Process for manufacture of textile yarns

In a process for draw fracturing yarn wherein the yarn is passed through a turbulent flow air suction device downstream of where the yarn is drawn and upstream of an air fracturing jet so that broken filaments extending from the yarn will be intermingled and immobilized by entangling them with unbroken filaments in the yarn so as to reduce yarn breaks.

DESCRIPTION 
1. Technical Field 
This invention relates to a novel process improvement useful in the 
manufacture of continuous filament yarn having a spun yarn character, and 
in particular it involves the use in a fracturing process of a turbulent 
flow fluid jet to intermingle and immobilize broken filaments in a yarn in 
order to minimize the occurrence of yarn breaks due to plugging of broken 
filaments in the fracturing means. 
2. Background Art 
U.S. Pat. No. 4,332,761 discloses a process for draw fracturing textile 
yarn using a feed yarn of fracturable filaments, stabilizing the yarn to a 
preselected level, fracturing the fracturable filaments and taking up the 
yarn. In such a process occasionally a broken filament will be stripped 
back along the yarn and cause an end break as the yarn passes through the 
fracturing process. 
An object of this invention is to provide a process by which trailing ends 
of broken filaments are intermingled and immobilized, thereby resulting in 
reduced ends down. 
DISCLOSURE OF THE INVENTION 
In accordance with the present invention, I provide an improvement in a 
process for draw fracturing yarn involving uniformly drawing to a 
preselected level of utility a yarn comprised of a plurality of continuous 
filaments having a fracturable cross-section, fracturing the filaments by 
passing the yarn through an operating fluid fracturing jet and taking up 
the yarn. The improvement involves passing the yarn through a turbulent 
flow air suction device downstream of the drawing and upstream of the 
fracturing jet, the air suction device being adjusted to provide suction 
at the entrance thereof to intermingle and immobilize broken filaments by 
entangling them with unbroken filaments in the yarn and thereby reduce end 
breaks in the fracturing operation.

BEST MODE FOR CARRYING OUT THE INVENTION 
In reference to FIG. 1 of the drawings, the draw fracturing process is 
shown at 10. The yarn 12 may be withdrawn from a feed yarn package 14, 
pass over a godet roll 16 and its separator roll 18, through a yarn heat 
stabilizing device 20, over a second godet roll 22 and its separator roll 
24, through an air suction device 26 to be described, and through an air 
fracturing jet 28 (such as disclosed in U.S. Pat. No. 4,332,761 above), 
over a haulout godet roll 30 and its separator roll 32 for subsequent 
forwarding to a winding device (not shown). The yarn 12 may be suitably 
drawn between the first and second godet rolls and their respective 
separator rolls by rotating the second godet roll set faster than the 
first. The heat stabilizing device 20 may be a slit heater for contact or 
noncontact with the yarn. 
As mentioned above, U.S. Pat. No. 4,332,761 describes a process for draw 
fracturing textile yarn; therefore the disclosure in that patent is 
incorporated herein to the extent necessary for a better understanding of 
my present invention. Reference is also made to U.S. Pat. No. 4,245,001 
which is related to U.S. Pat. No. 4,332,761 and which discloses the 
resulting product of the process patent. 
During the course of practicing the process described in the 
above-mentioned process patent, an occasional broken filament will occur 
in the yarn at a point prior to the location of the air fracturing jet. 
When the trailing end reaches the entrance of the air fracturing jet, the 
counter-current air flow initiates peeling back of the trailing end with a 
resulting snarl or wad of material quickly forming which will not pass 
through the small opening; hence the yarn will break. This yarn breakage, 
of course, necessitates again stringing up the yarn through the fracturing 
jet and its associated apparatus. 
My invention involves adding along the yarn path in the draw fracturing 
process at a location before the air fracturing jet an air suction device 
26, such as disclosed in more detail in FIG. 2. The air suction device is 
adjusted to create not only a suction but also a turbulent air flow within 
the suction device so that the trailing end of the broken filament will be 
intermingled and immobilized. This result is accomplished by the suction 
device eliminating peeling back of the trailing end while it is 
intermingled with its neighbor filaments by the turbulent action in the 
jet. In this manner, then, the broken filament becomes immobilized within 
the body of the yarn so as to maintain the yarn relatively intact and thus 
it cleanly passes through the air fracturing jet. 
In reference to FIG. 2, the air suction device 26 has an elongated housing 
34 provided with a central bore 36, which also defines in part a plenum 
chamber for receiving therein a gaseous fluid such as air. 
A venturi 38 is supported in the central bore in the exit end of the 
housing and has a passageway extending through the venturi with a central 
entry opening 40 of about 6.350 mm (0.250 inch) in diameter, a converging 
wall portion 42 of about 30.degree. angle, a constant diametered throat 44 
of about 1.27 mm (0.050 inch), a diverging wall portion 46 and a central 
exit opening 48 of about 6.degree. angle. The length of the venturi is 
about 47.225 mm (17/8 inches) and the smallest outer diameter of the major 
portion of the venturi is about 7.938 mm (5/16 inch). 
The yarn guiding needle 50 is also positioned within the central bore 32 of 
the housing and has an inner end portion 52 spaced closely adjacent the 
central entry opening 36 of the venturi 34. The yarn guiding needle has an 
axial yarn guiding passageway 54 of about 3.175 mm (0.125 inch) in 
diameter which extends through the needle and terminates in an exit 
opening 56 of about 0.635 mm (0.025 inch) in diameter. The outer wall of 
the inner end portion of the needle adjacent the exit opening 56 is 
inwardly tapered about 15.degree. toward the central entry opening 40 of 
the venturi 38. The length of the yarn guiding needle is about 56.159 mm 
(2 13/64 inches) and the outer diameter is about 9.525 mm (3/8 inch). 
An inlet or conduit 58 serves to introduce the gaseous treating fluid, such 
as air, into the plenum chamber of the central bore 36 of the housing 34. 
The needle may be adjustably held in position within the central bore by 
means of the threaded stem 60 extending from the elongated housing 34 and 
an adjustment nut 62. The needle is secured to the adjustment nut by means 
of cooperating grooves and retaining rings 64. O-ring 66 serves as a gas 
seal in a known manner. 
The venturi 38 may also be held in position within the elongated housing 34 
by means of a threaded plug 68 cooperating with a threaded bore 70 within 
one end of the elongated housing and a holder 72 while an O-ring 74 
provides a gas-tight seal in known manner with the holder to prevent gas 
from escaping from the plenum chamber. 
In operating the air suction device in the process, therefore, the inlet or 
conduit 58 of the device is connected to a suitable source of air supply 
and then the device is adjusted by moving the yarn guiding needle toward 
and away from the venturi 38 until the device is determined to be 
operating under suction conditions at the central exit opening 48 of the 
venturi. I have found, for instance, that there is significant suction 
when the device is operated at about 172.379 kilopascals (25 psig) to 
about 1379 kilopascals (200 psig) at about 0.007 m.sup.3 /m (0.25 scfm) to 
about 0.057 m.sup.3 /m (2.00 scfm) air. 
The following examples serve to illustrate the effectiveness of my process 
and are not intended to limit the scope of my invention. 
EXAMPLE I 
POY 270/(170)/30 spun as per Example 1 from U.S. Pat. No. 4,245,001. 
______________________________________ 
Draw Fracture Conditions 
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Draw Ratio 1.55:1 
Feed Roll Temp. 98.degree. C. 
Slit Heater 240.degree. C. 
Draw Roll Speed 808 m/minute 
Jet* 0.189 m.sup.3 /m (6.5 scfm) at 
3447.5 kilopascals (500 psig) 
Haulout Roll Speed 
800 m/minute 
Overfeed into jet 
1% 
End breaks per 454 
0.042 
grams (per pound) 
______________________________________ 
*(FIG. 2 of U.S. PAT. NO. 4,095,319 
When using the suction jet device prior to the fracturing jet at 0.0425 
m.sup.3 /m (1.5 scfm) at 1379 kilopascals (200 psig), the end break 
dropped to 0.014 end breaks per 454 grams (per pound). 
EXAMPLE II 
Same as Example I except the suction jet device was operated at about 0.014 
m.sup.3 /m (0.5 scfm) at 620.55 kilopascals (90 psig) with a corresponding 
end break per 454 grams (per pound) level of 0.020. 
The invention has been described in detail with particular reference to 
preferred embodiments thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.