhere to a flow-directing plunger or other transposing means, aboutto be described.

At the top of the sintering pass I5, the ow of the ignited stock or sinter is transposed in position, and that ignited stock or sinter which was the front layer located above thevbulk ofthe moving stock in the feeding chute now becomes the front layer locatedbelow the bulk of the moving stock in the sintering pass I5. Forthis purpose, a power driven plunger 2l or other power driven device is placed in the front side, at the top of vthe sintering pass I5. This plunger n2| has an inclined portion 55 (see Fig. 9) to facilitate the transposal of the sinter and lire line, and forces the newly made sinter with its A'dre line or the 'adjacent ignited stock, down along-'the front side of the sintering pass I5 at such a-speed kas'to match the flowof the rest of the ignited stock so as not to breakthe con- The inclined side of the plunger pushes the nre line 5I into an inclined, position` 5Ia, as shown in Figs. Then the plunger withdraws. The

theposition 5Ib. While theplunger withdraws, the initial `fire line -5I fkeeps' on moving in the same vdirectionas when formed. When the end reaches'thefront side of the sintering pass, the next movement of the plunger moves it tothe inclined position 5Ia.` Thence the sinter and ignited stock and Yunburned 'stock' continues to `flow or slide down on the front side of the inclined sintering lpass. Upon the induced air acting upon thel'lre 'line land superposed stock, the fire line-6I) ris jdrawn along and sinters the superposed stock. Astheistock and the sinter flows down the sintering pass I5, the fire line 6U takes a mean diagonal position, until the 'superposed-"stockis entirely sintered. The unburned stockis'restrained bythe back side I5c of the 'sintering pass for a` suitable' length.

To prevent excessive Vcompactingat the point of transposalof` flow, the bottom ofthe feeding chute is made to *project` as shown at 22 beyond the lowerface ofthe backside I5c. This will Yleave a portion of stockwithout any direct vertical' load with onlythe'side pressure to force this `portionof the stock b ack against the back side. A,This gives'a release vfor the sidevpressure developed by the 'corner plunger 2| or other turning device. `In the embodiment, the plunger 2| has alinkZI'a pivoted to a crank arm 2 Ib operated by a shaft 2Ic;

'Thesinter and `stock in the sintering pass I5 istraversed by an air flow-'fora space equal to the length of the air chamber 29. "The induced air ows from` the' front of 4the air chamber 29 throughthe perforations I5b in the wall I5a and 'transversely ythrough the-entire lwidth of the chamb erv 3U.

to cool the sinter. The speed of stock flow and amount of air or draft is so adjusted that the fire will burn entirely through the stock. Sintering, which begins at the ignition llame, is completed at a point 0 below the lower end of the back side I5c, at which place the stock surface is not restrained, and the top surface of the stock ilows free at its natural slope. In front of the fire line '59 and below the point U Where the re has burned through, allthe stock;V has become rigid sinter and its plastic character having been lost by the cooling, it will ilow or slide down to ,controlling crushing rollers 24 and 25, and when crushedV to a conveyor 26. The cooled and hardcned sinter is gripped and handled by the power driven controlling rollers 24 and 25.

Over the free surface of the sinter below the suction chamber, air locks 23 are arranged. The length of the sinter pass from the bottom of the suction chamber to below the lowest air lock 23 is such that there is no appreciable loss or airsuction through the sinter or stock held in the sinteringpass I5.

vThe controlling and crushing rollers 24 and'25 are driven at such speed as to give the desired flow of Istock in the sintering pass. Known ,means `(not shown) are provided for changing conveyor 26 discharges thesinter into the screen 2l vor processing room. The pan conveyor26 is the preferred formbut other forms of conveyor may be used. rlhe control and crushinglmeans may be modifiedasto the meansshownfbut the control feature is important.

The air flow induced from the ignition chamber I'I by the suction chamber 30, and from ther air chamber 29 bythe suction chamber .30, is produced by asuctionfan 34. The frontside of the air chamber 29 is indicated by 29a.. The front side |50. isr perforated by holesI5b, the location and number of which is established by ,the requirements of sinteringand the demand for air along the front side I5a. The bottom Ia of the lower part of the feeding chute I0 and the back side I5c ofthe sintering -pass are. also Yperforated vwith .holes I5d, the location size.. and number of which .lis established .by theamount of air which isA to4 be allowed to pass.

Anequalizing damper 354s placed in the suction This .damper 35 extends from end to end of the chamber- 30 andvtsloverlthe backside #5c of -thesinte'r-ing -pass toequalize thel airilow, or giventhe suction desired, tor bring the fire to the surfaceof'thestock at'the desired location D and to allow ample air for the cooling of the'fsinter. This damper 35 isarranged to be raised or lowered by known regulating devices-35a ateither end to equalize air ow and to compensate for any eccentric end ldraft from the'suctionduct'. Thus, this equalizing damper 35 provides means to bring the re to the surface of the stock yat the desired location 0. Y

lIfhe air lock 23 which is placed where thesinter leavesV the suction chamber, consists of flat-plates 3l suspended close together on a shaft1 38 (Figs. '7 and 8) The bottoms of these heavy plates rest on andutake the irregularities of the topof the sinter as it passes underneath. ThereA isvery little open space for the passage of air. One llock or more locks may be used, in series if necessary. In Fig. 2 is shown a separate suction chamber 30h ammo@ controlling theair lock arrangement, having a Vfan 34a inthe outlet channel casing |5e. Y j 'When the 'gravity' flow sintering machine is `in operation; the feeding chute an'd'sintering pass is full of stock and sinter. The stock fromv the supply atithegate and4 that in the machine puts'a pressure on thecontents of the machine which acts to force the stock and sinter down through themachine. .This force, which is gravityacting on the materials, forces the stock and sinter to follow downward `throughthe machine as vsinter isdischarged from the bottom of the sintering pass by .the controlling and crushing rollers* This discharging from the bottomof the rigid sinter acts to reduce the compacting of the stock in the upper part of the sintering pass.`

`With' the exception of the retarding'pocket or pockets |3a. there is no place in the machinefor the collectionor holding of stock. The machine is self-cleaning. and clearing when operated for this purpose.

'lhismachine may be so built as to be pracv` ticallydust proof. The inclosure which can in`r` cludefthe screen or processing room may have the dust. ,ladened air kdrawn into the air chamber through-an air intake 39 adjusted by the regulatorj.39a.. The air and gases resulting from the sintering' process may be run through a dust collector either before or4 after the suction fan. The air. intakes i9 and 39 to the air chamber 29 are so adjusted that the one I9 at the ignition chamber will have sufficient air passing to givev desired coolingblast for the. sinter. y Y

Hot sinterwillbe .in contact with the plungerV 2|; the-top of `the front side and with parts of the ends 6| of the sintering pass. The metal at these places including the plungers and supporting parts thereof is heat resisting and a metal to which the hot sinter'will not readily adhere.

The operation is as follows: To start the gravity flow sintering machine,fthe stock supply gate is opened filling the entire machine with stock. IfV the machinery is not running, the machine will stand full of stock as the conveyor 25 at the bottom is so placed that the stock will take its natural slope below the rollers and be held on the conveyor 26 as indicated by lines4 24a. and 25a. When the machine begins to operate, the conveyor will carry the stock away at a velocity to givethe stock the desired speed for the downward flow in thesintering pass.` The suction'fanv 34 is now started and the ignition fiame |'|a is now ignited. Sinter obtained bythisiiame ignition and maintained by the air suctionV will follow the stock, as indicated by the fire line 60, through the sintering pass. -Any stock going through the machine without being converted to sinter is separated from the sinter and is returned to the stock processing line. YPartial loss of fire orignition doesnot stop the process as the-stock and -sinter both pass through the'machine at the same velocity, thus allowing Va pick up in ignition. However, the machinery must run and the ignition. flame must be maintained to produce a continuous output of sinter. f

In Fig. 9 is shown diagrammatically the incom' ing flow of the stock, into the gravity acting in-v clined( sintering pass |5. When the stock 50 is ignited by the actionofthe ignitor Ila. upon the descending stock 50, a fire line 5| is formed contiguous to which the sintered stock 52 is formed, which increases indepthdue to the action of the incandescence. When thel Vflame Ila strikesthe stock, or is impinged against the stock, the incandescence is from the flame adjacentsurface inwardly into the stockt When' the sintering 4material and stockisrsubjected to an 'induced air flow, as through wall Illa, the desideratum is to pull the incandescencel into the unsintered stock. l

The surface 53 of this incandescent portion 52 is cooled by an air flow 54 (Figs. 9, l0 and 11). The lower end of this cooled surface 53 is subjected to the action of a plunger 2|. This plunger changes the flow of the sintered stock 5'2. `It acts as a sinter flow director. The surface of the sinter stock 52 corresponding tothe inclined face ofthe plunger 2|, is indicated by 53a, and this surface 53a, is diverted by the plunger 2|, which directs the firing line 5| to the position 5|a, so as to be at an angle to its original direction. Uponl the withdrawal of the plunger 2|, the firing line 5| a is pressed by the downwardly moving stock to the position 5|b, and'initiates the ring line 6i).

In Fig. 10, the plunger 2| engages the surface 53 forcingthe sinter and incandescent layer 52 (see Fig. 9) and stock downward along the front side of the sintering pass to the position between 52A-52B with the cooled surface 53a in contact Iwiththe plunger 2| at the low position of` plunger 2|. As the plunger 2| returns to its high position, the sinter and incandescent layer between 52A-52B is forced down against the front side |5a by the pressure of the stock 50 in the feeding chute. This-cycle is repeated with each stroke of the plunger 2| and places the cooled surface of the sinter against the front 'side |5a of the sintering pass l5 with the incandescent layer and stock above instead of below the sinter. Due to the induced air ilow and descent of the' stock, the incandescent layer or re line then takes an inclined line 69.

In Fig. 9 is shown the initial position of the iiow of the ignited stock down to the front side 55a. In Fig. 10 the down `position of the plunger 2| is shownwhereby the cooled surface sinter 53a` and the incandescent line 5| is diverted to the angular position shown. On the return of the plunger, there is a space left. The .pressure of the stock then forces the sinter and re line 5| downwards against the front side |5a, as shown in Fig, 11. The action of the plunger is intermittently continuous and its next descent then again acts on the -Inaterial asvshown in Fig. 9, which' material has in the meantime entered the space referred to and then is subjected to the action shown in Fig. 11.

Thus the vmachine takesV the prepared stock from a supply, passes this stock by gravity flow through an inclosed feeding chute so that the stock passes an ignition flame and continues the gravity iiow, the feeding' chute above and the air locks below forming air throttling-portions, one at each end of the sintering pass acted upon con by the induced air.

From theforegoingitis seen that Vthe invention includes a gravity flow sintering machine,`

in which the prepared stockfor thesame flows by gravitythrough a substantially vertical inclosed Y 55a feedingl chute blocking olf the air flow, with the stock feeding into an inclined sintering pass..

The bodyof the stock prior to its passage into the sintering pass, is` continuously acted yupon by;

a flame to ignite a locally exposed upper surface in its new or sliding through the.

of the stock. Thisignited and burning surfacev of stock is turned by turning means lwhile in af plastic and burniniT condition to become the hard lower surface of the body ofistock, from which a re line is formed dividing the stock The. body of sinter and stock divided bythe fire line. by; being traversed'transversely by air, enables thecombustionltorbe continuously carried on, andpnthe completion thereof, to be cooled, as these materials flow down the-.sintering pass, producing a practically rigid block of sinter, furnishinga blocking. oil" of airflow at its lower end. This block of sinter is engagedA bythe controlling and crushing means and is discharged bythe same from the sintering pass. The action iscontinuousvfrom the feedingof the stock to the crushingv of thelsinter, with the crushing car.- ried' on .relatively to the amount of sinter being produced, or conversely stated, the crushingl is regulated to bring about a co-related amount of sintering.

It will also be noted that in the feeding chute thefilarne action or ignition of' the stock at the ignition chamber is with Aiiame above the stock and the nre line drawn downwards by the air suction, but in the sintering pass the ignited stock is below the stock mass and the re line is drawn upwardly, these separate actions taking place at about 90 to each other.

It will be noted that the front side la with its openings |519 extends below the lower end of the backside l5c with its openings ld.y The upper surface of the stock below the lower endof the back side l5c is free and unrestrained, but is Subject to the suctionaction of the suction chamber 30. When the stock has been sintered, the upper surface of the sinter is free and unrestrained, and the upper part of the sinter in the sintering pass is subject to the suction chamber 3U. When a second suction chamber is used as shown by Fig. 2, air exhaust is taking place-by fan 34a, for instance, the upper air lock 23 acts as a barrier or separating means between the two suction chambers. This air lock acts as an air choke, or provides an air choking action. The fan 3A0. sucks air from the lower openings I5b of the front side I5a, and the sinter is thereby cooled.

The feed chute as described prevents air from being sucked in, and thus also actsV as an air Crusher 25, transmits power to the shaft of the roller 24, and to the drive shaft of the conveyor 26, and to the drive shaft 2lc of the plunger, in order to have these parts act in unison, suitable linkage being utilized.

I have described several forms of my invention, but obviously various changes may be made in the details disclosed without departing from the spirit of the inventionas set out in the following claims.

I claim:

l.' In a sintering machine, an enclosed stock feeding chute, vertically disposed, including a vertical stock guide having a vertical wall and an adjacent horizontal wall, said horizontalwall forming with its adjacent vertical wall a flow retarding pocket at the lower end of the first ing a vertical wall and an adjacenthorizontal wall, said horizontal wall' forming with its ad-,\

jacent vertical wall a flow retarding pocket at the lower end of the second stock guide, disposed laterally out of vertical alignment with the first stock guide for directing the stock at an angular direction to the vertical ow of the first stock guide, an inclined wall between the pockets for directingethe stock ow at an angular direction to the vertical ow in the second stock guide', an ignition chamber'atthe lower end of the inclined wall having an opening along the upper part of the stoclcflow for'igniting the stock, an opposed inclinedwall having air openings for sup'porting the stocky flow, and a suction chamber below horizontal wall forming with its adjacent verti-V cal wall a -flow retarding pocket at the lower end of the second stock guide, disposed laterally out of yvertical alignment with the rst stock guide for directing the stockat an angular directiony tothe vertical flow ofv the first stock guide, an

inclinedtwall between the pockets for directingthestock flow at an angular direction to the ver-4l tical flow in the second stock guide, an ignition chamber at the lower end of the inclined wall having lan opening along the upper part of the stock -fiow for igniting the stock, an opposed inclined wall having air openings for supporting the :stock flow, a suction chamber below the lastv named inclined wall for drawing 'air from the ignitedpart of the stock through' the stock flow, and a cooling device below the ignition chamber and adjacent to the same, for cooling the ignited stock,.and disposed out of the aforesaid air ow.

3. Ina sintering machine, an enclosed stock feeding'. chute, vertically disposed, including a vertical stock guidel having a vertical wall and an adjacent horizontal wall, said horizontal Wall forming ywith its adjacent vertical wall a flow retarding.pocket at the lower end of the rst stockguide, a second vertical stock guide, havinga vertical wall and an adjacent horizontal wall,-said horizontal wall forming with its adjacent vertical wall a ow retarding pocket at the lower: end of the second stock guide; disposed laterally out of vertical alignment with the first stock guidel for directing the stock at anangular direction to the vertical flow of the first stock guide, an inclined wall between the pockets for directing the stock ilow at an angular direction to the vertical iiow in the second stock guide, an

ignition chamber atfthe lower end of the inclined wall having an opening along the upper part of the stock-flow for igniting the stock, an opposed inclined wall having air openings for supporting the stock flow; a suction'chamber below'the last named inclined wall for drawing air from the ignited part of the stock through the stock iiow, a sintering pass for the flow of stock having parallel4 perforated topand bottom walls with closed side walls, inclined to the perpendicular, and a 5 suction chamber on a wall of the sinter pass for drawing air through the ys'tock'in the sinterpass through' the'penings of a wall of the sinter pass', whereby the stock descends by gravity from the chute, passes the ignition chamber and passes through the sinter pass to its discharge at the loweriend ofthe sinter'pass in the form of sinter.

4. In a sintering machine, anenclosed stock feeding chute, vertically disposed, including al vertical stock guide having a vertieal'wall and an adjacent lhorizontal Wall, said horizontal wall said horizontal` wall forming with its adjacentr vertical wall a flowY retarding pocket atthe lower end of the` second stock guide, disposed laterally out of lvertical alignment with they first stock guide for directing the stock at an angular direction to the flow Vof the first stock guide, a rst inclined wall between thel pockets for directing the stockiiow at an angular direction to the perpendicular in line withthe discharge flow in the second stock guide, a second inclined wall extending from the second horizontal wall, downwardly substantially parallel with the first inclined wall',` an ignition chamber-at the lower end of the first inclined wall having an opening alongthe upper part of the stock, flow for igniting the adjacent sur-face of the stock, said second inclinedwall having air openings; asuction chamn ber below the last named inclined wall for drawn ingair from the ignited part of the stock through the stock flow, a sinter pass for the flow of the ber, consisting of a pusher, for transposing the ignited surface of the stock from its direction along the first inclined wall adjacent the ignition chamber to a direction along the front wall of the sinter pass, the said inclinations of all of said inclined walls being such as to retard but not to prevent the flow of stock under the action of A gravity, whereby the stock descends in mass, passes the ignition chamber and passes through the sinter pass to its discharge at the lower end of the sinter pass in the form of sinter, being -f propelled in such passage by the action of gravity.

5. In a sintering machine, the combination of a vertically disposed feed ohutefor stock having spaced front, rear and side walls, and having an open top and an opening at its lower end, with means discharging the stock at an inclination to the perpendicular, an ignition device for igniting the adjacent'free upper surface of the stock flowing from said means in a mass discharging from the end of said means owing along said ignition device, an inclined sinter pass having an open top in communication with said chute discharge means, for receiving the stock passing along the ignition device, said sinter .pass having parallel perforated front and rear walls and closing side walls, said front surface of ignited stock mass being unimpeded to flow until it rests on the top of the front sinter pass wall, means for transposing the said front surface of said ignited stock at the top of the front sinter pass wall from a position above the stock as it moves from the ignition device to one below the stock along the front sinter pass wall, said means including a pusher having a pusher surface angularly disposed at an acute angle to the upper inclined surface of the stock as itimoves towards said front wall flowing from said ignition device and disposed at an obtuse angle to the front wall of said sinter pass, and means for intermittently operating said pusher, whereby when the pusher ieg is moved downward in a direction parallel to the front wall of the sinter pass, the ignited surface of the stock flowing from saidignition deviceis pushed into the lower part of the sinter stock of the sinter pass, and is held down by the stock in thes'inter ypass .to a position in the sinter pass below the stock therein,v and when the, pusher is moved in the reverse direction ignited stock flowing from the ignition device moves in front ofthe` pusher.

. .6. In'a sintering Vmachine, the combination of a vertically disposed feed chute forstock having spaced front, rear and side walls, andA having an open top and anopening at its lower end, with means discharging the stock at an inclina` tion to the perpendicular, an ignition device for igniting ,the kadjacent free upper` surface of the stock lovving'from said means in a mass discharging from the end of said means owing along ,said ignition device, an inclined sinter 'pass having an open top in communication withsaid chute discharge means, for receiving the stoclr` passing along the ignition device, said sinter pass having parallel perforated front and rear walls;

and'closing side walls, said front surface Vof,.ig nited stockmass being .unimpeded to flow until it rests on the top of the front sinter pass wall, means for transposing the said front surface of said'ignited stock at `the top of the front sinter pass wall from a position above the stock as it moves from the ignitiondevice to one below the stock along the front sinter pass wall, said means including a pusher having a pusher surface angularly disposed at an acute angle to the upper l, inclined surface of the stock as it moves towards said front wall flowing from said ignition device and disposed at an obtuse angle to the front wall of said sinter pass, and means for intermittently operating said pusher, whereby when the pusher is moved downward in a direction parallel to the front wall of the sinter pass, the ignited surface of the stock flowing -from said ignition device is pushed into the lower part of the sinter stock of the sinter pass, and is held down by the stock in the sinter pass to a position in the sinter pass below the stock therein, and when the pusher is moved in the reverse direction ignited stock flowing from the ignition device moves in front of the pusher, with an extension of the angular rear wall above the sinter pass into the sinter pass space at the upper end ofthe rear wall of the sinter pass, this extension forming an acute angle with the rear wall of the sinter pass providing a space free from the direct gravity flow of stock between said extension'and the rear wall of the sinter pass, whereby any pressure by the pusher on the stock is relieved and taken up in the said space.

7. In a sintering machine, the combination of a gravity iiow sinter pass including a front wall, a parallel rear wall spaced therefrom, and side walls connecting the front and rear walls forming an elongated chute for guiding stock in the mass throughout its cross-section, having an open upper receiving end, and an open lower discharging end, said front wall having an inclination to the perpendicular to retard but not to prevent the descent of the stock by gravity from the open upper receiving end towards the lower discharge end, a feed chute having an elongated upper portion of vertically disposed walls open at the top of said portion to receive the stock and open atthe bottom of said portion to discharge the stock, for enclosing stock throughout the cross-section of said portion from said top il to said bottom in vertical flow providing an air choke, said feed chute having a vertically dis'- posedy lower portion of substantially vertically disposed stock-enclosing walls, said walls having an opening at their upper end and with a discharge opening at their lower end, below lsaid upper portion and in continuation therewith, to

receive the stock discharged from thel bottom of said upper portion, said last named lower portion having an inwardly extending horizontal wall in the vertical downward path of the discharge of the upper portion, the lower portion below said horizontal wall being disposed laterally out of vertical alignment with the upper portion for directing the stockflow in a direction in an angular direction to .the vertical flow of the upper portion, all portions of the feed chute from ,its top Yto its bottom forming. avcontinuous air tight enclosure with thestock therein forming anoverall air choke, said feed chute being above the sinter 'pass receiving en d and having, the discharge opening of its llower portion in ,stock communication with the open upper end of the sinter pass and adjacent thereto, a stock igniting device above the free flowing surface of said stock asit discharges from the feed chute into said sinter pass, for igniting the surface of said stock adjacent said device, and means supplying air to the stock in the sinter pass chute for continuing the burning of the stock in the sinter pass 30 during the flow of the stock ink the sinter pass chute until the stock in said sinter pass chute is converted to sinter, the discharge of the sinter being from the lower end of thesinter pass, said sinter acting as an air choke in the lower end of the sinter pass.

8. The structure of claim 7, with sinter break-- ing roller means at said lower discharging end of the sinter pass for breaking the sinter discharging from the lower end of the sinter pass, and means varying the speed of said sinter breaking means, whereby the movement of the stock in the sinter pass is controlled.

WALTER KELSEY.

REFERENCES CITED The following references are of record inthe le of this patent:

UNITED STATES PA'I'Eiv'rsvv l Date v