US2982994A - Process and apparatus for quenching and steam-conditioning yarn - Google Patents

Description

y 9, 1951 G. A. FERNSTROM 2,982,994

PROCESS AND APPARATUS FOR QUENCHING AND STEAM-CONDITIONING YARN Filed Oct. 15, 1958 United States Patent o PROCESS AND APPARATUS FOR QUENCHING AND STEAM-CONDITIONING YARN George A. Fernstrom, Seaford, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Oct. 15, 1958, Ser. No. 767,401

5 Claims. (Cl. 18-8) This invention relates generally to the melt-spinning of fiber-forming synthetic polymers and, more particularly, to the quenching and steam-conditioning of melt-spun filaments.

The most important object of the present invention'is to provide an improved process and apparatus for quenching and steam-conditioning melt-spun synthetic filaments.

Another important object of this invention relates to the elimination of turbulence in the transition area between the air-quenching and steam-conditioning zones.

A further object is to provide a process and apparatus for producing a uniform, synthetic polyamide yarn with constant dye depth.

Additional objects of the present invention are to provide for the escape of spent chimney air from the upper section of the quenching chamber, to prevent turbulent mixing of quenching air and conditioning steam, to substantially isolate the running filaments from ambient air currents, and to control process conditions at the initial point of steaming of the yarn.

With these and other objects in view, the apparatus of the present invention involves, generally, the provision of a quenching chamber defined by a chimney having an imperforate door terminating at a point below the top of the chamber, side wings or extensions which project downwardly to the steam conditioner, and a shield inclined downwardly from the door to the convergence guide. In the use of such apparatus, a constant flow of quenching air runs essentially cross-current with the running filaments in the major part of the quenching chamber, and essentially co-current with the running filaments in the relatively small section of the quenching chamber immediately above the steam conditioner. Simultaneously, a constant flow of steam runs substantially counter-current with the running filaments in the steaming zone immediately below the quenching chamber.

In the drawing:

Figure 1 is a front view of the quenching apparatus of the present invention, with the associated spinneret and steam conditioner shown fragmentarily; and

Fig. 2 is a vertical sectional view of the apparatus shown in Fig. 1.

In known processes of melt-spinning synthetic polymers, the spun filaments pass directly from a spinneret to an air-quenching chamber. Before leaving the quenching chamber, the filaments are gathered into a bundle by a convergence guide. In high-speed spinning (greater than 500 yards per minute), a steam-conditioning step is required, i.e., the filaments are passed from the convergence guide through a tube which is exposed to a steam atmosphere. The steam-conditioning causes the filaments to absorb moisture and to grow in length before reaching the windup bobbin, and thus prevents them from picking up moisture and growing in length after being wound up.

In any particular spinning operation, the point of initial steam contact should remain constant if a uniform yarn is to be achieved. In order to obtain yarn with ice constant dyeing characteristics, it has been found that the conditions in thequ'enching chamber, and steam conditioner must also be constant, i.e., strayair currents and V turbulences must be avoided. Particularly undesirable factors are, for example, air currents which enter the region of the conditioner from the atmosphere around the conditioner and steam plumes which occasionally rise from the conditioner toward the quenching chamber.

- In Figs. 1 and 2, it is seen that a pluralityof filaments 10 is melt-extruded from a spinneret 12 and successively passes through a quenching chamber '14, a convergence guide 16, and a steam conditioner 18.

The chamber 14 is defined by a chimney which includes imperforate side walls 20, a front wall or door 22, and a perforated rear wall 24. A top wall 26 has an opening through which the filaments 10 pass on entering the chamber 14. An air chamber 28 is positioned on the rear distribution wall 24 and has an air inlet 30 by means of which quenching air is introduced. A bottom wall 32, in the form of an inclined shield, joins side walls 20 and is inclined downwardly to a point closely adjacent the convergence guide 16. -It has been foundthat suitable results are obtained when'the lower edge of shield 32 is positioned vertically Within a range of from six inches below to three inches above the guide 16 and horizontally within a range of from three inches in front to two inches behind guide 16. Preferably, such lower edge of shield '32 is positioned vertically somewhere between the guide and a point /8" thereabove and horizontally within /2" of the guide. In those instances where the shield 32 ex- 7 tends beyond guide 16, extensions are added which project downwardly in surrounding relationship to the guide. Additionally, the lower edge of shield 32 should be situated within nine inches and preferably within six inches of the top of steam conditioner 18.

The imperforate door 22 is hinged, as at 34, to one of the side walls 20 and extends from the shield 32 upwardly to a point spaced from the top wall 26, thereby leaving a passage 36 adjacent the top of the chimney for exhausting the quenching air. An auxiliary panel 38 is slidable in guides 40 and held in position by a pin 42 which extends through one of the holes 44 to support the panel 38 at the desired height. The location of exhaust passage 36 insures a cross-flow of quenching air immediately below the spinneret where the filaments are still molten. It is noted that the perforated rear wall 24 has a filtering screen 46 covering the inner surface thereof.

As shown in the drawing, the side walls 20 and the rear wall 24 extend downwardly and overlap the top of the steam conditioner 18. These wings or extensions thus act to block 01? ambient air currents from the transition area between the quenching and steaming zones. For best results, the walls 20, 24 should'extend at least to the top of the conditioner and preferably at least two inches therebelow, as shown in Figs. 1 and 2.

In operation, the quenching air enters chamber 14 through chamber 28 and flows substantially cross-current with the filaments 10 through a major portion of the height of the chimney, as shown by the arrows in Fig. 2. Most of the air is exhausted throughpassage 36, although a minor portion flows co-current with the running yarn and exhausts through the bottom of the chimney, as best shown by arrows in Fig. 2. In high-speed spinning, yarn windage insures this continuous co-current flow of air across shield 32 and through the bottom of the chimney toward the steam conditioner 18. The air rushing across the top of the steam shield 32 to the guide 16 provides an air blanket which sharply controls the initial point of steaming. This feature, in combination with the disposition of the shield 32 substantially eliminates the entrance of steam jets or plumes into the quenching zone from the steam conditioner. The extension of the side walls 20 and the rear wall 24 into a position closely adjacent to or the openings and passages disclosed. The adjustability' of panel 38 provides a variable that may be employed to achieve optimum results.

The process of this invention includes, along with the conventional steps of spinning, quenching and steam-conditioning, the additional steps of shielding the quenching zone from the steam zone and isolating the transition area between the zones from ambientair currents. Since the filaments are completely enclosed during the critical steps of quenching and steaming, the harmful and unpredictable effects of stray air currents are nullified.

Yarn spun according to the process and'with the apparatus disclosed herein has been tested for actual dye depth, interchimney deviation of dye depth, number of draw roll wraps and cleaner breaks, and for the number of process spinning incompletcs. In each of these respects, substantial improvement was noted when the results were compared with those obtained from yarn spun according to conventional processes.

I claim:

1. In melt-spinning apparatus including a spinneret and a steam conditioner into which a plurality of filaments extruded from said spinneret passes, an enclosed quenching chamber comprising: an elongated, hollow chimney having side walls, a first end wall having an opening therein registering with said spinneret, and a second, partial end wall having an opening therein registering with said steam conditioner; and a convergence guide in said chimney for gathering the filaments as they pass through the opening in said second end well, one of said side walls being perforated substantially through the length thereof for the admission of a quenching medium and the opposed side wall having a single unobstructed exhaust passage at the end thereof adjacent said first end'wall, said walls being otherwise imperforate, said second end well being inclined from said opposed side wall and terminating in spaced relationship to said one side wall.

2. The apparatus of claim 1 wherein said one side wall and the adjoining side walls extend to a position closely adjacent the steam conditioner.

3. The apparatus of claim 1 wherein said one side wall and the adjoining side walls extend beyond said convergence guide and overlap said steam conditioner.

4. The apparatus of claim 1 wherein is provided a panel and means mounting said panel for movement into and out of said exhaust passage for varying the size of the passage.

5. A melt-spinning process including the steps of successively extruding, quenching, and steam-conditioning a plurality of filaments, the improvement of which comprises: shielding the quenching zone from the steamconditioning zone by providing a restricted co-current flow of the quenching medium with the filaments as the latter exit the quenching zone and isolating the transition area between the zones from ambient air currents.

References Cited in the file of this patent UNITED STATES PATENTS 1,950,025 Dreyfus et a1. Mar. 6, 1934 2,161,354 lmray et al. June 6, 1939 2,273,105 Heckert Feb. 17, 1942 2,289,860 Babcock July 14, 1942 FOREIGN PATENTS 456,913 Canada May 24, 1949

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