CA1099111A - Method and apparatus for producing glass fibers - Google Patents
Method and apparatus for producing glass fibersInfo
- Publication number
- CA1099111A CA1099111A CA352,297A CA352297A CA1099111A CA 1099111 A CA1099111 A CA 1099111A CA 352297 A CA352297 A CA 352297A CA 1099111 A CA1099111 A CA 1099111A
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- orifice
- plate
- orifice plate
- nozzles
- orifices
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Abstract
ABSTRACT OF THE DISCLOSURE A cooling system for establishing and maintaining the running mode of a bushing used in production of glass fibers which embodies a heated orifice plate with closely spaced ori-fices and a bulk flow of upwardly directed gas (e.g., air), which cooling system comprises a series of opposing nozzles which provide a multiple air lance effect in starting up, clearing and maintaining the flow of individual glass fibers through each orifice.
Description
~99~
BacXground of ~he Invention This invention relates to the production of glass fibers and more particularly to the production of glass fibers employ-ing an orifice plate having clo~ely spaced orifices.
The production of glass fibers employing an orifice plate having closely spaced orifices is described in detail in Strick-land U. S. Patent 3,905,790. According to the method therein described, the orifice plate with orifice plate heating means and closely spaced orifices is employed in conjunction with a bulk flow of rapidly moving gas, preferably air, directed up-wardly at the orifice area in the plate. The bulk flow of gas, which is a generally single column of gas at the cone and plate area, is employed in an amount, velocity and angle sufficient to cool the cones to provide stable cone formation and maintain separation of cones. The bulk flow of gas impinges on the pla~e essentially to eliminate stagnant gas adjacent the plate and flows outwardly along the orifice plate in all directions. The bulk flow of gas also provides a supply of gas to be sucked downwardly by the fibers which are drawn from the cones o~
molten glass which form beneath the orifices of the orifice plate.
~-o~
As U. S. 3,905,790 indicates, start-up may be achieved by allowing the underside of the orifice plate to flood, estab-lishing the temperature of the orifice plate at from about 25C
to about 150C below normal operating temperatures to restrict the flow of further glass through the orifice plate, and slowly withdrawing the matrix or monolith of glass which is formed beneath the orifice plate. As the monolith is slowl~ withdrawn, individual fiber-forming cones will tend to form at each orifice.
The temperature of the orifice plate is then increased and the attenuation rate of the fiber is correspondingly increased with cone separation beiny maintained by the bulk air flow. This method is satisfactory but may require very careful operator attention, particularly with orifice plates having a larger num- ¦
ber of orifices.
It is an object of this invention to provide an improved method of start-up for a heated orifice plate having closely spaced orifices that permits the running mode to be established in a short period of time.
It is another object of this invention to provide an im-proved method of clearing flooding of a heated orifice platehaving closely spaced orifices that permits a rapid clearing of the flooded orifice plate.
It is a further object of this invention to provide a method of providing bulk gas flow for a heated orifice plate having closely spaced orifices that minimizes the volume of gas that is required.
It is yet another object of this invention to provide apparatus for start-up or for clearing flooding of a heated ori-fice plate having closely spaced orifices employing a gas deliv-ery manifold that permits the running mode to be established in -a short period of time.
It is still further an object of this invention to provide an apparatus for producing glass fibers from a heated orifice plate having closely spaced orifices employing a gas delivery manifold that minimizes the volume of gas that is required.
It is a still further object of this invention to provide a gas delivery manifold which may be employed both for clearing an orifice plate and for the production of glass fibers.
In this invention generally opposed nozzles are employed to maintain the running mode. The invention is directed to a method of forming glass fibers by (a) passing separate streams of molten glass through an orifice plate having orifice plate heating means and having at least four rows of orifices therein, with orifices being spaced in flooding relationship;
(b) drawing Eibers from cones of molten glass formed at each said orifice; and (c) directing a bulk flow of rapidly moving gas upwardly to the orifice area in said plate, (i) to cool said cones to provide a stable cone formation and to maintain separation of cones thus prevent-ing flooding;
(ii) to impinge on said plate essentiallyto eliminate stagnant gas adjacent said plate and to cause gas to move outwardly along said plate in all directions from said orifice area; and (iii) to supply a source of gas sucked down-wardly by the fibers and substantially eliminate ambient gas drawn into the region of the fiber cones, and contemplates the improvement comprising introducing cooling gas streams from at least two sides of said orifice area through generally opposed nozzles which impact below but closely adjacent to said orifice plate and create a turbulent bulk flow of upwardly moving gas at the cone and plate area.
An additional embodiment of this invention contemplates the use of generally opposed nozzles to es-tablish the running mode and thereafter employing generally opposed nozzles -to maintain the running mode.
Still further embodiments of the invention contemplate an apparatus for maintaining the running mode including generally opposed nozzles directed to impact below but closely adjacent to the orifice plate and provide a turbulent flow of upwardly directed bulk air; and an apparatus including generally opposed nozzles which may be altered from the clear ing position to the running position.
This invention provides a method and apparatus which may be used for the successful clearing of orifice plates having closely spaced orifices even though the orifice plate may contain a large number of orifices. It has been determined that the practice of this invention reduces the volume of cooling gas required as contrasted with nozzles mounted more vertically beneath the orifice plate. Moreover, the use of ~0 the method described herein permits clearing more expeditiously than with the use of more vertically mounted nozzles since the cooling gas has better access to the orifice plate as the monolith is pulled away.
This invention also provides a method and apparatus which utilizes a bulk flow of cooling gas to maintain the running mode of a glass fiber producing orifice plate having closely spaced orifices which minimizes the volume of cooling gas that is required.
The various embodiments of this invention are improve-ments in the production of glass fibers as described in U.S.3,905,790.
Broadly, the method described in U.S. 3,905,790 may be practiced with any glass melting means including conventional glass furnaces and auxiliary equipment. The molten glass is maintained in a reservoir which is in communication with the orifice plate. r~oSt often, the orifice plate will form the lower surface of the molten glass reservoir means and, indeed, the orifice plate can be formed as a bushing with the sides of the bushing extending upwardly into the furnace to form all or a portion of the sides of the reservoir which contains the molten glass.
The orifice plate itself may be made of any alloy acceptable for operation under glass fiber forming conditions and the surface of the orifice plate is generally flat. The orifices in the orifice plate are most often less than about 0.1 in. in diameter and may be as small as 0.02 in. in diameter.
In order to obtain maximum utilization of bushing area, the orlfices generally are spaced not more than about 2 diameters center:to:center, with spacings of about 1.25 to about 1.7 dia-meters, center:to:center, being preferred. For practical pro-duction, orifice density generally will be at least about 50 orifices per sq. in~, preferably at least about 100 orifices per sq. in., and most desirably about 200 orifices per sq. in. of the orifice area in the orifice plate. The orifice plates have at least 4 rows of orifices, preferably have at least about 10 or 11 rows of orifices, and most desirably have at least about 15 rows of orifices. The orifice plate configurations a~d assemblies described in co-pending Canadian Applications Nos. 254,353 filed June 8, 1976 and 256,769, entitled Apparatus and Method for Controlling Flooding in the Drawing of Glass filed July 12, 1976 are particularly suitable for use.
While a variety of cooling gases may be employed, air is particularly preferred. Since the gas is employed for cool-ing purposes it is preferred to employ gases having tempera-tures of about ambient temperature (e~g., about lOO~F or less).
The benefits can alsobe achieved by warmer gas which nay be, for , example, even at 500~F, providlng the volume of gas is increased accordingly. For ease of presentation, this discussion ~
be couched in terms of air but it should be understood that other gases are also contemplated.
The orifice plate is equipped with orifice plates heating means so that the temperature of the orifice plate can be reg-ulated independently of the heat lransferred to the orifice plate from the molten glassO Most often such heating means are electrical resistance heating means although other means are also contemplated.
The fibers are drawn from the fiber forming cones on a collet, or the like, and may be coated with conventional dress-ing fluids, sizing compounds and the like. The method to which this invention is directed is fully discussed in U. S. 3,905,790.
One of the essential means for achieving the above and other objects of this invention is the provision of an auxil-iary gas cooling system for use in establishing the desired running mode of flat orifice plate bushings. This gas cooling system is auxiliary in the sense that it is in addition to, and desirably not in lieti of, the bulk air system which flows in a generally upward fashion to cool the flat orifice plate and the attenuated filaments moving downward in the conventional operation of the process embodied in U. S. Patent 3,905,790.
The auxiliary system in effect is a multiple air lance that expedites the establishment of the normal running mode of the bushing, either at start up or after a breakout during the course of a run. The method of the invention contemplates sev-eral air nozzles disposed at opposite sides along the length of the bushing and a~ the a~gles her~etofore noted. The center line of the gas flowing from each nozzle exerts a cooling effect on ~he orifice plate 25 the matrix of glass flows or drops away from the plate face as flooding is being curtailed and termin-ated, all in the manner more ~ully described herein, and the jets of gas flow upwardly and in toward the center of the ori-fice plate. The multiplicity of nozzles projecting individual jets provide the multiple air lance effect heretofore noted.
The air, or any other gas, can be directed at random along the length of the orifice plate to maintain a uniform temperature and cooling effect along the length of the plate. The inven-tion is particularly useful for large bushings, that is,bushings in excess of 1000 orificesO For example, in bushings of 2000 orifices or more which are rectangular in shape and wherein there is a relatively long dimension at the ends of which the current is fed to effect the heating of the bushing, such as is shown in the bushing assembly of ~ig. 3 of the aforementioned Application NoO 256,769, the ends of the orifice plate adjacent the current leads may in some instances be at a higher temperature than the midsection of the orifice plate.
The nozzles can be readily adjusted to apply a greater cooling effect to the hotter ends to evenly cool the orifice plate along its length.
This auxiliary cooling system with its multiple air lance effect furnishes distinct advantages in starting up or clearing breakouts, particularly where substantial flooding is permitted to take place in the first instance, in that the time of the operator is substantially reduced in contrast to the time and cost for a single operator or multiple operators to clear the bushing manually with individual air lances. As the size of bushings increases, so also do the advantages flowing from the use of the multiple air lanceO In fact, in some instances -the need for an operator can be obviated entirely.
It is emphasized that the concept of opposing jets, par-ticularly when intended to impact directly on the orifice plate ~f the bushing, constitutes a most advantageous embodiment of this invention when employed to establish the running mode of the bushing on start up or after a major flood where an exten-sive matrix of glass has been permitted to fo.rm. Nevertheless, very useful results can also be obtained in another embodiment of the invention as elsewhere descrihedl where the center lines of opposing jets are permitted to impact against each other ahead of and before they reach the orifice plate. The effect of the impacting jets is to create an upward air flow onto the orifice plate.
Generally, where the jets of the auxiliary cooling system impact directly on the orifice plate and the running mode is established, the upward flow of bulk air is continued and the flow from the auxiliary system is terminated. However, the operator can continue the auxiliary flow if desirable.
In the e~bodiment of the invention involving impacting jets ahead of the orifice plate, it is possible to use the sy-stem, depending on the volume of air flow, to assist in estab-lishing the running mode of the bushing. Also, if desired, it can be used as the source of bulk air flow or to augment the conventional bulk air flow of the process of U. S. Patent 3,905,730.
In respect of the direction of air flow it is to be noted that in establishing the running mode of the bushing .
utilizing the multipl~e air.lance effect of the auxiliàry cooling system it is generally preferred to direct the opposing air nozzles so that the principal force of the respective jets is felt at the outer edges of the orifice plate and consequently ! the flooding effect giving rise to the~matrix of glass tends to 30 - flow inward toward the center of the orifice plate. It is more desirable to concentrate the matrix in this manner where its weight is relied upon' at least in part, to encourage filament ~l~99~
. . , à~tenuation.
Although the angle of the opposing jets to the orifice plate has been discussed elsewhere, it is pertinent to note that the range of the angles can vary from about 30 to about 60.
Below about 30 the air tends to blow by and not impact on the plate or if impacting with an opposing jet the air will not have a sufficient upward moment to provide an effective upward flow.
However, in the case of impacting jets, when one of the opposing jets is set as low as about 30 the immediate opposing jet should be at a greater angle. Also, it is the desired practice that the nozæles from which the jets at the lower angles ap-proaching about 30~ are ejected should be on the same side as the operator so that the flow of heated air and gas from the vicinity of the orifice plate area after contact is away from the direction of the operator.
Another advangage of the auxiliary air cooling system, particularly the impacting jets, is that it aids in line dry-ing of the fibers that may have been sprayed with cooling water.
DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of one embodiment of glass fiber production equipment employing the clearing air delivery manifold of this invention.
Figure 2 is an enlarged sectional view taken along lines
BacXground of ~he Invention This invention relates to the production of glass fibers and more particularly to the production of glass fibers employ-ing an orifice plate having clo~ely spaced orifices.
The production of glass fibers employing an orifice plate having closely spaced orifices is described in detail in Strick-land U. S. Patent 3,905,790. According to the method therein described, the orifice plate with orifice plate heating means and closely spaced orifices is employed in conjunction with a bulk flow of rapidly moving gas, preferably air, directed up-wardly at the orifice area in the plate. The bulk flow of gas, which is a generally single column of gas at the cone and plate area, is employed in an amount, velocity and angle sufficient to cool the cones to provide stable cone formation and maintain separation of cones. The bulk flow of gas impinges on the pla~e essentially to eliminate stagnant gas adjacent the plate and flows outwardly along the orifice plate in all directions. The bulk flow of gas also provides a supply of gas to be sucked downwardly by the fibers which are drawn from the cones o~
molten glass which form beneath the orifices of the orifice plate.
~-o~
As U. S. 3,905,790 indicates, start-up may be achieved by allowing the underside of the orifice plate to flood, estab-lishing the temperature of the orifice plate at from about 25C
to about 150C below normal operating temperatures to restrict the flow of further glass through the orifice plate, and slowly withdrawing the matrix or monolith of glass which is formed beneath the orifice plate. As the monolith is slowl~ withdrawn, individual fiber-forming cones will tend to form at each orifice.
The temperature of the orifice plate is then increased and the attenuation rate of the fiber is correspondingly increased with cone separation beiny maintained by the bulk air flow. This method is satisfactory but may require very careful operator attention, particularly with orifice plates having a larger num- ¦
ber of orifices.
It is an object of this invention to provide an improved method of start-up for a heated orifice plate having closely spaced orifices that permits the running mode to be established in a short period of time.
It is another object of this invention to provide an im-proved method of clearing flooding of a heated orifice platehaving closely spaced orifices that permits a rapid clearing of the flooded orifice plate.
It is a further object of this invention to provide a method of providing bulk gas flow for a heated orifice plate having closely spaced orifices that minimizes the volume of gas that is required.
It is yet another object of this invention to provide apparatus for start-up or for clearing flooding of a heated ori-fice plate having closely spaced orifices employing a gas deliv-ery manifold that permits the running mode to be established in -a short period of time.
It is still further an object of this invention to provide an apparatus for producing glass fibers from a heated orifice plate having closely spaced orifices employing a gas delivery manifold that minimizes the volume of gas that is required.
It is a still further object of this invention to provide a gas delivery manifold which may be employed both for clearing an orifice plate and for the production of glass fibers.
In this invention generally opposed nozzles are employed to maintain the running mode. The invention is directed to a method of forming glass fibers by (a) passing separate streams of molten glass through an orifice plate having orifice plate heating means and having at least four rows of orifices therein, with orifices being spaced in flooding relationship;
(b) drawing Eibers from cones of molten glass formed at each said orifice; and (c) directing a bulk flow of rapidly moving gas upwardly to the orifice area in said plate, (i) to cool said cones to provide a stable cone formation and to maintain separation of cones thus prevent-ing flooding;
(ii) to impinge on said plate essentiallyto eliminate stagnant gas adjacent said plate and to cause gas to move outwardly along said plate in all directions from said orifice area; and (iii) to supply a source of gas sucked down-wardly by the fibers and substantially eliminate ambient gas drawn into the region of the fiber cones, and contemplates the improvement comprising introducing cooling gas streams from at least two sides of said orifice area through generally opposed nozzles which impact below but closely adjacent to said orifice plate and create a turbulent bulk flow of upwardly moving gas at the cone and plate area.
An additional embodiment of this invention contemplates the use of generally opposed nozzles to es-tablish the running mode and thereafter employing generally opposed nozzles -to maintain the running mode.
Still further embodiments of the invention contemplate an apparatus for maintaining the running mode including generally opposed nozzles directed to impact below but closely adjacent to the orifice plate and provide a turbulent flow of upwardly directed bulk air; and an apparatus including generally opposed nozzles which may be altered from the clear ing position to the running position.
This invention provides a method and apparatus which may be used for the successful clearing of orifice plates having closely spaced orifices even though the orifice plate may contain a large number of orifices. It has been determined that the practice of this invention reduces the volume of cooling gas required as contrasted with nozzles mounted more vertically beneath the orifice plate. Moreover, the use of ~0 the method described herein permits clearing more expeditiously than with the use of more vertically mounted nozzles since the cooling gas has better access to the orifice plate as the monolith is pulled away.
This invention also provides a method and apparatus which utilizes a bulk flow of cooling gas to maintain the running mode of a glass fiber producing orifice plate having closely spaced orifices which minimizes the volume of cooling gas that is required.
The various embodiments of this invention are improve-ments in the production of glass fibers as described in U.S.3,905,790.
Broadly, the method described in U.S. 3,905,790 may be practiced with any glass melting means including conventional glass furnaces and auxiliary equipment. The molten glass is maintained in a reservoir which is in communication with the orifice plate. r~oSt often, the orifice plate will form the lower surface of the molten glass reservoir means and, indeed, the orifice plate can be formed as a bushing with the sides of the bushing extending upwardly into the furnace to form all or a portion of the sides of the reservoir which contains the molten glass.
The orifice plate itself may be made of any alloy acceptable for operation under glass fiber forming conditions and the surface of the orifice plate is generally flat. The orifices in the orifice plate are most often less than about 0.1 in. in diameter and may be as small as 0.02 in. in diameter.
In order to obtain maximum utilization of bushing area, the orlfices generally are spaced not more than about 2 diameters center:to:center, with spacings of about 1.25 to about 1.7 dia-meters, center:to:center, being preferred. For practical pro-duction, orifice density generally will be at least about 50 orifices per sq. in~, preferably at least about 100 orifices per sq. in., and most desirably about 200 orifices per sq. in. of the orifice area in the orifice plate. The orifice plates have at least 4 rows of orifices, preferably have at least about 10 or 11 rows of orifices, and most desirably have at least about 15 rows of orifices. The orifice plate configurations a~d assemblies described in co-pending Canadian Applications Nos. 254,353 filed June 8, 1976 and 256,769, entitled Apparatus and Method for Controlling Flooding in the Drawing of Glass filed July 12, 1976 are particularly suitable for use.
While a variety of cooling gases may be employed, air is particularly preferred. Since the gas is employed for cool-ing purposes it is preferred to employ gases having tempera-tures of about ambient temperature (e~g., about lOO~F or less).
The benefits can alsobe achieved by warmer gas which nay be, for , example, even at 500~F, providlng the volume of gas is increased accordingly. For ease of presentation, this discussion ~
be couched in terms of air but it should be understood that other gases are also contemplated.
The orifice plate is equipped with orifice plates heating means so that the temperature of the orifice plate can be reg-ulated independently of the heat lransferred to the orifice plate from the molten glassO Most often such heating means are electrical resistance heating means although other means are also contemplated.
The fibers are drawn from the fiber forming cones on a collet, or the like, and may be coated with conventional dress-ing fluids, sizing compounds and the like. The method to which this invention is directed is fully discussed in U. S. 3,905,790.
One of the essential means for achieving the above and other objects of this invention is the provision of an auxil-iary gas cooling system for use in establishing the desired running mode of flat orifice plate bushings. This gas cooling system is auxiliary in the sense that it is in addition to, and desirably not in lieti of, the bulk air system which flows in a generally upward fashion to cool the flat orifice plate and the attenuated filaments moving downward in the conventional operation of the process embodied in U. S. Patent 3,905,790.
The auxiliary system in effect is a multiple air lance that expedites the establishment of the normal running mode of the bushing, either at start up or after a breakout during the course of a run. The method of the invention contemplates sev-eral air nozzles disposed at opposite sides along the length of the bushing and a~ the a~gles her~etofore noted. The center line of the gas flowing from each nozzle exerts a cooling effect on ~he orifice plate 25 the matrix of glass flows or drops away from the plate face as flooding is being curtailed and termin-ated, all in the manner more ~ully described herein, and the jets of gas flow upwardly and in toward the center of the ori-fice plate. The multiplicity of nozzles projecting individual jets provide the multiple air lance effect heretofore noted.
The air, or any other gas, can be directed at random along the length of the orifice plate to maintain a uniform temperature and cooling effect along the length of the plate. The inven-tion is particularly useful for large bushings, that is,bushings in excess of 1000 orificesO For example, in bushings of 2000 orifices or more which are rectangular in shape and wherein there is a relatively long dimension at the ends of which the current is fed to effect the heating of the bushing, such as is shown in the bushing assembly of ~ig. 3 of the aforementioned Application NoO 256,769, the ends of the orifice plate adjacent the current leads may in some instances be at a higher temperature than the midsection of the orifice plate.
The nozzles can be readily adjusted to apply a greater cooling effect to the hotter ends to evenly cool the orifice plate along its length.
This auxiliary cooling system with its multiple air lance effect furnishes distinct advantages in starting up or clearing breakouts, particularly where substantial flooding is permitted to take place in the first instance, in that the time of the operator is substantially reduced in contrast to the time and cost for a single operator or multiple operators to clear the bushing manually with individual air lances. As the size of bushings increases, so also do the advantages flowing from the use of the multiple air lanceO In fact, in some instances -the need for an operator can be obviated entirely.
It is emphasized that the concept of opposing jets, par-ticularly when intended to impact directly on the orifice plate ~f the bushing, constitutes a most advantageous embodiment of this invention when employed to establish the running mode of the bushing on start up or after a major flood where an exten-sive matrix of glass has been permitted to fo.rm. Nevertheless, very useful results can also be obtained in another embodiment of the invention as elsewhere descrihedl where the center lines of opposing jets are permitted to impact against each other ahead of and before they reach the orifice plate. The effect of the impacting jets is to create an upward air flow onto the orifice plate.
Generally, where the jets of the auxiliary cooling system impact directly on the orifice plate and the running mode is established, the upward flow of bulk air is continued and the flow from the auxiliary system is terminated. However, the operator can continue the auxiliary flow if desirable.
In the e~bodiment of the invention involving impacting jets ahead of the orifice plate, it is possible to use the sy-stem, depending on the volume of air flow, to assist in estab-lishing the running mode of the bushing. Also, if desired, it can be used as the source of bulk air flow or to augment the conventional bulk air flow of the process of U. S. Patent 3,905,730.
In respect of the direction of air flow it is to be noted that in establishing the running mode of the bushing .
utilizing the multipl~e air.lance effect of the auxiliàry cooling system it is generally preferred to direct the opposing air nozzles so that the principal force of the respective jets is felt at the outer edges of the orifice plate and consequently ! the flooding effect giving rise to the~matrix of glass tends to 30 - flow inward toward the center of the orifice plate. It is more desirable to concentrate the matrix in this manner where its weight is relied upon' at least in part, to encourage filament ~l~99~
. . , à~tenuation.
Although the angle of the opposing jets to the orifice plate has been discussed elsewhere, it is pertinent to note that the range of the angles can vary from about 30 to about 60.
Below about 30 the air tends to blow by and not impact on the plate or if impacting with an opposing jet the air will not have a sufficient upward moment to provide an effective upward flow.
However, in the case of impacting jets, when one of the opposing jets is set as low as about 30 the immediate opposing jet should be at a greater angle. Also, it is the desired practice that the nozæles from which the jets at the lower angles ap-proaching about 30~ are ejected should be on the same side as the operator so that the flow of heated air and gas from the vicinity of the orifice plate area after contact is away from the direction of the operator.
Another advangage of the auxiliary air cooling system, particularly the impacting jets, is that it aids in line dry-ing of the fibers that may have been sprayed with cooling water.
DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of one embodiment of glass fiber production equipment employing the clearing air delivery manifold of this invention.
Figure 2 is an enlarged sectional view taken along lines
2-2 of Figure 1.
Figure 3 is a schematic graph showing the variations in air velocities and orifice plate temperatures which occur when establishing the running mode.
Figure 4 is a schematic view of glass fiber production equipment employing the air delivery manifold of this invention in the running mode.
DETAILED DESCRIPTON OF THE INVENTION
Referring to schematic Figure 1 and sectional Figure 2 ( ( ~
.le glass is rnelted in furnace 1 and a res~rvoir of moll-en glass ~ is maintained in reservoir means or bushing 3. The temperature of orifice plate 4 is controlled by electrical re-sistance heating means attached to the orifice plate.
Cooling air is introduced from at least two sides of the orifice plate through nozzles 6 and 6', which, in the apparatus shown, are connected to manifolds 7 and 7'. The nozzles are arranged in generally opposing relationship on two sides of the orifice area. A bulk air system is provided below the orifice pla~e 4 and comprises a plurality of nozzles 20 which are arranged in a row and securely mounted on a supporter 21 and the inlets of which are communicated with a source of air under pressure through individual hoses (not shown). The glass fibers 8 are drawn from the orifices and are wound on collet 9. Auxiliary equipment including sizing or dressing fluid applicators are not shown in Figure 1.
Figure 2 shows the arrangement of nozzles 6 and 6' in side-by-side relationship.
For establishing the running mode (i.e., start-up or clearing), the air is introduced at an angle of from about 30 to about 60 to the orifice plate. This angle permits as much cooling air as possible to reach the orifice plate over the edge of the glass monolith as the monolith moves away from the orifice plate ~hile at the same time maintaining a flow of air at the cone area. The air is directed generally at the center of the plate but may vary somewhat because of the fan-ning effect as the air leaves the nozzle. If over-cooling occurs at the edge of the orifice plate while the center is under-cooled, the impact centers of the cooling air are separated too far outwardly from the center. On the other hand, if the air streams overlap too much, the edges will tend to be-come too hot. The air leaving the nozzles will, of course;
.llcrease in cross-section or fan out. The nozzles should be located relative to the orifice area so the cross-section of air flow at the orifice plate extends at least sufficiently to include the edge of the orifices nearest the nozzle. The air flow from all the nozzles should, of course, be of suffici-ent total cross-section at the orifice plate that lla-it encompasses the entire orifice area. A preferred angle for the nozzles is from about ~0 to about 50 to said orifice plate, while a particularly preferred angle is about ~5.
The use of nozzles, as contrasted for example to the use of an elongated slit, is important in order to maintain impact pressure while avoiding the use of excessive air as produced by an elongated slit. Generally nozzle diameter will range from about 1/32 in. to about 6/32 in. and are spaced sufficiently close to each other to obtain a substantially even flow of air along the orifice plate. Nozzles having a diameter of 1/16 in.
spaced on 1/2 in. centers positioned about 3 in. from the center of the orifice area have successfully been employed for a 2000 hole orifice plate which was 1.65 in. wide and 8.3 in. long.
The orifice area was 21 rows wide. Generally, the nozzles may be placed from about 2 to about 5 in. from the center of the orifice area. Representative air exit velocity at the nozzle ranges from about 100 to about 400 feet per second.
The present invention may be employed to establish the running mode at start-up according to the following procedure.
The orifice plate is heated sufficiently to cause flood-ing of the entire underside thereof and form a gLas-s matrix or monolith. While it is not necessary, it is desirable to use cooling air from the multiple air lance,to assist the matrix to form more quickly. During this stage of start up the tempera-tures of the orifice plate will generally be from about 25 to about 150C below normal operating temperatures and glass vis-cosities flowing through the orifices,will be above about 100n poises. Normal operating temperature of an orifice plate for E
glass, depending upon orifice diameter and desired throughput rate, will be within the range of from about 1150 to 1350C.
Operating temperatures for other types of glass will vary but such temperatures are well known to the art.
( Inasmuch as the molten glass passing through the orifices must be fiberized, the viscosity of the glass in the fiber form-ing cone beneath the orifices from this point forward in the process should be ~ithin the normal fiberizing viscosity range of from about 300 to about 1000 poises, preferably from about 500 to about 700 poises.
After the monolith is formed, it is moved slowly away from the underside of the orifice plate. The movement of the monolith may be accomplished by mechanical means such as by tongs or a glass rod embedded in the monolith. Alternatively, but generally less desirably, the monolith can be permitted to fall of its own weight.
As the monolith moves away from the underside of the ori-fice plate the clearing air from the multiple air lance is employed and will begin to impact on the orifice "late itself and to assist clearing. Generally clearing will occur beginning at the edges of the orifice area nearest the clearing air sources. Because of normal manufacturing tolerances, minor variations in heat patterns and the like, however, some axeas ~0 will fiberize while other isolated areas will remain flooded.
At this point, the air flow from the multiple air lance may be reduced somewhat. The reduced air flow will permit the viscosity of the molten glass in the isolated flooded areas to decrease and become more fluid. As a result, these floods will tend to flow into adjacent cones from wh~ch fibers are being formed. At about the same time the air floh7 is first reduced, the temperature of the orifice plate is increased slowly and the increase in plate temperature continues until normal opera-ting temperatures and viscosities are achieved.
l~hen the flooded areas spread to ad~acent fiber forming cones the cooling air from the multiple air lance is again in-creased. This increase in cooling air offsets the effect on the fiber forming cones of the mcr~2si~(3 plate temperat-lre and al50 provides sufficicnt cooling to increase the viscosity of the fiber formin~ cones so ~hat enough tension can be applied to the fibers dra~n from those cones to cause the adjacent flooded areas to ~iberize.
In order to clear the remaining localized flooded areas, the air from the multiple air lance may be increased and decrea-sed again with a typical cycle (i.e., one air increase to the next) taking from about 15 to about: 20 seconds, although it should be understood that the time frequency may vary somewhat depending upon operating conditions. It can be expected that not all floods will be cleared with the first variation of air flow and that additional alternating increases and decreases in air flow can be employedO In the event a few small isolated flooded areas remain, a hand air lance may be employed to direct cooling air selectively to those areas as descri~ed below.
The above procedure has provided 80-90% clearing for a 2000 hole bushing in a period of only about one and one-half minutes. Once this condition has been achieved, bulk air, in-cluding the bulk air configuration described herein, can be em-ployed to maintain the running mode. A hand air lance whichpermits a stream of cooling air to be directed t~ specific areas can be used to separate the remaining few floodea areas after the bulk air is turned on.
While the above description has been directed to the start-up of an orifice plate, essentially the same procedure can be employed if an operating orifice for some reason floods. In this latter instance, the temperature of the orifice plate is simply dropped 25 to about 150C below operating temperatures and the above steps are repeated. By turning the bulk air off after a flood begins to occur, the complete flooding desir-able for restarting can be accelerated.
A schematic representation of the variation in orifice -late teml~c~ tures (~) and air Llo~ rates (B) during clearing lS sho~n in Fi~. 3. ~hen a major flood occurs, the air flow from the multiple air lance is decreased to ins~re the entire orifice area floods. After the entire area is flooded, the plate temperature is decreased and the air flow is increased to assist in forming a matrix or monolith of glass. The matriY. is then slowly pulled away from the orifice plate and the cooling air from the multiple air lance begins clearing. This air flow is then cycled to permit alternate spreading of glass in remaining flooded areas interspersed with periods of additional clearing.
The plate temperature is slowly raised to normal and the air cycles continue until at least most of the flooded areas are cleared.
As noted earlier, auxiliary cooling air from the multiple air lance for separation is introduced along at least the two major sides of an orifice plate so as to attain a substantially even cooling effect. In the event an orifice plate has a hexa-gonal, circular or similar configuration and space permits, this cooling air is desirably introduced along the entire periphery of the orifice area and, again, directed generally at the center of the orifice area. The system can be adjusted so as to con-form to the heat pattern of the orifice plate. It has been determined that during clearing the cones at the edges of the orifice area tend to be somewhat cooler than the cones at the center of the orifice area. Even though the cones at the center ~ tend to be somewhat warmer, that fact does not adversely affect clearing. The clearing mode described above, however, is not satisfactory to provide the uniform cooling required for running conditions.
The use of generally opposed nozzles to maintain the run-ning mode during production of glass fibers will now be described.
~ ig. 4 is a schematic rcpresentation o~ the apparc~tus for use in the running mode for the produc'~ion of glass fibers.
Referring to schematic ~igure 9, the glass is melted in -15a-furnace ll and a reservoir of molten glass 12 is maintained in reservoir means or bushing 13. The temperature of orifice plate 14 is controlled by electrical resistance heating means (see aforementioned Application No. 256,769) attached to the orifice plate.
Cooling air is introduced from at least two sides of the orifice plate through nozzles 16 and 16' which, in the apparatus shown, are connected to manifolds 17 and 17'. The nozzles are arranged in generally opposing relationship on two sides of the orifice area. The glass fibers 18 are drawn from the ori-fices and are wound on collet l9. Auxiliary equipment including sizing or dressing fluid applicators are not shown in Figure 4.
For the running mode, the air is introduced through one set of the generally opposed nozzles at an angle of from about 30 to about 60 to the orifice plate. Pairs of opposing noz-zles need not be at the same angle and, indeed, it has been found to be desirable that opposing nozzles be at somewhat dif-ferent angles to minimize the amount of air which tends to "bounce back" into the operator's face. Good operating results have been achieved with one set of nozzles at an angle from about 40 to about 60 and the other set of nozzles at a dif-ferent angle within a range from about 30 to about 45 to the plate. A particularly preferred arrangement contemplates the use of one set of nozzles at an angle of about 45 to the plate and the opposing se-t of nozzles at an angle of about 40 to the orifice plate.
The centerline of the air stream from a nozzle is gen-erally directed to about the far edge of the orifice area in the orifice plate. The air streams from the nozzle thereupon im-pact below the orifice plate to cause turbulence and to result in a bulk flow of air upwardly at the cone and orifice plate, as schematically shown in Fig. 4. The centerlines of the air streams issuing from opposed nozzles will generally intersect at `a distance of not more than about one inch below the orifice plate. The area of turbulence created by the intersecting air streams should, of course, be at least as great as the area occupied by the orifices in the orifice plate.
As in the case of clearing, the nozzles are spaced suf-ficiently close to each other to obtain a substantially even flow of air along the edges of the orifice plate. The use of nozzles, as contrasted for example to the use of an elongated slit, is important for the running mode in order to maintain impact pressure and create turbulence while avoiding the use of excessive air. Substantially less cooling alr is required for the running mode according to this invention as compared, for example, to the use of more vertically oriented nozzles mounted at an angle of about 80 to the orifice plate. Indeed, cooling air volume can be reduced on the order of about one-half because the nozzles are closely ad~acent the orifice area.
Generally nozzle diameter will range from about 1/32 in.
to about 6/32 in. and are spaced sufficiently close to each other to obtain a substantially even flow of air along the ori-fice plate. Nozzles having a diameter of 1/16 in. spaced on1/2 in. centers positioned about 3 in. from the center of im-pact at the orifice area have successfully been employed for a 2000 hole orifice plate which was 1.65 in. wide and 8.3 in.
long. The orifice area was 21 rows wideO In general, the noz-zles may be placed from about 2 to about 5 in. from the center of the orifice area. Representative air exit velocity at the nozzle range from about 50 to about 200 feet per second.
Once again, cooling air for separation has been described as being introduced so as to attain a substantially even heat .
pattern along the two major sides of an orifice plate. In the event an orifice plate has a hexagonal, circular or similar configuration and space permits, the cooling air is desirably g~
introduced along -the entire periphery of the orifice area and, again, directed so that the centerline of the streams will intersect below the orifice plate but within about 1 inch of the orifice plate to create the desired bulk flow.
While an air manifold may be designed solely for clearing or may be designed solely for the running mode, this invention also contemplates apparatus with nozzles that are adjustable and can be used both for clearing and for the running mode.
The following specific examples are included for illus-trative purposes only and are not intended to limit the scopeof the invention.
Example 1 A molten bath of E glass having a bu]k temperature of about 2300F was established over an orifice plate assembly as shown in copending application No. 256,769 filed July 12, 1976.
The orifice plate was made of platinum and contained 2068 orifices having a diameter of 0.052 in. and spaced centers that varied from 0.065 to 0.080 in.. The orifice area was 21 rows wide and occupied an area 1.65 in. wide and 8.3 in. long.
A clearing manifold was mounted on each of the long sides of the orifice area. Each manifold contained 16 nozzles having about a 0.063 in. inside diameter. Pairs of nozzles were mounted on 0.5 in. centers with 0.63 in. spacing between pairs to accommoda-te reinforcing ribs in the orifice plate. The nozzles were at an angle of about 45 to the orifice plate and the nozzle outlets were about 3 in. from the center of the plate.
The centerline of the air stream of the nozzles was aimed at about the center of the orifice area in the orifice plate.
The orifice plate was allowed to flood and the tempera-ture of the plate was reduced about 50C (a reduction of 50-80F measured about 1/2 in. up on a flange which defined a slc~ 211 o~ the r~scrvoir). The coolin~ air ~:as employed at a m~nifold pressure of 4-12 psig.
The matriY. of ~lass was pulled slowly from the plate and the air ~as cycled at about 15 second intervals as the orifice plate temperature was slowly increased to its normal operating temperature of about 2265F. The matrix and then the fibers were initially hand pulled from the orifice plate until oper-ating orifice plate temperature was reached and, thereafter, the fibers were pulled by a pull roll. About 80~ separation was achieved after only about 3 cycles of the clearing air and after only about 1 1/2 minutes. At that point bulk air was introduced onto the plate and the remaining flooded areas were cleared with a hand air lance within about another 2 1/2 minutes. The bulk air was introduced from 12-1/4" I.D. nozzles on 0.7 in.
centers mounted 9 in. below the plate and at an angle of about 80 to the plate. The manifold pressure for the bulk air was about 1.5 pounds.
In clearing floods on numerous occasions, the air from the auxiliary cooling system was often cycled from 2 to 4 times to provide 80~ clearing of floods. On other occasions, the floods were entirely cleared with the auxiliary cooling system.
Example 2 Employing the orifice assembly and molten glass bath of Example 1, glass fibers were produced utilizing opposed nozzles to provide a bulk air flow. The manifold nozzle spacings and size were the same as employed in Example 1.- The nozzle out-lets on one side were at an angle of about 45 to the orifice plate. The opposing nozzle outlets were at an angle of about 30 to the orifice plate.
The centerlines of the air streams were directed at the far edge of the orifice area and the centerlines of the streams intersected within 1 in. below the orlfice plate. Employing a ~L~9~
manifold pressure o~ about 3 psig., a bulk 10w of air was established which ~aintained cone separation and permitted the production of glass fibers.
Because less cooling air was employed, it was found to be desirable to spray the formed and solidified fibers with a water spray to cool them to about ambient temperature.
Although the foregoing description and the examples have been directed to glass, it should be understood that the inven-tion is not necessarily limited to use with glass. The process and apparatus disclosed herein can also be used in the manufac-ture of ceramic fibers which have processing propexties similar to glass. These may include fibers containing various metal oxides, for example alumina borosilicate, alumina silica, zirconi-silica, and the like. The bushing and the orifice plate, of course, should be made of an alloy or other material capable of withstanding the elevated temperatures of the various types of ceramic material which can be formed into fiber.
The invention is not intended to be limited to the spec-ifics of the described embodiments, but rather is defined by the following claims.
Figure 3 is a schematic graph showing the variations in air velocities and orifice plate temperatures which occur when establishing the running mode.
Figure 4 is a schematic view of glass fiber production equipment employing the air delivery manifold of this invention in the running mode.
DETAILED DESCRIPTON OF THE INVENTION
Referring to schematic Figure 1 and sectional Figure 2 ( ( ~
.le glass is rnelted in furnace 1 and a res~rvoir of moll-en glass ~ is maintained in reservoir means or bushing 3. The temperature of orifice plate 4 is controlled by electrical re-sistance heating means attached to the orifice plate.
Cooling air is introduced from at least two sides of the orifice plate through nozzles 6 and 6', which, in the apparatus shown, are connected to manifolds 7 and 7'. The nozzles are arranged in generally opposing relationship on two sides of the orifice area. A bulk air system is provided below the orifice pla~e 4 and comprises a plurality of nozzles 20 which are arranged in a row and securely mounted on a supporter 21 and the inlets of which are communicated with a source of air under pressure through individual hoses (not shown). The glass fibers 8 are drawn from the orifices and are wound on collet 9. Auxiliary equipment including sizing or dressing fluid applicators are not shown in Figure 1.
Figure 2 shows the arrangement of nozzles 6 and 6' in side-by-side relationship.
For establishing the running mode (i.e., start-up or clearing), the air is introduced at an angle of from about 30 to about 60 to the orifice plate. This angle permits as much cooling air as possible to reach the orifice plate over the edge of the glass monolith as the monolith moves away from the orifice plate ~hile at the same time maintaining a flow of air at the cone area. The air is directed generally at the center of the plate but may vary somewhat because of the fan-ning effect as the air leaves the nozzle. If over-cooling occurs at the edge of the orifice plate while the center is under-cooled, the impact centers of the cooling air are separated too far outwardly from the center. On the other hand, if the air streams overlap too much, the edges will tend to be-come too hot. The air leaving the nozzles will, of course;
.llcrease in cross-section or fan out. The nozzles should be located relative to the orifice area so the cross-section of air flow at the orifice plate extends at least sufficiently to include the edge of the orifices nearest the nozzle. The air flow from all the nozzles should, of course, be of suffici-ent total cross-section at the orifice plate that lla-it encompasses the entire orifice area. A preferred angle for the nozzles is from about ~0 to about 50 to said orifice plate, while a particularly preferred angle is about ~5.
The use of nozzles, as contrasted for example to the use of an elongated slit, is important in order to maintain impact pressure while avoiding the use of excessive air as produced by an elongated slit. Generally nozzle diameter will range from about 1/32 in. to about 6/32 in. and are spaced sufficiently close to each other to obtain a substantially even flow of air along the orifice plate. Nozzles having a diameter of 1/16 in.
spaced on 1/2 in. centers positioned about 3 in. from the center of the orifice area have successfully been employed for a 2000 hole orifice plate which was 1.65 in. wide and 8.3 in. long.
The orifice area was 21 rows wide. Generally, the nozzles may be placed from about 2 to about 5 in. from the center of the orifice area. Representative air exit velocity at the nozzle ranges from about 100 to about 400 feet per second.
The present invention may be employed to establish the running mode at start-up according to the following procedure.
The orifice plate is heated sufficiently to cause flood-ing of the entire underside thereof and form a gLas-s matrix or monolith. While it is not necessary, it is desirable to use cooling air from the multiple air lance,to assist the matrix to form more quickly. During this stage of start up the tempera-tures of the orifice plate will generally be from about 25 to about 150C below normal operating temperatures and glass vis-cosities flowing through the orifices,will be above about 100n poises. Normal operating temperature of an orifice plate for E
glass, depending upon orifice diameter and desired throughput rate, will be within the range of from about 1150 to 1350C.
Operating temperatures for other types of glass will vary but such temperatures are well known to the art.
( Inasmuch as the molten glass passing through the orifices must be fiberized, the viscosity of the glass in the fiber form-ing cone beneath the orifices from this point forward in the process should be ~ithin the normal fiberizing viscosity range of from about 300 to about 1000 poises, preferably from about 500 to about 700 poises.
After the monolith is formed, it is moved slowly away from the underside of the orifice plate. The movement of the monolith may be accomplished by mechanical means such as by tongs or a glass rod embedded in the monolith. Alternatively, but generally less desirably, the monolith can be permitted to fall of its own weight.
As the monolith moves away from the underside of the ori-fice plate the clearing air from the multiple air lance is employed and will begin to impact on the orifice "late itself and to assist clearing. Generally clearing will occur beginning at the edges of the orifice area nearest the clearing air sources. Because of normal manufacturing tolerances, minor variations in heat patterns and the like, however, some axeas ~0 will fiberize while other isolated areas will remain flooded.
At this point, the air flow from the multiple air lance may be reduced somewhat. The reduced air flow will permit the viscosity of the molten glass in the isolated flooded areas to decrease and become more fluid. As a result, these floods will tend to flow into adjacent cones from wh~ch fibers are being formed. At about the same time the air floh7 is first reduced, the temperature of the orifice plate is increased slowly and the increase in plate temperature continues until normal opera-ting temperatures and viscosities are achieved.
l~hen the flooded areas spread to ad~acent fiber forming cones the cooling air from the multiple air lance is again in-creased. This increase in cooling air offsets the effect on the fiber forming cones of the mcr~2si~(3 plate temperat-lre and al50 provides sufficicnt cooling to increase the viscosity of the fiber formin~ cones so ~hat enough tension can be applied to the fibers dra~n from those cones to cause the adjacent flooded areas to ~iberize.
In order to clear the remaining localized flooded areas, the air from the multiple air lance may be increased and decrea-sed again with a typical cycle (i.e., one air increase to the next) taking from about 15 to about: 20 seconds, although it should be understood that the time frequency may vary somewhat depending upon operating conditions. It can be expected that not all floods will be cleared with the first variation of air flow and that additional alternating increases and decreases in air flow can be employedO In the event a few small isolated flooded areas remain, a hand air lance may be employed to direct cooling air selectively to those areas as descri~ed below.
The above procedure has provided 80-90% clearing for a 2000 hole bushing in a period of only about one and one-half minutes. Once this condition has been achieved, bulk air, in-cluding the bulk air configuration described herein, can be em-ployed to maintain the running mode. A hand air lance whichpermits a stream of cooling air to be directed t~ specific areas can be used to separate the remaining few floodea areas after the bulk air is turned on.
While the above description has been directed to the start-up of an orifice plate, essentially the same procedure can be employed if an operating orifice for some reason floods. In this latter instance, the temperature of the orifice plate is simply dropped 25 to about 150C below operating temperatures and the above steps are repeated. By turning the bulk air off after a flood begins to occur, the complete flooding desir-able for restarting can be accelerated.
A schematic representation of the variation in orifice -late teml~c~ tures (~) and air Llo~ rates (B) during clearing lS sho~n in Fi~. 3. ~hen a major flood occurs, the air flow from the multiple air lance is decreased to ins~re the entire orifice area floods. After the entire area is flooded, the plate temperature is decreased and the air flow is increased to assist in forming a matrix or monolith of glass. The matriY. is then slowly pulled away from the orifice plate and the cooling air from the multiple air lance begins clearing. This air flow is then cycled to permit alternate spreading of glass in remaining flooded areas interspersed with periods of additional clearing.
The plate temperature is slowly raised to normal and the air cycles continue until at least most of the flooded areas are cleared.
As noted earlier, auxiliary cooling air from the multiple air lance for separation is introduced along at least the two major sides of an orifice plate so as to attain a substantially even cooling effect. In the event an orifice plate has a hexa-gonal, circular or similar configuration and space permits, this cooling air is desirably introduced along the entire periphery of the orifice area and, again, directed generally at the center of the orifice area. The system can be adjusted so as to con-form to the heat pattern of the orifice plate. It has been determined that during clearing the cones at the edges of the orifice area tend to be somewhat cooler than the cones at the center of the orifice area. Even though the cones at the center ~ tend to be somewhat warmer, that fact does not adversely affect clearing. The clearing mode described above, however, is not satisfactory to provide the uniform cooling required for running conditions.
The use of generally opposed nozzles to maintain the run-ning mode during production of glass fibers will now be described.
~ ig. 4 is a schematic rcpresentation o~ the apparc~tus for use in the running mode for the produc'~ion of glass fibers.
Referring to schematic ~igure 9, the glass is melted in -15a-furnace ll and a reservoir of molten glass 12 is maintained in reservoir means or bushing 13. The temperature of orifice plate 14 is controlled by electrical resistance heating means (see aforementioned Application No. 256,769) attached to the orifice plate.
Cooling air is introduced from at least two sides of the orifice plate through nozzles 16 and 16' which, in the apparatus shown, are connected to manifolds 17 and 17'. The nozzles are arranged in generally opposing relationship on two sides of the orifice area. The glass fibers 18 are drawn from the ori-fices and are wound on collet l9. Auxiliary equipment including sizing or dressing fluid applicators are not shown in Figure 4.
For the running mode, the air is introduced through one set of the generally opposed nozzles at an angle of from about 30 to about 60 to the orifice plate. Pairs of opposing noz-zles need not be at the same angle and, indeed, it has been found to be desirable that opposing nozzles be at somewhat dif-ferent angles to minimize the amount of air which tends to "bounce back" into the operator's face. Good operating results have been achieved with one set of nozzles at an angle from about 40 to about 60 and the other set of nozzles at a dif-ferent angle within a range from about 30 to about 45 to the plate. A particularly preferred arrangement contemplates the use of one set of nozzles at an angle of about 45 to the plate and the opposing se-t of nozzles at an angle of about 40 to the orifice plate.
The centerline of the air stream from a nozzle is gen-erally directed to about the far edge of the orifice area in the orifice plate. The air streams from the nozzle thereupon im-pact below the orifice plate to cause turbulence and to result in a bulk flow of air upwardly at the cone and orifice plate, as schematically shown in Fig. 4. The centerlines of the air streams issuing from opposed nozzles will generally intersect at `a distance of not more than about one inch below the orifice plate. The area of turbulence created by the intersecting air streams should, of course, be at least as great as the area occupied by the orifices in the orifice plate.
As in the case of clearing, the nozzles are spaced suf-ficiently close to each other to obtain a substantially even flow of air along the edges of the orifice plate. The use of nozzles, as contrasted for example to the use of an elongated slit, is important for the running mode in order to maintain impact pressure and create turbulence while avoiding the use of excessive air. Substantially less cooling alr is required for the running mode according to this invention as compared, for example, to the use of more vertically oriented nozzles mounted at an angle of about 80 to the orifice plate. Indeed, cooling air volume can be reduced on the order of about one-half because the nozzles are closely ad~acent the orifice area.
Generally nozzle diameter will range from about 1/32 in.
to about 6/32 in. and are spaced sufficiently close to each other to obtain a substantially even flow of air along the ori-fice plate. Nozzles having a diameter of 1/16 in. spaced on1/2 in. centers positioned about 3 in. from the center of im-pact at the orifice area have successfully been employed for a 2000 hole orifice plate which was 1.65 in. wide and 8.3 in.
long. The orifice area was 21 rows wideO In general, the noz-zles may be placed from about 2 to about 5 in. from the center of the orifice area. Representative air exit velocity at the nozzle range from about 50 to about 200 feet per second.
Once again, cooling air for separation has been described as being introduced so as to attain a substantially even heat .
pattern along the two major sides of an orifice plate. In the event an orifice plate has a hexagonal, circular or similar configuration and space permits, the cooling air is desirably g~
introduced along -the entire periphery of the orifice area and, again, directed so that the centerline of the streams will intersect below the orifice plate but within about 1 inch of the orifice plate to create the desired bulk flow.
While an air manifold may be designed solely for clearing or may be designed solely for the running mode, this invention also contemplates apparatus with nozzles that are adjustable and can be used both for clearing and for the running mode.
The following specific examples are included for illus-trative purposes only and are not intended to limit the scopeof the invention.
Example 1 A molten bath of E glass having a bu]k temperature of about 2300F was established over an orifice plate assembly as shown in copending application No. 256,769 filed July 12, 1976.
The orifice plate was made of platinum and contained 2068 orifices having a diameter of 0.052 in. and spaced centers that varied from 0.065 to 0.080 in.. The orifice area was 21 rows wide and occupied an area 1.65 in. wide and 8.3 in. long.
A clearing manifold was mounted on each of the long sides of the orifice area. Each manifold contained 16 nozzles having about a 0.063 in. inside diameter. Pairs of nozzles were mounted on 0.5 in. centers with 0.63 in. spacing between pairs to accommoda-te reinforcing ribs in the orifice plate. The nozzles were at an angle of about 45 to the orifice plate and the nozzle outlets were about 3 in. from the center of the plate.
The centerline of the air stream of the nozzles was aimed at about the center of the orifice area in the orifice plate.
The orifice plate was allowed to flood and the tempera-ture of the plate was reduced about 50C (a reduction of 50-80F measured about 1/2 in. up on a flange which defined a slc~ 211 o~ the r~scrvoir). The coolin~ air ~:as employed at a m~nifold pressure of 4-12 psig.
The matriY. of ~lass was pulled slowly from the plate and the air ~as cycled at about 15 second intervals as the orifice plate temperature was slowly increased to its normal operating temperature of about 2265F. The matrix and then the fibers were initially hand pulled from the orifice plate until oper-ating orifice plate temperature was reached and, thereafter, the fibers were pulled by a pull roll. About 80~ separation was achieved after only about 3 cycles of the clearing air and after only about 1 1/2 minutes. At that point bulk air was introduced onto the plate and the remaining flooded areas were cleared with a hand air lance within about another 2 1/2 minutes. The bulk air was introduced from 12-1/4" I.D. nozzles on 0.7 in.
centers mounted 9 in. below the plate and at an angle of about 80 to the plate. The manifold pressure for the bulk air was about 1.5 pounds.
In clearing floods on numerous occasions, the air from the auxiliary cooling system was often cycled from 2 to 4 times to provide 80~ clearing of floods. On other occasions, the floods were entirely cleared with the auxiliary cooling system.
Example 2 Employing the orifice assembly and molten glass bath of Example 1, glass fibers were produced utilizing opposed nozzles to provide a bulk air flow. The manifold nozzle spacings and size were the same as employed in Example 1.- The nozzle out-lets on one side were at an angle of about 45 to the orifice plate. The opposing nozzle outlets were at an angle of about 30 to the orifice plate.
The centerlines of the air streams were directed at the far edge of the orifice area and the centerlines of the streams intersected within 1 in. below the orlfice plate. Employing a ~L~9~
manifold pressure o~ about 3 psig., a bulk 10w of air was established which ~aintained cone separation and permitted the production of glass fibers.
Because less cooling air was employed, it was found to be desirable to spray the formed and solidified fibers with a water spray to cool them to about ambient temperature.
Although the foregoing description and the examples have been directed to glass, it should be understood that the inven-tion is not necessarily limited to use with glass. The process and apparatus disclosed herein can also be used in the manufac-ture of ceramic fibers which have processing propexties similar to glass. These may include fibers containing various metal oxides, for example alumina borosilicate, alumina silica, zirconi-silica, and the like. The bushing and the orifice plate, of course, should be made of an alloy or other material capable of withstanding the elevated temperatures of the various types of ceramic material which can be formed into fiber.
The invention is not intended to be limited to the spec-ifics of the described embodiments, but rather is defined by the following claims.
Claims (11)
1. In a method of forming glass fibers by (a) passing separate streams of molten glass through an orifice plate having orifice plate heating means and having at least four rows of orifices therein, with orifices being spaced in flooding relationship;
(b) drawing fibers from cones of molten glass formed at each said orifice; and (c) directing a bulk flow of rapidly moving gas upwardly to the orifice area in said plate, (i) to cool said cones to provide a stable cone formation and to maintain separation of cones thus preventing flooding;
(ii) to impinge on said plate essentially to eliminate stagnant gas adjacent said plate and to cause gas to move outwardly along said plate in all directions from said orifice area; and (iii) to supply a source of gas sucked down-wardly by the fibers and substantially eliminate ambient gas drawn into the region of the fiber cones, the improvement comprising introducing cooling gas streams from at least two sides of said orifice area at an angle of from about 30° to about 60° through generally opposed nozzles which impact below but closely adjacent to said orifice plate and create a turbulent bulk flow of upwardly moving gas at the cone and plate area.
(b) drawing fibers from cones of molten glass formed at each said orifice; and (c) directing a bulk flow of rapidly moving gas upwardly to the orifice area in said plate, (i) to cool said cones to provide a stable cone formation and to maintain separation of cones thus preventing flooding;
(ii) to impinge on said plate essentially to eliminate stagnant gas adjacent said plate and to cause gas to move outwardly along said plate in all directions from said orifice area; and (iii) to supply a source of gas sucked down-wardly by the fibers and substantially eliminate ambient gas drawn into the region of the fiber cones, the improvement comprising introducing cooling gas streams from at least two sides of said orifice area at an angle of from about 30° to about 60° through generally opposed nozzles which impact below but closely adjacent to said orifice plate and create a turbulent bulk flow of upwardly moving gas at the cone and plate area.
2. The method of Claim 1 wherein said nozzles are located around the entire periphery of said area occupied by orifices in said orifice plate.
3. The method of Claim 1 wherein opposing nozzles are at different angles.
4. The method of Claim 3 wherein one set of nozzles is at an angle of from about 40° to about 60° to said orifice plate and the set-of opposing nozzles are at a different angle within the range of from about 30° to about 45° to said orifice plate.
5. The method of Claim 1 wherein said nozzle outlets are located on two sides of said orifice area at a distance of from about 2 to about 5 inches from the center of said orifice area.
6. The method of Claim 1 wherein said nozzles have an inside diameter of from about 1/32 to about 3/16 in.
7. An apparatus for the production of glass fibers comprising:
(a) means for containing a head of molten glass;
(b) an orifice plate having orifice plate heating means, said orifice plate having at least four rows of orifices there-in, with orifices being spaced in flooding relationship through which said glass fibers are drawn, said plate being constructed of a heat resistant material and being disposed at the base of said containing means;
(c) means for controlling the temperature of said plate;
(d) means for withdrawing said filaments from said plate forming cones at said orifices; and (e) cooling gas means disposed below said orifice plate and on at least two sides of area occupied by orifices in said orifice plate including generally opposed nozzles located closely adjacent to the area occupied by orifices in said orifice plate and at an angle of from about 30° to about 60° to said plate, said nozzles being directed to cause cooling gas to impact beneath but closely adjacent to said orifice area.
(a) means for containing a head of molten glass;
(b) an orifice plate having orifice plate heating means, said orifice plate having at least four rows of orifices there-in, with orifices being spaced in flooding relationship through which said glass fibers are drawn, said plate being constructed of a heat resistant material and being disposed at the base of said containing means;
(c) means for controlling the temperature of said plate;
(d) means for withdrawing said filaments from said plate forming cones at said orifices; and (e) cooling gas means disposed below said orifice plate and on at least two sides of area occupied by orifices in said orifice plate including generally opposed nozzles located closely adjacent to the area occupied by orifices in said orifice plate and at an angle of from about 30° to about 60° to said plate, said nozzles being directed to cause cooling gas to impact beneath but closely adjacent to said orifice area.
8. The apparatus of Claim 7 wherein said nozzles are located around the entire periphery of said area occupied by orifices in said orifice plate.
9. The apparatus of Claim 7 wherein opposing nozzles are at different angles.
10. The apparatus of Claim 9 wherein one set of nozzles is at an angle of from about 40° to about 60° and the opposing nozzles are at an angle of from about 30° to about 45°.
11. The apparatus of Claim 7 wherein said nozzle outlets are located on two sides of said orifice area at a distance of from about 2 to about 5 in. from the center of said orifice area.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA352,297A CA1099111A (en) | 1976-02-13 | 1980-05-20 | Method and apparatus for producing glass fibers |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US658,122 | 1976-02-13 | ||
| US05/658,122 US4033742A (en) | 1976-02-13 | 1976-02-13 | Method for producing glass fibers |
| CA271,646A CA1087855A (en) | 1976-02-13 | 1977-02-11 | Method and apparatus for producing glass fibers |
| CA352,297A CA1099111A (en) | 1976-02-13 | 1980-05-20 | Method and apparatus for producing glass fibers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1099111A true CA1099111A (en) | 1981-04-14 |
Family
ID=27164909
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA352,297A Expired CA1099111A (en) | 1976-02-13 | 1980-05-20 | Method and apparatus for producing glass fibers |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1099111A (en) |
-
1980
- 1980-05-20 CA CA352,297A patent/CA1099111A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 19980414 |