In the manufacture of continuous glass filaments, glass can be melted in a glass melter or furnace and flows to one or more bushings. Each bushing has a number of nozzles or tips through which streams of molten glass flow. The glass streams are mechanically pulled from the nozzles by a winding apparatus to form continuous glass filaments.
The temperature of the molten glass within the bushing must be high enough to maintain the glass in a liquid state. However, if the temperature is too high, the molten glass will not cool sufficiently so as to become viscous enough to form filaments after passing through the bushing tips. Thus, the glass must be quickly cooled or quenched after it flows from the bushing tips and forms glass filaments. If the glass cools too slowly, the glass filaments will break and the filament forming process will stop.
There are numerous types of apparatus for cooling the glass filament forming area beneath a filament forming machine. A conventional cooling apparatus uses air, water, or both to transfer heat from the filament forming area beneath a bushing and cool the glass filaments. An example of a glass filament forming apparatus is disclosed in U.S. Pat. No. 6,192,714 to Dowlati et al., the disclosure of which is expressly incorporated herein by reference.
Cooling apparatus can include a plurality of cooling fins. Filaments drawn from the bushing can pass on either side of a cooling fin. Heat from the glass can be radiantly and convectively transferred to the fins from the glass filaments. The heat can pass conductively through the fins and to a water-cooled manifold. Such cooling fins increase the surface area of the cooling apparatus, thereby increasing the amount of heat that can be transferred from the filaments and from the filament forming area.
A cooling fluid supply, such as water, can enter the manifold, travel through a channel within the manifold, and exit the opposite end of the manifold as a cooling fluid return. The cooling fluid absorbs heat as it flows through the manifold, thereby cooling the manifold, the cooling fins, and indirectly, the filament forming area. However, the amount of heat that such a cooling apparatus can remove from the filament forming area can be limited. If heat can be more rapidly removed from the filament forming area beneath a bushing, the operating temperatures of the bushing and the molten glass in the bushing can be increased, thereby allowing overall throughput to be increased.
Accordingly, it would be advantageous to provide an improved method and apparatus for cooling a filament forming area beneath a bushing to remove a greater amount of heat.
In accordance with embodiments of this invention there are provided cooling fin assemblies constructed of materials suitable for use in manufacturing glass filaments. The cooling fin assemblies include a manifold having a first end, a second end and an internal passage therebetween. The internal passage is configured for a flow of cooling fluid. A plurality of baffles is positioned within the internal passage. A plurality of blades is connected to the manifold. The blades are configured to conduct heat to the manifold. The baffles are configured to create a serpentine flow path for the cooling fluid within the manifold.
In accordance with embodiments of this invention there are also provided apparatus configured for the manufacture of glass filaments. The apparatus include a bushing having a plurality of nozzles. The bushing is configured to provide a supply of molten glass to the plurality of nozzles. The nozzles are configured for the production of glass filaments. The nozzles form a filament forming area. A cooling fin assembly is positioned in the filament forming area. The cooling fin assembly includes a plurality of blades connected to a manifold. The manifold has a first end, a second end and an internal passage therebetween. The internal passage is configured for a flow of cooling fluid. A plurality of baffles is positioned within the internal passage. The plurality of blades is configured to conduct heat to the manifold. The baffles are configured to create a serpentine flow path for the cooling fluid within the manifold. A mechanism is configured to collect the formed filaments.
In accordance with embodiments of this invention there are also provided methods of manufacturing glass filaments. The methods include the steps of providing a bushing, the bushing configured to provide a supply of molten glass to the plurality of nozzles, the plurality of nozzles configured for the production of glass filaments, wherein the nozzles form a filament forming area, positioning a cooling fin assembly in the filament forming area, the cooling fin assembly including a plurality of blades connected to a manifold, the manifold having a first end, a second end and an internal passage therebetween, the internal passage configured for a flow of cooling fluid, a plurality of baffles being positioned within the internal passage, the plurality of blades configured to conduct heat to the manifold, wherein the baffles are configured to create a serpentine flow path for the cooling fluid within the manifold, providing a supply of molten glass to the bushing, forming glass filaments through the nozzles, providing a flow of cooling fluid through the manifold, absorbing and conducting heat from the filament forming area to the manifold and transferring heat from the manifold to the cooling fluid as the cooling fluid flows through the manifold along a serpentine path.
Various advantages of this invention will become apparent to those skilled in the art from the following detailed description of the invention, when read in light of the accompanying drawings.
The present invention will now be described with occasional reference to the specific embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
Unless otherwise indicated, all numbers expressing quantities of dimensions such as length, width, height, and so forth as used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained in embodiments of the present invention. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements.
In accordance with embodiments of the present invention, improved methods and apparatus for cooling a filament forming area beneath a bushing are provided. The term “filament” as used herein, is defined to mean any fiber formed from a filament forming apparatus. The term “bushing”, as used herein, is defined to mean any structure, device or mechanism configured to supply molten glass to filament forming nozzles. The term “filament forming area”, as used herein, is defined to mean as area adjacent to filament forming nozzles. The term “manifold” as used herein, is defined to mean any structure, device or mechanism configured transfer heat away from the filament forming area. The term “blade” as used herein, is defined to mean any structure, device or mechanism configured transfer heat from the filament forming area to the manifold. The term “serpentine” as used herein, is defined to mean any non-linear path.
The description and figures disclose improved apparatus and methods configured for cooling a filament forming area beneath a bushing. Generally, the apparatus includes a fin assembly having a plurality of blades and a manifold. The manifold is configured to force a cooling fluid through a serpentine-shaped passage within the manifold.
Referring now to the drawings, a glass filament forming apparatus is shown generally at 10 in
Referring again to
The cooling fin assembly 12 also includes a plurality of blades 38 coupled to the manifold 36. The blades 38 are spaced apart along the length LM of the manifold 36. The blades 38 are configured to absorb heat from the filament forming area 34 and conduct the absorbed heat to the manifold 36. In the illustrated embodiment, the blades 38 have a substantially rectangular cross-sectional shape. However, the blades 38 can have other desired cross-sectional shapes. While the illustrated embodiment shows a quantity of six blades 38, it should be appreciated that any desired number of blades 38 can be used.
Referring again to
Referring again to
The blades 38 can be formed of any desired high temperature, corrosion resistant, heat transferring material. Non-limiting examples of blade material include copper, stainless steel, nickel, titanium, silver and alloys such as the non-limiting example of nickel-chromium-molybdenum-tungsten alloy. The blades 38 can have any desired dimensions and can have any desired surface, finish or coatings.
Referring again to
The top and bottom baffles, 64 and 66, are connected to the manifold 36 in a manner such as to seal the top and bottom baffle slots, 60 and 62, thereby preventing leakage of the internal cooling fluid around the top and bottom baffles 64 and 66. Any desired method can be used to connect the baffles, 64 and 66, to the manifold 36 including the non-limiting example of silver brazing.
As shown in
The manifold 36 and the top and bottom baffles, 64 and 66, can be formed of any desired high temperature, corrosion resistant, heat transferring material. Non-limiting examples of manifold and baffle material include copper, stainless steel, nickel, titanium, silver and alloys such as the non-limiting example of nickel-chromium-molybdenum-tungsten alloy. The manifold 36 and the top and bottom baffles, 64 and 66, can have any desired surface, finish or coatings.
Referring now to
While the manifold 36 illustrated in
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The internal fluid passage 37 has a width WFP and a height HFP. In the illustrated embodiment, the width WFP and height HFP of the internal fluid passage 37 are in a range of from about 0.625 inches to about 1.50 inches. Alternatively, the width WFP and height HFP of the internal fluid passage 37 can be less than about 0.625 inches or more than about 1.50 inches.
The width WFP and height HFP of the internal fluid passage 37 result in a passage cross-sectional area. The size of the passage cross-sectional area can be a factor in the transfer of heat from the manifold 36 to the'cooling fluid passing through the manifold. In the illustrated embodiment, the ratio of the passage cross-sectional area to a manifold cross-sectional area is in a range of from about 40% to about 70%. In other embodiments, the ratio of the passage cross-sectional area to the manifold cross-sectional area can be less than about 40% or more than about 70%.
Referring again to
Referring now to
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As discussed above, the cooling fluid enters the manifold 36 from the second conduit 76, travels a serpentine path through the manifold 36 and finally exits the manifold 36 through the first conduit 74. As the cooling fluid travels through the manifold 36, the cooling fluid absorbs heat from the blades 38. The serpentine path of the cooling fluid provides for substantially uniform temperature of the cooling fluid as the cooling fluid flows through the manifold. In the illustrated embodiment, the difference in the temperature of the cooling fluid entering the manifold 36 and exiting the manifold 36 is in a range of from about 3° F. to about 15° F. In other embodiments, the difference in the temperature of the cooling fluid entering the manifold 36 and exiting the manifold 36 can be less than about 3° F. or more than about 15° F.
In the embodiment illustrated in
The manifold 36 having a serpentine flow of the cooling fluid advantageously provides a number of benefits. First, the serpentine flow produces consistent turbulence levels of the cooling fluid throughout the length of the manifold 36. The consistent turbulence level of the cooling fluid provides a higher overall rate of heat extraction from the filament forming area. A higher overall rate of heat extraction allows the glass filament forming apparatus 10 to be operated at higher throughput levels.
Second, a consistent turbulence level of the cooling fluid results in more uniformity of temperature along the length of the manifold 36. Uniformity of temperature along the length of the manifold 36 results in a decrease of mineral scale formation within the manifold 36 and a decrease of localized boiling of cooling fluid.
Third, the uniformity of temperature along the length of the manifold 36 also allows the use of less costly treatment of cooling fluid.
Fourth, the uniformity of temperature along the length of the manifold 36 results in a decrease of low cooling fluid flow areas or recirculation zones.
Referring now to
The bottom baffle 66 has a height HB and a thickness TB. The height HB of the bottom baffle 66 is configured to extend the bottom baffles 66 a desired distance into the passage 37 as discussed above. In the illustrated embodiment, the height HB of the bottom baffle 66 is approximately 0.75 inches. However, the height HB of the bottom baffle 66 can be more or less than approximately 0.75 inches. The thickness TB of the bottom baffle is configured to correspond to the width of the bottom baffle slot 62. In the illustrated embodiment, the thickness TB of the bottom baffle 66 is approximately 0.125 inches. However, the thickness TB of the bottom baffle 66 can be more or less than approximately 0.125 inches.
Referring now to
Similarly, the width WBP of the blocking portion 82 is configured to be substantially the same as the width WFP of the internal fluid passage 37. In the illustrated embodiment, the width WSP is in a range of from about 0.625 inches to about 1.50 inches. Alternatively, the width WBP can be less than about 0.625 inches or more than about 1.50 inches.
As discussed above, the baffle aperture 78 is configured to allow a flow of cooling fluid to pass through the bottom baffle 66. In the illustrated embodiment, the baffle aperture 78 has a circular cross-sectional shape and a diameter D of approximately 0.19 inches. However, the baffle aperture 78 can have other desired cross-sectional shapes, such as for example a rectangular cross-sectional shape and a diameter D or major dimension of more or less than approximately 0.19 inches.
Without being bound by the theory, it is believed the shape of the blocking edge 84 contributes to the level of turbulence imparted by the baffles to the flow of the cooling fluid. In the embodiment shown in
Referring now to
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It is further within the contemplation of the invention that the blocking portion of the baffles can have apertures configured for further turbulence inducing action. The apertures can have any desired cross-sectional shape or form including circles or slots.
Referring now to
It is further within the contemplation of the invention that the blocking portion of the baffles can have apertures configured for further turbulence inducing action. The apertures can have any desired cross-sectional shape or form including circles or slots.
The principle and mode of operation of this invention have been described in certain embodiments. However, it should be noted that this invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.