Spinning machine for wet-spinning process

A wet-spinning process for producing filament utilizes a pair of rollers in the spinning machine which have axes which are skewed to one another, i.e. include angles in projections both in vertical and horizontal planes and so inclined that the interturn spacing of the filament decreases from the upstream wet zone to the downstream drying zone.

FIELD OF THE INVENTION 
My present invention relates to a spinning machine for the continuous 
production of filaments and, more particularly, to a machine for 
continuously spinning a filament by a wet-spinning process with or without 
an air gap and wherein the spun filament from the coagulating bath or the 
spinning nozzle passes onto at least one roller pair formed by elongated 
rollers having their axes inclined to one another so that the turns of the 
filament progressively pass along these rollers from a wet zone to drying 
zone downstream of the wet zone. 
BACKGROUND OF THE INVENTION 
Gotze, "Chemiefasern nach dem Viskoseverfahren", 3. Auflage, 1967, page 
900, Verlag-Springer, Berlin, Heidelberg, New York (Chemical Fibers 
According to the Viscose Process) describes a system in which freshly 
formed filaments from a spinning nozzle or spinneret are drawn from a 
coagulation bath by a roller pair. The filament passes in a helical 
pattern over the roller pair whose rollers have coplanar axes which are 
not, however, parallel to one another but rather include an angle with one 
another. 
The threads looped over the roller pair move progressively therealong 
toward the imaginary intersection point of the two axes and automatically 
distribute themselves along the rollers to pass from the wet zone to a 
drying zone. 
The wet zone encompasses that region of the path of the turns over the 
rollers in which filament or thread consolidation takes place and can 
include a deacidification zone in which the turns of the threads can be 
washed to free them from the acid. The drying zone encompasses a heated 
region of the rollers. The angular orientation of the roller axes ensures 
a constant spacing of the thread turns which can be about 6 millimeters 
from turn to turn over the entire length of the rollers. 
This large spacing of the thread turns is important in the wet region or 
zone to avoid sticking of the turns together. Once the threads have 
consolidated, however, and especially in the drying zone, there is no 
longer a need for such a large spacing although it is in the nature of 
earlier systems of this type that such spacings are provided in the drying 
zone as well. 
What is important for the drying zone is that the thread remain for a 
sufficient residence time in contact with the heated length of the rollers 
that the drying can be effected in a reliable manner. In the past, the 
constant spacing of the turns required rollers of considerable length to 
ensure a sufficient residence time in the drying zone. 
OBJECTS OF THE INVENTION 
It is, therefore, the principal object of the present invention to provide 
a spinning machine for the type described which can ensure a sufficient 
spacing of the turns in the wet zone (a spacing amounting to 4 to 6 
millimeters, for example, in the case of 110 dtex filaments) while 
nevertheless enabling a smaller spacing of the turns in the drying zone or 
downstream of the wet zone. 
Another object of the invention is to provide a spinning machine of the 
aforedescribed type which can provide a minimum spacing of the turns of 
the filament in the drying zone with a progressive reduction in the 
interturn spacing at least along the drying zone. 
Still another object of the invention is to provide a spinning machine of 
the type described which can afford better utilization of the drying 
energy, optimum production speed and reliable production of a wet spun 
filament, utilizing a roller pair of reduced length. 
SUMMARY OF THE INVENTION 
These objects and others which will become apparent hereinafter are 
attained, in accordance with the present invention in an apparatus of the 
type described but wherein the axes of the roller pair are skew to one 
another, i.e. the axes include angles with one both in a horizontal 
projection (on a vertical reference plane) and in a vertical projection 
(on a horizontal reference plane). 
More particularly, the apparatus can comprise: 
means for wet-spinning an extruded filament; 
at least one roller pair of mutually inclined longitudinally extending 
rollers for receiving the extruded filament and processing same, the 
roller pair defining axially therealong a wet zone initially receiving the 
filament and a drying zone downstream of the wet zone in a direction of 
travel of successive turns of the filaments looped around the rollers of 
the pair, the turns progressively advancing in the direction along the 
rollers, 
axes of the rollers being skew to one another and having projections in a 
vertical plane including an angle between them and projections in a 
horizontal plane including an angle between them. 
When the axes include an angle with one another not only in a projection on 
a vertical plane but also are oriented so that they do not lie in a common 
vertical plane, i.e. are truly skewed to one another, by determination of 
the angles and selection of the roll diameters and the axial spacing of 
the rollers, I am able to achieve a filament travel pattern in a 
multiplicity of turns over the rollers of the pair whereby the interturn 
spacing in the wet zone or the upstream portion of the rollers is large 
and can progressively reduce, e.g. in a continuous or monotonic 
relationship, to and through the drying zone. 
In practical terms, therefore, I can operate with a spacing between the 
turns of 6 millimeters at the beginning or upstream end of the wet zone 
and reduce the interturn spacing to say 0.5 millimeters in the drying 
zone, all with a roller pair of comparatively small length and with 
substantially reduced energy consumption, especially for the roller 
heating in the drying zone. As a consequence, the overall efficiency of 
the process can be greatly improved. 
According to a feature for the invention, the rollers of the pair are 
constituted as a main roller of relatively large diameter and an auxiliary 
roller of relatively small diameter, the ratio of the auxiliary roller 
diameter to the main roller diameter being substantially 1:2 to 1:4 and 
preferably 1:3 to 1:4. 
In practice it has been found to be advantageous to provide, with a 
horizontal orientation of the axis of one of the rollers, for example, the 
main roller, the axis of the other roller, for example, the auxiliary 
roller, so that vertical projections of the axes will intersect 
approximately one-third of the way along the lengths of the rollers in the 
direction of travel of the turns (more generally between one-quarter and 
one-half of the way from the upstream end) and in the region of the wet 
zones. The coordinates of the axial bearing locations of the auxiliary 
roller can deviate in two coordinate directions from the axial bearing 
positions of an imaginary roller parallel to the main roller. 
To improve the thread contraction and stretching and elongation on 
coagulation, the consolidation, the washing phase and the drying phase, at 
least one of the rollers of the pair can be formed with a conical section 
over a portion of its axial length, preferably in the deacidification 
zone. This conical portion can widen in the direction of travel of the 
turns, i.e. can diverge toward the drying zone. If desired, the other 
roller, especially the auxiliary roller, can have a diameter profile along 
its length which remains in proportion to the diameter profile along the 
length of the main roller which can be provided with that frustoconical 
portion if desired.

SPECIFIC DESCRIPTION 
A viscose thread 1 (FIG. 2) is formed in a coagulation bath 2 by means of a 
spinneret 3 from which the viscose is extruded. The thread 1, together 
with entrained coagulating agent from the bath 2, is drawn upwardly and 
winds in turn about a roller pair formed by a main roller 4 and an 
auxiliary roller 5. 
The treatment path along the main roller 4 encompasses a wet portion or 
zone 6 which can extend approximately over three-fourths of the length of 
the main roller and a heated drying zone 7 which may, as seen in FIG. 4 at 
11, be equipped with a heater. 
In the wet zone 6, an acid treatment phase over a zone 8 for thread 
consolidation, followed by deacidification in a washing or deacidification 
zone 9, precede the drying zone 7. 
The axis 5' of the auxiliary roller 5 is inclined to the axis 4' of the 
main roller 4 in a projection in a vertical plane (FIG. 1) and 
additionally is twisted out of the vertical plane (FIG. 3) so that it 
includes an angle in a projection on a horizontal plane as well. 
The inclination of the axis 5' relative to the horizontal can be seen 
readily from FIG. 1 while the twist of the axis 5' out of the vertical 
plane of the axis 4' is best seen in the plan view of FIG. 3. 
FIG. 3 also shows that the axes of the main roller 4 and the auxiliary 
roller 5 are skew to one another. 
This arrangement gives rise to a thread travel along the rollers with a 
progressively decreasing interturn spacing. 
Thus I can ensure that in the thread consolidation zone or acid zone 8, in 
which significant quantities of the acidic coagulation bath are entrained 
along with the filament, successive turns will not contact one another and 
stick together. In the washing zone, nozzles, e.g. (the nozzles 12 shown 
in FIG. 4) can be provided so that water can be directed onto the 
filament, now already consolidated, for deacidification. The winding 
spacing in the zone is substantially less than the drying zone, the turns 
come close together as can be readily seen from FIG. 1 to reach their 
minimum spacing just before the dried filament is withdrawn at 13. Because 
of the close spacing, optimum drying can be effected over a limited 
portion of the length of the roller pair. 
By varying the mutual inclinations of the axes, the winding spacing can be 
increased or reduced. If it is desired to stretch or elongate the filament 
during the washing process, the main roller 104 and, if desired, the 
auxiliary roller 105 can have slightly conical regions which widen in the 
direction of the drying zone as has been shown at 15 for the main roller 
104 in FIG. 4. This conical region can be limited to the zone 109 in which 
deacidification is effected. This zone can extend from the intersection 
point 10 to the heated drying zone 7. 
The rollers can be driven as represented by the motor 14 in FIG. 4. 
By way of a specific example, the diameter of the main roller 1 was about 
180 millimeters and that of the auxiliary roller about 50 millimeters. 
With respect to the coagulation bath side (FIG. 2) the downstream end of 
the axis 5' of the auxiliary roller was located about 136 millimeters 
below the corresponding end of the axis 4' of the main roller and about 61 
millimeters to the left while at the coagulation bath side the auxiliary 
roller axis 5' was located about 113 millimeters below the main roller 
axis 4' and about 52 millimeters to the right of the vertical plane of the 
axis 4'. The intersection point in projection on a horizontal plane of the 
two axes was located in the first quarter of the roller lengths toward the 
coagulation bath side. The lateral spacing of the first helical turns in 
the region 8 (FIG. 1) for 110 dtex filament amounted to about 9 
millimeters and reduced continuously over the length of the rollers to a 
spacing of the last turn in the region 7 of about 0.8 millimeters. The 
interturn spacing is determined by the angle at which roller axes cross 
and could be adjusted as a function of the roller diameters and roller 
spacing for all spinning titers. 
With the same roller spacing but with the roller axes in a common plane, 
utilizing a 110 dtex yarn, the minimum interturn spacing of 4.5 
millimeters was held uniformly over the length of the rollers and for the 
same drying length as that used with the invention of 270 millimeters, 
only 60 turns could be accommodated, corresponding to 36% of the number of 
turns which could be accommodated in the drying region of the roller pair 
of the invention. For the same roller length and available space, 
therefore, the drying effectiveness can be increased with the system of 
the invention and the energy consumption significantly reduced. Because 
generally shorter roller pairs can be used, replacement and maintenance is 
simplified. 
The textile data for spun yarn of the example correspond to those for 
continuous process yarns and the spinning machine has been found to be 
effective for the viscose process as well as for the wet-spinning process 
with or without air gaps, including, for example, the solution spinning 
process and the NMMO process.