US2577431A - Method and apparatus for the manufacture of mineral wool - Google Patents

Description

Dec. 4, 1951 E. R. POWELL 2,577,431

METHOD AND APPARATUS FOR THE MANUFACTURE OF MINERAL WOOL Filed March 18, 1949 INVENTOR [DIM/P0 A? Pay 44.

' A/WQ A ATTO R N EY Patented Dec. 4, 1951 METHOD AND APPARATUS FOR THE MANU- FACTURE OF MINERAL WOOL Edward R. Powell, North Plainfield, N. L, assignor to Johns-Manvillc Corporation, New York, N. Y., a corporation of New York Application March 18, 1949, Serial No. 82,182

10 Claims. 1

The present invention relates to the manufacture of mineral wool and more particularly to an improved fiberizing device and method. The term mineral wool is employed in the instant application in a generic sense to include wool or fibers formed from rock, slag, fused clays, mixtures thereof and other such heat-liquefiable raw materials.

It has been proposed to fiberize the molten, raw mineral wool forming material by a spinning process in which a stream of the molten material is discharged onto spinners or rotors rotated at high speed, the centrifugal forces set up causing portions of the material to be drawn out into fibers. An apparatus and method for this purpose is shown and claimed in my prior patent, 2,428,810, issued October 14, 1947. The instant invention has for its principal object the provision of an improved device and method of this type which promotes greater distribution of the molten material over the surfaces of the rotors whereby a higher production rateand more eflicient operation are achieved.

Another object of the invention is the provision of a method and apparatus in which the velocity of movement of the molten material is greatly increased before it reaches the fiberizing rotors whereby greater adherence of the material to the fiberizing rotors is obtained and, hence, a higher production of fibers, as distinguished from unfiberized particles or shot, results.

More specifically an object of the invention is the provision of an improved apparatus and method employing fiberizing rotors, the apparatus including a nozzle positioned to direct a blast of a fluid medium against the stream of molten material to increase its velocity and to distribute it onto the fiberizing rotor or rotors.

My invention will be more fully understood and further objects and advantages thereof will become apparent when reference is made to the more detailed description of a preferred embodiment of the invention which is to follow, and to the accompanying drawings in which:

Fig. 1 is a diagrammatic, side elevational View of an apparatus embodying the invention;

Fig. 2 is a front elevational view of the apparatus of Fig. 1; V

Fig. 3 is a detail plan view, on an enlarged scale, of the fiberizing apparatus and stream distributing device; and,

Fig. 4 is a detail, front elevational view, on an enlarged scale, of the apparatus of Fig. 3.

In the drawings there is shown an apparatus comprising a melting furnace which may be 2 of any suitable type, such as a cupola, tank furnace, or the like. The furnace includes a discharge trough l2 from which a stream of molten material I4 is drawn from the furnace and allowed to fall by gravity. The raw material melted in the furnace and delivered in the form of the molten stream may be any of the materials conventionally used in the manufacture of mineral wool or other heat-liquefiable materials suitable for conversion into fibrous wool by the method hereinafter described.

The fiberizing operation is performed by a rotary fiberizing device illustrated as constituting a pair of rotors l6 and l8. The rotors are mounted for rotation on shafts 20 and 22, respectively, and are driven in opposite directions, as indicated by the arrows (see Fig. 2), and at relatively high speeds by suitable drivin means, indicated diagrammatically at 23. The rotors are of a heat-resistant steel or other alloy of a character to chill and bond a portion of the matrial and thus 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 have means to insure the bonding of a ring or rings of the molten material thereto. This means may consist of a series of preformed, relatively fine grooves 24, as illustrated in Fig. or of the roughened or other surface character istics of the rotors developed after they have been subjected for a relatively short period of time tothe action of molten material. However, the use of the more positive means for this purpose, such as the grooves 24, is preferred.

Supported above rotors l6 and I8 is a stream spreader and accelerator, indicated generally at 26. This device comprises a nozzle 28 formed as a hollow casing having a forward face provided with a plurality of jet openings 30. The nozzle is connected to a suitable source of fluid under pressure, such as steam or compressed air, throu h conduit 3!. A valve 32 is located in the conduit to permit control of the intensity of the fluid blast issuing from the openings 30 of the nozzle. The forward face of nozzle 28 is preferably made concave, as illustrated in Fig. 3, so that the individual jets which make up the blast, converge.

The support for the nozzle may be of any suitable type which permits adjustment of the nozzle vertically and horizontally. The adjustment also provides for the aimingor directing of the fluid blast onto the surface of rotor I 6. The construction shown forthis purpose comprises a bracket 34 mounted for vertical adjustment at a convenient location on the apparatus, and an arm 36 swingably mounted for angular adjustment on the bracket and carrying a sleeve 38 embracing a horizontal section of line 3 I. Any suitable means, such as the set screws shown at 40 and 42 may be used to secure the arm in any angularly adjusted position on the bracket and the line in longitudinally adjusted position relative to the sleeve. The aiming of the nozzle is permitted by the swing L 44 connected into the line adjacent the nozzle.

In the operation of the apparatus described above and in carrying out the method of the instant invention, the fiberizing rotors are positioned relatively to the trough I2 so that the molten stream falls by gravity adjacent to, but preferably slightly to the rear of, the downturningside of initial fiberizing rotor l6. Steam or other fluid under pressure is supplied to nozzle 28 through line 3|. The nozzle is adjusted to lie behind the stream andsomewhat above the downturning peripheral surface of rotor l6. Theexact positioning of the nozzle and its angular adjustment, and the velocity of the blast issuing from the nozzle, are correlated to the size and viscosity of. the molten material stream to change the directionof the stream, greatly increase its velocity and to spread it on the surface of rotor 16 without, however, spreading itbeyond the area subtended by the-rotorsurface;

Rotors l8 and [8 are driven at relatively high speeds and in opposite directions, as indicated by the arrows. The material'discharged onto rotor H5 in spread condition is partially bonded thereto to form a ring of incandescent material, and the excess material over that bonded is discharged by rotor l6 onto rotor I8 where it bonds to the surface of the rotor to form an incandescent ring of the molten material. Any excess over that bonded is again projected back against rotor l6,

this action continuing until the excess material is bonded to one or-theother of the rotors. The high speed rotation of rotors I6 and !8 causes portions of the incandescent rings to be thrown or drawn from the rotors by the centrifugal forces created, these portions being drawn out into long, fine fibers.

The particular dimensions of the rotors are not critical within reasonable limits and may be selected on the basis of the capacity desired, i. e., the quantity per hour of molten material to be delivered thereto. Also, the particular peripheral speeds at which the rotorsare driven will depend upon the operating conditions, such as the fluidity of the molten material, and the like but, for purposes of example, it may be stated that in employing a substantially conventional mineral wool melt and a pair of rotors I6 and I8, successful operation is obtained by driving the rotors at peripheral speeds in the ranges of 12,000 to 16,000 feet per minute, and 14,000 to 30,000 feet per minute, respectively. It will be understood that the molten material must beat a sufficiently high temperature, the specific temperature range depending upon the character of the raw material selected, to maintain the molten material on the surfaces of the bonded rings in a highly fluid or incandescent state to permit efficient fiberization to take place.

The fiber formed. as described above may be collected in any suitable manner and a binder may be introduced if desired, either before or after initial fiber collection, the particular apparatus for these purposes forming no part of the instant invention.

The construction has been found to be much better adapted for commercial operation than a rotor fiberizing apparatus such as shown in my said prior patent, where the original, concentrated stream, moving by gravity, falls directly onto the peripheral surface of the high speed fiberizing rotor. Both the acceleration and the spreading of the stream promote bonding of the material to the surface of the initial fiberizing rotor. Also, the spreading of the stream makes a much wider area of the rotor surface available for fiberization. Similarly, the molten material discharged from the first rotor to the second rotor occupies a wide area of the second rotor, whereby the total area available for fiberization is greatly increased. These factors allow a relatively large volume discharge of the molten material from the cupola without the production of excessive amounts of unfiberized particles, coarse fibers, and the like, with the result that maximum efficiency and production capacity is obtained. Also,- fine, more uniform fibers are produced.

Having thus described my invention in rather full detail, it will be understood that these details need not be strictly adhered to but thatvarious changes and modifications may suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.

What I claimis:

1. In an apparatus for converting a molten raw material to fibers, said apparatus including means for discharging a fluid stream of molten material, the improvement comprising, means for directing a fluid jet against the stream for spreading said stream and increasing its velocity, a rotor having a fiberizing surface, means mounting said rotor for rotation with its fiberizing surface in the-path of the spread stream, a second rotor having afiberizing surface, means mounting said second rotor for rotation with its fiberizing surface adjacent said surface of the first rotor, and means for rotating said rotors at high speeds and in opposite directions.

2. In an apparatus for converting a molten raw material to fibers, the apparatus including means for discharging a fluid stream of the molten material, the improvement comprising, a nozzle, means for supplying a fluid medium under pressure to the nozzle to create a fluid blast, adjustable means supporting said nozzle to direct the blast against the stream to spread the stream and increaseits velocity, a rotor having a peripheral surface, means mounting said rotor for rotation with its. peripheral surface in the path of the spread stream, a second rotor having a pcripheral surface, means mounting said second rotor for rotation with its peripheral surface adjacent that of the first rotor, and means for rotating said rotors at high speeds and in opposite directions.

3. In an apparatus for converting a molten raw material to fibers, said apparatus including means for discharging a fluid stream of the molten material, the improvement comprising, a nozzle including a casing, means for supplying a fluid medium under pressure to said casing, openings in said casing arranged to discharge converging jets of said fluid medium to create a fluid blast, means supporting said nozzle adjacent the stream to direct the blast against said stream to spread the stream and increase its velocity, and rotor fiberizing means in the path of the, spread stream for converting the material into fibrous form.

4. In an apparatus for converting a molten raw material to fibers, said apparatus including means for discharging a fluid stream of the molten material, the improvement comprising, a nozzle including a casing, means for supplying a fluid medium under pressure to said casing, openings in said casing arranged to discharge converging jets of said fluid medium to create a fluid blast, means supporting said nozzle adjacent the stream to direct the blast against said stream to spread the stream and increase its velocity, rotor fiberizing means in the path of the spread stream, and means for rotating said rotor fiberizing means at peripheral velocities greater than the velocity of said spread stream.

5. In an apparatus for converting a molten raw material to fibers, said apparatus including means for discharging a fluid stream of the molten material, the improvement comprising, a nozzle including a casing having a concave face, openings in said face arranged to discharge converging jets of said fluid medium to create a fluid blast, means supporting said nozzle adjacent the stream to direct the blast against said stream to spread it and increase its velocity, and rotor fiberizing means in the path of said stream.

6. A method of making fibers from a molten material comprising, delivering a stream of the material, discharging a blast of a fluid medium, aiming the blast against the stream to spread the stream and increase its velocity, intercepting the spread stream on the peripheral surface of a rotor and forming an incandescent ring of the molten material from a portion of the material, and rotating said rotor at a higher speed than the velocity of the spread stream to form fibers from said incandescent ring.

7: A method of making mineral wool from a molten mineral material comprising, delivering a stream of the molten material, discharging a blast of a fluid medium against the stream to spread the stream and increase its velocity, intercepting the spread stream on the peripheral surface of a rotor to form an incandescent ring from a portion of the stream, discharging another portion of the material from the first rotor onto the peripheral surface of a second rotor to form an incandescent ring, and rotating said rotors at high speeds and in opposite directions to form fibers from said incandescent rings.

8. An apparatus for converting a molten raw material to fibers, said apparatus including means for delivering a stream of the molten material, rotor fiberizing means, and means spaced from said stream and said rotor fiberizing means and positioned to direct a fluid blast against the stream of molten material and toward the fiberizing surface of the fiberizing means whereby the stream is spread on the fiberizing rotor.

9. An apparatus for converting a molten raw material to fibers, said apparatus including means for delivering a stream of the molten material, a rotor having a fiberizing surface, means spaced from the molten stream and the rotor fiberizing surface and positioned to direct a fluid blast against the molten stream and toward the fiberizing surface of the fiberizing means whereby the molten material is spread on the fiberizing surface and means for rotating the said rotor at high speed.

10. A method of making fibers from a molten material by fiberizing on a rotor comprising, delivering a stream of the material, discharging a concentrated blast of a fluid medium transversely against the stream, and toward the fiberizing surface of the rotor to spread the stream and increase its velocity, and intercepting the spread stream on the fiberizing surface of the rotor to form fibers from the molten material.

EDWARD R. POWELL.

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

UNITED STATES PATENTS Number Name Date 1,051,844 Passow Jan. 28, 1913 1,769,181 Jackson July 1, 1930 2,126,411 Powell Aug. 9, 1938 2,318,244 McClure May 4, 1943

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