Method for evaluation of balloons of yarn-like products

A method for evaluation of balloons of yarn-like materials. Ballooning of yarn-like materials is converted to an electric signal, the electric signal is amplified and the electric signal is analyed by a Fourier analyzer to know respective frequency components and voltage amplitude components which show the condition of ballooning.

FIELD OF THE INVENTION 
The present invention relates to a method for evaluation of balloons of 
ballooning yarn-like products, and more particularly, the present 
invention relates to a method for evaluation of balloons of yarns in the 
process for obtaining spun yarns by a pneumatic spinning method such as an 
open end spinning method or a false-twisting spinning method. 
BACKGROUND OF THE INVENTION 
The steps of preparing spun yarns according to the pneumatic spinning 
method are quite different from the steps of preparing spun yarns 
according to the ring spinning method except the step using a drafting 
device, and in the pneumatic spinning method, a drafted sliver is 
ballooned by using a fluid jet nozzle and twists are imparted when 
balloons are formed, and spun yarns are thus obtained. 
Accordingly, the structure of a yarn obtained according to the pneumatic 
spinning method is different from the structure of a yarn obtained 
according to the ring spinning method. In the pneumatic spinning method, 
the properties of yarns, such as uniformity, strength and feeling, are 
greatly influenced by balloon factors such as the rotation number and 
diameter of balloons, and the pneumatic spinning method is inferior to the 
ring spinning method in the stability of the yarn properties. 
Since the above-mentioned balloon factors are changed comprehensively by 
spinning conditions, for example, the nozzle structure (fluid jetting 
angle, inner diameter and the like), the fluid pressure, the spinning 
tension and the drafting unevenness, analysis of factors changing the 
ballooning state is very difficult, and even at the present, spinning 
conditions are independently determined in respective plants according to 
empirical laws while a method for analyzing these factors is not 
established. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a method for evaluating 
balloons in the process for producing spun yarns by means of a pneumatic 
yarn spinning. 
According to the present invention, a ballooning phenomenon is detected as 
an electric signal by a detector comprising a luminous diode and photo 
transistor and the detected electric signal is subjected to Fourier 
transformation by using a Fourier analyzer to be spectrally analyzed to 
respective frequency components and voltage amplitude components so that 
optimum spinning conditions are set by analyzing the respective balloon 
characteristics. 
The method of the present invention satisifes all the following conditions 
required in the detecting zone; 
(a) a very fine yarn-like product can be detected and a sufficient output 
signal can be produced; 
(b) the detector is fully responsive to a high-speed rotation of a balloon; 
(c) the measuring zone is narrow and the detector has a small size; and 
(d) drifts are small and detection can be accomplished stably even if the 
measurement is conducted for a long time. 
Since the ballooning phenomenon is analyzed based on results obtained by 
the present invention, spinning conditions capable of forming an optimum 
balloon can be set. 
Furthermore, by analyzing the ballooning phenomenon in the actual 
production process, the spinning conditions having influences on the yarn 
properties such as uniformity, strength, formation of fluffs and feelings 
can be known.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention will now be described in detail with reference to 
embodiments illustrated in the accompanying drawings. 
FIG. 1 illustrates one embodiment of the process for preparing spun yarns 
according to the pneumatic spinning method. Referring to FIG. 1, a sliver 
drafted by a drafting device and delivered from a front roller 1 is passed 
through two fluid jet nozzles 2 and 3 rotating in directions opposite to 
each other, and when the sliver is being passed through the two fluid jet 
nozzles 2 and 3, the sliver is twisted and a yarn Y is formed. The yarn Y 
is wound on a winding bobbin not shown in the drawings through a take-up 
roller 4. 
As shown in FIG. 2, in each of the fluid jet nozzles 2 and 3, a fluid jet 
hole 5 is opened slantingly at an angle .alpha.1 or .alpha.2 to the yarn 
running direction in the tangential direction to the inner circumference 
of a yarn passage pipe 6 and in the axial direction thereof. A turning and 
swirling stream of a fluid flowing in the yarn running direction is 
produced in the yarn passage pipe 6 by a fluid jetted into the yarn 
passage pipe 6 from the fluid jetting hole 5. At this time, rotation, that 
is, revolution and turning, is given to the fiber bundle passing through 
the fluid jet nozzles 2 and 3, and the fiber bundle is positively guided 
in the yarn running direction (indicated by an arrow X). 
Since the first fluid jet nozzle 2 exerts a function different from the 
function of the second fluid nozzle 3, the inclination angles .alpha.1 and 
.alpha.2 of the fluid jetting holes of the fluid jet nozzles 2 and 3 are 
different from each other. More specifically, the first fluid jet nozzle 2 
exerts functions of sucking the fiber bundle delivered from the front 
roller 1 into the first fluid jet nozzle 2 and turning the fiber bundle, 
and the second fluid jet nozzle 3 exerts a function of imparting 
revolution to the fiber bundle, that is, imparting twists to the fiber 
bundle, though it similarly exerts a function of turning the fiber bundle. 
From the foregoing explanation, it will readily be understood that good 
results are obtained when the inclination angle .alpha.1 is smaller than 
the inclination angle .alpha.2. From the results of the experiments, it 
has been confirmed that better results are obtained when the inclination 
angle .alpha.1 is about 48.degree. and the inclination angle .alpha.2 is 
about 90.degree.. 
The inclination angles .alpha.1 and .alpha.2 have important influences on 
the rotation number of the balloon. As the inclination angles become close 
to 90.degree., the rotation number of the balloon is increased. 
Accordingly, rotation numbers of balloons produced between the front 
roller 1 and the takeup roller 4 differ from one another, and especially 
between the first and second fluid jet nozzles, balloons rotating in 
opposite directions interfere with each other, and balloon variations 
readily become conspicuous. 
Furthermore, the balloon rotation number is changed according to the inner 
diameters of the yarn passage pipes 6 of the fluid jet nozzles 2 and 3, 
the inner diameters of balloon control rings 7 and 8 arranged in the yarn 
introduction portions of the first and second fluid jet nozzles 2 and 3 
and the inner diameter of a twist regulating pipe 9 arranged in the yarn 
introduction portion of the first fluid jet nozzle 2, especially the inner 
diameter of the twist regulating pipe 9 arranged at a position where 
balloons rotating in opposite directions interfere with each other. 
Incidentally, not only the balloon rotation number, but also the balloon 
wavelength and amplitude are influenced by the inner diameters of the yarn 
passage pipes 6, balloon control rings 7 and 8 and twist regulating pipe 
9. 
The above-mentioned balloon rotation number and balloon diameter are always 
changed according to the position and time, and it is not too much to say 
that the yarn properties, such as uniformity, strength and feeling, and 
influenced by these balloon variations. Accordingly, in order to improve 
the yarn quality, it is most important to analyze phenomena of variations 
of balloons. 
A detector for detecting such balloon variations is illustrated in FIG. 3. 
It is indispensable that this detector should satisfy at least the 
conditions described below. More specifically, the detector can detect a 
yarnlike product which rotates at a high speed and is fully responsive to 
variations of this high-speed rotation. Furthermore, this detector should 
be a small-sized detector capable of measuring balloons from the outside 
during the actual production of spun yarns. In other words, since the 
ballooning phenomenon differs according to the spinning conditions, the 
detector should perform measurements in the actual production process or 
the same model as the actual production process. Moreover, even if the 
measurement is conducted for a long time, drifts are small and detection 
can be accomplished stably. As the detector satisfying the foregoing 
requirements, a detector comprising a luminous diode and a photo 
transistor is most preferred. 
Incidentally, even by using a detector of the electrostatic capacity type, 
for example, a condenser, detection is possible. 
The method using this detector is a kind of the so-called photoelectric 
conversion method in which the quantity of light emitted from a luminous 
diode 10 is detected by a photo transistor 11 and the detected light 
quantity is converted to an electric quantity. This detecting method has 
higher sensitivity and response characteristic than the photoelectric 
conversion method customarily adopted for measurement of fluffs and the 
like. 
When a fiber bundle forming a balloon 12 passes through the zone of the 
above detector, a part of light emitted from the luminous diode 10 is 
shaded, and the change of the quantity of light by this interception is 
detected by the photo transistor 11 and analyzed by a Fourier analyzer 
described hereinafter. 
The frequency detected by the detector is varied according to the 
measurement method. For example, the wave form of signals detected when 
the luminous diode and photo transistor are arranged so that they confront 
each other with the center of the balloon center being substantially as 
the center between the two elements as shown in FIG. 4 is different from 
the wave form of signals detected when the luminous diode and photo 
transistor are arranged so that they confront each other substantially on 
the tangential line on the balloon circle as shown in FIG. 5. In case of 
the measurement method shown in FIG. 4, a wave form as shown in FIG. 6 
appears, and in case of the measurement method shown in FIG. 5, a wave 
form as shown in FIG. 7 appears. However, the frequency measured in one 
method is 1/2 of the frequency measured in the other method or 2 times the 
frequency measured in the other method, and the measurement results are 
not different between the two methods. 
In FIGS. 6 and 7, ideal signal wave forms are shown based on the 
supposition that the balloon 12 is not changed at all. If such balloon is 
always obtained, Fourier analysis described below need not be performed at 
all. 
In the actual production process, however, balloon variations are always 
caused even under the same spinning conditions, and these balloon 
variations are drastically changed by changes of the spinning conditions 
such as the structures of the fluid jet nozzles, 2, 3 for example, the 
inclination angles .alpha.1 and .alpha.2 of the jet holes 5, the inner 
diameters of the yarn passage pipes 6, the inner diameters of the balloon 
control rings 7 and 8 and the inner diameter of the twist regulating pipe 
9, the pressure of the jetted fluid, the spinning tension between the 
front roller 1 and take-up roller 4 and the yarn unevenness produced at 
the preliminary spinning step or in the drafting device. Accordingly, 
under the same spinning conditions, certain balloon variations can take 
place. However, an optimum yarn Y can be obtained by spinning when the 
above-mentioned respective spinning conditions are selected and combined 
so that balloon variations are reduced to minimum levels stably. In order 
to determine optimum spinning conditions, it is necessary to analyze the 
ballooning phenomenon moment by moment in the actual production process. 
FIG. 8 shows a wave form of combined balloon signals. If only this signal 
wave form is seen, it only is recognized that balloon variations take 
place. Accordingly, it is necessary to analyze the signal wave form and 
clarify causes of the variations. The method for analyzing the signal wave 
form is shown in FIG. 9. The signal wave form shown in FIG. 8, which has 
been detected by the above-mentioned detector, is amplified to a signal 
wave form most suitable for AD converter by amplifier, and the amplified 
combined electric signals are spectrally analyzed to respective frequency 
components and voltage amplitude components (a), (b), (c), (d) by a 
Fourier analyzer. 
As shown in FIG. 10, the basic principle of analysis of electric signals by 
the Fourier analyzer resembles the principle of seeing seven color spectra 
by passing the sunlight through a triangular prism 13. 
FIG. 11 is a block diagram of the Fourier analyzer. Referring to FIG. 11, a 
signal is first introduced into an amplifier 101 and is then passed 
through an area-effect preventing low-pass filter 102 to effect AD 
conversion 103, and the converted signal is stored in a data memory 104. 
The data stored in the data memory 104 are subjected to operations such as 
averaging, correlation and Fourier conversion by a data processor 105 and 
then to an output processing 106, and processed data are displayed on an 
indicator 107. 
More specifically, when a yarn balloon passes through the detecting zone 
including the luminous diode 10 and the photo transistor 11, the 
ballooning phenomenon is converted to an electric quantity and is detected 
as an electric signal. The detected electric signal, that is, the combined 
signal wave form, is passed through the amplifier and analyzed to 
respective frequency and voltage amplitude components (a), (b), (c) and 
(d) shown in FIG. 8 by the Fourier analyzer, and these components (a), 
(b), (c) and (d) are displayed. 
TABLE 1 
______________________________________ 
spinning condition 
______________________________________ 
yarn count Ne 35 
spinning velocity 
150 m/min 
feeding ratio 0.98 
pressure of fluid 
first nozzle 4 kg/cm.sup.2 
second nozzle 4 kg/cm.sup.2 
______________________________________ 
The results of experiments conducted under conditions shown in Table 1 are 
shown in FIGS. 12 and 13. The wave form of signals detected by the 
detector is shown in FIG. 13, and the results of analysis of this wave 
form are shown in FIG. 13. From the wave form shown in FIG. 12, it can be 
conjectured that balloon variations take place, but it is impossible to 
analyze what variations actually take place. From the analysis results 
shown in FIG. 13, the actual state of the ballooning phenomenon can 
precisely be grasped. More specifically, from the analysis results shown 
in FIG. 13, it is seen that the frequency of the balloon rotation number 
is highest at about 190,000 r.p.m. (3150 Hz.times.60 c/s) (point P) and 
deviations (l) of the rotation number appear before and after this point. 
The rotation number at the point Q has a frequency 2 times the frequency at 
the point P. As pointed out hereinbefore, in the method shown in FIG. 5, 
one rotation of the balloon is detected as one signal, and in the method 
shown in FIG. 4, one rotation of the balloon is detected as two signals. 
Accordingly, it is seen that the above phenomenon indicates that the yarn 
balloon moves in the vertical direction. 
The frequency of the rotation number at the point R is substantially the 
same as the frequency of the rotation number at the point Q. 
The frequency of the rotation number at the point O is inherent to the 
measurement method. More specifically, in FIG. 1, the measurement can be 
made at a point A between the front roller 1 and the first fluid jet 
nozzle 2, at a point B between the first fluid jet nozzle 2 and the second 
fluid jet nozzle 3 or at a point C between the second fluid jet nozzle and 
the take-up roller 4, and the results shown in FIG. 13 are those obtained 
by conducting the measurement at the point A according to the method shown 
in FIG. 5. At the above-mentioned point O, the results obtained by 
detection of the light of the detector reflected from concave and convex 
grooves formed at predetermined intervals on the peripheral surface of the 
front roller 1 are shown. Accordingly, if these detection results are 
analyzed, it becomes possible to know the rotation number of the front 
roller 1, variations of this rotation and the spinning speed of the fiber 
bundle delivered from the drafting device. 
FIG. 14 shows the results of spectral analysis obtained when the experiment 
is carried out under the same conditions as shown in Table 1 except that 
the pressure of the fluid jetted from the first fluid jet nozzle is 
reduced to 3 kg/cm.sup.2. From the results shown in FIG. 14, changes of 
the balloon owing to changes of the pressure of the fluid jetted from the 
first fluid jet nozzle 2 can readily be understood. The balloon rotation 
number at the point P' is about 160,000 r.p.m. (2725 Hz.times.60 c/s) and 
the rotation number appearing at the point Q' is two times the rotation 
number appearing at the point P'. 
As will be apparent from the foregoing illustration, if various spinning 
conditions such as the spinning speed, the feed rate, the spinning 
tension, the fluid pressure and the fluid jet nozzle structure are set in 
various manners and the results of experiments conducted under these 
various spinning conditions are analyzed, it is possible to determine 
spinning conditions capable of producing an optimum ballooning phenomenon. 
In the foregoing embodiment, the ballooning phenomenon in the process for 
production of spun yarns is analyzed and evaluated. The present invention 
can be applied to ballooning phenomena of all of ballooning yarn-like 
products. 
As will be apparent from the foregoing description, according to the 
present invention, a ballooning phenomenon of a yarn in the process for 
production of spun yarns is detected as an electrical signal, the thus 
detected signal, that is, a combined signal wave form, is analyzed to 
respective frequency components and voltage amplitude components, and the 
ballooning phenomenon is analyzed based on these analysis results and 
spinning conditions capable of forming an optimum balloon can be set. 
Furthermore, by analyzing the ballooning phenomenon in the actual 
production process, the spinning conditions having influences on the yarn 
properties such as uniformity, strength, formation of fluffs and feeling 
can be known.