JPS588132A - Pneumatic duct of open end spinning frame - Google Patents

Abstract

PURPOSE:To reduce the amount of fibers to be sucked in a pneumatic duct remarkably, by making the flow velocity of in the direction to an air false twisting nozzle in a pneumatic duct higher than that at an angle to a nozzle yarn guide to a negative pressure source before the nozzle. CONSTITUTION:The front part (8a) of a pneumatic duct 8 is in the shape of a trumpet, and an opening 9 is provided at the end of the duct 8. A suction pipe 10 is connected to the opening 9 and further to a negative pressure system. The cross-sectional area (n) of the opening 9 to the negative pressure system is increased from the minimal corss-sectional area (N) of the pneumatic duct 8. In spinning fibers having the good opening property, free fibers are not easily sucked to the opening part 9 connected to the negative pressure source.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of a pneumatic duct for an air whirlpool spinning machine, and particularly when spinning using fibers with good spreadability.
The purpose of the present invention is to provide a pneumatic duct in which free fibers are difficult to be sucked into an opening connected to a negative pressure source.

A method for producing spun yarn by air whirlpool spinning is known, for example, from Japanese Patent Publication No. 52-43257.

In this method, short fiber bundles are roller-drafted, kept in an open state, supplied to an apron where the temporary twist imparted downstream of the apron can propagate upstream to the nip point, and then transported to the apron, mainly at the center. A temporary twist is applied to the short fibers (main fiber bundle) located at the part, and short fibers (free short fibers) with both ends unrestrained or in a state close to this are generated from the temporary twist action around the short fiber bundle, Thereafter, the air vortex nozzle is configured to wrap the short fibers around the emerging main fiber bundle at the time of unrolling. In addition, free short fibers are loosely wound or attached around the main fiber bundle that is strengthened in the temporary twisting process, and when the main fiber bundle is reversely rotated in the unrolling process. In this method, the free staple fibers wound around the fiber bundle are reversely wound and wound around the fiber bundle to obtain a spun yarn.

The spun yarn obtained by the above method has a double structure in which the main fiber bundle, which makes up the majority of the yarn, is almost untwisted and bound by free short fibers from the periphery.

Therefore, the properties of this spun yarn largely depend on the amount of free short fibers wrapped around the main fiber bundle. If the amount of free short fibers is large, the amount of fibers wrapped around the main fiber bundle will be large, so the resulting spun yarn will have high strength and stability; conversely, if the amount of free short fibers is small, the strength will decrease. There is a problem with doing so.

On the other hand, a pneumatic duct is used between the roller draft section and the air temporary twist section in order to smooth the collection of free short fibers wound around the main fiber bundle, and the present invention relates to an improvement of this device. .

First, the schematic structure of an air swirl spinning machine will be explained with reference to the drawings.

In FIG. 1, the roving 1 is drafted by a back roller 2, a cradle 6, and a float/troller 4. On the outer periphery of the front roller 4, aprons 5, 5' are arranged to rotate together with the roller 4. A gap S is formed at the sending ends of the two aprons 5, 5', and the drafted short strips are The fiber bundle 1a is transferred as is. This short fiber bundle 1a is given a temporary twist by the air temporary twist nozzle 6, but in this case, the plate twist is concentrated in the short fiber bundle (main fiber bundle) in the center of the apron 5', and the twist is not propagated by the second process. 15.
5' through the gap S and extends to the nip point.

The short fibers (free short fibers) on both sides of the apron that are not subjected to the temporary twisting effect are transported by the apron, but after being sent out from the apron, the main fibers are already twisted with both ends unrestrained or in a similar state. When integrated into a bundle in a parallel state or with a relatively small number of twists, the strongly twisted main fiber bundle passes through the air temporary twist nozzle 6 and is simultaneously unraveled, and free fibers are wound around it. It is. In the present invention, an example of a type of spinning machine with an apron 5° 5' has been shown, but even if the spinning machine does not have an apron 5, 5' and has a plurality of temporary air twist nozzles arranged in series. good.

A pneumatic duct 7 is provided in front of the temporary air nozzle 6, and the air is exhausted by a suction pipe 10 connected to a negative pressure system through an opening 9 formed at the rear end of the pneumatic pipe 8.

The spun yarn 1b obtained as described above is wound up into a package 12 via a delivery roller 11.

FIG. 2 is a side sectional view of a device that combines a pneumatic duct 7 and an air temporary nozzle 6. The pneumatic duct 7 is composed of a cylindrical pneumatic tube 8 and a suction tube 10 connected to an opening 9 at the end of the cylindrical pneumatic tube 8. has been done. The temporary air twist nozzle 6 is provided with a thread passage hole 13 in the center, and a blowout hole 14 for swirling air flow that communicates with the hole 13. Compressed air is supplied from a compressed air supply pipe 15 and compressed from the blowout hole 14. Air is blown out to give a temporary twisting effect to the yarn passing through the hole 16.

In the conventional 221 maduct 7, the minimum cross-sectional area N of the pneumatic tube 8 is formed sufficiently larger than the area n of the negative pressure opening 9, and the front row 2 is inserted into the suction tube 10 when the thread breaks.
It is configured to smoothly suck the short fiber bundle sent out from 4.

When the short fiber bundle is composed of 100% synthetic fibers such as acrylic fibers and polyester fibers.

The relationship between the cross-sectional area N of the pneuma tube and the area n of the negative pressure opening is N. Even if the pneumatic tube is opened at n, a large amount of floating short fibers, that is, free short fibers, are sucked into the suction tube during spinning. There is no such thing, and the suction amount is generally 0.0 relative to the total short edge amount.
It was 5 to 0.17%, which was not a particular problem.

However, problems arose when short fiber bundles made of fibers other than synthetic fibers were used. In other words, when spinning fibers with good spreadability such as rayon and cotton, or short fiber bundles mixed with these fibers, free short fibers are not twisted into the main fiber bundle even under normal spinning conditions, but are simply sucked into the pneumatic duct. It had the disadvantage of increasing the amount of fiber (staple cotton).

For example, in a conventional pneumatic duct with an aperture ratio of ~2.78, polyester 6! In the case of spinning a spun yarn of 35 inches of cotton and a count of 458, about 2 inches of the amount of spun yarn is sucked into the pneumatic duct.

The amount of short fibers sucked into this pneumatic duct increases as the blending ratio of fibers with good spreadability such as cotton increases. The amount of short fibers produced reached 9 inches, resulting in a large loss.

In addition, the short fibers that are sucked into the pneuma duct are supposed to be free short fibers that are supposed to be the binding fibers of the spun yarn, and it is natural that these are sucked and discharged by the pneuma duct due to the strong strength of the spun yarn. This results in a decline. The present invention was obtained as a result of studying how to reduce the free short fibers sucked into the pneumatic duct, and the flow velocity in the direction toward the temporary air nozzle within the pneumatic duct is changed to a negative pressure source in front of the nozzle. They discovered that by increasing the flow velocity, which has an angle with the opposite nozzle thread path, the amount of pneuma absorbed can be greatly reduced.

The present invention is characterized by increasing the flow in the thread path direction among the two directions of flow flowing through the pneuma tube. Specifically, the minimum cross-sectional area N of the pneuma tube is set by the negative pressure opening. It is characterized in that the area is smaller than n.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 3 shows an embodiment of the present invention, in which the front part 8a of the pneuma tube 8 is shaped like a trumpet, and an opening 9 is provided at the terminal end of the pneuma tube 8, to which a suction tube 10 is connected. Connected to negative pressure system. In this embodiment, the cross-sectional area of the opening 9 is made larger than the minimum cross-sectional area N of the pneumatic tube 8.

FIG. 4 shows a second embodiment of the present invention, in which the entire circumference of the rear end of the pneuma tube 8 is opened, and the opening communicating with the suction tube 10 is opened along the entire circumference of the pneuma tube 8. It has become. Also in this embodiment, the cross-sectional area n of the opening 9 is made significantly larger than the minimum cross-sectional area N of the pneumatic tube 8.

According to many experiments by the inventor, the ratio of cross-sectional areas N/n≦1
is the minimum value, and when N/n≦0.7, the effect of pneuma suction cotton is significantly large.

When determining the value of N/n, consider that free short fibers are pneuminated in the addition process. It is important to select the conditions under which the air is sufficiently accelerated in the pneumatic tube 8 and supplied to the hole 13 of the temporary twisting nozzle. Consideration should be given to giving an effect.

From the above facts, the smaller the value of N/n, the better, but considering the suction of free short fibers, the pore diameter of the N part is 211I! degree, that is, N≧π−. The maximum value of n varies depending on the configuration of the spinning machine, but is not particularly limited.

Furthermore, observing the state in which the free short fibers are transported within the pneumonic tube, the free short fibers are transported around the twisted main fiber bundle. Therefore, care must be taken so that the opening connected to the negative pressure system does not interfere with the transport of free short fibers.

Although the embodiment described above uses an apron in the yarn forming section, the present invention is not limited to this, and can be applied to any spinning machine that uses a roller draft section and an air temporary twist nozzle. It is possible.

Example 1 As shown in Fig. 1, the material was spun using an air whirlpool spinning machine having a three-line draft section, a pair of upper and lower aprons with open ends, and a pneumatic duct and an air twist nozzle following the apron. .

The roving used was polyester 1,3dX 38”6
5%, floor cotton combed rhino (35% blended), 5
sy/m was used. The spinning conditions are: total draft 42 times, spinning count 45S1, front roller speed 1
00m layer, air pressure used was 1.75 m/d, and oats were fed from the front roller to the delivery roller (feed rate was 5%).

The results are shown in the table below. In the method of the present invention, pneumatic suction cotton is
/S, and its strength has also improved.

Example 2 Spinning was carried out under the same conditions as in Example 1, and the amount of sucked cotton was investigated by changing N/n. The results are shown in the table below, N/n
There is an effect when ≦1.0, and the effect increases when N/n≦0.7. If the diameter of the N part is smaller than 4 m*, it will not be very effective, and if it is smaller than 2111 m, it is not preferable because it may cause poor focusing of free fibers due to a decrease in suction flow rate and clogging of fibers when the thread breaks. (Margins below this page)

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of an air swirl spinning machine, Fig. 2 is a sectional view of the main parts of a conventional pneumatic duct and an air temporary nozzle, and Figs. 3 and 4 are according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a pneuma duct. 4...Front roller, 6...Air temporary twist nozzle,
7... Pneuma duct, 8... Pneuma tube, 9...
・Opening part, N... Minimum cross-sectional area of pneuma tube, n...
Area of opening.

Claims (1)

[Claims] A pneumatic tube is provided between the front roller of the roller draft section and the air temporary twist nozzle, through which the yarn being added can pass, and a negative pressure source is provided on the side of the pneumatic tube. A pneumatic duct for an air whirlpool spinning machine, wherein the pneumatic duct has an opening, wherein the minimum cross-sectional area of the pneumatic tube is smaller than the area of the opening.