US2255379A

US2255379A - Furnace charging means

Info

Publication number: US2255379A
Application number: US236451A
Authority: US
Inventors: John F Crawford
Original assignee: JI Case Co
Current assignee: Case LLC
Priority date: 1938-10-22
Filing date: 1938-10-22
Publication date: 1941-09-09
Anticipated expiration: 1958-09-09

Description

S-Pt 9, 1941 J. F. cRAwFoRD 2,255,379

FURNACE CHARGING MEANS Filed Oct. 22, 1958 2 Sheets-Sheet 1 BYWLM ATTORNEY Sept 9, 1941 .1. F. CRAWFORD 2,255,379

FURNACE GHARGING MEANS Filed oct.' 22, 1958 2 sheets-sheei 2 v? G D o cQQOQ Hoppe/2 i INVENTOR. Jo/zrz f Cra w/fora/ A TTORNEY Patented Sept. 9, 1941 FUnNAcEcHAnoINo MEANS John F. Crawford, Racine, Wis., assigner to J. I.. Case Company, Racine, Wis., a corporation Application october 2z, 193s, serial No. 236,451

21 claims.-

The present invention relates to cupolas, and an object of the invention is to generally improve the construction and operation thereof.l

Fig. 2 is a similar View, enlarged, of certain portions of the device indicated in Fig. 1.

In the operation of cupolas it has long been desirable to be able to utilize metal chips, turn ings, fragments and the like as part of. the charge to lbe melted, both for the purpose of utilizing the metal involved and also for modifying the properties of the metal discharged from the cupola.

coke and metal are introduced through a charging door high up in the furnace, the introduction of chips with the other metal is generally unsuccessful because the relatively small particles, when they reach the melting zone, are exposed to an oxidizing atmosphere and consequently they are to ay large extent, if not entirely consumed. Furthermore such of the chips as are not consumed, being relatively much smaller than the other or ordinarycontents of the cupola have a tendency to adhere together and arch or bridge across the furnace body and arrest the normal downward movement of the charge. vIn the present instance these diiiiculties are avoided by introducing the chips at a point remote from the charging door where conditions are normally favorable for the rapid melting of the chips and unfavorable for combustion thereof.

The novel method of operating the cupola ac.- cordingly comprises introducing the chips at a point well down in the body of incandescent coke, for example at about the point where the usual pig iron and scrap material is thoroughly heated and about to liquefy or possibly already partially liquefied. the action may be at this point it appears that the partially liquefied metal may tend to take In the ordinary operation of the, vcupola however wherein alternate charges of While it is not known exactly what (c1. 26e-fev) protect them from the oxygen in the combustion zone, heating them and melting them substantially instantly. On the other hand it is possible that thepreponderance of carbon at a. high temperature in this zone may have such an afnity for oxygen as to protect the chips therefrom, the effects being what might be expected if the chips were introduced into a reducing zon in the furnace.

'In any event it appears that chips introduced at such a zone'are substantially all melted-and appear promptly inthe accumulation of melted metal in the base of the furnace. This results in further possibilities in ythe operation of the cupola, particularly inthe prompt and accurate control of the quality ofthe output. For example'the composition of the metal in the chips is generally known and can be very accurately controlled, whereas the vcomposition ofthe melty ed metal .accumulating `in the bottom of thecupola is apt' to vary. in accordance. gwiththe, v 1V.

amount of carbon picked up -fromthepokelin its A' descent throughfthe furnace. I f the composi'.. l

.tion of the metal discharging vfrom the furnace is important and a test shows 'an excess of carbon, for example, according to prior vpractice more steel scrap low in carbon would'be .introduced through the charging door in the usual manner. A considerable time would then elapse before this change in proportion would make itself felt inthe composition of the output. Then if it turned out that too muchflow carbon metal had been introduced, a similar delay would ensue before further correction could be accomplished.

In the practice of the present invention such a correction can be effected in 'a matter of a few minutes by simply increasing the rate of introduction of the chips, assuming a similar situation and that the chips are of low carbon material. This appears to be so because the chips melt immediately and promptly find their way to the accumulatio-n of metal n the base. Of course if a test shows that the change in the chip feeding rate has been too small or too great, correction of this error can be made just as promptly. As a result it is a simple matter to hold the quality of the output metal very close to that desired, whereas in `the past much greater fluctuations in the proportions of iron, steel, carbon, etc. have been necessarily tolerated.

As seen in Fig. 1 a typical arrangement for practicing the above disclosed method includes a furnace tube, body or casing I of the usual or suitable type having an insulating or other lining the chips and fragments into suspension and 2 and a refractory or heat resisting lining 3, the

casing having a floor 4 covered with a layer of sand or the like 5, a blast chamber 6 surrounding the casing at the lower end, the blast being supplied from a suitable source not shown through a duct 1 and passing into the furnace through openings or tuyres 8 and 9 An opening I is provided for drawing off the `melted metal into a trough II and an opening or charging door I2 is provided relatively high up in Ithe casing through which the fuel and metal are introduced.

In operation pig iron P, coke C and scrap S are introduced through the charging door I2 so as to produce alternate layers of metal and coke as shownl the material settling gradually asl the coke is consumed and the metal melted. the

metal reaching a temperature approximatelyat zone Z such that it becomesplastic and begins to melt and trickle down through the body of incandescent coke 'and accumulate at I on the sand oor 5, the fused ash from the coke, and other impurities, floating on the iron as a layer of slag I3. y

The desirable point for introduction of the chips appears=to be in the neighborhood of zone Z and accordingly injecting mechanism generally designated as I4 is arranged substantially at this point for introducing the chips.

As seen in Fig. 2 an opening I5 is provided Athrough -the casing I and

linings

2 and 3 in which is fixed, in the present instance, a fitting I6, in the form of a sleeve which may have a flange I1 for a purpose to appear, the injecting mechanism operating through the sleeve.

Said injecting mechanism maybe of any suitable or.well known type capable of forcing granular or powdered material through sleeve I6, and it is toI be understood that the invention is not to be taken as limited by the particular disclosed mechanism "I4, or in fact in any manner except as defined by the claims. Mechanism I4 coni--A prises a hopper or reservoir I8 having a trough or auger chamber I9 inthe lower part thereof, and a delivery sleeve arranged to be introduced into above mentioned sleeve I6, sleeve 20 for convenience having a flange 2I engaged with a flange 22 on the hopper whereby sleeve 20 may be readily removed and replaced. A flange 23 also on sleeve 20 approaches flange I1 on sleeve I6 when sleeves I8 and 28 are fitted together and a sealing ring, clamp or the like 24 is iittedabout the flanges to make' a fluid-tight connection. This is desirable because the pressure in the furnace due to the blast is considerably above atmospheric at this point and would otherwise cause leakage of objectionable amounts of gas and smoke into the building.

An auger 25 of suitable or well known form occupies auger chamber IS and may advantageously extend through sleeve 20 into sleeve I6, substantially or entirely through the wall of the furnace. Rotation of the auger will accordingly rfeed chips from hopper I8 through the sleeves and into the furnace, the end of the auger being protected by the flow of relatively cool chips thereover from the heat of the charge in the cupola.

Difficulty may be experienced with gas and smoke backing up through the body of chips and sleeve 28 into the hopper I8, objectionable amounts issuing from the hopper. This is avoided by introducing, as for example by a hose 21, air or other unobjectionable fluid at a pressure higher than that obtaining in the furnace, through sealing ring 24, a spud 28 or the like extending through the wall of the ring, the fluid iindingits way through a clearance space 29 to a point spaced materially back from the mouth of sleeve amounts of air, for example, at this point produces a flow of clean air in both directions from the mouth of sleeve 28, part of the air passing into the furnace and part of it passing backwardly into the hopper, the result being to completely prevent any flow of smoke backwardly along the auger.

Auger 25 may be driven in any suitable or well known manner, in the present instance, a. motor 30 being carried on bracket 3I and driving, through

pulleys

32 and 33 and a belt 34, a speed lreducer generally designated as 35. Such reducersbeing well known and the particular type used being immaterial insofar as the operation of the rest ofthe device is concerned, it is not necessary to describe it further than to say that it has a= shaft 36 driven by pulley 33 and which through internal mechanism drives an output shaft 31 at a reduced speed. Shaft 31 may be directly connected with auger `25 and operates at a large reduction in speed from shaft 38. The speed of shaft 31 may be variable if desired as by a lever 38 although this is not essential since other means is contemplated for controlling the amount of material fed. The lever may be locked in various positions by engagement of a detent 39 with one or another of sockets as 48. Other means is contemplated for locking the-lever, or for varying the speed of the auger within the scope of the invention.

Since the cupola requires some time to reach operating temperature it is usually fired up with the injecting mechanism I4 retracted and sleeve I6 plugged with clay or the like. For convenience in so retracting the mechanism, hopper I8 is carried by means of a sliding member or trolley 4I engaged on a beam, track or the like 42 suitably supported as from casing I and for example part of the enclosing building in any well-known mannr, member 4I being movable on beam 42 wherebyy hopper I8 and its attached parts may be readily moved away from casing I. Suitable means may be used for so moving hopper I8, in the present instance a bar 43 ex,

tending from the hopper in a direction away from the cupola. A rack 44 fixed withl the bar en-i gages a gear 45 on the shaft 46 suitably journaled in relation to the rack to provide proper interengagement between it and the gear, a hand wheel orother suitable means 41 being fixed with the shaft for rotating it and gear 45. By the use of hand wheel 41 mechanism I4 is readily moved toward or away from the cupola as desired.

'I'he operation of the mechanism is thought to be clear from the above description, the cupola operating in the usual manner except that the chips or other fine material are introduced well below the surface of the charge in the zone Z where melting of the larger pieces of metal has already commenced, or where the chips will melt substantially as fast as they are introduced. This obviates any resistance on the part of the charge already in the furnace to the introduction of the chips and avoids the building up of pressure at the mouth of sleeve I6. The rate of introduction of the chips may be changed by controlling the speed of auger 25, as by lever 38, although other means are contemplated as equivalent. The injecting mechanism may be readily applied to or removed from the injecting opening by means of the gearing 44-45, and smoke and I6. 'The introduction of sufficient" sure introduced through clearance-'space v29.

The eboveibeing e full and 'complete descrip-- `tion of the novel method of. operation of a cupola.

and typical mechanism for the practice 'of Vsucll method, what is claimed as new and-desired to besecured by Letters Patent of-theUnited States -is 1. In;l a cupola a body .portion having .side

walls, a bottom for collecting melted metal, a

through the passageway into the contents of the body portion and including a delivery sleeve, and

means for introducing a fluid under pressure into the body of granulated material in said de- 1 livery sleeve peripherally thereof at a point removed from that at which said passageway opens into the interior of the body portion of the blast'openlng above the bottom, a charging door l above the blastA opening, and means including an "auger conveyorprojecting into and beyond the `wa1l of the body portion between the blast opening and the charging door arranged for injecting granularv material into lthe body portion at a point where the charge is partly melted, whereby to melt the granular material before it can be destroyed by oxidation, means for supplying granular material to the auger, and power driven mechanism for driving theauger.

2. In la cupola a' body -portion having side wells, e `bottom for collecting melted metal, e

blast opening above the bottom, a charging door above the blast`opening, said side walls providing an opening above the blast opening and below the charging door, and injecting mechanism including a hopper, an 'auger conveyor in the hopper including an enclosing sleeve projecting from the hopper, supporting means for the mechanism, and said mechanism being movably mounted on the supporting means said enclosing sleevebeing adapted to be inserted in said opening between the blast opening and the charging door, andfmeans for moving said mechanism on said y supporting means for applying or removing said inclosing sleevefrom said opening. Y

3. Inv a chip feeding means for a cupola means .providing an opening vthrough the wall of the cupola and injecting mechanism adapted to be applied ltov the opening for propelling chips through the opening into the cupola, and supporting means for the mechanism including a track and a trolley movable on thetrack and connected to support the mechanism.

,4. In a -cupola having a body portion including side walls, a bottom for collecting melted metal, a blast opening above the bottom, a charging door above the blast opening, said side walls providing an` opening above the blast opening and below the charging door, an injecting mechanism including a hopper, an auger conveyor in the hopper including an 'auger and an enclosing sleeve projecting from the hopper and said auger projecting into land beyond the opening provided in the wall of the cupola.

5. In a cupola a body portion having side walls,.a bottom for collecting meltedv metal, a blast opening above thebottom, a charging door above the blast opening, said side walls providing an opening above the blast opening and below the charging door,`an injecting mechanism including an auger conveyor having an enclosing sleeve' projecting into said opening and partly through said side walls, said auger extending into the opening substantially beyond the end of the sleeve.

6. In a cupola a body portion including side walls, a charging door high up-in the body portion, and a blast opening near the bottom of said body portion, said body portion providing a passageway leading through the side walls between the charging door and blast opening, injecting means for introducingl granulated material cupola whereby to prevent seepage of gas from the cupola backwardly through the granulated material into the injecting means.

'1. In a chip injecting means for a cupola a sleeve fixed in the side wall of the cupola and defining an opening through the wall, injecting mechanism adapted to introduce granular material into the opening for passage into the body of material in the cupola, and means for introducing fluid under pressure peripherally into the body of granular material between the inner and outer ends of the sleeve for preventing seepage of gas from the cupola backwardly through the body of granular material. V

8. In a chip injecting means for a cupola a sleeve xed in the side wall of the cupola and defining an opening therethrough, injecting mechanism for introducing granular material throughthe opening and including a sleeve extending into and partly through the first men- A tioned sleeve, there being clearance between said sleeves, and means -for introducing fluid under pressure into the clearance space to prevent seepage of gas from the cupola backwardly through the body of granular material being introduced sealing band engaging the margins of said flanges f to prevent the escape of iluid therebetween, and a. pipe arranged to introduce fluid between the ilanges for preventing seepage of objectionable gases from the cupola backwardly into .the body of Vgranular material being introduced by the feeding means. y 10. In a chip injecting means for a cupol a sleeve fixed in the side wall of the cupola and y opening into the interior thereof, an auger con-.

veyor included in the injecting mechanism and ,having an enclosing sleeve, said enclosing sleeve being inserted in the first mentioned sleeve with clearance and projecting partially therethrough to provide an annular passageway leading into the body of chips issuing from said auger conveyor, and means for introducing air under pressure into the clearance space between the sleeves for penetrating the body of chips beyond the enclosing sleeve for preventing ltration of objectionable gases from the cupola through the body of chips in the conveyor. Y

1l. In a chip injecting means for a cupola a sleevefxed in theside wall of the cupola and having an outer iiange, an auger conveyor havlng an enclosing sleeve, said inclosing sleeve belng adapted to be inserted in the first mentioned sleeve with clearance to provide a passageway extending longitudinally of the first mentioned sleeve and into the cupola.' a flange on said enclosing sleeve adapted to approach the first mentioned flange but to be spaced therefrom when said sleeves are placed together, a sealing band engaging the margins of said anges to prevent the escape of ud therebetween, and means for introducing a fluid under pressure into the space between said flanges. v

12. In acupola a body portion having side walls, a charging door high up in the side walls, a blast opening near the bottom of the body portion, said `side walls providing an opening between the charging door and the blast opening, and means for injecting granular material through the opening including a conveyor projecting into the cupola beyond the side walls, means fordriving the conveyor including power actuated mechanism, and means for selectively changing the rate at which the conveyor introduces material through the opening.

13. In a chip feeding means for a. cupola, means providing an opening through the wall of the cupola and injecting mechanism adapted to be applied to the opening for propelling chips therethrough, and into the cupola, and means for supporting the mechanism for movement toward and away from the opening whereby said injecting mechanism may be applied to the opening when desired,v and-readily removed from the cupola when not in use.

14. In a cupola a "body portion having side walls, a bottom for collecting melted metal, a blast opening above the bottom, a charging door above the blast opening, said side walls providing an opening above the blast opening and below the charging door, and injecting mechanism including an auger conveyor, an enclosing sleeve for the conveyor and supporting means for the mechanism, and said mechanism being Amovably mounted on the supporting means, said enclosing sleeve being adapted to be'inserted in said opening between the blast opening and the charging door, and -means for moving said mechanism on said supporting means for applying y or removing said enclosing sleeve from said open- 15. In a cupola a body portion having side walls, a bottom for collecting melted metal, a blast opening above the bottom, a charging door above the blast opening, said side walls providingV an opening above the blast opening and below the charging door, injecting mechanism including a hopper, a conveyor in the hopper including an enclosing sleeve projecting from the hopper, supporting means for the mechanism an-d said mechanism being movably mounted on the supporting means, said enclosing sleeve being adapted to be inserted in said opening between the blast opening and the charging door, and means for moving said mechanism on said supporting means for applying or removing said enclosing sleeve from said opening.

16. In a cupola, a body portion having side walls, a bottom for collecting melted metal, a

blast opening above the bottom, a charging doorv above the blast opening, said side Walls providing an opening above thev blast opening and below the charging door, and injecting mechanism including a hopper, an auger conveyor in the hopper, supporting means for the mechanism and said mechanism being movably mounted on the supporting means, said conveyor being adapted to be inserted in said opening between the blast opening and the charging door, and means for moving said mechanism on said supporting means for applying or removing said conveyor from said opening.

.opening above the bottom, a charging door aboveA the blast opening, said side walls providing an opening above the blast opening and below the charging door, and injecting mechanism including a hopper, an auger conveyor in the hopper including an auger having an enclosing sleeve and projecting from the hopper, supporting means for the mechanism and said mechanism being movably mounted on the supporting means, said conveyor being adapted to be inserted in said opening between the blast opening and the charging door, and means for moving said mecharism on said supporting means for applying or removing said conveyor from said opening.

18. In a cupola, a body portion having sidev walls, a bottom for collecting melted metal, a blast opening above the bottom, a charging door above the blast opening, said side walls providing an opening above the blast opening and below the charging door, and injecting mechanism including a hopper, an auger conveyor in the 17. In cupola, a body portion having side walls,

a bottom for collecting melted metal, a blast hopper including an enclosing sleeve projecting from the hopper, supporting means for the mechanism, and said mechanism being movably mounted on the supporting means, said conveyor being adapted to be inserted in said opening between the blast opening and the charging door,

and means for moving said mechanism on said supporting means for applying or removing said conveyor from said opening.

19. In a cupola, a body portion having side walls, a bottom for collecting melted metal, a blast opening above'the bottom, a charging door above the blast opening, said side Walls providing-an opening above the blast opening and below the charging door, and injecting mechanism including a hopper, an auger conveyor in the hopper including an enclosing sleeve projecting from the hopper, supporting means for the mechanism and said mechanism being movably mounted on the supporting means, and said enclosing sleeve being adapted to be inserted in said opening between the blast opening and the charging door.

20. In a cupola, a body portion having side walls, a bottom for collecting melted metal, a. blast opening above the bottom, a charging door above the blast opening, said side walls providing an opening above the blast opening and below the charging door, and located substantially at a level where the usual melted, an injecting mechanism including a conveyor having an enclosing sleeve projecting into said opening and partly through said side walls, and said conveyor extending into the opening substantially beyond the end of the sleeve for acting on material being injected at a region beyond the end of the enclosing sleeve.

21. In a cupola a body portion having side JOHN F. CRAWFORD.

metal charge is partly,