JPH0474465B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a fibrous web. More specifically, a method for producing a fibrous web includes colliding multifilament yarns from a long pipe line with compressed air toward a collision plate, and collecting the multifilament yarns opened by the collision in a sheet form on a conveyor. This is related to the improvement of.

[Prior art]

As a method for directly producing a fiber web from multifilament yarn during spinning, the multifilament yarn is ejected and collided with compressed air from a long pipe toward a collision plate, and the collision causes the multifilament yarn to Some fibers are spread and collected on a conveyor. This method for producing a fiber web has the advantage that the faster the compressed air is pumped through the long pipe, the more the fibers are opened and expanded on the collision plate, and the productivity can be improved.

However, as mentioned above, when compressed air is made faster,
The compressed air ejected from the tip of the long pipe disturbs the fiber web collected on the conveyor, resulting in uneven thickness and uneven fabric weight, resulting in a disadvantage of deteriorating product quality. In addition, the back pressure of the compressed air reflected from the collision plate increases, so it also serves as a brake for increasing the speed of the compressed air.

[Purpose of the invention]

In view of the above-mentioned problems of the prior art, an object of the present invention is to increase the speed of compressed air without causing uneven thickness or area weight on the fiber web even when the speed of compressed air is increased, and to increase the speed by back pressure of compressed air that reflects the collision plate. It is an object of the present invention to provide a method for producing a fiber web that does not cause the occurrence of braking.

[Structure of the Invention] The present invention achieves the above object by spinning a multifilament yarn spun from a spinneret having a large number of discharge holes from an ejector provided at a certain distance below the spinneret. Together with the compressed air supplied to the ventilate section, the multifilament yarn is ejected and collided with the collision plate arranged below through a long pipe of a certain length connected to the ejector, and the fibers are opened by this collision. A method for producing a fibrous web in which fiber webs are collected in a sheet form on a conveyor, characterized in that compressed air is forcibly exhausted from near the bottom of the elongated pipe in a direction that is separate from the direction in which the multifilament yarns are ejected. That is.

[Embodiments of the invention]

Hereinafter, the present invention will be described along with an apparatus for carrying out the invention.

In FIG. 1, 1 is a melt spinneret having a large number of discharge holes, and a multifilament yarn Y is melt-spun from this spinneret 1. Spinneret 1
A heating and heat-retaining tube 2 is provided around the periphery of the yarn to improve spinnability by lowering the melt viscosity. Reference numeral 3 denotes an ejector whose details will be described later, which suctions the multifilament yarn Y melt-spun from the spinneret 1 at high speed by the ejector effect of compressed air. A drawing pipe 4 is connected to the downstream side of the ejector 3, and this drawing pipe 4 accelerates the compressed air injected from the ejector 3 and pulls the multifilament yarn along with it, and uses the pulling force to draw the multifilament yarn. Allow stretching to occur.

An exhaust pipe 5, the details of which will be described later, is provided at the lower end of the extending pipe 4. This exhaust pipe 5 is connected to a forced suction means such as a blower (not shown), and the forced suction means forcibly sucks and exhausts compressed air from the exhaust pipe 5, thereby further accelerating the flow velocity in the stretching pipe 4. to increase suction power.
The multifilament yarn Y thus attracted by the compressed air is ejected together with the compressed air from the slide pipe 16a below the exhaust pipe 5, and collides with the obliquely installed collision plate 6. Due to this collision, the multifilament yarn Y changes direction, and when changing direction, it is opened and expanded.

As shown in FIG. 2, a plurality of the collision plates 6 are arranged in rows across the conveyor 7 for each spinning head, and each of the collision plates 6 swings from side to side. The multifilament yarn Y, which changes direction due to the collision, is further spread out while swinging from side to side on the plurality of collision plates 6 to form a sheet-like fiber web W having a uniform thickness on the conveyor 7 below. let

The above-mentioned ejector 3 has a pressure chamber 9 formed in the main body 8 as shown in FIGS.
A compressed air supply pipe 10 communicating with a compressed air pump (not shown) is connected to the side thereof. A bench lily part 11 is provided following the pressure chamber 9, and this bench lily part 1
The tip of the thread guide tube 12 faces the throat 11a of the pipe 1, and an annular injection nozzle 13 with a constricted flow path is formed around the tip. A rectifying mechanism 14 having a large number of nozzles 14a is provided upstream of this injection nozzle 13. A large number of nozzles 14
a are arranged at approximately equal intervals along the circumferential direction, and correspond equally to the annular slits of the injection nozzle 13. Therefore, the compressed air supplied to the pressure chamber 9 is rectified by the rectification mechanism 14, and the air density is evenly distributed to the annular slit of the injection nozzle 13 without unevenness. Therefore, the compressed air ejected from the injection nozzle 13 becomes a substantially straight direct jet flow and does not swirl. Therefore, no false twist is applied to the multifilament yarn Y, and no fusion occurs on the upstream side thereof.

The stretching pipe 4 connected to the ejector 3 is
In this embodiment, the length l ₁ from the throat 11a of the bench lily 11 to the upper end of the exhaust pipe 5 is at least 400 mm.
mm. In this way, the above-mentioned rectifying mechanism 1 is installed in the long pipe line set to a length of 400 mm or more.
By flowing the direct jet flow corrected by 4, the flow velocity is accelerated, and a high velocity of 4000 m/min or more is possible. Therefore, the suction force of the compressed air increases, and the multifilament yarn Y is conveyed while being highly stretched.

5 and 6 show details of the exhaust pipe 5 provided at the bottom of the extension pipe 4. The lower end of the upper extension pipe 4 is fixed through the upper plate of the main body case 15, and the bottom plate is fixed to the exhaust pipe 5. The upper end of the guide pipe 16 is fixed through the guide pipe 16, and a lower slide pipe 16a is slidably fitted into the guide pipe 16. An exhaust port ₁₉ with a length l 2 is formed between the lower end of the extension pipe 4 and the upper end of the guide pipe 16, and a plurality of annular plates 17 are assembled at the exhaust port 19 with small gaps between them. A stacked rectifying mechanism 18 is provided, and a cylindrical porous filter 20 is further provided surrounding the outer periphery of the rectifying mechanism 18.
An exhaust pipe 21 is provided on the side of the main body case 15, and the exhaust pipe 21 is connected to forced suction means (not shown) such as a blower as described above.

When forced suction is performed from the exhaust pipe 21 by the forced suction means, in response to the rectifying action of the porous filter 20, the compressed air of the stretching pipe 4 is radially directed from the slit between the annular plates 17, 17 in the rectifying mechanism 18. Air is discharged uniformly over the entire circumference. Due to this uniform exhaust, the multifilament yarn Y
There is no problem such as biasing to one side in the stretching pipe 4.

The shape of the slit in the rectifying mechanism 18 may be a vertical slit instead of the horizontal slit as in the embodiment, and the rectifying mechanism 18 itself may be constituted by a cylinder with holes.

According to the method for producing a fibrous web described above, since forced exhaust is performed from the exhaust pipe 5 at the bottom of the drawing pipe 4, the static pressure inside the drawing pipe 4 is reduced.
The flow rate of compressed air can be further increased. moreover,
By forcibly suctioning and exhausting the compressed air from the exhaust pipe 5 in this manner, it is possible to reduce the amount of compressed air that is ejected from the lower end of the slide hype 16a together with the multifilament yarn Y.

That is, the supply and exhaust balance of compressed air in the above device is as shown in _FIG .
The sum of the amount of air Q ₀ that is accompanied by the multifilament yarn Y is the sum of the amount of compressed air exhausted from the exhaust pipe 5 Q ₂ and the amount of compressed air that is ejected from the lower end of the slide hype 16a together with the multifilament yarn Y.
Q It is in a relationship that is equal to the sum of ₃ . Therefore, if the compressed air exhaust amount Q ₂ due to the above forced exhaust is increased,
The amount _Q3 of compressed air jetted from the lower end of the stretching pipe 4a decreases. Therefore, the amount of compressed air flowing out onto the conveyor 7 after colliding with the collision plate 6 is also reduced.
The sheet-like fiber web W collected on the conveyor 7 is not unnecessarily disturbed by the compressed air.

Furthermore, since the amount of compressed air ejected from the lower end of the slide pipe 16a is small, the back pressure of the compressed air that is reversed from the collision plate 6 to the lower end of the slide pipe 16a is also reduced, and therefore the reduction in suction speed caused by this back pressure is also prevented.

If the above-mentioned forced suction and exhaust from the exhaust pipe 5 is performed also when threading the first spun yarn, the thread tension of the first spun yarn is low, so the yarn is inserted into the slit of the straightening mechanism 18. There is a risk of getting caught. The exhaust pipe 5 is a slide pipe 16 on the lower side.
a can be slid, and by raising it, its upper end can be brought into contact with the lower end of the upper extension pipe 4, and the exhaust port 19 can be closed, as shown by the chain line in FIG. Therefore, when threading, by raising the slide pipe 16a to the position shown by the chain line and closing the exhaust port 19, it is possible to prevent the thread from being caught in the slit of the rectifying mechanism 18.

〔Effect of the invention〕

As described above, the method for manufacturing a fibrous web of the present invention includes forcibly exhausting the compressed air in a direction away from the direction in which the multifilament yarn is ejected from the lower part of the long pipe line through which the multifilament yarn is ejected together with the compressed air. , the amount of compressed air ejected together with the multifilament yarn can be reduced. Therefore, the amount of compressed air that reaches the conveyor via the collision plate is reduced, the fiber web on the conveyor is not disturbed, and the occurrence of thickness unevenness and fabric weight unevenness can be suppressed.

Further, as the amount of compressed air ejected from the long pipe line is reduced, the back pressure reflected by the collision plate is also reduced, so that it no longer acts as a brake on high speed.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of an apparatus for carrying out the present invention, Fig. 2 is a plan view showing a portion of the apparatus downstream from the lower end of the stretching pipe, and Fig. 3 is an ejector section provided in the apparatus. FIG. 4 is a cross-sectional view taken in the - arrow direction of FIG. 3, FIG. 5 is a longitudinal cross-sectional view of the exhaust pipe portion provided in the same device, and FIG. It is a diagram. 1... Spinneret, 3... Ejector, 4... Drawing pipe (long pipe), 5... Exhaust tube, 6... Collision plate, 7
…Conveyor.

Claims (1)

[Claims] 1. A multifilament yarn spun from a spinneret having a large number of discharge holes is passed from an ejector provided at a certain distance below the spinneret.
Together with the compressed air supplied to the ventilate section, the multifilament yarn is ejected and collided with the collision plate arranged below through a long pipe of a certain length connected to the ejector, and the fibers are opened by this collision. A method for producing a fibrous web in which fiber webs are collected in a sheet form on a conveyor, characterized in that compressed air is forcibly exhausted from near the bottom of the elongated pipe in a direction that is separate from the direction in which the multifilament yarns are ejected. A method for producing a fibrous web.