METHOD AND APPARATUS FOR PRODUCTION OF FIBERS FROM THERMOPLASTIC MATERIALS, SUCH AS GLASS, ROCK, SLAG OR THE LIKE
United States Patent 3649234
The production of fibers from thermoplastic material, particularly vitreous material in a fluent viscous state, by successively intercepting one or more traveling streams of the material by a series of blades or vanes extending radially from a rotary body. The intercepted segments of the streams are flattened on the blades in sheet form, and are projected from channels formed at the ends of the blades, by centrifugal force, in the form of filaments which are then drawn out into fibers.
US Patent References:
Method of and apparatus for producing filaments or the like of glass and structures thereof
Lamesch - March 1943 - 2314944
Fiber spinning method and apparatus
O'Connor - October 1952 - 2612654
Production of mineral fibers
Nystrom - June 1966 - 3257182
Method of and apparatus for producing filaments or the like of glass and structures thereof
Lamesch - March 1943 - 2314944
Fiber spinning method and apparatus
O'Connor - October 1952 - 2612654
Production of mineral fibers
Nystrom - June 1966 - 3257182
Application Number:
04/831913
Publication Date:
03/14/1972
Filing Date:
06/10/1969
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
425/7, 264/12, 425/224, 264/8, 65/517, 425/8, 425/470, 264/164
International Classes:
C03B37/05; C03B37/04; C03B37/04
Field of Search:
264/8,176F 18/2.5RR,2.6,8SR,8R 65/1,2,6,8,11,14,15
Primary Examiner:
Bashore, Leon S.
Assistant Examiner:
Lindsay Jr., Robert
Claims:
I claim
1. The method of producing fibers from hardenable thermoplastic material in the viscous state which comprises
2. An apparatus for producing fine fibers from hardenable thermoplastic material in a viscous state comprising
3. The method set forth in claim 1, including the step of spreading the portion of the material entrapped by each blade in a layer along the surface thereof, and subdividing the layer of the material at the outer end of the blade by centrifugal force, for the formation of the filaments projected therefrom by said force.
4. The method set forth in claim 3, wherein the layer of material is subdivided by channelling it along a plurality of channels extending along the radial length of the blades.
5. The method set forth in claim 3, wherein the layer of material is subdivided by projecting the material past a plurality of sharp points at the free end of each blade.
6. The method set forth in claim 1, including the step of forming an excess reserve of the portion of material entrapped by each blade for feeding the material therefrom by centrifugal force to the outer end of the latter.
7. The method set forth in claim 1, wherein the last-mentioned attenuating step is executed by blowing an annular heated gaseous blast onto the filaments in a direction transverse to the centrifugal projection of the filaments from the ends of the blades to draw them out into fibrous form.
8. The method set forth in claim 1, wherein the last-mentioned attenuating step is executed by projecting the filaments in a radial direction by centrifugal force and directing weak flames thereagainst in the course of the travel thereof by said force.
9. An apparatus as set forth in claim 2, wherein said last-mentioned means comprises an annular chamber arranged coaxially with said rotary body and provided with an annular slot beyond the free ends of said blades for blowing a heated gas against said filaments in a direction transverse to the planes of emission of said filaments to effect their attenuation into fine fibers.
10. An apparatus as set forth in claim 2, wherein said last-mentioned means comprises an annular chamber arranged coaxially with said rotary body and provided with a plurality of openings beyond the free ends of said blades for the discharge of soft flames into the path of the filaments projected from the end of said blades, to permit the attenuation thereof into fine fibers to be completed while the filaments are in a softened state.
11. An apparatus as set forth in claim 2, wherein the means at the outer end of each blade is provided with roughenings for subdividing the sheet of viscous material on the blades into a plurality of filaments.
12. An apparatus as set forth in claim 11, wherein the roughenings are in the form of a plurality of sharp points.
13. An apparatus as set forth in claim 2, wherein each blade is provided with a reservoir remote from the outer end thereof for a reserve supply of said viscous material to be fed to the end of each blade by centrifugal force.
14. An apparatus as set forth in claim 13, wherein said reservoir is shaped as a concavity in the surface of the blade adjacent to said rotary body, in the direction of rotation thereof.
15. An apparatus as set forth in claim 13, wherein said reservoir is formed by a retaining flange extending transversely from the plane of said blade and provided with an opening for the passage of the viscous material from the reservoir to the outer end of said blade.
16. An apparatus as set forth in claim 15, wherein said blade is curved convexly in the direction of rotation of said rotary body.
17. An apparatus as set forth in claim 2, wherein the rotary blades are inclined to the axis of revolution of the rotary body with the leading edge of each blade first encountering the supply of said viscous material.
18. The method set forth in claim 1, wherein the viscous material is fed into the path of the rotary blades in the form of a plurality of streams disposed equidistantly along the path of the rotary blades.
19. An apparatus as set forth in claim 2, including means acting on the stream of material in advance of said rotary body for accelerating the velocity of said stream.
1. The method of producing fibers from hardenable thermoplastic material in the viscous state which comprises
2. An apparatus for producing fine fibers from hardenable thermoplastic material in a viscous state comprising
3. The method set forth in claim 1, including the step of spreading the portion of the material entrapped by each blade in a layer along the surface thereof, and subdividing the layer of the material at the outer end of the blade by centrifugal force, for the formation of the filaments projected therefrom by said force.
4. The method set forth in claim 3, wherein the layer of material is subdivided by channelling it along a plurality of channels extending along the radial length of the blades.
5. The method set forth in claim 3, wherein the layer of material is subdivided by projecting the material past a plurality of sharp points at the free end of each blade.
6. The method set forth in claim 1, including the step of forming an excess reserve of the portion of material entrapped by each blade for feeding the material therefrom by centrifugal force to the outer end of the latter.
7. The method set forth in claim 1, wherein the last-mentioned attenuating step is executed by blowing an annular heated gaseous blast onto the filaments in a direction transverse to the centrifugal projection of the filaments from the ends of the blades to draw them out into fibrous form.
8. The method set forth in claim 1, wherein the last-mentioned attenuating step is executed by projecting the filaments in a radial direction by centrifugal force and directing weak flames thereagainst in the course of the travel thereof by said force.
9. An apparatus as set forth in claim 2, wherein said last-mentioned means comprises an annular chamber arranged coaxially with said rotary body and provided with an annular slot beyond the free ends of said blades for blowing a heated gas against said filaments in a direction transverse to the planes of emission of said filaments to effect their attenuation into fine fibers.
10. An apparatus as set forth in claim 2, wherein said last-mentioned means comprises an annular chamber arranged coaxially with said rotary body and provided with a plurality of openings beyond the free ends of said blades for the discharge of soft flames into the path of the filaments projected from the end of said blades, to permit the attenuation thereof into fine fibers to be completed while the filaments are in a softened state.
11. An apparatus as set forth in claim 2, wherein the means at the outer end of each blade is provided with roughenings for subdividing the sheet of viscous material on the blades into a plurality of filaments.
12. An apparatus as set forth in claim 11, wherein the roughenings are in the form of a plurality of sharp points.
13. An apparatus as set forth in claim 2, wherein each blade is provided with a reservoir remote from the outer end thereof for a reserve supply of said viscous material to be fed to the end of each blade by centrifugal force.
14. An apparatus as set forth in claim 13, wherein said reservoir is shaped as a concavity in the surface of the blade adjacent to said rotary body, in the direction of rotation thereof.
15. An apparatus as set forth in claim 13, wherein said reservoir is formed by a retaining flange extending transversely from the plane of said blade and provided with an opening for the passage of the viscous material from the reservoir to the outer end of said blade.
16. An apparatus as set forth in claim 15, wherein said blade is curved convexly in the direction of rotation of said rotary body.
17. An apparatus as set forth in claim 2, wherein the rotary blades are inclined to the axis of revolution of the rotary body with the leading edge of each blade first encountering the supply of said viscous material.
18. The method set forth in claim 1, wherein the viscous material is fed into the path of the rotary blades in the form of a plurality of streams disposed equidistantly along the path of the rotary blades.
19. An apparatus as set forth in claim 2, including means acting on the stream of material in advance of said rotary body for accelerating the velocity of said stream.
Description:
This invention relates to the production of fibers from mineral or organic materials in the viscous state, and particularly fibers from glass, rock or slag.
It is the object of the present invention to provide a method which comprises feeding the viscous material into contact with blades, fins, vanes or the like, which experience a rotary movement, each blade entraining on its surface a part of the material which, under the action of centrifugal force, reaches the extremity of the blade and escapes therefrom in the form of threads or filaments, which are then subjected to a drawing-out action in order to transform them into fibers.
In accordance with the invention, the viscous material may be supplied to the blades in the form of one or more streams which are intercepted by these blades.
According to one variant embodiment, the streams of viscous material which are brought into contact with the blades are previously subdivided.
According to another characteristic of the invention, the portion of the material which is entrained by each blade is brought to the form of filaments by making it pass into channels or on roughenings or sharp points provided on the extremity of the blade.
According to another characteristic of the invention, a reserve of starting material for the filaments is formed on the blade which intercepts the material, this reserve furnishing a sheet which is urged toward the extremity of the blade by the action of centrifugal force.
The invention also contemplates imparting to the blades an inclination with respect to the stream of viscous material, which permits a uniform distribution of the material over the entire height of the blade with lower stream velocities than those which would be necessary to obtain the same distribution with blades parallel to the thread.
The threads, or filaments of material projected by the blades may be drawn out into fibers solely by the action of centrifugal force. It is advantageous, in this case, to maintain these filaments at a suitable temperature by having a current of "soft" flames act on them, that is, flames having no kinetic energy.
The threads or filaments may also be drawn out into fibers by the action of a jet of hot gases produced particularly by a burner with a slotted outlet disposed coaxially with the rotor carrying the blades.
In order to maintain the material entrained by the blades in the viscous state suitable for its projection, the invention contemplates heating the extremities of these blades by electrical inductive effects.
It is also the object of the invention to provide devices for executing the inventive method, and several illustrative embodiments of such are described below in conjunction with the accompanying drawings, wherein
FIG. 1 is a vertical sectional view of one embodiment of the invention;
FIG. 2 is a schematic horizontal sectional view of FIG. 1, illustrating the radial arrangement of the blades;
FIG. 3 is a perspective view of the rotor with blades or vanes distributed uniformly thereon;
FIG. 4 is a perspective view of the details of a blade;
FIG. 5 is a vertical sectional view of a second embodiment of the invention;
FIG. 6 is a vertical sectional view of another embodiment;
FIGS. 7 to 9 are horizontal sectional views of different blade constructions for the formation of reserves of material on the blades; and
FIG. 10 is a front elevation of another embodiment of a blade mounting on the rotor, illustrating the inclination thereof with respect to the axis of rotation of the rotor.
The apparatus according to the invention comprises a rotor 1 fitted with radially disposed blades or vanes 2. A rotary movement is imparted to this rotor through its supporting shaft 3. A stream of viscous material 4, accelerated by a blower 5, flows in continuous fashion between the blades. The blades intercept and entrain an element of the stream of the material, the mass of which is a function of the space between the blades, the speed of rotation of the rotor 1, and the velocity of the stream of material. This element of the stream, which may be of molten glass or other vitreous material, is flattened in sheet form against the blade by virtue of the rotation of rotor 1, and is urged towards the end of the blade by centrifugal force. The end of each blade may be composed of points 6 (FIG. 4), or channels, which serve to bring the material into a divided state, before it is projected from the blades. The filaments 7 thus projected, are immediately subjected to the action of a jet of fluid 9, such as combustion gases or steam, at high velocity, which draws them out into fibers. In the embodiment shown in FIG. 1, the drawing-out or attenuation is attained by means of combustion gases issuing from an annular burner 8 arranged coaxially with respect to rotor 1.
The fibers may be evacuated by a blower crown 10, supplied with air or steam.
In order to impart to the material a sufficiently low viscosity to enable it to be projected from the blades by the action of centrifugal force, an electrical induction heating device 11 may be provided, which may be energized by a high-frequency current, to impart a suitable temperature to the ends of the blades, and particularly to the points thereat.
In the embodiment of the invention shown in FIG. 5, the attenuation by a gaseous fluid at high velocity is replaced by the attenuation by action of centrifugal force alone. In order to increase the drawing-out action, the filaments 7 are maintained at the suitable temperature by using a burner 12 with soft or indolent flames issuing therefrom, that is, flames without kinetic energy. In this embodiment, as well, a blower crown 13 may be used to induce evacuation of the produced fibers.
As in the preceding example, there may be provided an induction heating system 14 arranged concentrically about the rotor.
To obtain good homogeneity of the fineness of the obtained fibers, it is necessary that the flow of material at the ends of the blades be constant and permanent. Therefore, it is desirable and expedient to provide a reserve of material on each blade, this reserve being sufficiently large to allow continuous projection of the filaments or threads, in spite of the intermittent supply obtained by the passage of each blade through the viscous stream.
In the embodiment shown in FIG. 6, a jet 4a of previously divided viscous material is introduced between blades 27. This jet is derived from a freely falling stream 4 of the thermoplastic material onto the peripheral edge of a grooved disc 24, wherefrom it is projected in a divided state, in a substantially horizontal direction, by the action of centrifugal force. The apparatus comprises a body, rotatable on a horizontal axis, for mounting the blades 27, and a coaxial annular combustion chamber 25 discharging combustion gases at velocity and elevated temperatures transversely to the filaments 26 projected from the ends of the blades, which effect the attenuation of the filaments into fibers. The apparatus is completed by a blower crown 28 discharging air or steam therefrom, and by an induction heating device 29.
In FIGS. 7 to 9 are shown different arrangements for accumulating reserves of the thermoplastic material on each blade. In the embodiment shown in FIG. 7, the blade 15 is formed with a concave profile adjacent to the rotor body, in the direction of rotation. Thereby a cavity 16 is formed for holding a reserve supply of the viscous material.
In the embodiment illustrated in FIG. 8, blade 17 comprises a transverse screen 18 with an opening 19 therein to provide a passage for the material. The reserve supply is stored behind the screen, for ultimate passage through the opening 19. In the variant embodiment shown in FIG. 9, there is also provided a screen 18, but the blade 20 presents a profile conforming substantially to the curvature of the trajectory followed by the filaments ejected from the blade. This arrangement improves the flow of the material at the end of the blade.
By multiplying the number of streams of material 4 flowing between the blades, the reserves of material on the blades may be diminished or eliminated completely. For best results, the multiple streams are distributed equidistantly around the rotor.
In the foregoing description, the blades were considered to be arranged along the generatrixes of the rotor. In this case, a uniform distribution of the viscous material over the height of each blade is possible only if the segment of intercepted stream of material is of a length equal to the height of the blade. This condition requires high speeds of the stream of the material, which according to the dimensions of the rotor and its speed of rotation, may be comprised between 10 and 80 meters per second. This speed may be decreased substantially if the blades 21 are inclined with respect to the axis of rotation 22, as shown in FIG. 10. In this case, the length of the intercepted segment of the viscous stream 23 is less than the height of the blade. This segment of the stream is then distributed over the entire surface of the blade. The uniformity of this distribution depends on the angle α which the flange makes with the axis of rotation of the rotor, which, as indicated, is approximately 30°.
It is the object of the present invention to provide a method which comprises feeding the viscous material into contact with blades, fins, vanes or the like, which experience a rotary movement, each blade entraining on its surface a part of the material which, under the action of centrifugal force, reaches the extremity of the blade and escapes therefrom in the form of threads or filaments, which are then subjected to a drawing-out action in order to transform them into fibers.
In accordance with the invention, the viscous material may be supplied to the blades in the form of one or more streams which are intercepted by these blades.
According to one variant embodiment, the streams of viscous material which are brought into contact with the blades are previously subdivided.
According to another characteristic of the invention, the portion of the material which is entrained by each blade is brought to the form of filaments by making it pass into channels or on roughenings or sharp points provided on the extremity of the blade.
According to another characteristic of the invention, a reserve of starting material for the filaments is formed on the blade which intercepts the material, this reserve furnishing a sheet which is urged toward the extremity of the blade by the action of centrifugal force.
The invention also contemplates imparting to the blades an inclination with respect to the stream of viscous material, which permits a uniform distribution of the material over the entire height of the blade with lower stream velocities than those which would be necessary to obtain the same distribution with blades parallel to the thread.
The threads, or filaments of material projected by the blades may be drawn out into fibers solely by the action of centrifugal force. It is advantageous, in this case, to maintain these filaments at a suitable temperature by having a current of "soft" flames act on them, that is, flames having no kinetic energy.
The threads or filaments may also be drawn out into fibers by the action of a jet of hot gases produced particularly by a burner with a slotted outlet disposed coaxially with the rotor carrying the blades.
In order to maintain the material entrained by the blades in the viscous state suitable for its projection, the invention contemplates heating the extremities of these blades by electrical inductive effects.
It is also the object of the invention to provide devices for executing the inventive method, and several illustrative embodiments of such are described below in conjunction with the accompanying drawings, wherein
FIG. 1 is a vertical sectional view of one embodiment of the invention;
FIG. 2 is a schematic horizontal sectional view of FIG. 1, illustrating the radial arrangement of the blades;
FIG. 3 is a perspective view of the rotor with blades or vanes distributed uniformly thereon;
FIG. 4 is a perspective view of the details of a blade;
FIG. 5 is a vertical sectional view of a second embodiment of the invention;
FIG. 6 is a vertical sectional view of another embodiment;
FIGS. 7 to 9 are horizontal sectional views of different blade constructions for the formation of reserves of material on the blades; and
FIG. 10 is a front elevation of another embodiment of a blade mounting on the rotor, illustrating the inclination thereof with respect to the axis of rotation of the rotor.
The apparatus according to the invention comprises a rotor 1 fitted with radially disposed blades or vanes 2. A rotary movement is imparted to this rotor through its supporting shaft 3. A stream of viscous material 4, accelerated by a blower 5, flows in continuous fashion between the blades. The blades intercept and entrain an element of the stream of the material, the mass of which is a function of the space between the blades, the speed of rotation of the rotor 1, and the velocity of the stream of material. This element of the stream, which may be of molten glass or other vitreous material, is flattened in sheet form against the blade by virtue of the rotation of rotor 1, and is urged towards the end of the blade by centrifugal force. The end of each blade may be composed of points 6 (FIG. 4), or channels, which serve to bring the material into a divided state, before it is projected from the blades. The filaments 7 thus projected, are immediately subjected to the action of a jet of fluid 9, such as combustion gases or steam, at high velocity, which draws them out into fibers. In the embodiment shown in FIG. 1, the drawing-out or attenuation is attained by means of combustion gases issuing from an annular burner 8 arranged coaxially with respect to rotor 1.
The fibers may be evacuated by a blower crown 10, supplied with air or steam.
In order to impart to the material a sufficiently low viscosity to enable it to be projected from the blades by the action of centrifugal force, an electrical induction heating device 11 may be provided, which may be energized by a high-frequency current, to impart a suitable temperature to the ends of the blades, and particularly to the points thereat.
In the embodiment of the invention shown in FIG. 5, the attenuation by a gaseous fluid at high velocity is replaced by the attenuation by action of centrifugal force alone. In order to increase the drawing-out action, the filaments 7 are maintained at the suitable temperature by using a burner 12 with soft or indolent flames issuing therefrom, that is, flames without kinetic energy. In this embodiment, as well, a blower crown 13 may be used to induce evacuation of the produced fibers.
As in the preceding example, there may be provided an induction heating system 14 arranged concentrically about the rotor.
To obtain good homogeneity of the fineness of the obtained fibers, it is necessary that the flow of material at the ends of the blades be constant and permanent. Therefore, it is desirable and expedient to provide a reserve of material on each blade, this reserve being sufficiently large to allow continuous projection of the filaments or threads, in spite of the intermittent supply obtained by the passage of each blade through the viscous stream.
In the embodiment shown in FIG. 6, a jet 4a of previously divided viscous material is introduced between blades 27. This jet is derived from a freely falling stream 4 of the thermoplastic material onto the peripheral edge of a grooved disc 24, wherefrom it is projected in a divided state, in a substantially horizontal direction, by the action of centrifugal force. The apparatus comprises a body, rotatable on a horizontal axis, for mounting the blades 27, and a coaxial annular combustion chamber 25 discharging combustion gases at velocity and elevated temperatures transversely to the filaments 26 projected from the ends of the blades, which effect the attenuation of the filaments into fibers. The apparatus is completed by a blower crown 28 discharging air or steam therefrom, and by an induction heating device 29.
In FIGS. 7 to 9 are shown different arrangements for accumulating reserves of the thermoplastic material on each blade. In the embodiment shown in FIG. 7, the blade 15 is formed with a concave profile adjacent to the rotor body, in the direction of rotation. Thereby a cavity 16 is formed for holding a reserve supply of the viscous material.
In the embodiment illustrated in FIG. 8, blade 17 comprises a transverse screen 18 with an opening 19 therein to provide a passage for the material. The reserve supply is stored behind the screen, for ultimate passage through the opening 19. In the variant embodiment shown in FIG. 9, there is also provided a screen 18, but the blade 20 presents a profile conforming substantially to the curvature of the trajectory followed by the filaments ejected from the blade. This arrangement improves the flow of the material at the end of the blade.
By multiplying the number of streams of material 4 flowing between the blades, the reserves of material on the blades may be diminished or eliminated completely. For best results, the multiple streams are distributed equidistantly around the rotor.
In the foregoing description, the blades were considered to be arranged along the generatrixes of the rotor. In this case, a uniform distribution of the viscous material over the height of each blade is possible only if the segment of intercepted stream of material is of a length equal to the height of the blade. This condition requires high speeds of the stream of the material, which according to the dimensions of the rotor and its speed of rotation, may be comprised between 10 and 80 meters per second. This speed may be decreased substantially if the blades 21 are inclined with respect to the axis of rotation 22, as shown in FIG. 10. In this case, the length of the intercepted segment of the viscous stream 23 is less than the height of the blade. This segment of the stream is then distributed over the entire surface of the blade. The uniformity of this distribution depends on the angle α which the flange makes with the axis of rotation of the rotor, which, as indicated, is approximately 30°.