US2520169A

US2520169A - Method and apparatus for fiberizing molten material

Info

Publication number: US2520169A
Application number: US51750A
Authority: US
Inventors: Edward R Powell
Original assignee: Johns Manville
Current assignee: Johns Manville Corp; Johns Manville
Priority date: 1948-09-29
Filing date: 1948-09-29
Publication date: 1950-08-29
Anticipated expiration: 1967-08-29
Also published as: GB673561A; FR1018547A; US2520168A; DE919096C

Description

METHOD AND APPARATUS FOR FIBERIZING MOLTEN MATERIAL Filed Sept. 29, 1948 E. R. POWELL Aug. 29, 1950 2 Sheets-Sheet l l7 INVENTOR.

{OW/4P0 x? Pay 44,. 121 4/ fi Armlemsy Aug. 29, 1950 E. R POWELL METHOD AND APRARATUS FOR FIBERIZING MOLTEN MATERIAL Filed Sept. 29, 1948 2 Sheets-Sheet 2 INVENTOR. fa /4P0" A. flan/ELL.

ATTORNEY.

Patented Aug. 29, 1950 METHOD. AND APPARATUS, FOR FIBERIZING BIOLTEN. MATERIAL Edward-R. Powell; North Plainfield, N. J assignor to J ohns-Manville Corporation, New: York, N. Y.,, a corporation of New York Application September 29, 1948; Serial No. 51,750

1 12 Claims: The present invention relates tothe manufacture of mineral wool and, more particularly, to an improved apparatus and method for converting a molten mineral material into fibers. iheapplication is a continuation in part as to all common subject matter with my copending application, S. N. 742,054, filed April 17, 1947" now abandoned which, in turn, was a continuation in part of copending application's, S. N. 485',009,filed April29, 1943, now Patent No. 2,428,810 and-S. N. 555,359, filed September22, 1'9el4.v The term mineral wool is employed in the instant application as in my said priorapplications, in a generic sense to include wool or fibers formed from'rock, slag, glass, mixtures thereof and like raw materials.

Heretofore molten raw-materials of the type referred to above have beenconverted into fibers-in. a number of ways, including the commonly used method of disintegrating-a stream of the molten material by the action of: ahigh pressure steam jet. More recently, it has been proposed; to fiberize the material by a spinning process in which the stream is discharged onto spinners or rotors rotated at high speed, the centrifugal forces set up causing portions; of the material to leave the rotors and to be drawn into fillers. "The instant invention has ,forit'sjprincipal object the provision.

of'an' improvedapparatus and method of the lat.- ter type which will. handle larger quantities of the molten material, provide a greater fiber yield, andproduce finer and more uniform fibers.

One of the major difficu'lties, of" adapting the spinning method to operations on a commercialscale has been the inability of the equipment; to efiectively handle the outputof' the modern cupola conventionally used in mineral wool operations. An object ofthe instant invention is'th'e provision of an improved apparatus and-method employing a plurality of rotors or-spinners which secure a wider distribution or spreading ofthe' molten material to substantially increase the fiberization area and, hence, the capacity and efficiency of the operation.

Another objectof'the invention is the provisionofi a1 method and apparatus in which the movement of the molten material is gradually accelerated. as its passes through the equipment and, at thev same time, the stream is gradually: divided or spread, whereby conversion of the greater portion of the; stream into fibers, with only a.

minimmn'. of unfiberized particles or shot" is. achieved;

It has been found that. by the present method. a fiber yield as high as.45 can be obtained on a commercial scale in. contrast to. the conven. tional blowing operations where it has beenv unusual to. obtain yields greater than, say, 27% 01" the molten slaga Furthermore, the fibers: pro:- duced arelonger and liner than those obtained by: the. priorprocesses and a cleaner, more shot! free product isv achieved.

My'invention willibe more fully understood: and. further objects. and advantages thereof will be-- come apparent when reference is made. to the; more detailed description which is to follow and; to-the accompanying drawings in which:

Fig. 1 is a diagrammatic, front elevationalview: of apparatus embodying the invention;

Fig. 2 is-v a top. plan View of the fiberizing apparatus of Fig. 1;

Fig. 3 1s a side elevational view of the fiberizing" apparatus of Fig. '1.

Fig. 4' is a viewsimilar to Fig. 3-but with parts broken away, illustrating a minor modification of" the invention; and

Fig. 5 is a view similar to Fig. 1 but illustrating the modification ofFi'g. 4".

Referring now to the daw-ings, there is shown an apparatuscomprising a melting furnace m:

which may be ofany suitable type, such as: a

cupola, tank furnace, or the like. The furnace includes a discharge; trough [2 from which a stream of-molten material is drawn from the furnace and discharged in position for fiberization.

: Thai-awmaterialmelted in the furnace and converted into the molten stream may be rock, slag, glass, mixtures thereof, or other liquefiable materials, suitable for conversion into fibrous wooli by the method hereinafter described, allsuchman-- terials: being herein referred to as mineral materials.

The major fiberizin operation isperformed by a pair of rotors i6 and 18? having relatively wide,

peripheral surfaces I? and it, respectively. The rotors are mounted for rotation on shafts 2115 and 22, respectively, the shafts. as best illustrated in Fig. 2, preferably extending at. a. slight angle; say, anangleof 9to each other.

Rotors 8:6 andv 5.8. are. driven in opposite directions; as. indicated; the arrows, and at. rela tively high speeds. The rotors are of heat-resistant steel or other alloy of a character to resist the high temperature of the material, which may run as high as 2900 F., without excessive erosion or wear. The surfaces of the rotors are also preferably provided with a series of grooves 24, suitably of U-shape, to insure the bonding of a ring or rings of the molten material thereto, although bonding of the rings is not necessarily dependent on such grooves. It has been found that, even if plane surfaced rotors are used, after the rotors are subjected for a period of time to the action of the molten material, the latter will tend to bond to the surfaces. However, the use of more positive means for this purpose, such as the grooves 2 3,15 preferred.

Supported above the main fiberizing rotors l6 and I8 are a pair of

rotors

26 and 28. Rotors 2B and 28 are supported on

shafts

30 and 32, respectively. Shaft 32 lies in an approximately horizontal plane substantially parallel to the planes of shafts 2i) and 22, but shaft 35 preferably extends upwardly at a small angle to define an acute angle, say, an angle of about 6 between the planes of the shafts, as illustrated.

Rotors

26 and 28, similarly to the other rotors, have surfaces of steel or other heat-resistant metal, capable of resisting the temperatures of the molten material without excessive erosion.

Rotors

26 and 28 constitute what is, in effect, a stream spreading or distributing device, although, particularly rotor 28, also performs a fiberizing funct on as will be later pointed out.

In the form of the invention illustrated in Figs. 1, 2 and 3, the

rotors

26 and 28 are of frustoconical form with the coned surfaces preferably in reversed relationship. Rotor 25 may be smooth surfaced, as illustrated, while rotor 28 may be provided with one or more grooves 34 of relatively large cross-section. It will be appreciated that these grooves, as well as the grooves in the main fiberizing rotors, are shown of somewhat exaggerated size. In the embodiment illustrated in Figs. 4 and the upper rotors, indicated in these figures by the reference characters 33 and 38, are of cylindrical, rather than conical form. Rotor 36 preferably has a deep groove All, while the surface of rotor 38 is preferably smooth. This embodiment of the invention is otherwise similar to the previous embodiment.

The several shafts are supported from a suitable framework 42 on bearings M. At least the front bearings are carried by yieldable mountings of any suitable or conventional type which will permit the rotors to move apart in the event a solid chunk of slag or fuel should fall between them. The rotors may be driven by individual motors or by a suitable drive, illustrated only diagrammatically, and mounted in any desired location on the frame structure 42. The drive is arranged so that the rotors 2i; and 28 or 36 and 38, as the case may be, rotate in opposite directions, as indicated by the arrows in Figs. 1 and 5, with their upper surfaces approaching, and rotors l5 and IB also rotate in opposite di-- rections with their upper surfaces approaching, as previously mentioned.

In the operation of the apparatus described above, and in carrying out the method of the instant invention, the fiberizing device is positioned to have the molten material stream issuing from the cupola impinge against

rotor

26 or 36, depending upon the embodiment of the invention employed, at a point to the right 0f.a

vertical line through the axis of the rotor, as viewed in Figs. 1 and 5; that is, on a downturning segment of the rotor. This is diagrammatically illustrated in Figs. 1 and 5 where the course of the main bod of the stream to the initial rotor and from there through the equipment is indicated by broken lines. The rotors are tilted to have the shafts slant downwardly,

shafts

20, 22 and 32 extending at an angle of about 12 to the horizontal, as indicated in Fig. 4 but retaining What is herein termed an approximately horizontal position. The main purpose of the tilting of the shafts is to avoid interference between the fibers being formed and the molten stream. Inasmuch as the fibers are drawn out in planes approximately at right angles to the shafts of the rotors by which they are formed, if the shafts are horizontal, at least part of the fibers are projected directly into the path of the stream. It will be appreciated that, as indicated in Fig. l, the rotors are forwardly of the melting furnace I0.

Molten material issuing from the cupola and forming a molten stream is in a highly fluid, incandescent condition and, for economy, the stream is of considerable size of, say, diameter. The condition of fluidity employed for the molten material in mineral wool fiberization by the conventional steam jet process is an example,

although somewhat more fluid streams may be used if desired. The rotors are driven at successively higher speeds to constantly accelerate the movement of the molten material on its way to fiberization. Also, the contact with the first 4 .rotor is at only a slight angle to avoid spattering this very large and flu'd stream. As the stream is gradually dispersed, it is possible to direct it more directly against the surfaces for better bonding. Thus, the impact on the first rotor surface is nearly tangent to it while the impact on the surface of rotor 16 may be substant'ally perpendicular. The molten material impinging upon

rotor

26 or 36 is only lightly bonded, if bonded at all, and is discharged at a greatly accelerated speed and in a spread, distributed. or partially disintegrated condition onto the peripheral surface of rotor 23 or 38, as the case may be. The spread'ng of the material apparently is caused in most part by the separation of the stream into a plurality of components as it leaves the initial rotor. In the embodiment of Figs. 1-3, spreading is further encouraged by the fact that some of the material is discharged at approximately right angles to the rotor axis, and other of the material is discharged approximately normal to the conical surface. However, it has been found that the rotors of the form shown in Figs. 4 and 5 produce adequate spreading of the stream and, inasmuch as it is easier to control the operation, their use is often preferred.

The material discharged on

rotor

28 or 38, as the case may be, is partially bonded thereto to form a molten ring, but is mostly projected tangentially from the rotor in a spread, distributed, or partially disintegrated stream which, at least for the most part, strikes rotor l6. Some of the material may also pass directly from

rotor

28 or 38 to rotor l8. The material discharged onto rotor I5 is partially bonded thereto to form a ring of incandescent material, the grooved surface promoting such bonding, and the excess material over that bonded is discharged by rotor l6 onto rotor 18 where it, together with any material reaching rotor [8 directly from rotor 28 or 5. fly' bonds to athe :surface of the :rotor ito :form an incandescentring of the molten materialflbonm ins lot the :material again being :promoted. :by the-grooved :surface. Any excess of the molten materlelover fthatbonded may-again be projected backegains't motor [6, this =action-continuingnintil the excess material is bonded :to one -or the other-of the rotor-s.

The high speed rotation-of rotors -I6 -and lli causes portions of the incandescent rings '-to be throwrror drawn from 'the rotors-by the 'centrif ugalforcescreated, these portions being drawn out into long, fine fibers. Although rotors I 6 and" I8 perform the main fiberizing function, rotor-28 or-38, -dependi-ng upon which is u-sed, also-opcrates-as a fiberizer to a substantial extent. Rotor ZS or 35 may also flberizetoa minor extent, but itsprimary function is that of-receiving'the stream of molten material, increasing its velocity, and initiating its distribution on the other-motors.

(Zrltical features -of-the-=invention, as previouslypointed out, are the increase in "velocity and the spreading or gradual disintegration 0f the stream as it passes to the main flberizing rotors, whereby'the material bonds thereto rather than being-thrown off or splattered and lost as wouldbe the case if-a concentrated, high volume stream :of .the type here used was discharged directly and :perpendicularlyvonto the high speed rotor iDI rotors.

The particular dimensionsof the rotors are not critical uvithinreasonable limitsand may be selooted; on'th'e basis of thecapacity desired; i. e., the uantity per hour of molten material to be delivered by the meltingfurnace. However, the sizeirelationship between .these elementszis preferably approximately that illustrated in the drawings. atiwhich the rotors are-driven Will depend upon the; operating conditions, Suchas the --.-fluidity:

of'theimolten material, and the like; but again, for-purposes .of example, it may :be stated that,

in employing; a: substantially conventional mine eralevvool; melt, successful operation was obtained byldriving rotors 28hr 36 and281or38 atperiphe eral speedsin the ranges of 2500 to '5000 feet per minute and .6500 to..10,000- feet ;perminutc-,;whilerotors l6 and ltwere driven inranges of.-L2,000

to. .16,000-feet per minute and 1.4,000to 20,000 feet per minute, respectively; The peripheral speeds of the rotors, .the fluidity of the melt, andthe like, .may be varied .to meet, given conditions, as pointed out above. It will be understood, :however, that the molten materialmustbezof a sufiiciently .high temperature, the specific temperatime range depending upon the character ot the material, -.to maintain the molten material on the surfaces. ,of the bonded rings .in a highlyfluid or incandescent .state to. permit .fiberization .to take.

place,

The .fiber; formed as described. above may be collected v.in any suitable manner .and .abinder be introduced if desired, either. before or after initial fiber collection, the particular appatatus. forthese purposes forming .no part of theinstant invention.

The,.construction has been found to. deliver .a greatly-increased fiber yield over the earlier .types ofarotor .fiberization, apparatus. The original stream which. mayhaye a diameter of, say, is greatly. expanded. in Width when .reccivedon thesur'faoes of the main fiberiz'ingrotors. The

PrQduotion-of. fine fibers is enhanced 'throughtho Also, the particular peripheral speeds.

accelerationof thesstream and its.=.reduction-sirom an original, relatively solid stream to, .whattisin 1 effect, 4 azpartially disintegrated stream :or streams of droplets.

Having thusdescribed my :invention :inrathcr" full detail, itwill .be understood "that :these details need :not be strictly adhered to but that various :changes .and modifications may suggest.

themselves to one skilled in the art, all .falling Within the scope of the invention aswdefined by the 'subjoined claims.

What I claim is:

"1. In an'apparatus for converting a molten raw material to fibers having means for discharging -a fluid stream-of the molten material, the improvement comprising means in the path of'the stream for spreading the stream laterally, said stream spreading means including a rotor'having a coned peripheral surface, a shaft supporting said fIOtOY'fOI' rotation with said surface in thepath of the stream, a second rotor =having an' oppositely coned peripher-al surface, a shaft 'sup porting 'said second rotor for -rotation with its: surface adiacentthe first rotor, said shafts extending at'an acute angle to each other; a third path of the stream, a second rotor'havingav peripheral surface, and a shaft supporting sald' second rotor for rotation with its surface adjacent'tothe surface of the first rotor'toreceive the material from the first rotor, a "third "rotor having an unobstructed, molten materialretainingperipheral surface, meansmounting said third rotor for rotation with its peripheral surface in the path of. the material discharged cysaid stream spreading means, whereby a portion-of the materialof said stream'is retained on said surface and anotherportion is thrown off,'a fourth rotor having an unobstructed, molten material retain ing .peripheral surface, means mounting said fourth rotor .for rotation with its peripheral surfacein the path of the material discharged bysaid third. rotor, and means for rotating said rotors.

3.. In an apparatus for converting a molten raw materialtofibershaving means for discharging a fluid stream of .the .molten material, the im provementcomprising means for spreading thestream, .saidspreading means including a frusto-conical rotor, a shaft supporting said rotor for. rotation. on an approximately horizontal axis, asecond frusto-conical rotor :in reversed) relationshiptosaid first rotor, a shaft supporting said .second. rotor for rotation on an approximately. horizontal axis and 'means for r0,-

tatingsaid rotors inopposite directions; a third rotor'having. a peripheral surface with means to.

retain molten. materialthereon, a shaft mountingsaid. third rotorfor rotation withits peripheral .surfacein. the path of material discharged by the spreading means, whereby a portionofj the material is retained on the rotor and another portion is thrown off, a fourth rotor having a peripheral surface with means to retain molten material thereon, a shaft for mounting said fourth rotor for rotation with its peripheral surface in the path of the material thrown off by said third rotor, and means for rotating said third and fourth rotors in opposite directions at high speeds.

4. An apparatus as defined by claim 2, having means for yieldably supporting the shafts for the rotors.

5. A method of making mineral wool from a molten mineral material comprising discharging a stream of the molten material onto the peripheral surface of a rotating rotor, discharging the material from the rotor onto the peripheral surface of an adjacent rotor rotating at a higher peripheral speed to spread and divide the stream, discharging the spread and divided stream at a relatively high velocity onto the peripheral surface of a third rotor to form an incandescent ring thereon from a portion of the mater al, discharging another portion of the material from the third rotor onto the peripheral surface of a fourth rotor to form an incandescent ring thereon, and rotating said third and fourth rotors at higher speeds than said first and second rotors to form fibers from said incandescent rings.

6. In an apparatus for converting a molten raw material to fibers having means for discharging a flu d. stream of the molten material, the improvem nt co pri ing means for accelerating the stream including a rotor located to have its peri heral surface in the path of the stream to receive the material and discharge it therefrom, m ans for rotating said rotor, a second rotor having a eripheral surface to receive material d scharged by the first rotor, means for rotating said s cond rotor at a hi her peripheral speed than the fir t rotor; and fiberi'zin means ineludin a third rotor having a molten material retainin p ri heral sur ace, means mounting said rotor for rotation with its peripheral surface in the ath of mat rial di char ed by the accel rat ng means, a fourth rotor havin an unob"tructed, molten material r tainin eri heral surface, rneans mounting said fourth rotor for rotation with its p ph ral surface ad ac nt said third rotor, and means for rotating said th rd and fo rth rotors at a speed greater than that of said fir-t and s cond rotors.

7. In an a a atu for converting a molt n raw mat rial to fiber having means for di charging a fluid stream of the molten mate ial. the improver ent compris ng means for spreading and accelerating the str am includin a substantially cylindrical rotor having an annular surface, means suppo ting said rotor for rotation with its annular surface in the path of the stream, a second, sub tantially cylindrical rotor having an annular surface and means supporting said second rotor for rotation with its annular surface adjacent the first rotor; and fiberizing means ineluding a third rotor having an unobstructed, molten material retaining, annular surface, means mounting said third rotor for rotation with its annular surface in the path of the spread stream, a fourth rotor having an unob structed, molten material retaining annular surface, means mounting said rotor for rotation with its annular surface in the path of material discharged by said third rotor, and means for rotating said rotors.

8. In an apparatus for converting a molten raw material to fibers having means for dis-' charging a fluid stream of the molten material, the improvement comprising means in the path of the stream for spreading and accelerating the stream, said stream spreading and accelerating means including a substantially cylindrical rotor having a peripheral surface, means supporting stream, a fourth rotor having an unobstructed, molten material retaining peripheral surface,

means mounting said fourth rotor for rotation with its peripheral surface in the path of material discharged by said third rotor, and means for rotating said rotors at successively higher.

peripheral speeds.

9. In an apparatus for converting a molten raw material to fibers, said apparatus having.

means for discharging the molten material, the improvement comprising, a rotor in the path of discharged material to receive material and project it therefrom, a second rotor in the path of material projected by said first rotor to receive material from said first rotor and project it therefrom, a third rotor having an unobstructed, molten material retaining annular surface positioned to receive material projected by said second rotor, a fourth rotor having an unobstructed, molten material retaining annular surface positioned to receive material from said third rotor,

and means for rotating said rotors.

10. The method comprising, discharging molten mineral wool forming material and converting the same into fibers by intercepting discharged material on a rotating annular surface and project ing material therefrom, intercepting material projected by said surface on a second rotating annular surface and projecting it therefrom, intercepting material projected by said second annular surface on an unobstructed, molten material retaining annular surface rotating at high speed and discharging material thereirom to anothe unobstructed, molten material retaining annular surface rotating at high speed.

11. In an apparatus incuding means for discharging a stream of molten material, devices positioned in the ath of the discharged material for converting the material into fibers, said 12. The method comprising, discharging molten mineral wool forming material and converting the same into fibers by intercepting discharged material on a rotating annular surface and projecting material therefrom, intercepting material projected by said surface on a second rotating annular surface and projecting it therefrom, intercepting material projected by said second annular surface on an unobstructed, molten mate- EDWARD R. POWELL.

10 REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Lessing July 18, 1911 White Nov. 15, 1938 Buss Apr. 11 1939 Ramseyer May 27, 1941 Powell Oct. 14, 1947

Claims

1. IN AN APPARATUS FOR CONVERTING A MOLTEN RAW MATERIAL TO FIBERS HAVING MEANS FOR DISCHARGING A FLUID STREAM OF THE MOLTEN MATERIAL, THE IMPROVEMENT COMPRISING MEANS IN THE PATH OF THE STREAM FOR SPREADING THE STREAM LATERALLY, SAID STREAM SPREADING MEANS INCLUDING A ROTOR HAVING A CONED PERIPHERAL SURFACE, A SHAFT SUPPORTING SAID ROTOR FOR ROTATION WITH SAID SURFACE IN THE PATH OF THE STREAM, A SECOND ROTOR HAVING AN OPPOSITELY CONED PERIPHERAL SURFACE, A SHAFT SUPPORTING SAID SECOND ROTOR FOR ROTATION WITH ITS SURFACE ADJACENT THE FIRST ROTOR, SAID SHAFTS EXTENDING AT AN ACUTE ANGLE TO EACH OTHER; A THIRD ROTOR HAVING A PERIPHERAL SURFACE, MEANS MOUNTING SAID ROTOR FOR ROTATION WITH ITS PERIPHERAL SURFACE IN THE PATH OF THE SPREAD STREAM, A FOURTH ROTOR HAVING A PERIPHERAL SURFACE IN THE PATH OF THE MATERIAL DISCHARGED BY SAID THIRD ROTOR, AND MEANS FOR ROTATING SAID ROTORS.