GB2048236A - Integrating Filaments into a Strand - Google Patents

Abstract

A method and apparatus for integrating a newly formed continuous filament into a continuous strand by the operations of drawing a plurality of continuous filaments 3 from a bushing 1 into a filament fan 4 by gathering the filaments 3 into a continuous strand 6 at a deflection roller 5. Should one of the filaments 3 break, a new continuous filament 8 is formed which is deflected by a chute 9 toward the roller 5. A water stream 13 separates the filament 8 from its associated initially formed needle and drop section and concomitantly predraws the filament 8 to an initial diameter conducive to integration. The filament 8 is further predrawn and conducted by the stream 13 between guide bars 15 to the roller 5 where the strand 6 and the filament 8 are jointly deflected along a common path X defined at least by the roller 5 and another roller 7 such that the newly formed filament 8 is drawn to its final diameter and integrated with strand 6. <IMAGE>

Description

SPECIFICATION Method and Apparatus for the Integration of Newly Formed Filaments into a Continuous .Strand Technical Field This invention relates to a method and apparatus for producing glass and similar plastic filaments and more particularly to a method and apparatus for integrating newly formed filaments into a moving continuous strand.

Background of Prior Art The operation of drawing continuous filaments into a filament fan, gathering them into a strand, and winding them on bobbins is well known.

When glass is used as the raw material the product thus formed, hereinafter referred to as "continuous strands", may be used for widely varying purposes. In the form of fabrics, rovings, or in the form of cut short pieces or staples, the products serve advantageously as an insulating medium or as reinforcing means. Furthermore the continuous strands may be used in the fabrication of a wet fiber mat typified by U.S. Patent 3,766,003. In the plastics industry substantial quantities of continuous strands are used as reinforcement for glass fiber-reinforced plastics.

In order to ensure uniformity of the continuous strand, breakage of the individual continuous filaments must be avoided during the winding operation when the filaments are being drawn onto the bobbin. This is difficult to accomplish since even slight variations in homogeneity, fluctuations of temperature during the filament formation or spinning process and the like, may be sufficient to cause the continuous glass filaments, which are relatively delicate, to break.

In the production of continuous strands from continuous glass filaments, a particular difficulty resides in producing new filament sufficiently quickly to replace the broken filaments and in introducing or integrating these newly formed filaments into the continuous strand of filaments being wound on the bobbin. When a continuous filament breaks or is otherwise terminated during the collection of the continuous filaments from the filament fan into the continuous strand, a new filament is formed at the filament former or bush by a newly formed drop or bead of glass which drops vertically under the influences of gravity from an orifice at the bush pulling the new filament along.The gradual transition from the drop to the new filament has been cailed a "cone", "needle" or "icicle" and together with the drop constitute the initially formed section of the new filament. The newly formed filament can be integrated into the moving continuous strand only after it has been separated from its associated drop and needle. It is also known that integration also requires that the newly formed filament must be predrawn such that its diameter is substantially as fine as the diameter of the other filaments making up the continuous strand.

Known devices for integrating such newly formed filaments are disclosed in German Patent No. 1,062,399 and German Patent No.

1,246,937 and incorporate a V-shaped trough which extends longitudinally underneath the point where the filaments are formed. The V-shaped trough deflects a newly formed filament from the direction of its vertical fall and allows the newly formed filament to be conducted by means of mechanical devices to a rapidly rotating drawing and joining drum which aids in the joining of the new filament with the continuous strand bering formed. The drum separates the new filament from its associated drop and needle, predraws it to a preliminary diameter, draws it into a filament of proper thickness and thereafter conducts the newly formed filament toward the continuous strand into which it may then be integrated with the help of a mechanical thread guide.

In practice, however, this known apparatus does not always ensure that the drops and needles are safely caught by the rapidly rotating drawing and joining drum. The drops and needles tend to be relatively inflexible and are rarely able to conform to the circumference of the drum and thus tend to rebound from the drum. Additionally, guide and deflector plates which surround the drum and prevent the newly formed filament from being projected in an undesired direction, interfere with and render the transfer of the predrawn filament to its place in the continuous strand more difficult. This complicated device suffers from additional disadvantages including high wear of the rotating drawing drum, of the integrating mechanical thread guide, and of the rapidly moving mechanical conducting or guiding devices, due to the high abrasiveness of the continuous glass filaments.Furthermore, the rapidly rotating drawing and joining drum necessitate high manufacturing standards and needs to be precisely balanced and supported in bearings. Moreover, faultless performance of the device requires constant servicing and lubrication.

Thus, the known devices entail high initial capital expenditure and high operational costs.

In the production of rayon fibers a plurality of single fibers are drawn parallel to each other from a rapidly rotating drawing drum, lifted before being completely wound around the surface of the drum and divided into rayon fibers which are then further processed into a flat fiber formation, such as mats or fibrous webs, or into velvety roves or fiber bands. German laid-open Patent Application 1,796,143 teaches that the abovedescribed rotating drum and other mechanical parts may be dispensed with in the production of rayon fibers by utilizing water as a guiding medium in order to predraw the filaments and subsequently to guide the filaments to a drawing drum.

Apparently this method is feasible in the production of rayon fibers because a rapidly rotating drum is still used and, as a result, the individual filaments can be run parallel to and separated from each other by a slight distance.

Using streams of water allows the individual filaments to be predrawn to a desired preliminary diameter without the combined steps of predrawing to a preliminary diameter and subsequently drawing to a final diameter as in the case when using only the heretofore-described drum. Unfortunately, the efficient predrawing device disclosed by German laid-open Patent Application 1 796,1 34 has not proved adaptable to the integration of newly formed filaments into a continuous strand of glass filaments.

Brief Summary of Invention It is therefore an object of the present invention to provide a method and apparatus for continuously predrawing and integrating newly formed filaments into a continuous strand.

A further object of the present invention is to provide an apparatus for forming continuous strands of glass filaments which is uncomplicated, inexpensive and long lasting.

These and other objects are accomplished in the present invention by deflecting a continuous strand, which is collected from a fiber fan, at a plurality of deflecting points from the plane of the fiber fan into a particular direction. The predrawing of a newly formed filament and the separation of the associated drops and needle is accomplished by utilizing liquid stream means. A newly formed filament may thus be conducted to a first deflection point of the continuous strand where it may be caught by the continuous strand and drawn via a "common" deflection path between the points of deflection of the continuous strand to a desired diameter.

Brief Description of the Drawings Apparatus embodying the invention is diagrammatically illustrated by way of example in the accompanying drawings wherein: Fig. 1 is a simplified front elevational view of an apparatus for carrying out the method of the present invention, Fig. 2 is a side elevational view of the apparatus of-Fig. 1, Fig. 3 is a side elevational view showing modifications of a part of the apparatus illustrated in Figs. 1 and 2.

Detailed Description of the Invention While a series of fiber forming means or bushes would be used in actual practice, Figs. 1 and 2 illustrate a single bush 1 which comprises an array of filament spinning nipples or orifices 2 from which fine diameter streams of molten glass flow and are drawn into filament 3. The filaments 3 shown in Fig. 1 represent the outer extremities of a filament fan 4 which comprises a plurality of continuous filaments 3. The individual filaments 3 forming the fan 4 are collected at a first deflection roller 5 into a continuous strand 6 which is drawn over a second deflection roller 7 in the direction of the arrow (see Fig. 2) and guided by suitable means to a winding device or bobbin (not shown).

Rollers 5 and 7 are made of a- low friction material such as graphite and are constructed with V shaped-grooves running around their outer peripheries.

As its well known, after a filament 3 breaks or tears, a glass drop or bead forms at the corresponding orifice and, after reaching a sufficient size, sinks vertically downward under the influence of gravity so that a cone, needle or icicle which forms is further drawn and ultimately results in- a newly formed filament 8. Two of these newly formed filaments are indicated in Fig. 1. As best shown in Fig. 1, during this sinking movement, the filaments 8 hit a chute 9 comprising downward converging sidewalls 10 and a transverse forwardly extending inclined rear wall 11.

The filaments 8 and their associated drops and needles are deflected by the chute 9 from their direction of sinking or falling and are guided toward the center of the chute 9 and toward the continuous strand 6. The glass drops, the needles and the trailing newly formed filaments 8 are caught by a strong stream of cold water 13 beneath the lower edge 12 of the chute 9. Each of the filaments 8 is predrawn and the associated glass drop and needle of each of the filaments 8 is separated by the chilling effect of the cold water 1 3 so that the drop and needle are-blasted into a fine granulate. The resultant granulate is carried away through water trough 14 as each of the newly formed filaments 8 is carried along by the stream of water 13.The new filaments 8 are further predrawn and conducted between -stationary guiding or conducting bars 1 5 to the first deflection roller 5 by the water stream 13.

The newly formed filaments 8 are caught by the moving continuous strand 6 and are conducted and drawn along a "common" deflection path X to a final diameter. Within the path X, the deflection rollers 5 and 7 draw the filaments 8 to the final diameter, thereby performing the same function as the heretofore used expensive and intensively serviced rotating drawings and joining drums. The stream of water 1 3 performs not only the role of a mobile mechanical guiding means which, in the past, led the newly formed threads to the rotating drawing and joining drums, thereby facilitating the integration of the predrawn filaments into the moving continuous strand, but also predraws the filaments in a fashion similar to the prior art rotating drawing and joining drums.

Although it is basically possible to deflect the filaments 3 laterally outward using a trough which is inclined merely with respect to the longitudinal direction of the bush 1 as in the known integration devices further represented by U.S. Patent No. 3,008,183, the present invention effects not only a lateral deflection of the filaments 3, but also conducts the filaments 3 away from the area of the falling drops which form the riew filaments 8 (see Fig. 2). An advantage of the present invention is that the free fall length of the drops can be shortened which is especially important with respect to the multi-row nozzle bushes presently used because if the glass drops.fall and swing along a longer fall path they can very easily swing into the emanating filament fan 4 and cause additional filaments 3 to break.

It has also proven advantageous to moisten the deflecting rollers 5 and 7 with an agent such as water containing additives such as a black wash, sizing or similar lubricating agents. A suitable arrangement of spray nozzles may be located proximate the deflecting rollers to provide the wetting agent which may or may not be pressurized, in order to effect a cleansing of the deflecting rollers so that any filament remnants which may eventually adhere to the deflecting rollers can be washed off or removed. In order to - avoid any deleterious effect on the continuous strand, the spraying effect of the nozzles should be directed to the side of the rollers opposite to that contacting the strand.

Fig. 3 sdhemafically shows an alternate arrangement of the deflecting rollers in which a number df additional deflection rollers 1 6 made of a graphite-like material are arranged on a support means 1 8 rotatable in the arrow-designated direction. The first roller 5, also made of graphite, is especially stressed by its function of collecting the filament fan 4 and may be rotated by support means 18 when it is worn such that a new roller 1 6 may rotate into the position of the worn roller 5 through an angle which corresponds to the number of the available deflection rollers 16.The roller previously used on point 5 can eventually be used as the deflection roller 7 since the load at roller 7 is not as high as the load experienced by the roller at point 5 which is incurred as a result of collecting the filament fan 4 and the newly formed filaments 8 into the continuous strand 6.

Of course all of the deflection rollers 16 may be used to replace worn rollers by rotating support means 18 through an appropriate angular displacement.

While the drive of the rotary support 1 8 may be discontinuous as described above, it can also be continuous. In either case a uniform wear of all deflection rollers 16 may take place while the free or unoccupied deflection rollers may be additionally continuously cleaned by means of a cleaning device (not shown) which removes any remnants of filaments and any build-up of black wash or sizing.

Fig. 3 also illustrates a modification in which roller wear, caused by the movement of the continuous strand 6, may be reduced by reducing the looping angle of the individual deflection rollers by providing one or more additional deflection points 1 7 whereby the path for drawing the filaments is lengthened so that the path extends between the deflecting points 5, 7 and 17.

The inclination of the sidewalls 10 should not be too great. It is recommended therefore to subdivide the bushes along their lengths when very long bushes are used. The filaments can then be collected on two or more filament fans by providing two or more guiding and leading devices of the present invention consisting of the guiding plates 9, the streams of--water 13, the water trough 14 and the stationary guiding or conducting bars 15 for the newly formed filaments corresponding to the number of filament fans. By this type of arrangement the total height of the sidewalls 10 and the total height of a guiding and leading device. can be kept relatively low.

The invention in its broader aspects is not limited to the specific steps, methods, compositions and improvements shown and described herein, but departures may be made therefrom within the scope of the accompanying claim.s without departing from the principal of the invention and without sacrificing its chief advantages.

Claims (17)

Claims

1. A process for integrating newly formed filaments derived from torn off filaments occurring during the production of continuous strands of thermoplastic materials, -comprising: (a) drawing continuous filaments of said thermoplastic material into a filament fan, (b) gathering the filaments in said fan into a continuous strand, (c) utilizing a vertically falling glass drop.and needle after one of said cmntinuous filaments is broken in order to form a new filament, (d) separating said drop and said needle fromthe newly formed filament by utilizing a rapidly moving liquid stream, (e) predrawing said newly formed filament to an initial diameter by means of said liquid stream, (f) conducting said newly formed filament to a - first deflection point of said continuous strand by means of said liquid stream, (g) joining said newly formed filament with said continuous strand, and (h) drawing and deflecting said newly formed filament with said continuous strand along a common deflection path comprising a plurality of deflection points whereby said newly formed filament is drawn to a desired final diameter and simultaneously introduced into and carried along with said continuous strand.

2. The process of Claim 1, wherein said continuous strand is deflected from a direction which coincides with a center plane of said fan.

3. The process of Claim 1, wherein said newly formed filament is deflected laterally from said fan in a direction which corresponds to the vertical fall of said glass drop.

4. An apparatus for integrating a newly formed filament derived from a broken filament occurring during the production of a continuous strand from a plurality of filaments of thermoplastic material, comprising: means for forming said new filament after a filament forming a part of said continuous strand breaks, means for separating the initially formed section of said newly formed filament and said new filament from the region of said plurality of filaments, means forming a liquid stream for separating said newly formed filament from its associated initially formed section, for drawing said newly formed filament to an initial diameter and for conducting said newly formed filament into contact with said continuous strand, means for deflecting said newly formed filament and said continuous strand along a common path so that said newly formed filament may be drawn to its final diameter and integrated with said continuous strand.

5. Apparatus according to Claim 4, wherein said separating means comprises a chute, said liquid stream forming means being located beneath the lower edge of said chute.

6. Apparatus according to Claim 5, further comprising guide bars for guiding said newly formed filament as it is being conducted to said continuous strarid by said liquid stream.

7. Apparatus according to Claim 5, wherein said chute comprises two lateral, downwardly convergent sidewalls and-a rear wall inclined relative to the direction of the vertical fall of the initially formed section of said newly formed filament.

8. Apparatus according to Claim 4, wherein said common path is defined by a plurality of points and said deflection means comprises a plurality of rollers, said rollers each having a peripheral grove running around its outer circumference.

9. Apparatus according to Claim 8, wherein said rollers are made from graphite.

10. Apparatus according to Claim 8, further comprising means for wetting said rollers in order to lubricate and clean said rollers.

11. Apparatus according to Claim 10, wherein said wetting means comprises a plurality of nozzles directing a wetting a-gent against said rollers.

12. Apparatus according to Claim 1 wherein said wetting agent comprises water.

1 3. Apparatus according to Claim 11, wherein said wetting agent is water and sizing.

1 4. Apparatus according to Claim 1 wherein said nozzles are disposed on opposite the side of said rollers contacting said continuous strand and new filament.

1 5. Apparatus according to Claims 8 or 11 wherein said rollers are mounted about a rotary support means.

16. Apparatus according to Claim 15, wherein said rotary support means are- provided with an intermittent drive in order to intermittently present a new contacting roller to said continuous strand and said new filament when an old contacting roller is worn.

17. Apparatus according to Claim 15, wherein said rotary support means is provided with a continuous drive in order to continuously present a different contacting roller to said continuous strand and said new filament.

1 8. A process, for integrating newly formed filaments derived from torn off filaments during the production of continuous strands of thermoplastic material, substantially as hereinbefore described with reference to the accompanying drawings.

1 9. An apparatus, for integrating a newly formed filament derived from a broken filament occurring during the production of a continuous strand from a plurality of filaments of thermoplastic material, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.