HK40000017A - System and method of continuous glass filament manufacture - Google Patents

Description

System and method for manufacturing continuous glass filaments

Cross Reference to Related Applications

This application is a continuation-in-part application of U.S. patent application No.14/181,426 filed on 14/2/2014. This application also claims the rights of U.S. provisional application No.62/282,444, filed on 31/7/2015. The above application is incorporated by reference herein in its entirety.

Technical Field

The present invention relates to the manufacture of continuous glass filament strands, and more particularly, to an improved apparatus and method for manufacturing continuous glass filament strands and glass fiber filter media. It is particularly useful in the manufacture of expanded continuous glass filament glass fiber media (lofted continuous glass fiber media) for filtration or composite manufacture.

Background

The present invention relates to improvements to the Modigliani process as outlined in U.S. patent nos. 2,081,060, 2,546,230, and 2,913,037. Subsequent modifications and variations to the Modigliani process have been made and are known in the art. Little work has been done to improve the efficiency of manufacturing methods and equipment through new control methods or through process changes.

The Modigliani process and its derivatives generally involve a melting furnace that feeds molten glass, which discharges fine glass filaments. The glass fibers are sequentially wound around a rotating drum. During the placement of the fibers on the drum, the resin is applied to the glass surface as it collects on the drum.

Strands of molten glass exit the melting furnace through a perforated metal plate (bushing plate) attached to the underside of the melting furnace. The diameter of the strand is determined by a combination of the diameter of the holes provided in the bushing, the surface speed of the rotating drum below the melting furnace, on which the glass filaments are drawn and gathered, and the chemical composition of the glass.

The drum length is a determining factor in the length of the cured fiberglass media produced from the fiberglass curing apparatus. Consumers of consolidated glass fibers typically require lightweight glass fibers having roll lengths (roll lengths) of up to 1200 feet. These consumers also require heavier rolls as short as 200 feet in length.

The loft height (loft height) of the consolidated glass fibers is an important feature. Consumers typically require a loft (loft) of 1/4 inch to 6 inches. When rolled, the thinner the puff, the easier it is to compress, and the thicker the puff, the harder it is to compress. The reason for this is that the cross-linked resin bond in the cured glass fiber resists bending. This resistance to bending increases with the distance the cross-linking bond must travel when the bulks are compressed in the process. If the bond undergoes too much deformation, it will eventually break, which reduces the ability of the cured glass fiber to recover to its specified loft upon unwinding of the roll.

There is a mutual interaction between the drum circumference and the curing device width which affects the geometry of the filament cross-linking in the final product. The design of the curing apparatus is limited by a number of factors, one of which is the width of the conveyor belt (or chain) that sets the puff above the puff that sets the product. Because the customer product specifications for puffs have narrow tolerances, typically + or-8 or 4-one inches, a conveyor with an upper set puff may have very little variation in its width. When the design width exceeds 132 inches, it becomes mechanically complex and extremely expensive to adequately limit deflection. If the width of the unexpanded fiberglass mat (which is typically equal to the circumference of the drum) is greater than 22 feet, it becomes very difficult to cure the filaments such that the crosslinked filaments are cured at an angle of about 90 degrees. And the curing can make the longitudinal and transverse stiffness of the finished media nearly equal (which is a common customer requirement).

Longitudinal filament bonding will result in defects in stiffness and rigidity in the X or Y (horizontal) axis. It also reduces compressive strength and reduces the ability of the media to capture and retain solid liquid particles (particularly in air filtration applications).

If the circumference of the drum (i.e., the approximate unexpanded mat width) is less than 12 feet or greater than 22 feet, then the filaments will bond longitudinally to each other an excessive distance in either the X or Y axis as they are solidified, which will result in an insufficient stiffness of the final product in one of the two axes. Such conditions also cause an insufficient compressive strength (another typical customer requirement) in the bulk of the final product. In air filtration applications, these conditions will reduce the ability of the media to capture and retain particles. Insufficient compressive strength can further lead to appearance defects, such as bunching (bunching), thereby reducing the appeal of the product to consumers in air and light filtration applications.

Rotating drums having circumferences ranging from 12 to 22 feet and lengths ranging from 12 to 24 feet have varying drum weights and various typical rotational speeds. The combination of the varying rotational speed and the drum length and circumference produces vibrations that tend to cause premature failure of the drum shaft. Failure to properly calculate the proper shaft diameter required to safely operate a drum of various sizes at various surface speeds will result in shaft failure, which can create an unsafe condition.

Several resin binder formulations are known in the art and may be sprayed onto the glass fibers. Typically, the process is designed so that the sheeted (swath) filaments are sprayed with adhesive almost immediately after being placed on the drum. The resin covers the newly applied glass filaments on all sides and bonds the glass filaments to the rest of the filament mat. If the centrifugal force of the rotating drum overcomes the viscosity of the adhesive and moves the adhesive closer to the drum further from the drum to the filaments, proper adhesive coverage of the filaments may not be achieved.

There remains a substantial need for systems, apparatuses, and methods that can improve the efficiency and quality of the manufacture of continuous glass filament media.

Disclosure of Invention

In the present invention, the terms filament, fiber and tow are used interchangeably and in all instances refer to continuous glass filaments as opposed to, for example, glass staple fibers used to make fiberglass insulation.

In the present invention, the glass-melting furnace is configured to traverse over a rotatable hollow drum of a specific range of sizes. The furnace includes a temperature-controlled melting tank (reservoir) that is contiguously connected to a bushing that is perforated with a specified number of a specified range of sizes of counter-bores. The tip plate is adjacently connected to the cooling circuit and further connected to the side shield. The cooling circuit is connected to a water and air supply system that maintains a specific range of temperatures and pressures. A control system with sensors may be used to prevent clogging. The furnace assembly is mounted on rails and traverses over the drum to place a large sheet of continuous glass filaments of a specific range of diameters on the drum. The oven assembly is communicatively connected to a control system and sensors for controlling the speed of the traversing and the rotational speed of the drum. The furnace assembly is further connected to a spray arm with nozzles that spray a resin binder and optionally other aqueous solutions over the continuous glass filaments placed on the drum. The drum rotates about an axis (draft) of a particular range of sizes. The shaft is connected to load cells (load cells) that are communicatively coupled to the control system. When these load cells inform the control system that the total weight of the continuous fiber glass mat saturated with binder and optional other aqueous solutions has reached the target weight, the operator stops the drum, makes a longitudinal cut in the mat, and removes the mat from the drum. The felt is then wound on a rod and subsequently unwound over a let-off table comprising: with chain conveyors heated from above and below and nip rollers (nip rollers) for controlling the tension on the mat as it expands. As the mat exits the let-off table, it proceeds to the roll and water spray assembly and then to the curing apparatus. The curing apparatus includes a plurality of heating zones, a lower conveyor belt (or chain) and an upper set bulk belt (or chain). Once the mat exits the curing apparatus, it proceeds to a slitter-accumulator assembly and then to a winder. Operators remove the fiberglass media slit into rolls from the winder and package the rolls for shipment.

Drawings

The detailed description refers to the accompanying drawings in which:

FIG. 1 shows a traversing glass melting furnace (traversing glass melting furnace) with associated components.

FIG. 2 shows a top view of a glass melting furnace.

Fig. 3 shows a bottom view of the placement of the holes on the bushing plate.

Fig. 4 shows a cross-sectional view of the bottom hole pattern of the bushing.

Fig. 5A shows a cross-sectional view of the orifice tip.

FIG. 5B shows an alternative cross-sectional view of the orifice tip.

Fig. 6 shows a front cross-sectional view of a bushing.

Fig. 7 shows a racetrack pattern for a cooling circuit assembly.

FIG. 8 shows an end cross-sectional view of the drum relative to the melting furnace.

Fig. 9 shows a front view of the drum showing the position of the drum shaft.

Fig. 10 shows a let-off table having upper and lower heat sources.

Fig. 11 shows a water and resin spraying apparatus.

Fig. 12 shows a curing oven assembly.

These drawings are merely for convenience in describing the principles described herein. These drawings do not illustrate every aspect of the subject matter described herein and do not limit the scope of the subject matter described herein. Other objects, features and characteristics will become more apparent in conjunction with the following detailed description.

Detailed Description

The raw material input comprises: recycled glass cullet or in some cases non-recycled glass in various configurations, urea formaldehyde or styrene resin and optionally acrylic copolymer, acrylate polymer, water or other additives or diluents. The mixed resin is called a binder. The recycled glass cullet is sorted according to purity and clarity or turbidity and screened to obtain a maximum size of 1/2 inch to 11/4 inch. Referring to fig. 1, glass chips fall from a glass hopper 1 onto a fixed glass feeder 2 and are then vibrated using a vibrator 3 to remove any particulates or excess glass dust. The vibrated glass fragments are then dropped from the glass feeder 2 to a second chute 4 connected to the top of the melting furnace 10. The glass melting process involves the use of a natural gas and combustion air mixture controlled by a feedback loop based on a flame temperature sensor 6. The air/fuel mixture may be manually controlled as desired during operation and at system start-up and shut-down. Based on the set point controller 8, the molten glass level is controlled to maintain a minimum level within the furnace. Once the minimum value of the set point controller is reached, more glass is automatically fed into the furnace through a glass hopper 1, which glass hopper 1 is connected to a vibrator 3 mounted below a fixed glass feeder 2, all of which are controlled by a feedback loop based on a set point controller 8.

Referring to fig. 2, the melting furnace 10 is mounted on a lateral cart 20 that moves along the rails 16. The rails 16 run the longitudinal length 18 of the drum 12, which is located below the transverse path of the melting furnace 10. The bushing 22 is positioned at an angle of 6 degrees + -1 degree with respect to a line perpendicular to the longitudinal axis of the drum 12, as indicated by arrow 14.

The molten glass exits the melting furnace 10 through an Inconel (Inconel) bushing. Fig. 3 depicts an exemplary configuration 34 of holes in the bushing 22. Preferably, the hole pattern is configured to have at least 7 rows and no more than 10 rows. The number of wells may also vary, with 7 rows of plates preferably having 298 wells and 10 rows of plates preferably having 425 wells. The tip plate 22 provides continuous tow filaments having a diameter of about 20 to 35 microns, depending on the desired end product. The final product specifications determine the configuration of the bushing 22. Design changes are accomplished by changing the bushing design and adjusting the orientation of the bushing relative to the longitudinal axis of the drum below it. For example, the relative pattern of glass fibers fed onto the drum can be adjusted by adjusting the orientation of the bushing. Varying the pore diameter will vary the filament diameter, resulting in the formation of a layer of fiberglass mat for increased strength and/or improved particle capture.

Referring to FIG. 4, the bushing holes 36 each have a hole size ranging from 0.14 inches to 0.19 inches, depending on the product. In some embodiments, the holes may have selectable hole sizes. Various patterns in different embodiments may have the holes have a spacing from 0.313 inches to 0.500 inches (center-to-center). Preferably, the depth of the tip plate is about 3/8-inch.

As shown in fig. 5A, the holes are countersunk to remove excess mass, thereby reducing heat transfer to the hole tip 38, which facilitates faster cooling of the glass filaments exiting the hole tip. In addition, the length of the orifice tips and the arrangement of the orifice tips relative to each other allow for faster cooling of the molten glass. In some embodiments, depending on the product being manufactured, the inlet throats (entry throats) of the holes are countersunk at angles in the range of 70 to 100 degrees, which removes mass and thereby reduces heat transfer from the tip plate area. In some embodiments, the orifice tip length is in the range of.095 inches to as much as.25 inches, which allows for more rapid cooling of the molten glass exiting the molten glass furnace.

Fig. 5B shows an alternative embodiment in which the holes are countersunk on both the inlet side and the outlet side of the nozzle plate. A countersunk outlet throat is provided which reduces the surface area exposed to the glass fibers. As a result, the glass fiber filaments exiting the heated bushing are cooler. This configuration of the holes may be used in applications where the glass filaments exiting the bushing would be overheated if not used. In another embodiment, the holes of the nozzle plate may be countersunk only at the outlet side of the nozzle plate.

To accommodate the various uses of continuous glass filaments, it is desirable to control the final diameter of the glass fiber bundles. The finer diameter glass fiber bundles improve the efficiency of the expanded glass fiber air filtration media in capturing and retaining smaller diameter solid and liquid particles. Larger diameter glass fiber bundles are superior in capturing and retaining larger solid and liquid particles, and also increase the stiffness and compressive strength of the final glass fiber media. For composite applications, a thinner diameter is required to wrap around an acute angle, while a larger glass fiber bundle diameter enhances tensile strength. In other applications, such as light filtration, the glass fiber bundle diameter affects the aesthetics of light diffusion. A bushing of 0.14 inches, in which the hole diameter was the smallest, was used to produce a strand of glass fibers to achieve the ASHRAEMERV 8 gauge. A bushing with a maximum hole diameter of 0.19-inch is used to produce continuous glass filaments that retain the largest and heaviest particles (e.g., coating droplets) and retain sufficient rigidity and compressive strength.

FIG. 6 illustrates a front cross-sectional view of the bushing 22 and the cooling circuit assembly 24. The front cross-sectional view shows the circuit (or coil) 26 of the cooling circuit assembly 24. The cooling circuit assembly 24 cools the tows of continuous filaments after they exit the bushing to a temperature that is cool to the touch and slightly above ambient temperature. The cooling circuit assembly 24 includes 7-15 rows of one-quarter inch copper tubing wrapped around the bottom of the melter 10, opposite the bushing 22. These cooling coils are looped in a racetrack or rectangular pattern (as shown in FIG. 7) within 1 inch of the bushing. A liner cooling circuit assembly (mounting) 24 implements a circuit that is at least 15 inches long and has an inner diameter that is more than 3 inches wide. The angle of the circuit 26 (labeled as angle 28) is 60-90 degrees relative to horizontal. An angle of 60-90 degrees or close to 60-90 degrees may distance the bottom of the coil from the falling glass filaments, which will prevent the filaments from contacting the coil and provide improved heat loss around the bottom of the bushing 22.

The top 7-15 layers of the coil 26 are made of 1/4-inch copper cold tubes 30 carrying cooling water. The cooling water is supplied by a chiller (chiller) or from a near constant temperature water well. A pressure sensor monitored and controlled by the controller 46 detects whether the cooling water circuit is clogged. The temperature sensor provides feedback to the chiller through thermal software (thermal software) and sensor control of the controller 46 to control the temperature of the cooling circuit assembly 24.

The bottom coil is a 3/8-inch copper tube 32 perforated with side air holes (side air holes) pointing up to 1/32 inch in diameter of the bushing 22. The cooling circuit 32 comprises a single copper air coil of 3/8-inch diameter and allows air to be exhausted to rapidly cool the glass filaments exiting the bushing and impede the flow of glass through the bushing as needed.

The shield 40 is preferably comprised of a metal plate and is placed around the area under the bushing to prevent ambient air flow from causing the filaments to collide as they exit the bushing holes. Preferably, the shields are placed on three sides under the bushing, leaving one side open to allow operator access. Preferably, the shield is 6-24 inches long. In some embodiments, shorter or longer shields may be used, and the shields may be placed around the entire area under the bushing, or in other configurations suitable for preventing the filaments from being broken by the air stream after they exit the bushing.

Fig. 8 depicts an end view of the drum 12 and the controller 46, the controller 46 operatively controlling the spray arms 42 and 44. The controller 46 also controls the manufacture of the filaments 48 that exit the glass melting furnace 10 and are disposed on the rotating drum 12. The controller 46 includes computer hardware and software for monitoring, measuring and controlling the manufacture of the glass fiber filaments, for example. As shown in fig. 8, the spray arms 42 and 44 are connected to the melting furnace 10. In some embodiments, the spray arm may be separate from the furnace and driven to traverse the drum independently of the furnace.

The rotating drum 12 is coated with plastic sheet material to enable the fiberglass mat to be removed from the drum. After the plastic sheet is wrapped around the drum, release oil is thinly applied to the surface of the sheet. As the filament bundles fall from the bushing, the operator assists in the process of attaching the falling filament bundles of molten glass to the drum of coated plastic sheet. Alternatively, the operator may apply the filaments that have been detached from the drum again. The drum 12 has a circumferentially increasing surface and a longitudinally extending length with an axis of extension 50 (as shown in fig. 9). This allows the controller 46 to have substantial and sustainable control over the rotation of the drum 12, which enables the controller 46 to control the speed of the forming layer (layering) of glass fibers on the drum.

It is desirable to wind the fiberglass media onto a drum of a particular length to produce the desired roll length. Using a specific drum length, this will avoid breaking the cross-linked resin bonds (cross-linked resin bonds). Drums of at least 12 feet in length are used to produce continuous glass filament media in shorter roll lengths for heavier weight and higher loft fiberglass products. Drums up to 24 feet in length are used to produce longer rolls of lighter weight, lower loft fiberglass media.

A drum circumference of less than 12 feet produces a fiberglass mat that exhibits nearly parallel resin bond filament crosslinking as the fiberglass mat is expanded. Such acute angles minimize the lateral stiffness of the media, resulting in higher failure conditions. The angle of the cross-linked filaments approaching 90 degrees provides stiffness in both the X and Y axes, provides higher compressive strength, increases filtration efficiency in both air and light filtration applications, and improves the aesthetic appearance. Most preferably, the acute angle formed by the intersection of the solidified filaments should not be less than 60 degrees and should be close to 90 degrees for the most part.

Drum circumferences greater than 22 feet do not allow sufficient expansion of the fiberglass media or mat. This results in the filaments being longitudinally bonded to each other for an excessive distance. Longitudinal bonding of filaments results in defects in transverse stiffness and rigidity, reduces compressive strength, and reduces the ability of the media (particularly in air filtration applications) to capture and retain solid and liquid particles. It further introduces appearance defects such as bunching of filaments, thereby reducing the appeal of the product to the consumer in air and light filtration applications.

Rotating drums having a circumference in the range of 12-22 feet and a length in the range of 12-24 feet have different drum weights and operate at various rotational speeds. The particular combination of drum length, drum circumference and rotational speed can produce vibrations that tend to cause premature failure of the drum shaft. To avoid shaft vibration, the shaft diameter is calculated from the drum weight and the rotating surface speed, with an optimal steel shaft diameter of a minimum of 2.5 inches and no greater than 4.5 inches.

The furnace traverses repeatedly (as shown in FIG. 2) along a specific longitudinally continuous path of transverse rails 16 relative to the length 18 of the drum. This covers the drum 12 with a layer of glass fibers. In some embodiments, the resin mixture is sprayed from a resin arm (resin arm)42 connected to the cross-car as the glass is applied to the drum 12. Water is sprayed from a water spray arm 44 connected to the lateral cart. The resin and water are sprayed onto the glass fibers on the drum 12 by nozzles on a resin spray arm 42 and a water spray arm 44, which are located and aligned in front of the drum 12, slightly below the topmost section of the drum 12. The spray nozzle is linked to the movement of the traversing of the oven and traverses in front of the drum 12 in synchronism with the traversing of the oven over the drum 12. The physical elements of the process are controlled by a computer and software program through a controller 46, which controller 46 controls the number and speed of oven movements or oven traverses, the rotational speed of the drum 12, and the application of the resin spray mixture and the water spray mixture. The computer controls these parameters through a software program and controls these variables and operating parameters through the controller 46, which causes the mat to have a progressive density as the mat expands. The traverse melting furnace 10 moves along a traverse rail 16 as the filaments are wound around the rotary drum 12. The filaments are sprayed with an aqueous solution from a water spray arm 44 that moves along the drum 12 as the oven moves along the longitudinal length of the drum 12. The filaments are also sprayed with a binder (or binder species consisting essentially of resin, chemical additives and diluents) from a resin spray arm 42 that moves along the drum 12 as the oven moves along the longitudinal length of the drum 12. The temperature of the adhesive in the tank is controlled by the controller 46 to 72 degrees fahrenheit ± 7 degrees. The temperature controlled binder or combination binder species may be sprayed onto the drum 12 simultaneously with water or aqueous solution from the resin spray arm 42 and water spray arm 44.

The urea-formaldehyde resin for filtration applications is mixed with specific additives and diluents, most preferably under shear mixer conditions. The percentage of diluent is controlled to be in the range of 5% to 10% by weight of the binder. The adhesive was kept at room temperature by cooling and heating the coil in the batching tank and stirred in the batching tank. And monitoring the pH and controlling the pH within the range of 7.0-7.8. The percent binder solids were sampled, tested and controlled to range from 60% to 68% solids. In addition, the adhesive temperature is controlled by a reservoir as a reservoir for the temperature-controlled adhesive, which is sprayed by a resin spray arm 42 (shown in fig. 8).

In some cases, a styrene resin for compounding use is mixed with other diluents, optimally with a shear mixer for better mixing, and temperature control is performed by heating and cooling coils in a reservoir and/or a dispensing tank. The percentage of diluent is controlled to be in the range of 1% to 5% by weight of the binder. The pH is monitored and controlled to be in the range of 7.0-7.8 and the tank is continuously stirred to ensure complete mixing of the styrene binder in the reservoir and/or batching tank at a uniform temperature. The percent binder solids were sampled, tested and controlled to range from 60% to 68% solids.

The water is softened and, in some cases, mixed with the resin to form an aqueous solution. As shown in fig. 8, when water is applied to the filaments by the water spray arm 44, the water can be sprayed onto the resin. This controls the moisture level of the resulting prepared fiberglass mat. The nozzles can apply water and binder to the fiberglass mat as the filaments collect on the drum to control the moisture to a target moisture level ± 5.0%. Additionally, referring to fig. 11, water or an aqueous solution may be applied as a spray, as a mist or fine mist, or by roll coating on either or both surfaces of the expanded fiberglass mat before the fiberglass mat enters the next stage of the process. Applying water through a water mist nozzle onto a flat felt surface will apply water more permanently, resulting in a higher quality skin (skin).

Referring to fig. 8, uniformity of coverage of the resin adhesive is achieved by atomizing the adhesive formulation with compressed air at the resin spray arm 42 and the nozzle of the resin spray assembly. Because the adhesive formulation may contain water, it evaporates as it atomizes. To control the viscosity of the adhesive applied to the continuous glass filaments on the drum, computer hardware and software are preferably used to control the pressure of the compressed air to atomize the adhesive as the outside relative humidity changes. A controller 46 (which controls the sensors used to monitor and perform the test) provides information from the sensors to computer hardware and software.

Due to the centrifugal force of the rotating drum, the adhesive is not sufficiently viscous to allow the adhesive to migrate from filaments near the drum surface to filaments remote from the drum surface. When the fiberglass mat is cured, this migration results in insufficient crosslinking of the fibers on the side of the mat closest to the drum and an excessive amount of binder on the side furthest from the drum. This results in one side of the final fiberglass media lacking in outer layers, rigidity and stiffness, and the other side having an excess of outer layers, with excess rigidity and stiffness. In addition, the side with excess binder will tend to have cured resin particles detached. Any of these conditions will render the final fiberglass media less than ideal or even unusable by the customer.

In addition, excessive binder viscosity results in an uneven binder spray and causes the atomized binder particles to adhere to each other and not flow through the glass filaments with uniform coverage. This results in binder crosslinking of the filaments, which is neither uniform nor sufficiently rigid to have an effective surface skin or compressive strength. At least, in extreme cases of ambient relative humidity, controlling the adhesive viscosity at very low relative humidity requires air pressures at the resin spray nozzle as low as 6 psi. Furthermore, for high relative humidity, air pressure at the resin spray nozzle is required to be as high as 32 psi.

To achieve proper coverage of the adhesive, the width of the adhesive spray pattern is monitored and controlled by the operator. In some embodiments, the adhesive spray pattern width is monitored and controlled by the controller 46 through the use of sensors. Because the glass-melting furnace 10 is continuously traversed back and forth over the rotating drum 12, and because the traverse speed can vary from product to product, the width of the conical spray pattern must be controlled by an operator or controller 46 to ensure proper coating and bonding of a sheet of fiber. Preferably, the spray width ranges from 2 inches to 6 inches.

The fiberglass mat is completed when the total weight of the glass fibers, resin mixture and water is measured to reach the weight specified in the formulation for each particular product. In some cases, control of a particular weight of a product may be achieved by a load cell or by calculating the time required for a particular weight of a product to be achieved. The formula for load cell weight control is achieved by taking the weight of the mat on the drum and subtracting the drum weight. When the felt reaches a certain weight of the product, the winding of the drum is complete and the operator operates the brake mechanism on the drum drive. The drum has a V-shaped groove running longitudinally parallel to the axis of rotation of the drum from end to end across the width of the drum and thereby across the width of the continuous tow filament mat placed on the drum. The operator uses the slot to cut the felt from the drum. At this point, the felt was immediately removed from the drum, placed on a flat surface, and covered with a plastic sheet. From there, the felt is wound on steel strips in a direction parallel to the longitudinal axis of the drum. The weight of the mat was confirmed and recorded by weighing the mat after the roll and calculating the net roll weight.

Referring to FIG. 10, the rolled mat is conveyed to a let-off station that includes a jogger conveyor 52 supported by a flat surface 54, the flat surface 54 being slightly larger than the unrolled mat. The mat is spread (in the direction of arrow 58) on a moving conveyor and the top layer of plastic is removed. The spreading process requires that the felt be spread without wrinkles or folds, straight and with edges equidistant from both sides of the conveyor belt. Otherwise, the spread felt cannot expand properly. The resin coating the glass strands is heated from above and below. If ambient temperature is required, heat is used to soften the resin. The side cross-sectional view of the let-off table shows the gas burner 60 below the fiberglass mat and the radiant heater 56 above the fiberglass mat, with arrow 74 indicating the direction of travel of the fiberglass mat. As the leading edge of the spread mat emerges beyond the exit edge 62 of the conveyor, a bottom layer of plastic falls off the mat and the leading edge of the mat is directed in the direction indicated by arrow 64.

Referring to FIG. 11, the fiberglass mat is directed through the rollers 66 in the direction of arrow 70. The fiberglass mat travels through a water sprayer 68, which water sprayer 68 applies water or other aqueous solution to the fiberglass mat. By using water jets to make the arrangement of the filaments more uniform and form a more rigid outer layer on the top or bottom surface or both surfaces. The mat is then transferred to a bottom conveyor chain using guide ropes attached to the leading edge of the mat. As each mat exits the let-off table, it is attached to the end of the mat in front of it with a rope so that the continuous mat is continuously drawn in the direction of travel. The felt is attached with a string because the string does not damage the slitting knife used later in the process. The fiber glass mat is then fed into a curing oven having a forced air heating system with a multi-zone temperature configuration.

Fig. 12 is a side elevation cutaway view of a curing oven (curing oven)80 and conveyor assembly with the oven's controls and temperature zone 76. The mat is fed into the curing oven in direction 78 by a conveyor system having an upper chain conveyor 74 and a lower chain conveyor 72. The upper conveyor 74 moves at a different speed relative to the lower chain conveyor 72 to keep the mat from bunching and stretching (stretching) of the mat. The process parameters were controlled by a controller with a computer, software, temperature sensors, and separate heating zones above and below the conveyor.

The quality of the final product is maintained through an extension of the in-line and post-cure quality control process steps. Such steps include: the loft and roll width were measured by using a fixture that cut out a single square foot of sample. Another fixture was used to measure the compressive strength of a square foot sample. Each square foot of sample was weighed. In addition, the bottom outer layer and (optionally included) the top outer layer of the sample were removed and the weight percentage of the outer layer was determined using a scale pan (scale).

The detailed description is not intended to be a limiting or exhaustive list of the subject matter described herein. It will be apparent to those skilled in the art that numerous changes in the details described above may be made without departing from the spirit of the subject matter described herein.

Claims (19)

1. An apparatus for making continuous glass filaments, comprising:

a reservoir comprising a binder and configured to control a temperature of the binder;

a drum;

a traverse melting furnace configured to move in a first direction parallel to a rotation axis of the rotary drum;

a bushing;

an adhesive sprayer connected to the traversing melting furnace; and

one or more shields located at least partially under the bushing.

2. The apparatus of claim 1, wherein the bushing is oriented at an angle of 5-7 degrees with respect to the axis of rotation of the drum.

3. The apparatus of claim 1, wherein the first and second electrodes are disposed on opposite sides of the housing,

wherein the length of the rotary drum is 12-24 feet; and is

Wherein the circumference of the rotary drum is 12-22 feet.

4. The apparatus of claim 3 wherein said drum comprises a shaft having a diameter of 2.5 inches to 4.5 inches.

5. The apparatus of claim 1 wherein the one or more shields surround three sides below the bushing.

6. The apparatus of claim 5 wherein the one or more shrouds extend between 6 inches and 24 inches below the bushing.

7. The apparatus of claim 1, wherein the bushing comprises at least one hole having a countersunk opening.

8. The device of claim 7, wherein the at least one orifice has an inlet throat angle of 70-100 degrees.

9. The device of claim 7, wherein the at least one aperture has a tip length of 0.095 inches to 0.25 inches.

10. The device of claim 1, further comprising an aqueous solution sprayer connected to the traversing melting furnace.

11. The device of claim 1, further comprising an adhesive sprayer connected to the traversing melting furnace.

12. The apparatus of claim 11, wherein the binder sprayer is configured to spray binder onto a piece of fiberglass filaments on the drum.

13. The device of claim 12, wherein the adhesive comprises at least one of the group consisting of urea formaldehyde, styrene, acrylic acid copolymer, and acrylate polymer.

14. The apparatus of claim 1, further comprising a cooling circuit assembly.

15. The apparatus of claim 14, wherein the cooling circuit assembly comprises:

a plurality of tubes containing a frozen liquid; and

an air tube comprising a plurality of openings.

16. The apparatus of claim 15, wherein,

the plurality of tubes comprises copper tubes; and

at least one of the plurality of tubes is located within one inch of the bushing.

17. The apparatus of claim 1, wherein the bushing comprises 298-425 holes.

18. The apparatus of claim 17, wherein each of the holes has a diameter of 0.14-0.19 inches.

19. The device of claim 17, wherein the apertures are configured in 7-10 rows.