US2255206A - Apparatus for providing uniformly graded fibrous materials - Google Patents

Description

J. K. DUNCAN 2,255,206

Filed July l5, 1938 5 Sheets-Sheet l m.. d u

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APPARATUS FOR PROVIDING` UIFKORMLY GRADED FIBROUS MATERIALS Sept. 9, i941. J. K. DUNCAN APPARATUS FOR PROVIDING UNIFORMLY GRADED FIBROUS MATERIALS 5 sheets-sheet 2 Filed July 13, 1938 sept. 9, 1941. J, K DUNCAN 2,255,20

APPARATUS Foa PROVIDING .UNIFORMLY GRADED FIRoUs MATERIALS Filed July 15, 1938 5 sheets-sheet is SBP- 9, 1941. J. K. DUNCAN APPARATUS FOR PROVIDING UNIFORMLY GRADED FIBROUS MATERIALS `Filed July 13, 1938 5 Sheets-Sheet 4 Sept 9, 1941- J. K. DUNCAN, 2,255,206

APPARATUS FOR PROVIDING UNIFORMLY GRADED FIBRQUS MATERIALS 5 Sheets-Sheet 5 Filed July l5, 1938 Patented Sept. 9, 1941 UNITED STATES-.PATENT OFFICE APPARATUS FOR PROVIDING UNIFORMLY GRADED FIBROUS MATERIALS James K. Duncan, Chicago, Ill.,` assignor to United States -Gypsum Company, Chicago, Ill., a. corporation of Illinois Application July 1s, 193s, serial No. 219,067

(ci. 209-135) y r l 4 Claims.

-according to size has been screening. Screening,v however, is not always applicable to such mixtures which consist entirely of, -or contain a large proportion of, fibrous material, such as Wood fibers, asbestos bers, or other mineral fibers', No method has been developed up to the present vtime which is entirely satisfactory for classifying such materials, which `for certain purposes is often desirable.

fibers, wood fibers, andthe like.. Due to the nature of such materials it has been impracticable to do so in the past.

An object of this invention is to providea` method of separating bers from other particles that may be contained within a fibrous mixture.

A further object of this invention is to provide a method for the classification of fibrous substances into fibers of various sizes and densities.

The process for the manufacture of rock wool from a molten vitreous material at' the present time comprises passing a small stream ofthe molten substance into a stream ofgas, such as steam or air, in such a manner that the molten material is pulled out andsolidies in the form of iine bers. It is desirable inthe manufacture of rock Wool for insulating purposes to make a product of standard uniform density, depending upon the use to which the product is to be put. The density of the rock wool material produced by the commonly accepted methods, as above indicated, will depend largely upon the relative size of the fibers in the material and the proportion of beads or shot contained in the iinal product. No method has thus far been developed wherein it is possible to produce rock wool Yfibers of uniform consistency and size without having included therein some beads of vitreous material which have not been drawn out into bers.` A satisfactory method is thus desirable A further object of this invention is to provide a method for the production of a rock wool of uniform brous structure. Y

A still further object of this invention is to provide a method for the separation of beads or shot from rock wool during the process and manufacture.

A further and additional object of this invention is to provide a continuous method for the production of a uniform rock wool .which is substantially free of beads and suitable for insulation purposes. f

Other objects of this invention will be evident from the following description and claims.

To illustrate 'the invention, suitable drawings are provided, in which Figure v`1 represents, diagrammatically, a cross section of a preferred embodiment of apparatus V suitablefor carrying out the present invention;

Fig. 2 represents a plan view of the structure shown in Fig. 1 wherein like numerals represent like parts; Y

o Fig. 3 represents, diagrammatically, a variation in a method for collecting the bers wherein the conveyor belts travel in the same direction as the fibers; A

Fig. 4 represents a p an view of the structure shown in Fig. 3; 1

Fig. 5 represents, diagrammatically, a further and particulate material in accordance with this invention; A Fig. 6 represents a plan view of the structure shown in Fig. 5; l

Fig. 7 represents, diagnammatically,` a further variation in a method for collecting the bers wherein the belt conveyors run at an angle to the direction of the movement of the bers;

uniform product. Due to the nature of the material, the classification of such fibrous substances and the separation of particles in the resulting product by sifting or screening are usually impossible.

It is also desirable to classify certain other particles according to their shapes and sizes, particularly fibrous materials, such as asbestos Fig. 8 represents a plan view of the structure vshown in Fig. '1;

'Fig'. 9 represents, diagrammatically, a screw conveyor means for collecting the iibers in accordance with a modification of this invention;

Fig. 10 represents a plan view of the structure shown in Fig. 9.

In general, the method of the present invention comprises introducing a stream of fibrous particles (or a fluid capable of forming4 particles or fibers) into a stream of a rapidly moving and expanding gas in an open space whereby the particles are suspended, removing the 'particles from suspension by the force of gravity or by suitably controlled forces acting perpendicularly to the direction of the movement of the particles at varying distances from the point of introduction into the i'lowing stream, and collecting the particles in separate zones to obtain uniformly graded masses of fibers. In general, in the flowing gaseous stream the larger and heavier particles are the first to settle out, while the finer particles become collected at some further distance from the point where the material is introduced into the rapidly moving and expanding gas.

For a more complete understanding of this invention an example is specifically described in the following. It is to be understood, however, that it isnot intended that the invention be limited in any manner by the example given, since it is presented for illustrative purposes only.

Attention is now directed to-Fig. l and Fig. 2, whichare diagrammatic views voi? an apparatus suitable for preparing rock wool and classifying the various fibers as they are produced. Molten rock or other vitreous material is contained in a cupola I which is heated by any suitable means (not shown). The molten material is discharged through opening II into a stream of atomizing gas. such as steam or air, introduced by pipe I2 and according to the conventional practice for preparing mineral wool by this method. The fibers and other particles I3 thus produced are discharged into a large enclosed chamber I4, within which are erected a plurality of substantially vertical partitions I5, I6, and I1, transverse to the direction of the movement of the gaseous stream. The partitions preferably extend across the entire width of the chamber I4.

At the bottom of the compartments formed by the partitions, -belt conveyors I8, I9, and 20 may be placed for the continuous or intermittent removal of the material settling to the bottom of each compartment. The belts of the conveyors I8, I9,- land 2li may be porous, and.. as shown,

suction means 2| and 22 are provided for producing suction under the porous belt of the said conveyor. 'Ihis means preferably comprises a suction ian 22 'of some .known design and suitable connections 2|. 'I'he fan 22 may be constructed so that it will force air in the opposite direction through the belts |81, I9, and 20 by means of suitable connections 2 Ia and dampers 2lb. Consequently. air may be blown into the chamber I4 through certain of the porous belts may either settle out at once into the first compartment 24 or may be projected against the partitins I5, I6, or I'I by the stream of gas. The successively lighter materials or bers will settle out successively in compartments 25 and 26, and the finest material is collected in compartment 21. Flanges 28 attached to the partitions and the side walls of chamber I4 guide the material to the belt conveyors in each compartment. A

space 32, if desired, may be left between the belt conveyor and the side of the partitions against which the beads strike in order that the beads may not collect on the belt conveyor. The beads thus collected may be removed intermittently or continuously by any suitable means.

The resulting rock wool is thus collected in various grades on conveyor belts I8, I9, and 20, and it may be continuously or intermittently removed from the chamber` I4 thereby. `The rock wool collected on conveyor I8 may consist of comparatively flne fibers and may have an apparent density of about 12 pounds per cubic foot under certainloperating conditions. A dense rock wool of this type is suitable-for use in high temperature insulation such as is used for insulating furnaces and the like. The wool collected in compartments 26 .and 21 is substantially lighter in weight per cubic foot, often haviing'an apparent density of from only 11/2 to 3 pounds per cubic foot. This lightweight insulation material is lmost suitable for low temperature insulation such as is used in houses or in packing for refrigerators, or under high humidity conditions.

Under certain conditions fibers may collect on the tops of the partitions during settling. 'I'hese fibers may be removed intermittently or continuously by any suitable means. In a preferred form of this invention fingers 29 attached to endless wire 30 may be employed for this purpose. The fingers 28 are pulled `along the upper edges of partition I1, for example, by rotation of pulleys 3|. Motion may be imparted to the pulleys3l by any suitable means, such as an electric motor (not shown).

A large number of modifications are possible in the' above-described apparatus. For example, many other types of fibers and particles may be classified and graded according to their size by the general method illustrated above. Suitable materials that may be classified by this method may be asbestos fibers, wood fibers, sand particles,

ceramic particles, abrasive particlesl metal filings,

' and the like. It is noi-,necessary'that the parand removed by suction from others in order to lset up any desired non-turbulent current of air within the chamber I4. 'I'he outlet ofthe suction fan 22 may be equipped with a .suitable dust collecting means (not shown). Suitable openings 23 in chamber I4 are provided to permit the entrance of air to the chamber if desired.

In the operation ot this machine the molten rock is fiberized in a rapidly moving and expanding gas, and the resulting spray of solidified fibers and particles is discharged into the chamber`l4 near the top. There is a continuous flow of the gas over the top of the chamber due to' the continuous removal of the gas throughthe porous belts of conveyors I8, i9,or 2l by means of the suction fan 22. The heavy beads or shot inadvertently produced during the atomizing ticles be introduced into the gasl streamgin the molten condition as is shown in the above modification. For example, a heterogeneous mixture of fibers and' other solid particles may be introduced into the gaseous stream` by a suitable type of screw conveyor or merely by iiowing through a suitable constriction.

It is not necessary that air be used as the fluid for suspending the particles or bers. For example, steam or other inert gases may also be used. It is not necessary for carrying out this invention that theenclosed chamber I4 be employed. It is usually desirable, however, in order to prevent dust and very fine particles from escaping into the surrounding air.

,A 'I'he classification of the particles may be controlled, if desired, by; any of several difIerent methods. Thus, various grades can be produced by raising or lowering the several partitions particles and the uidare introduced into the chamber will aect to a degree the classification of particles obtained. It may be desirable in some cases to provide suction or pressure on the belts of conveyors I8, I9, and 20 in order to regulate the size of particles settling into the respective compartments or to regulate further the density of the mass settling upon the belt conveyors. An advantage in having a suction means provided on conveyor belt I8 is to restrict and, in some instances, prevent the iibrous material from entering into space 32 wherein fall the glass beads.

While belt conveyors are shown iny the specic example given in the description, it is not vcontemplated that this is the only means by which the material may be removed from the compartments. Figs. 3 to 10 show diagrammatically various modifications whereby the material collected in the bottom of the compartments may be removed therefrom. Referring now to Figs.

3 and 4, the fibers I3 may be discharged in akv gaseous stream from any suitable container 33 by any desired method. The bers may be collected in compartments, as before described, but may be removed by a plurality of conveyor belts I8, I9, and 20 which convey the material from the chamber I4 (shown in Fig, 1) in a direction substantially parallel to that in which the iibers are introduced into the chamber.

Figs. 5 and 6 show diagrammatically a modification wherein the conveyor belts are inclined from a horizontal plane with further means for collecting the material from the conveyor belts. For example, the material from conveyor belt I8 may be discharged into a hopper or compartment 34, which in turn may discharge to a conveyor belt 35. `If desred, the conveyor belt I9 may discharge the material into a suitable hopper or granulator 36 directly.

Referring now to Figs. 7 and 8, a ymethod is shown for the removal of the iibrous material at an angle to the direction in which the fibrous material is introduced into the chamber Il (shown in Fig. l). lected in compartments 25, 26 and 21, as heretofore described, and may be dischargedfrom the compartments onto the conveyor belts I8, I3, and 20. Suitable guides 31 may be installed in connection with the conveyor belts in order to retain the iibrous materialonthe belt.

Figs. 9 and lrepresent diagrammatically means whereby the material collecting in the compartments 25, 2i, and-2`I may be removed'by a screw conveyor 38. If desired, a suitable suction means 2I and y22 may be applied to the screw conveyor, which in general may have the same function as the suction means applied to the belt conveyors hereinabove described. Various other arrangements for effecting the removal of the material A from the compartments will readily occur to those skilled in the art.

It is preferable that a turbulent ilow of the gaseous suspension through the top of the chamber be minimized or prevented; otherwise the The turbulent iiow may beminimizedv by providing a means for continuously removing the gas from the chamber by a suitable method, preferably near the'end opposite that in which the suspension is introduced. It is not necessary that the gas be removed from the bottom of compartment 2l as shown in the preferred embodiment of this invention. For example, the gas made, it is not contemplated that this invention v shall be limited thereby, and any number of compartments may be employed for separating products of varying sizes and densities.

While several particular embodiments of this invention are shown above, it will be understood, of course, that the invention is not to be limited thereto since many modifications may be made, and it is'contemplated, therefore, to coverany such modifications as fall within the true spirit rality of substantially perpendicular partitions adjacent to the bottom of the chamber forming a plurality of Acompartments therein, means for The iibrous material is coll ner particles will be carried back, while still in suspension, and settle in the first compartments.

introducing a gaseous suspension of mineral wool fibers into the top of the chamber in a flow-f ing stream transverse to and over the top of the partitions, means for collecting said fibers in the compartments, separate conveyor means for removing said iibers from the compartments, and suction means applied to said conveyor means for removing the gasl from said enclosed chamber through the separate compartments at controllable predetermined rates.

2. In an apparatus for producing mineral wool.V

ing means for the vremoval or introduction of airl into said chamber adjacent the base of a plurality of the compartments.

3. The apparatus recited in claim 1, including means for the removal of iibers settling on the upper 'edges of said partitions.

4. The apparatus recited in claim 2, including means for the removal of iibers settling on the upper edges of said partitions.

JAMES K. DUNCAN.

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