Method And Apparatus For Texturing Yarn

Abstract

A wad of textured yarn is removed from the texturing apparatus by passing the wad into the inlet of an elongated tube having one or more openings intermediate the ends. A fluid is passed through the tube toward the inlet end, with a substantial quantity of the fluid being vented through the opening. This cools the yarn and assists in breaking up the wad.

Description

Synthetic fibers are commonly produced by extruding molten polymer through a spinneret. In order to produce yarns which have properties approximating those of wool or other natural materials, it is common practice to subject the extrudate to a texturing process. This can be accomplished by a variety of procedures known in the art, such as stuffer-box crimping, false twisting, and fluid jet texturing. One particularly effective procedure involves contacting the fiber with a high velocity fluid stream in a turbulent zone at an elevated temperature. The turbulence imparted to the fiber produces crimps which give the fiber a textured appearance.

It has recently been found that improved texturing can be accomplished by passing yarn from a turbulent zone through a chamber which contains a plurality of discrete members, such as balls. These members exert a force on the yarn to produce a wad which extends through the chamber to suitable removal equipment.

In accordance with this invention, an improved system is provided for removing textured yarn from a yarn wad produced in texturing operations. This is accomplished by introducing the yarn wad into the inlet end of an elongated tube which is provided with one or more openings intermediate the ends thereof. A fluid is passed through the tube toward the inlet end, with a substantial quantity of the fluid being vented through the openings. The fluid thus exerts a retarding force which tends to prevent break-up of the yarn wad until the yarn has been cooled. The cooled textured yarn is withdrawn from the outlet end of the tube. In accordance with another embodiment of this invention, fluid is passed through the tube during the startup procedure in the direction of yarn removal.

In the accompanying drawing,

FIG. 1 illustrates an embodiment of the apparatus of this invention.

FIG. 2 is a view taken along line 2--2 in FIG. 1.

Referring now to the drawing in detail and to FIG. 1 in particular, there is shown a housing 10 which has a hollow needle 11 positioned therein. A conduit 12 communicates with housing 10 to introduce a fluid, such as steam or air, at an elevated temperature. A tube 13 is secured to housing 10 so that the opening therethrough forms an extension of the passage through needle 11. The inlet end of the tube 13 is tapered to provide a seat 13a adjacent the end of needle 11. The angle of seat 13a can be the same as the angle of the tapered end of needle 11, but this is not necessary.

A hollow chamber 14 is secured to the tube 13 to enclose the upper end of the tube. A large number of relatively small balls 15a and 15b are disposed within chamber 14. Chamber 14 can be provided with an outlet conduit 16 which is connected to a drain or to a source of reduced pressure, not shown. A screen 16a is positioned across conduit 16 to retain balls 15a and 15b within chamber 14. A sleeve 17 encloses tube 13 within chamber 14 and extends upwardly above the tube to form a zone 18 of high turbulence. Four rods 20 surround sleeve 17 and extend upwardly through chamber 14. As illustrated in FIG. 2, these rods are 90.degree. apart.

In the operation of the apparatus, one or more filaments 21are inserted through the interior passage of needle 11 into tube 13. These filaments can be delivered to the apparatus by any suitable feed means, not shown. In the normal startup operation, the filaments are threaded completely through the apparatus. Fluid is introduced through conduit 12 and flows upwardly through tube 13 into zone 18. The fluid so introduced surrounds needle 11 to elevate the temperature of the incoming filaments. The velocity of the introduced fluid is sufficiently high to produce considerable turbulence in the passage defined by zone 18. This turbulence imparts crimp to the filaments to produce textured yarn 21b. The yarn passes upwardly to form an elongated generally cylindrical wad 21c in the region between rods 20. The wad in this region is engaged by balls 15a and 15b which exert a restraining force. Rods 20 confine the yarn wad to the central region of chamber 14. It is important that rods 20 be spaced a sufficient distance from one another that balls 15a and 15b are free to move therebetween to exert a force on the yarn wad. While four rods have been found to be satisfactory to retain the wad, more can be used if desired. In some operations, three rods spaced 120.degree. apart will provide the desired support. The rods 20 prevent the yarn wad from collapsing or bending under the surface of the balls.

As previously mentioned, the velocity and temperature of the fluid introduced through conduit 12 are such as to impart the desired degree of crimp in the yarn in zone 18. If desired, an external heater can be employed to assist in elevating the temperature of the filaments in needle 11. The texturing fluid escapes from zone 18 and the yarn wad through the surrounding balls. When steam is employed as the texturing fluid, it may be desirable to provide vent conduit 16 to remove vapor and any condensate which may be formed. Balls 15a and 15b can be formed of metal, glass or any other material which is inert to the yarn at the temperatures encountered. The balls are advantageously of spherical configuration, but this is not essential to the operation of the invention. As illustrated, balls 15a are larger than balls 15b to provide better packing. However, the balls can all be the same size. The height of the balls in chamber 14 should be sufficient to permit the yarn to be cooled by a substantial amount before removal from the chamber. In general, the upper surface of the balls should be at least one diameter of balls 15a below the tops of rods 20.

An elongated tube 25 is positioned above chamber 14. In the illustrated embodiment of this invention, tube 25 comprises a generally vertical inlet section 25a and a generally horizontal outlet section 25b. The lower end of section 25a can be provided with a flared inlet 26 which is positioned above rods 20 so that yarn wad 21c moves upwardly into the tube. The diameter of tube 25 is preferably somewhat greater than the diameter of the yarn wad entering the tube so that the wad can move freely through the tube. Tube section 25b is provided with a plurality of slots 27. Yarn is removed through the end of tube section 25b by means of a suitable takeup device 28 and is passed to a storage area, not shown.

A conduit 29 communicates with tube section 25b in a direction so that fluid passed through conduit 29 flows through tube 25 toward inlet end 26. A second conduit 30 communicates with tube section 25b in a direction so that fluid flowing through this conduit flows through tube 25 toward the outlet end. Conduits 29 and 30 are connected to a comon inlet conduit 31. Valves 32 and 33 are disposed in respective conduits 29 and 30.

In the normal operation of the texturing apparatus, valve 32 is opened and valve 33 is closed so that fluid, such as air, entering through conduit 31 flows through conduit 29 and through tube 25 toward the inlet end. A substantial quantity of this fluid is vented through openings 27, with the remainder passing through the tube section 25a to the end of the tube. The outlet end of tube 25 is open. This results in some atmospheric air being drawn into the outlet end of the tube by aspiration. The yarn wad 21c rises through the inlet section of the tube to a region in the vicinity of openings 27. At this point, the yarn wad tends to be broken up so that the individual textured strands 21d are passed through the remainder of tube 25. The flow of air through tube 25 serves to cool the yarn to assist in imparting a permanent crimp. In order to accomplish this result, it is desirable that openings 27 be positioned at a spaced location from inlet 26. This provides greater cooling before the yarn wad is broken up. During startup operation, valve 32 is closed and valve 33 is opened so that flow through the tubing is in the opposite direction. This provides an aspirating effect which tends to withdraw the yarn through the tubing by drawing air through opening 26 and slots 27.

Any type of synthetic fiber which can be textured by the application of external forces at elevated temperatures can be treated by the process of this invention. Typical fibers which can be so treated are polyolefins, nylons and polyesters, for example.

In one specific example of this invention as illustrated in FIG. 1, needle 11 has an internal diameter of about 0.06 inch. The end of needle 11 is tapered at an angle of about 45.degree., as is flared inlet 13a of tube 13. The central passage of tube 13 is about 11/4 inches in length and has an internal diamater of about 0.125 inch. Chamber 18 is about one-half inch in length and has a diameter of about one-half inch. Balls 15a have a diameter of about one-fourth inch; and balls 15b have a diameter of about one-eighth inch. Approximately 70 percent of the total number of balls in chamber 14 are balls 15a. Chamber 14 has an internal diameter of about 3 inches, with the depth of balls being about 6 inches. Tube 25 has an internal diameter of about 1 inch. Four slots 27 are provided, each of which is approximately 7 inches long and approximately three-eighths inch wide. Tubing section 25a can have a length of from 12 to 18 inches, and tubing section 25b can have a length of at least 24 inches, preferably longer.

In one specific mode of operation, a bundle of 126 polypropylene filaments having a denier of about 1,800 (approximately 14 denier per filament) is introduced into needle 11 at a velocity of about 1,125 meters per minute. Steam at 100 psig is introduced through conduit 12 at a rate of about 20 pounds per hour. The textured yarn is removed from tube 25 at a velocity of about 700 meters per minute. Air at a pressure of about 30 psig is introduced into conduit 31. This results in air being delivered to tube 25 at a rate of about 17.7 standard cubic feet per minute.

In the illustrated embodiment of this invention, tube 25 is provided with a 90.degree. bend. Openings 27 can be located upstream or downstream from the bend. The bend facilitates the removal of the textured yarn to suitable takeup equipment. However, it is not necessary that the tube be provided with any bend at all. The tube should be constructed of a material having smooth walls so that there is minimum resistance exerted on the yarn. A lining of Teflon can be employed to advantage for this purpose.

While this invention has been described in conjunction with a presently preferred embodiment, it obviously is not limited thereto.

Claims

What is claimed is:

1. In a process for texturing fibers by subjecting the fibers to external crimping forces at an elevated temperature and thereby establishing an elongated wad of crimped yarn, the method of removing crimped yarn from the wad which comprises:

passing the yarn wad into the first end of an elongated confined zone which has at least one external opening therein at a region intermediate first and second ends of the confined zone, and passing the yarn wad through said confined zone from said first end to said region;

passing a cooling fluid stream through said confined zone from a point spaced from said region toward said region in a direction opposite the direction the yarn wad is passed through said confined zone so that the fluid stream engages the yarn wad at said region and exerts a retarding force on the yarn wad which tends to prevent breakup of the yarn wad until the yarn has been cooled, and venting a substantial amount of said fluid stream from said confined zone at said region through said at least one external opening; and

withdrawing crimped yarn from said wad at said region and passing the withdrawn yarn through said confined zone to the second end thereof counter-current to said fluid stream.

2. The process of claim 1 wherein the fluid stream is air.

3. The process of claim 1 wherein said region is spaced from the second end of said confined zone, the crimped yarn is removed from said second end, and air is drawn into said second end by aspiration.

4. The process of claim 1 wherein the fibers are subjected to external forces by passing the fibers through a second confined zone into an enlarged chamber, a second heated fluid stream is passed through said second confined zone with the fibers, and the wad of yarn is formed in the enlarged chamber by surrounding the yarn in said chamber with a plurality of balls which are free to engage the yarn wad.

5. Apparatus for texturing fibers comprising:

means to subject fibers to mechanical forces to form an elongated wad of crimped yarn;

an elongated tube positioned adjacent said means to subject fibers to mechanical forces so that said wad enters the first end of said tube, said tube being provided with at least one opening in the wall thereof intermediate first and second ends of the tube;

first conduit means communicating with said tube to convey a first fluid stream selectively into said tube at a location and in a direction so that said first fluid stream passes through the tube in a direction extending toward said opening from said second end and is vented through said at least one opening during normal operation; and

second conduit means communicating with said tube at a location between said opening and said second end and in a direction so that a second fluid stream can be passed selectively through said second conduit means so as to flow through said tube toward said second end during startup.

6. The apparatus of claim 5 wherein said at least one opening comprises a plurality of elongated slots.

7. The apparatus of claim 5 wherein said tube is open at said second end and said first conduit means communicates with said tube between said second end and said opening so that air is drawn into the second end of said tube by aspiration.

8. The apparatus of claim 5 wherein said means to subject fibers to mechanical forces comprises a second tube, means to pass the fibers to be textured and a fluid stream through said second tube, a chamber enclosing the downstream end of said second tube, and a plurality of balls positioned in said chamber.

9. Apparatus for texturing fibers comprising:

means to subject fibers to mechanical forces to form an elongated wad of crimped yarn comprising a first tube, means to pass the fibers to be textured and a first heated fluid stream through said first tube, a chamber enclosing the downstream end of said first tube, and a plurality of balls positioned in said chamber to surround an elongated wad of crimped yarn formed therein;

an elongated second tube positioned adjacent said chamber so that the yarn wad enters the first end of said second tube, said second tube being provided with at least one opening in the wall thereof intermediate the first and second ends of the tube;

conduit means communicating with said second tube to convey a second cooling fluid stream into said second tube at a location and in a direction so that fluid passes through the tube in a direction extending toward said opening from said second end to tend to prevent breakup of the yarn wad until the yarn has been cooled and is vented through said at least one opening; and

means for withdrawing yarn from said wad in the vicinity of said at least one opening and for passing the thus withdrawn yarn out of said second end of said tube.