Abstract:
A fiber-forming bushing comprises a tip plate and a lateral support. The tip plate comprises at least two tip sections and the section spacing between the tip sections. The lateral support extends laterally along the section spacing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 10/066,892, filed Feb. 4, 2002, entitled SUPPORT FOR FIBER BUSHING AND BUSHING WITH SAME. 
     
    
     TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION  
       [0002]     This invention relates in general to an apparatus for producing continuous materials, and in particular, to a bushing for producing glass fibers. Most particularly, the invention relates to a lateral support for a fiber bushing tip plate and a fiber bushing with the same.  
       BACKGROUND OF THE INVENTION  
       [0003]     Apparatus for producing continuous materials are well known. A conventional apparatus comprises a melter, into which a batch of material is fed, or a remelt apparatus or foremelter, into which marbles or cullet is fed. The melter melts the material to form molten glass. In a direct melt operation, the molten glass exits from the melter through a throat into a main channel. The main channel feeds a plurality of cross channels. Each cross channel, in turn, feeds molten glass to a plurality of forehearths. Each forehearth feeds molten glass downward through a plurality of bushing blocks. Each bushing block feeds molten glass into a bushing supported by a frame, which is mounted beneath the bushing block. In a remelt operation, the molten glass is fed directly into each bushing. The molten glass exits from each bushing in the form of glass fibers. A typical bushing produces hundreds to thousands of glass fibers.  
         [0004]     As shown in  FIG. 1A , the glass fibers  10  are produced by passing the molten glass  12  through a tip plate  14 . The tip plate  14  has a plurality of tips  16 . Each tip  16  has an orifice  18  through which molten glass  12  passes. Glass exiting the tip  16  is in the form of a fiber  10 . The fibers  10  are cooled by cooling fins  20  supported beneath the tip plate  14  and attenuated to a desired filament diameter with a rotating cylindrical winder or chopper.  
         [0005]     As shown in  FIG. 1B , heating a tip plate  14  decreases the structural properties of the tip plate material  14 . Stresses resulting from the hydrostatic glass pressure, gravitational force, and forming tension result in high temperature creep of the alloy from which the tip plate is formed. This alloy creep causes deformation of the tip plate  14 , causing it to sag downward. As the tip plate  14  sags, tips  16  assume different orientations. Consequently, some of the tips  16  are situated closer the cooling fins  20  than others. The cooling fins  20  must be lowered to the bottom of the lowest tips  16 . Consequently, the cooling fins  20  are not equidistant from all the tips  16 . Hence, some of the tips  16  are too close to the cooling fins  20  and therefore too cold and some of the tips  16  are too far from the cooling fins  20  and therefore too hot. If a tip  16  is too cold, the fiber  10  produced by the tip will decrease in diameter. This along a subsequent increase in forming tension may cause a breakout. The tips that are too hot have an increase in glass flow and a reduction in viscosity, which leads to flow instability that can also cause a breakout. A breakout is an interruption or separation of the fiber  10  formed from the tip  16 . After the fiber breaks, a globule or bead forms on the tip  16 .  
         [0006]     When producing high temperature fiber products, such as the Advantex glass fiber product produced by Owens Corning, of Toledo, Ohio, U.S.A., the bushing must be heated to greater elevations, which further assaults the integrity of the tip plate  14 , further reducing the life expectancy of the bushing.  
         [0007]     At the end of the life of the bushing, the bushing is chopped up, refined and used to construct a new bushing. This process is labor intensive and results in some loss of precious resources.  
         [0008]     What is needed is a support for a fiber bushing and a bushing construction that further resists tip plate deformation.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention is directed toward a support for a fiber bushing. More particularly, the invention is directed toward a fiber-forming bushing comprising a tip plate and a lateral support. The tip plate comprises at least two tip sections and a section spacing between the tip sections. The lateral support extends laterally along the section spacing.  
         [0010]     According to the invention, there is also provided a fiber bushing comprising a bushing body. A throat is provided at an upper end of the bushing. An elongate tip plate is provided at a lower end of the bushing. The tip plate comprises at least two tip sections and a section spacing between the tip sections. A support extends longitudinally along the tip plate. A lateral support extends laterally along the section spacing.  
         [0011]     According to the invention, there is further provided a fiber bushing comprising a bushing body. A throat is provided at an upper end of the bushing. An elongate tip plate is provided at a lower end of the bushing. The tip plate comprises at least two tip sections and a section spacing between the tip sections. A support comprises an elongate center support extending between a pair of laterally extending end supports. The center support extends longitudinally along the tip plate. The end supports extend laterally along opposing ends of the tip plate. A lateral support extends laterally along the section spacings.  
         [0012]     Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1A  is an enlarged partial side elevational view of a prior art fiber bushing with a non-deformed tip plate and cooling fins below the tip plate.  
         [0014]      FIG. 1B  is an enlarged partial side elevational view of the prior art fiber bushing with a deformed tip plate and cooling fins below the tip plate.  
         [0015]      FIG. 2  is a top perspective view of a bushing according to a preferred embodiment of the invention.  
         [0016]      FIG. 3  is an environmental bottom perspective view of a bushing with lateral supports extending along the section spacing of the tip plates according to a preferred embodiment of the invention.  
         [0017]      FIG. 4  is an enlarged bottom plan view of the bushing shown in  FIG. 3 .  
         [0018]      FIG. 5  is an enlarged sectional view of the bushing taken along line  5 - 5  in  FIG. 4 .  
         [0019]      FIG. 6  is an enlarged sectional view of the lateral support shown in  FIG. 5 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     Referring now to the drawings, there is illustrated in  FIG. 2 a  bushing  30  comprising a bushing body  32  having opposing ends  34 ,  36 . The bushing body  32  is constructed of a pair of longitudinally spaced end plates  38 ,  40  and a pair of laterally spaced side walls  42 ,  44 , triangulated to form a substantially rectangular structure. Each side wall  42 ,  44  includes a upper side wall  46  and a lower side wall, or tip side plate  48 . An ear  50  extends laterally from each end plate  38 ,  40 . A side rail support bar  52  extends longitudinally along each tip side plate  48 .  
         [0021]     A throat  54  is provided at an upper end  56  of the bushing  30 . A flange  58  is provided at an upper end of the throat  54 . As shown in  FIGS. 3-5 , an elongate tip plate  60  is provided at a lower end  62  of the bushing  30 . In a preferred embodiment of the invention, a pair of laterally spaced tip plates  60  is provided. An elongate (inverted) center-V  64  extends between the laterally spaced tip plates  60 . As shown in  FIG. 5 , a screen  66  is provided within an upper region of the bushing  30 . A plurality of elongate gussets  68  is provided within a lower region of the bushing  30 . More particularly, the gussets  68  are spaced discrete longitudinal distances apart and tacked to an upper surface of the tip plate  60 .  
         [0022]     As shown in  FIGS. 3-5 , the bushing  30  is suspended within a frame  70 . Refractory material  72  is poured around the bushing  30 , between the frame  70  and the bushing  30 . Refractory material  72  is also poured into the center-V  64 . The refractory material  72  is permitted to harden.  
         [0023]     An elongate center support  74  may extend longitudinally along the center-V  64 , adjacent the refractory material  72  therein. In a preferred embodiment of the invention, the center support  74  extends between, and is connected to, a pair of laterally extending end supports  76 ,  78  to form a generally H-shaped support, generally indicated at  80 . Mounting pads  82  extending from the end supports  76 ,  78  are secured to the frame  70  to hold the support  80  in a fixed position relative to the bushing  30 . The center support  74  and the end supports  76 ,  78  are hollow and in fluid communication with each other. A nipple  84  extending from each end of each end support  76 ,  78  is in fluid communication with the end supports  76 ,  78 . The term “nipple” used throughout this description is intended to be broadly interpreted to encompass any junction for the connection of fluid conduit.  
         [0024]     A lateral support  86  extends laterally along the section spacing  88 , containing no tips, between the tip sections  90  of the tip plates  60 . A plurality of tips  16  (best shown in  FIG. 1 ) occupies each tip section  90 . No tips  16  occupy the section spacing  88  (see  FIGS. 1 and 4 ). Each tip  16  has an orifice  18  (shown in  FIG. 1 ) through which molten glass  12  passes. Glass fibers  10  are formed from molten glass  12  exiting the tips  16 , passing the fibers  10  between cooling fins  20  (shown in  FIGS. 1 and 3 ) beneath the tip plates  60 .  
         [0025]     The term “tip plates” is defined as a plurality of plates which include a plurality of tips  61  formed with an orifice. The term “section spacing” is defined as the spaces, containing no orifices or tips  61 , surrounding the tip section  90 . In  FIG. 4 , section spacing  88  forms a “frame” around tip section  90 . The tip plates  60  each contain a tip section  90  surrounded by section spacing  88  (see  FIG. 4 ).  
         [0026]     As shown in  FIGS. 5 and 6 , the lateral support  86  is an elongate support having opposing ends  92 ,  94 . Mounting pads  96  extending from the ends  92 ,  94  are secured to the frame  70  (as clearly shown in  FIG. 5 ) to hold the lateral support  86  in a fixed position relative to the bushing  30 . A nipple  98  extends from each end  92 ,  94  of the lateral support  86 . As shown in  FIG. 6 , the lateral support  86  is hollow and in fluid communication with the nipples  98 .  
         [0027]     The center and lateral supports  74  and  86  traverse one another. In a preferred embodiment of the invention, the lateral support  86  is comprised of two hollow members  100 ,  102  having a fluid conduit  104  extending therebetween. The conduit  104  is preferably a generally U-shaped conduit having two legs  106 ,  108 , each of which is connected to a corresponding hollow member  100 ,  102  so that the conduit  104  is in fluid communication with the hollow members  100 ,  102 . The U-shaped conduit  104  extends downward and crosses over the center support  74 .  
         [0028]     The supports  80 ,  86  are preferably thermally and electrically insulated from the tip plate  60 , as shown in  FIG. 5 . In a preferred embodiment of the invention, the top of each support  80 ,  86  is sprayed with a ceramic material  110 . In the most preferred embodiment of the invention, an eighth inch layer of zirconium oxide is applied to the bottom of the lateral support  86 .  
         [0029]     In operation, a terminal clamp, generally indicated at  112 , is connected to each ear  50 . Each terminal clamp  112  is connected to a flexible bus bar (not shown). Each flexible bus bar is connected to a transformer pad via a tubular bus bar (not shown). The clamps  112 , the tubular bus bars and the pads are hollow and water cooled. Supply and discharge lines (not shown) are connected to the nipples  84 ,  98 . In a preferred embodiment of the invention, high-pressure hoses are connected to the nipples  84 ,  98  with compression fittings. A cooling fluid is passed through each of the clamps  112 , bus bars, and supports  80 ,  86 .  
         [0030]     The bushing  30  is resistance heated by passing a high current (e.g., 2,000 to 10,000 amps) through the ears  50  and bushing body  32 . The bushing  30  is gradually heated until it reaches an operating temperature that can range from 2,100 to 2,800 degrees Fahrenheit, depending on the glass composition that is being formed. The heated bushing  30  is intended to condition the state of the molten glass, rather than melt the glass. The resistance heat is retained in the bushing body  32  by the hardened refractory material  72  formed about the bushing body  32 .  
         [0031]     Molten glass  12  (shown in  FIG. 1 ) is introduced into the bushing  30  through its throat  54 . The flange  58  forms a seal between the bushing block (not shown) and the throat  54 . A coolant conduit (not shown) is provided about the periphery of the flange  58  to cool any molten glass  12  that may exit between the bushing block and the flange  58 . This cooled glass blocks other molten glass  12  from exiting between the bushing block and the flange  58 .  
         [0032]     The molten glass  12  passes through the screen  66  as it passes through the bushing body  32 . The screen  66  functions to capture solid matter suspended in the molten glass and assist in distributing the resistance heat uniformly throughout the molten glass  12 .  
         [0033]     As stated above, the tip plate  60  is provided with a plurality of tip sections  90 , each separated by dead space, or section spacing  88 . A plurality of tips  16  (best shown in  FIG. 1 ) occupies each tip section  90 . No tips  16  occupy the section spacing  88 . Each tip  16  has an orifice  18  (shown in  FIG. 1 ) through which molten glass  12  passes. Glass fibers  10  are formed from molten glass  12  exiting the tips  16 , passing the fibers  10  between cooling fins  20  (shown in  FIGS. 1 and 3 ) beneath the tip plates  60 . The cooling fins  20  cool the tips  16  and consequently the glass fibers  10  exiting the tips  16 .  
         [0034]     In a preferred embodiment of the invention, the tip plate  60  has an easily divisible number of tips  16 . For example, the tip plate  60  may have 4,000 tips  16 , and may be separated into four sections  90 , each having 1,000 tips  16 . Consequently, the bushing  30  may produce 4,000 fibers  10 . The fibers  10  may be gathered into one or more strands, which are used to produce packages. The fibers  10  can be gathered in discrete amounts (e.g., 1,000, 2,000, 3,000 or 4,000) to produce various strands for various packages.  
         [0035]     The center-V  64  provides external resistance to deformation of the tip plates  60 . Filling the center-V  64  with refractory material insulates the center support from the tip plates  60 . The gussets  68  support the tip plates  60  internally from above, also resisting deformation of the tip plates  60 . To further resist deformation, the supports  80 ,  86  provide subjacent external support for the tip plates  60 . The center support  74  provides longitudinal support for the tip plate  60  along the center-V  64 . The end supports  76 ,  78  support the center support. The lateral support  86  provides lateral support for the tip plate  60  along the section spacing  88  between the tip sections  90 . Resisting tip plate deformation prolongs the life of the bushing  30 .  
         [0036]     In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention can be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.