Fluid flow method and apparatus used in manufacture of glass fibers

The present invention embraces fluid flow apparatus comprising a first nozzle for discharge of a first fluid therefrom, duct means for receiving the first fluid discharged from the first nozzle and for discharging the first fluid therefrom, and a second nozzle for discharge of a second fluid therefrom for modifying the first fluid upon discharge from the duct means. The present invention also embraces a method of controlling the environment of the fiber forming region of a glass fiber forming bushing comprising establishing a first flow of fluid in which the fluid in the center region of the first flow has a flow velocity at least as high as the flow velocity of fluid in all other regions of the first flow, directing a second flow of fluid into contact with the first flow to establish a combined flow in which the fluid in the center region of the combined flow has a flow velocity lower than the flow velocity of fluid in other regions of the combined flow and contacting the fiber forming region with the combined flow.

This invention relates to a method and apparatus for fluid flow. More 
specifically, this invention relates to method of, and an apparatus for, 
introducing a fluid to a fiber forming bushing from which streams of glass 
are drawn for controlling the fiber forming environment. 
Developments in the production of glass fibers have led to the utilization 
of streams of fluid, such as air and other gases, impinging upwardly on a 
fiber forming bushing. The upwardly moving gas streams control the fiber 
forming environment. Such streams of gas maintain separation of the 
streams of glass and prevent flooding of the bushing. Also, the cooling 
effect of the gas streams serves to rapidly quench the glass streams as 
glass fibers or filaments are attenuated from the bushing. 
It has been found that a generally uniform flow of gas at the glass cone 
region of the bushing is desired. Thus, method and apparatus for 
delivering or creating such a uniform flow of gas at the glass cone region 
is important and improvements in such method and apparatus are desired. 
The present invention embraces fluid flow apparatus comprising a first 
nozzle for discharge of a first fluid therefrom, duct means for receiving 
the first fluid discharged from the first nozzle and for discharging the 
first fluid therefrom, and a second nozzle for discharge of a second fluid 
therefrom for modifying the first fluid upon discharge from the duct 
means. The first and second fluids can be alike or can differ. 
The present invention also embraces a method of controlling the environment 
of the fiber forming region of a glass fiber forming bushing comprising 
establishings a first flow of fluid in which the fluid in the center 
region of the first flow has a flow velocity at least as high as the flow 
velocity of fluid in all other regions of the first flow, directing a 
second flow of fluid into contact with the first flow to establish a 
combined flow in which the fluid in the center region of the combined flow 
has a flow velocity lower than the flow velocity of fluid in other regions 
in the combined flow and contacting the fiber forming region with the 
combined flow. 
An object of the invention is to provide an improved method and apparatus 
for fluid flow. 
Another object of the invention is to provide an improved fluid flow method 
and apparatus for use in a glass fiber forming operation.

With respect to the drawings, FIG. 1 shows bushing 10 connected to a 
forehearth (not shown) of a furnace for melting glass or glass forming 
materials. The bushing is provided with a plurality of orifices at which 
cones 12 of molten glass material are produced for the attenuation of 
glass filaments 14 therefrom for collection on winding apparatus 20. The 
filaments are passed over sizing applicator 15 and also over gathering 
pulley 16 which gathers the filaments into strand 18 for winding into 
package 26 on the winder apparatus. 
Winder 20 has a winding collect 22 mounted for rotation about a horizontal 
axis for the collection of strand into packages. A collection tube (not 
shown) can be placed over the collet for collection of the wound package 
thereon. A variable speed drive (not shown) within the housing of the 
winder rotates the collet. Conventional winder speed controls (not shown) 
modify the rotational speed of the collet during formation of packages. 
Strand traversing apparatus 24, such as a spiral wire traverse, is provided 
for distributing the strand along the length of the collet during strand 
collection. 
Bushing 10 in FIG. 1 is shown as a tipless bushing. However, the bushing 
can have a plurality of orificed projections, or tips, through which the 
molten glass is supplied for attenuation into fibers. 
The glass fiber forming process shown in FIG. 1 is provided with a fluid 
flow or blower assembly for controlling the fiber forming environment. 
Control of the fiber forming environment adjacent the glass cones at the 
regions of the orifices is particularly important. As shown, blower 
assembly 30 comprises a first flow nozzle 32, a conduit or duct means 34 
and a second flow nozzle 36. 
FIGS. 2 and 3 show the blower assembly in more detail. 
The first flow nozzle comprises a chamber 45 with a fluid inlet 43 for the 
supply of said fluid from a source 42 and fluid outlets 44 for discharge 
of the fluid therefrom. Although it is preferred that the fluid be a 
gaseous material such as air, the fluid can be steam, air mixed with water 
droplets or various other gases. The fluid source can be a conventional 
supply source such as an air compressor. 
In the embodiment shown, the first flow nozzle is positioned to discharge 
into channel or duct means 34 and the air discharged from nozzle forms a 
first fluid flow which passes through the duct means. Duct means 34 can be 
of any configuration. As shown, the end walls are parallel, and front wall 
35 and back wall 37 diverge upwardly and outwardly from the point of 
discharge of the first fluid into the duct means. As shown, nozzle 32 and 
the duct means form an induced air blower apparatus such that ambient air 
is induced into the duct means at the nozzle. The induced air is combined 
in the duct means for discharge with the air from the nozzle as the first 
fluid flow. 
The nozzle and the duct shown in this embodiment are merely illustrative. 
It is within the scope of the invention that other nozzle and duct 
arrangements can be used. For example, duct means which enclose the nozzle 
or which comprise a series of tubes enclosing individual nozzle discharge 
orifices can be used. Other duct or conduit means, such as those having 
internal veins or tubes, can also be used so long as the fluid received 
from nozzle 32 is properly controlled as the fluid passes through the 
duct. 
The duct means, or channel, directs the fluid passing therethrough and 
establishes a fluid flow steam such that an established fluid flow stream 
is discharged from the duct. Establishment of a flow stream is 
particularly important with an elongated blower, such as rectangular 
blower, so as to establish a flow exiting therefrom which has a generally 
uniform velocity profile along its length. 
Second flow nozzle 36 modifies the fluid flow being discharged from the 
discharge region 50 of the duct means. As can be seen from FIG. 3, the 
discharge outlet 50 of the duct means is substantially larger than the 
discharge outlet 48 of the second nozzle. Gaseous flow discharging from 
the duct means is substantially larger than the flow discharging from the 
second nozzle as can be seen in FIG. 4. The second nozzle is positioned 
downstream from nozzle 32. As shown, the second nozzle supplies a second 
fluid flow into contact with the fluid flow being discharged from the duct 
means establishing a combined flow. The second flow nozzle comprises a 
chamber 49 having a fluid inlet portion 47 for the supply of fluid from a 
source 46 and fluid outlets 48 for discharge of the fluid therefrom. As 
discussed in regard to nozzle 32, the fluid of nozzle 36 can be air or 
other fluids such as steam, air mixed with water droplets or various other 
gases. 
Blower assembly 30 is constructed of an appropriate shape to provide 
uniform cooling in the fiber forming region of a bushing. A fiber forming 
bushing which is rectangular in shape can have a blower assembly as 
illustrated which is rectangular in shape with nozzles 32 and 36 extending 
along the length of the bushing. Nozzle 36 is downstream of nozzle 32 and 
is shown at the fluid discharge end of the duct means. In the embodiment 
shown, nozzle 36 extends along the length of the duct means and is mounted 
on the duct. It is within the scope of the invention that the control 
nozzle can be spaced apart from the discharge end of the duct means and 
that the control nozzle can be mounted other than on the duct, such as on 
an independent support means. 
FIG. 4 shows two fluid flow velocity profiles taken across the width of the 
fluid flow. Velocity curve 60 illustrates a bell-shaped velocity profile 
such that the fluid in the center region of the flow, as marked by line 
61, has a flow velocity that is as least as high as the flow velocity of 
fluid in all other regions of the flow. The flow being discharged from the 
first nozzle 32 through the duct means has a velocity profile taken across 
its width as shown in curve 60. The velocity profile of the combined flow 
illustrated by curve 62 is such that the fluid in the center region of the 
flow, as indicated by line 63, has a flow velocity that is lower than the 
flow velocity of fluid in other regions of the combined flow. The combined 
flow from nozzles 32 and 36 has a velocity profile taken across its width 
as shown by curve 62. Such velocity profiles can be measured with a pitot 
tube or a hot wire anemometer. 
It has been found that an offset air pattern such as that illustrated by 
curve 62 provides a more uniform velocity distribution of the air (and 
more uniform cooling) at the glass cone region of a fiber forming bushing 
than that provided when a bell-shaped air pattern such as that illustrated 
by curve 60 is used. The higher velocity portion of the velocity profile 
is directed toward the side of the bushing furthest from the blower 
assembly. 
Having described the invention in detail, it will be understood that the 
specific embodiments designated are for the sake of explanation only and 
that the invention is not limited thereto. Various modifications and 
substitutions can be made without departing from the scope of the 
invention as defined in the following claims.