JPH0569780B2 - - Google Patents

Description

Claim 1: A method for producing a continuous inorganic filament in an operation with interruptions in the formation of the filament, comprising: directing a flow of molten inorganic material from a discharge wall; in a filament forming zone adjacent to the discharge wall;
Mechanically drawing a flow of molten inorganic material into a continuous filament, the filament advancing along a predetermined path, and removing heat from the filament forming zone by a heat transfer element positioned between the flow of molten inorganic material in the filament forming zone. and during the interruption of filament formation, directing a gas flow from a position between the flow of molten inorganic material in the filament forming zone in an amount and velocity sufficient to induce ambient air to flow into the filament forming zone. supply and direct it away from the discharge wall along the advancement path of the filament to mimic the induction of ambient air into said filament forming zone created by the advancing filament during filament formation. between the formation of the filament and the interruption of the formation of the filament.
A method characterized in that the difference in thermal loads of heat transfer elements is substantially reduced.

TECHNICAL FIELD The invention disclosed herein provides a method for producing filaments in which the movement of air into a forming zone occurs prior to filament production to substantially mimic the flow of directed air into the forming zone that normally occurs during filament production. The present invention relates to a glass filament forming apparatus that cools a forming zone and increases the flow of guided air.

BACKGROUND OF THE INVENTION In the manufacture of "woven" or continuous glass filaments, there has been a continuing quest to increase the throughput and operating efficiency of filament forming equipment. To increase production, some feeders have been designed with a large number of orifices, and other devices have attempted to increase production by increasing the operating temperature of the feeder and glass. In either case, the cooling device must be removed as it heats up. One of the most widely used cooling devices consists of a plurality of blade-like members or fins attached to a forming zone and a water-cooled header for removing heat from the glass.

In the "operating" or "running" state, the continuous filament pulls or pumps surrounding air with the filament, directing the air into the interior of the forming zone and leaving the feeder at a high rate that cools the molten glass somewhat. mechanically pulled.

When at least some, usually all, of the filaments are not drawn at production speed and molten glass continues to flow slowly from the feeder, a condition known as "sag" occurs. During drooping, the induced air flow into the fiber forming zone due to the rapid advancement of the filament is clearly absent if the filament is not drawn. Insufficient guided air flow reduces cooling.

In order to quickly start filament attenuation again after frequent interruptions in filament attenuation, the forming device must be properly cooled during drooping. Without proper cooling, it becomes very difficult to quickly start filament production again, reducing the operating efficiency of the equipment. Historically, the cooling requirements of filament forming equipment in the "dragged" condition have been a significant factor in limiting the production output and operating temperature of the forming equipment.

The present invention dramatically enhances heat removal from the forming zone during droop conditions, as well as significantly enhances heat removal from the forming zone during run conditions. Therefore, utilization of the concepts of the present invention provides continuous filament forming equipment with high throughput and operating efficiency.

DISCLOSURE OF THE INVENTION The present invention involves directing streams of molten glass out of an orifice in a discharge wall; drawing these streams along a predetermined path into a continuous filament; and in the direction of advancement of the filament around and into the filament forming zone. of air to 1) mimic the heat removal characteristics of a filament forming operation during operating conditions while the filament forming apparatus is in a droop condition and/or 2) remove heat that occurs during operating conditions. The present invention relates to a method and apparatus for producing a continuous filament characterized in that it increases the .

[Brief explanation of the drawing]

FIG. 1 is a semi-schematic front elevational view of a continuous filament forming apparatus. FIG. 2 is a side cross-sectional view of a portion of the filament forming apparatus shown in FIG. 1. 3 is a side cross-sectional view of another application of the invention similar to the apparatus shown in FIG. 2; FIG. FIG. 4 is a bottom view of the fiber forming apparatus shown in FIG. 3. FIG. 5 is a graph showing the relationship between the thermal load of the fin-type cooling device according to the principles of the present invention and the flow rate of jetted air from the fluid jetting device for the type of fiber forming device shown in FIGS. 3 and 4. be. FIG. 6 is a graph illustrating the increases in temperature and throughput operating range that are possible when using a cooling system according to the principles of the present invention for a fiber forming apparatus of the type shown in FIGS. 3 and 4. FIG. FIG. 7 is a bottom view of a filament forming device similar to FIG. 4 showing a multi-part fluid ejection device.

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, a feeder 10 provides multiple streams of molten inorganic material, such as glass, and combines these streams with the action of a winder 33 as is known in the art. mechanically attenuate into a continuous filament 24. After typically receiving a protective coating or sizing material from coating applicator 30, filament 24 is transferred to focusing device 2.
8 to converge into a continuous strand 25. Next, the strand 25 is passed through the rotating collection 34 of the winder 33.
Wrap it around package 26.

The feeder 10 comprises a container portion 12 adapted to receive heated softened glass and a discharge wall or plate 14 having a plurality of orifices 20 adapted to allow the molten glass to flow out. Typically, feeder 10 is electrically energized to heat condition the glass.

FIG. 2 generally shows a process in which molten glass is advanced from the peripheral filament forming zone laterally along the discharge wall 14 to the inner or central region of the fiber forming zone to cool the molten glass, in accordance with the principles of the present invention. It shows the direction of movement of air flowing downward with the filament.

The feeder 10 has a plurality of projections or tips 17 depending from the discharge wall 14, each projection 17 having at least one associated orifice 20 for dispensing molten glass into the filament 24. have one. As is known in the art, filament 24 is formed from molten glass ejected from protrusion 17 in the form of cone 22 during attenuation. The area around such cones and/or tips is commonly known as the filamentation zone.

Air outside the filament forming zone is memorably directed here to cool the molten glass by any suitable device. Advantageously, such induced flow is generated (ie, formed) by a fluid region flowing downwardly into or immediately adjacent to the filament forming zone along the advancement path of the filament. The jetting device 55 directs the high-energy working fluid in the direction of filament advancement and generally downwardly along the path of filament advancement to direct the air surrounding the feeder or bushing into the feeder according to the principles of the present invention, as shown. guided to move along the discharge wall. As air from around feeder 10 moves laterally inward along discharge wall 14 toward nozzle 55, this directed air flowing through the fiber forming region removes heat from the molten glass, chips, and discharge wall. Remove.

The air in the forming zone surrounding the flow of working fluid is drawn by the working fluid in substantially the same way that air is drawn with the advancing filament during filament production. Thus, as the air in the forming zone is drawn from the forming zone by the fluid flow, a reduced pressure region is created around the working fluid flow. The air around the reduced pressure area flows laterally to the fluid flow and out of its source. The flow of working fluid must have sufficient energy to induce the air to flow in sufficient volume and velocity to adequately cool the glass in the forming zone.

Preferably, an ejection device 55 positioned below the wall 14 directs a small amount of gas, such as air, from the ejection wall 14 at high speed along the path of the advancing filament so as not to impinge directly on the glass cone 22 or the tip 17. and point it away from you. In doing so, the working fluid, or air, is directed to augment the naturally occurring induced air flow during filament manufacture. The working fluid discharged from the ejector 55 must not oppose or overcome the naturally occurring induced air flow, but rather enhances this induced air flow. This is in contrast to cooling systems in which the working fluid is directed directly upwardly to the discharge wall 14 in a direction opposite to the flow of the advancing filament and naturally occurring induced air.

An important aspect of the invention is that the air from around the feeder 10 is drawn, even if the filament is not drawn, as it is in the drooping condition, in order to approximate the induced air flow that occurs during filament production. It is directed to flow laterally through the filament forming zone and then downwardly with the advancing filament.

To aid in cooling the molten glass, the fiber forming apparatus is shown in U.S. Pat.
A plurality of heat transfer elements or fins 43 similar to the fin type cooling device disclosed in No. 2908036 is incorporated. Desirably, the present invention is used with such fins to remove a desired amount of heat from the filament forming zone, whether or not attenuation is occurring. Air from around the feeder is directed to flow generally along the length of the fins 43 as opposed to the lateral flow across the fins 43 to provide a generally uniform and smooth flow of the directed air through the fiber forming zone. It is desirable to accommodate lateral movement.

By being able to generate such an induced air flow, when the feeder is in a hanging state,
This feeder can be operated at high temperatures. This results in
Provides increased glass production for a given design of the feeder. Additionally, the present invention also provides a cooling system through an increased guided air flow through the fiber forming zone to aid and supplement the heat removal capacity of the cooling system components when the feeder is in production conditions. Cooling can be enhanced by increasing the overall heat removal capacity of.

Although the fiber forming apparatus shown in FIG. 2 uses complex protrusions 17 and fin-type heat removal elements 43, it can be used without the aid of other types of cooling equipment or without the use of such protrusions or chips. It should be understood that the invention may be used.

As shown in FIGS. 3 and 4, the feeder 1
0 consists of a container part 12 with a discharge wall 14 having a plurality of projections 17 depending from it, each projection 17 having an orifice for supplying a flow of molten glass. It has 20. The discharge wall 14 has a recess 15 extending along the length of the feeder 10 for mechanically supporting the wall 14 as described below.

The protruding portion 17 has areas 21 separated by a plurality of intervals,
22 and these areas are further subdivided into generally parallel rows with heat transfer elements or fins 43 of the first heat removal device 40 positioned between alternating rows of protrusions 17. have
The parallel rows of protrusions 17 are oriented at right angles to the longitudinal centerline of the discharge wall 14 in which the recesses 15 are positioned.

The first heat removal device 40 includes a pair of rows of heat transfer elements or fins 43 positioned in the filament forming zone and extending along the length of the feeder 10.
Consists of. Each row of heat transfer elements 43 is rigidly joined to a manifold 41 that extends along the length of feeder 10. Typically, a cooling fluid, such as water, is circulated through a manifold to cool the fins 43.
conducts heat from

Heat is removed by convection from the forming zone due to the movement of ambient air generated by the jetting device 55. The ejection device 55 comprises a substantially straight hollow tubular member or nozzle 56 having a plurality of holes 58 along its bottom.
To cool the filament forming apparatus according to the principles of the present invention, a stream of high energy fluid, such as air, is passed along the length of the feeder and then inwardly into the filament forming zone and then forward of the filament. The filament is adapted to be directed along the path of advancement of the filament to direct the filament to flow in the same direction. The ejection device 55 is comprised of a substantially straight tubular member 56 having a plurality of orifices extending along its length so that the working fluid forms a substantially flat flow or zone. A tubular member having an axial slot extending along its length creates a similar ejected air flow pattern.

To support the discharge wall 14, a support portion 52 is provided.
extends along the length of the recess 15. A refractory material 36 is provided between the support portion 52 and the discharge wall portion 14 . Since the support member 52 is cooled by circulating a cooling fluid, such as water, through the passageways 53 of the tubular portion 52, the refractory material 36 is used for thermal as well as electrical insulation.

As shown in FIG.
6 and member 56. For ease and stability of installation, tubular member 56 and support portion 52 are securely joined together by any suitable means, such as welding. In this manner, the perforated portion of tubular member 56 is positioned below discharge wall 14 in a generally plane defined by bottom edge 44 of heat transfer element 43 . Other positioning of the nozzle is within the scope of the invention, as described below.

For droop conditions, the blowing device 55 shapes and adjusts the movement of ambient air into the fiber forming zone to approximately resemble the induced air that otherwise occurs by the advancing filament during filament attenuation. Thus, the feeder, chips, fin shields and other equipment do not overheat as much and the fiber forming equipment is in a "sagging" condition. The transition period between the "sagging" state and the "running" or manufacturing state is significantly reduced. This is because the temperatures of the various components of the fiber forming apparatus are close to their steady state "operating" values even when the apparatus is in droop condition. The operating efficiency of the fiber forming device is thus increased by reducing downtime.

In terms of operating conditions, the blowing device 55 directs a range of air movement into the filament forming zone to increase the cooling effect of the guided air movement due to the action of the advancing filament and thus increase the overall heat removal capacity of the cooling device, thus increasing the overall heat removal capacity of the cooling device. so as to facilitate high production output and efficiency.

The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

EXAMPLES Conventional "chip type" fiber forming equipment similar to that shown in FIGS. 3 and 4 was used to produce continuous glass filaments from conventional glass compositions.
The action of a winder, as known in the industry, reduces the filament to approximately 0.0234 mm (0.00092 inch).
mechanically thinned.

The bushing or feeder used in this example is constructed of a typical platinum/rhodium alloy and the orifice tip is divided into two equal parts by a single tubular member or nozzle 56 extending along the length of the feeder. placed in the area. The discharge wall had the following characteristics.

Number of tips: 4048 Orifice size: Internal diameter 1.676 mm (0.066 inch) Chip length: 3.302 mm (0.130 inch) Discharge wall: 470 mm length x 178 mm width (18.5 inch x 7 inch) Tips per row Number of: 22 The details of the tubular portion 56 of the ejection device 55 are as follows.

Tube size: Outside diameter 6.35 mm (0.25 inches) Inside diameter 4.57 mm (0.18 inches) Hole diameter: 0.305 mm (0.012 inches) Hole spacing: 12 holes per cm (30 holes per inch) Length of perforated section The perforated portion of tube 56 was located approximately 1/2 inch below the bottom of discharge wall 14 and extended slightly beyond the area of the orifice.
Conventional fin type heat transfer elements 43 were used between successive pairs of chip rows. Each fin is solid metal and has a height
19.05mm x 2.5mm thick x 92.1mm long (0.75 inch x
0.100 inch x 3.625 inch).

FIG. 5 shows the change in heat removed by the fin cooling device as the flow rate of air flowing from the blower 55 increases. The feed rate of the feeder remains substantially constant and is shown in running and droop conditions.

As can be seen from line AB in FIG. 5, the heat removed by the fins when the feeder is in the drooping condition is dramatically reduced as the blowout air flow rate increases. Point A represents the amount of heat removed by the fin cooler when there is no blowing air flow, and point B represents the amount of heat removed by the fin cooler when there is no blowing air flow, and point B represents the amount of heat removed by the fin cooler when there is ^no blowing air flow. Represents the amount of heat removed by the FinShield device when ejected. In this case, the heat load acting on the fin-type cooling device is approximately 3147 cm ³ /sec (400 SCFH) (point B), it decreased by about 27%.

Additionally, the amount of heat removed by the fin cooler during operating conditions decreased slightly as the blowout air flow rate increased, as represented by line C--D in FIG. Point C represents the heat removed by the fin cooling device in the absence of blowing air flow, and point D represents the heat removed by the fin cooling device in the absence of blowing air flow, and point D represents the heat removed by the fin cooling device at 3147 cm ³ /s ( 400SCFH)
It represents the heat load acting on the fin type cooling device at the flow rate of ejected air.

The difference between the sag heat load removed by the fin cooler and the operating heat load is reduced by use of the present invention, so that the period of transition between the sag and steady-state operating conditions is less likely to cause fiber formation. When starting or starting again, it is correspondingly substantially shortened. For example, the difference between points B and D is significantly smaller than the difference between points A and C. As the fiber forming apparatus progresses from the droop condition to the desired steady-state operating condition, the filaments produced during the transition period described above are of unacceptable quality. Thus, shortening the transition period is highly desirable for maximum operating efficiency.

In general, it is believed that reducing the thermal load on the fin shield will correspondingly reduce the temperature of the fin and maintain a substantially constant flow rate of cooling fluid through the manifold of the fin device.

FIG. 6 shows that the production yield of a given feeder design can be dramatically increased using the present invention. It is well known in the art that such filament forming feeders are designed to operate within a temperature range around an indicated set point temperature. The feeder demonstrated the ability to operate within a range of temperatures from 14° C. (25°) below set point to approximately 8° C. (15°) above set point when no jetting device was used. These temperatures are shown as points A and B in FIG. 6, respectively. The proven nominal output of standard fiber forming equipment is line A-
approximately 68 Kg/hr (150 lb/hr), as represented by point N on B, and the set point temperature is approximately 1212°C, as represented by the "0" point on the vertical axis of the graph in Figure 6.
(2214〓). The upper limit of production when no ejection device is installed, that is, point B, is approximately 73Kg (162
pound)/hour. Above this temperature, the feeder becomes "unmanageable". That is, the ability to restart the feeder after an interruption is significantly reduced.

In use of the present invention, the feeder is located at line A-- in FIG.
It was possible to operate within a range along C. Thus, the bushing was able to operate within a temperature range of about 14°C (25°) below the set point to about 17°C (30°) above the set point. As you can see from this graph, the feeder is 17°C below the demonstration set point.
(30〓) When operating at high temperature (point C), bush production increased to about 85 Kg (188 lb)/hour. Thus, the production ceiling for bush production operations has increased by approximately 16%.

The air flow rate at which this data was obtained was varied along with point A, which occurred without supplying blowing air from the control device 55. The flow rate of the blowout air may be adjusted to any suitable amount as required by the droop and/or operating conditions. For example, the flow rate of the ejection fluid may be reduced due to operating conditions. Additionally, if desired, the flow of blowing air may be completely stopped, either manually or automatically, during operating conditions. However, preferably fluid flow from the ejection device is reduced but not eliminated.

Thus, through use of the present invention, the transition period between the "droop" and "run" states following a forming interruption is shortened, greatly increasing the throughput capacity of the fiber forming equipment. Any suitable combination of working fluid field volume and velocity from the induced air control device 55 that meets the cooling requirements of the fiber forming device is acceptable. The fluid ejected from ejector 55 must have a sufficiently high energy or moment to create the desired induced air flow. For devices using compressed air as the working fluid, the velocity of the air as it exits the blowout device 55 is desirably at least about 11 m/sec (35 ft/sec);
More preferably, from 11m/sec at an appropriate amount.
In the range of up to 107 m/s (35-350 ft/s). More desirably, the exit velocity of the gas from the ejector 55 is at least 23 m/sec (75 ft/sec), preferably 23 m/sec to 56 m/sec (75 ft/sec).
The compressed air is delivered at a flow rate within the range of about 787 cm ³ /sec to 3147 cm ³ /sec (100-400 cubic feet/hour).

Devices for controlling the flow of fluid from holes 58 include flow control valves and/or flow control valves associated with such fluid supply devices.
or any suitable type, such as a pressure regulator.

For some types of feeder designs, the innermost orifice is close to the injector 55 to reduce or eliminate any trapped air area along the support member 52. is required to be positioned above the position shown in FIG. For example, as shown in FIG. 3A, a guided air control or blowout device 55 is positioned within a channel 72 of a refractory body 71 that is positioned within a recess 15A of the discharge wall 14. In such a case, the perforated portion of the tubular member 56 may extend beyond the innermost tip or orifice above the distal end or bottom 18 of the projection 17 to promote a lateral flow of substantial guided air. position. As shown, the perforated portion of tubular portion 56 lies generally within the plane defined by discharge wall 14 .

Preferably, the outlet hole of the working fluid supply nozzle is
The plane of the bottom edge 44 of the heat transfer element 43 and the bottom wall 1
4 is positioned within a laterally extending zone formed by the planes of 4. However, if you wish,
The outlet of the nozzle may be positioned above or below the zone.

As shown in FIG. 7, the discharge wall 114 of the feeder 110 has a plurality of protrusions or tips 117 having orifices 120 adapted to supply a flow of molten glass. These protrusions 117 are arranged in areas 121, 122 which are further subdivided into several pairs of rows from which the heat transfer elements or fins 130 of the first cooling device 125 extend. Similar to the previously described device, heat transfer element 130 is attached to water cooling manifold 127.

A guided air control or jetting device 140 directs the working fluid region in a plane that substantially bisects the feeder 110 along its length between regions 121, 122. In this embodiment, the ejection device 1
40 is comprised of a pair of independently controlled fluid supply sections adapted to independently create guided air flows for different regions of feeder 110. As shown, the ejection device 140 includes a first supply portion 142
and a second supply portion 152. Of course, the controller 140 may consist of any suitable number of independent feed sections rather than just two, as desired.

The first fluid supply portion 142 is comprised of a tube 143 having a plurality of holes 144 along its bottom, which allow high velocity fluid to flow to direct air to the fiber forming zone in accordance with the principles of the present invention. supply. Conduit 143 communicates with a valve or controller 146, which in turn communicates with a suitable source of pressurized fluid via supply line 147. Similarly, the second portion 152 is comprised of a tube 153 having a row of holes 154 along the bottom. Conduit 153 communicates with a valve or controller 156 which is connected by supply line 147 to a source of pressurized fluid. Thus, the guided air flows in the right and left portions of feeder 110 are substantially independently created and controlled.

Preferably, the working fluid of the ejection device of the invention is air. However, it should be understood that other gases including steam as well as fluids such as water may be used as the working fluid exiting the induced air control device. Additionally, for structures where the ejected fluid contacts the filament row, the working fluid may contain or consist of a liquid sizing agent or binder to coat the glass filaments. .

As is apparent from the foregoing embodiments, the apparatus and method described herein provide a device for increasing the throughput and efficiency of known filament forming equipment by increasing cooling capacity. The high capacity of induced air flow across the filament forming zone is useful during droop conditions to bring the same temperature conditions closer to operating conditions, and also during operating conditions, i.e. standard conditions, where induced air flow increases the natural induced air flow. It is also useful inside. This is achieved by a fluid flow in the direction of movement of the filament with minimal energy consumption as described above.

Obviously, modifications and different constructions other than those disclosed herein may be practiced within the scope of the invention. This disclosure is merely illustrative of the invention, including all modifications.

Industrial Applicability The invention described herein can be easily applied to the glass fiber industry.