JPS643963B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improving a newer duct for an air whirlpool spinning machine, and in particular, provides a newer duct in which free fibers are less likely to be sucked into an opening connected to a negative pressure source when spinning using fibers with good spreadability. It is something to do. A method for producing spun yarn by air whirlpool spinning is known, for example, from Japanese Patent Publication No. 43257/1983. In this method, short fiber bundles are roller-drafted, kept in an open state, and transported while being supplied to an apron where the temporary twist imparted downstream of the apron can propagate to the nip point upstream. A temporary twist is applied to the short fibers (main fiber bundle) located at
Around this short fiber bundle, short fibers (free short fibers) with both ends unrestrained or in a state close to this are generated by the temporary twisting action, and then, when the main fiber bundle exits the air vortex nozzle, it is The short fibers are wound around each other. Furthermore, I would like to add that
Free short fibers are loosely wound or attached around the main fiber bundle that is strengthened in the temporary twisting process, and are wrapped around it when the main fiber bundle rotates reversely in the unrolling process. In this method, the free short fibers are reversely added 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 bound with free short fibers from the periphery without twisting. 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, whereas if the amount of free short fibers is small, the strength will decrease. There's a problem. On the other hand, a pneumatic duct is used between the roller draft section and the air temporary twist section to smooth the collection of free short fibers that are wound around the main fiber bundle.
The present invention relates to improvements to 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 has a cross roller 2,
It is drafted by the cradle 3 and the front roller 4. Aprons 5, 5' are arranged around the outer periphery of the front roller 4 to rotate together with the front roller 4, and a gap S is formed at the sending ends of the two aprons 5, 5', so that the drafted short fibers can be The bundle 1a is transferred as is. This short fiber bundle 1a
, a temporary twist is applied by the air temporary twist nozzle 6, but in this case, the temporary twist concentrates on the short fiber bundle (main fiber bundle) in the center of the apron 5', and the twist propagates through the apron 5, 5'. It passes through the gap S and reaches the nip point. The short fibers (free short fibers) on both sides of the apron that are not subjected to the temporary twisting action are either in the middle of being transported by the apron or after being sent out from the apron, the main fibers are already twisted with both ends unrestrained or in a similar state. It is integrated into the bundle in a parallel state or with a relatively small number of twists. The strongly twisted main fiber bundle passes through the air temporary twisting nozzle 6 and is simultaneously unraveled.
Free fibers are wound around this. In the present invention, a type of spinning machine with aprons 5, 5' shown in the drawings is exemplified and explained. The newer duct of the present invention can be applied to a spinning machine or a spinning machine in which a plurality of temporary air twist nozzles are arranged in series. Furthermore, the pneumatic tube is not particularly limited to the cylindrical shape shown in the drawings, and may have any shape such as a rectangular shape or a slit shape, as long as the yarn being threaded can pass through the inside. It can also be used. 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. There is.
The air temporary twist nozzle 6 has a hole 13 in the center for thread passage.
is provided, and an ejection hole 1 for swirling air flow leading to this is provided.
4 is provided, and compressed air is supplied from a compressed air supply pipe 15 and the compressed air is ejected from the jetting hole 14 to give a temporary twisting effect to the yarn passing through the hole 13. The conventional pneumatic duct 7 includes a pneumatic tube 8
The minimum cross-sectional area N of the suction tube 1 is formed to be sufficiently larger than the area n of the negative pressure opening 9, so that the suction tube 1
The short fiber bundle sent out from the front roller 4 is smoothly sucked into the inside of the roller. If the short fiber bundle is composed of 100% synthetic fibers such as acrylic fibers and polyester fibers,
Even if the relationship between the cross-sectional area N of the pneuma tube and the area n of the negative pressure opening is N>n, a large amount of floating short fibers, that is, free short fibers, may be sucked into the suction tube during spinning. The amount of suction was generally 0.05 to 0.17% of the total amount of short fibers, and 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 of these mixtures, free short fibers are not twisted into the main fiber bundle even under normal spinning conditions, but are simply sucked into the pneumatic duct ( The disadvantage was that there was a large amount of staple cotton. For example, in a conventional pneumatic duct with an aperture ratio of N/n = 2.78, 65% polyester and 35% cotton
%, and when spinning a spun yarn with a count of 45S, about 2% of the amount of spun yarn is sucked into the pneumatic duct. The amount of short fibers sucked into this numa duct increases as the blending ratio of fibers with good spreadability such as cotton increases. The amount of short fibers reached 9%, resulting in a large loss. Furthermore, the short fibers that are sucked into this pneumatic duct are supposed to be free short fibers that are supposed to become binding fibers for the spun yarn, and the fact that they are sucked and discharged by the pneumatic duct naturally reduces the strength of the spun yarn. It will become. The present invention was obtained as a result of studying how to reduce the free short fibers sucked into the pneumatic duct. They discovered that by increasing the flow rate faster than the flow rate, which has an angle with the thread path, the amount of pneumatic cotton absorbed can be significantly reduced. The present invention is characterized by increasing the flow in the thread path direction among the two directions of flow flowing through the pneumatic tube. Specifically, the minimum cross-sectional area N of the pneumatic tube is set by the negative pressure opening. It is characterized in that the area is smaller than n. Next, embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows an embodiment of the present invention, in which the front part 8a of the pneumatic tube 8 is shaped like a flap, an opening 9 is provided at the terminal end of the pneumatic tube 8, and the suction tube 1
0 is connected to the 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,
The entire circumference of the rear end of the pneuma tube 8 is open,
The opening communicating with the suction tube 10 extends around the entire circumference of the pneumatic tube 8. 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 conducted by the present inventors, the cross-sectional area ratio N/n≦1 is the minimum value, and when N/n≦0.7, the effect of Numa suction cotton is significantly large. When determining the value of N/n, it is important to select conditions in which the free short fibers are sufficiently accelerated in the numa tube 8 in the addition process and supplied to the hole 13 of the air temporary nozzle. Consideration is given to giving an inertial effect to the free short fibers so that they are not transferred inside the fibers 8 to the opening 9 side. From the above facts, the smaller the value of N/n, the better.
Considering the suction of free short fibers, it is necessary that the pore diameter of the N portion be approximately 2 mm, that is, N≧πmm ² . 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 pneumatic 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 in which an apron is used in the yarn forming section has been described above, the present invention is not limited thereto, and
It can be applied to any spinning machine that uses a roller draft section and air temporary nozzle. Example 1 As shown in FIG. 1, spinning was carried out using an air whirlpool spinning machine having a three-line draft section, a pair of upper and lower aprons with open ends, and a newer duct and an air temporary nozzle following the apron. The roving used was polyester 1.3 ^d × 38 ^mm 65
%, 0.55 blended with 35% rice cotton combed sliver
g/m was used. The spinning conditions were a total draft of 42 times, a spinning count of 45S, a front roller speed of 100 m/min, a working air pressure of 1.75 Kg/cm ² , and an overfeed ratio of the front roller to the delivery roller of 5%. The results are shown in the table below. In the method of the present invention, the amount of pneumatic suction cotton is reduced to 1/8, and the strength is also improved.

[Table] 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, and it is effective when N/n≦1.0, and when N/n≦0.7
The effect becomes larger. If the diameter of the N portion is reduced to 4 mm or less, it will not be very effective, and if it is reduced to 2 mm or less, the free fibers may become poorly focused due to a decrease in the suction flow rate, and the fibers may become clogged when the thread breaks, which is not preferable.

【table】

【table】 [Brief explanation of drawings]

Figure 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 air temporary nozzle, and FIGS. 3 and 4 are schematic diagrams of a pneumatic duct according to an embodiment of the present invention. 4...Front roller, 6...Air temporary nozzle, 7...Numa duct, 8...Numa tube,
9...Aperture, N...Minimum cross-sectional area of the numa tube,
n... Area of the opening.

Claims (1)

[Claims] 1. A pneumatic tube provided between the front roller of the roller draft section and the air temporary twisting nozzle, through which the yarn being added can pass;
A numa duct for an air whirlpool spinning machine, characterized in that the numa duct has an opening that communicates with a negative pressure source provided on a side surface of the numa tube, wherein the minimum cross-sectional area of the numa tube is smaller than the area of the opening. .