CN1608152A - Device for the production of cellulose staple fibers - Google Patents

Abstract

The invention is concerned with a device for the production of cellulosic staple fibers comprising a cutting device (1) for cutting cellulosic continuous filaments into staple fibers, a liquid-transport device (2) for transporting the staple fibers. The device according to the invention is characterized in that the liquid-transport device (2) is provided with a portion (4) shaped as a syphon (4).

Description

Production equipment of cellulose staple fiber

technical field

The present invention relates to a method and an apparatus for producing cellulose staple fibers.

Background technique

In the conventional manufacturing method of cellulose staple fibers, freshly spun cellulose filaments are chopped into staple fibers in a cutter. Short fibers are transported onwards from the cutter outlet and processed. For example, short fibers are suspended into fiber strands in the fiber suspending device. Subsequently, the fiber strands are subjected to further processing steps such as washing and finishing operations.

The device known from the prior art comprises a cutting device for cutting the filaments into staple fibers and a liquid delivery device for conveying the staple fibers.

According to the prior art, the liquid conveying device is usually configured as a groove whose origin is arranged eg below the shut-off device. A bundle of filaments to be cut enters the cutting device and is cut there into fibers of a certain length, usually by a rotating knife. After chopping, the chopped fibers form fiber bundles or staple fibers. The chopped fibers are flushed from the cutting device into the tank by means of a liquid such as water and are conveyed further in the tank by means of the liquid, eg to a fiber suspension device.

The problem with these known methods and devices arises that the short fibers formed during cutting are not unraveled into individual fibers before forming fiber strands in the fiber suspension device.

Unopened short fibers in the fiber strands cause inhomogeneities in the flushing and exchange properties during the fiber strand reprocessing stage. Typically, short fibers are not rinsed strongly enough, bleached poorly, crosslinked poorly, finished poorly, etc.

Furthermore, unopened staple fibers often cause quality problems during subsequent fiber handling and processing.

Contents of the invention

The object of the present invention is to provide a device and a method by means of which the above-mentioned disadvantages can be avoided and in particular the number and size of unopened short fibers in the fiber strand can be reduced.

This object is achieved by means of a device comprising a cutting device for cutting cellulose filaments into staple fibers and a liquid delivery device for transporting the staple fibers, wherein the liquid delivery device has a part in the shape of a siphon .

It has been found that by using a siphon instead of the trough known from the prior art, a surprisingly better spreading of the short fibers can be achieved during the conveying process.

The liquid and fibers flowing from the shut-off device fill the volume of the siphon. For this purpose, the staple fiber transport is no longer flowing but free-floating. The tendency to agglomerate and the tumbling movement of the short fibers which occur in known flow methods is avoided.

In addition, short fibers are able to swell freely because they are completely wetted by liquid.

Furthermore, the device according to the invention preferably comprises a fiber suspending device for suspending the short fibers into a fiber strand. The liquid delivery device preferably leads from the outlet of the cutting device to the fiber suspending device.

The siphon is preferably in close proximity to the shut-off means.

In a further preferred embodiment of the device according to the invention, a preferably substantially horizontally extending intermediate portion is arranged between the downward branch and the upward branch of the siphon.

The length of said intermediate portion is at least equal to, preferably at least 10 times, most preferably at least 30 times the length of the downward branch of the siphon.

In the middle part, preferably up to several times the length of the downward branch of the siphon, the flow of short fibers continues to form in the tube and the short fibers are even better dispersed.

The two branches of the siphon may be substantially equal in length.

In a further preferred embodiment, it is provided that the liquid supply device has a further part, which is also preferably tubular and leads from the siphon to the fiber suspension device.

Preferably said further portion comprises a downwardly extending section, and furthermore, the downwardly extending section preferably extends substantially vertically downwardly. The vertical height of the downwardly extending section is advantageously substantially equal to the vertical height of a branch of one of the siphons.

By providing a section extending downwards, at the exit of the tubular part of the siphon, the potential energy of the short fibers can be better utilized. During the downward movement, the short fibers are accelerated. For this purpose, it has proven to be advantageous if a hole for venting the tube is arranged high on the siphon.

The downwardly extending section preferably transitions into a further section leading to the fiber suspending means, which preferably extends substantially horizontally.

When the accelerated staple fibers hit the transition at the downwardly extending segment to another segment, the staple fibers are further dispersed.

For this purpose, preferably at the transition point between the downwardly extending section and the further section, a bend is provided downwards, with which bend the impact effect can be even further enhanced.

According to another aspect, the object of the invention is achieved in that the newly spun cellulose filaments are cut into staple fibers in the cutter, and the staple fibers are sent to a fiber suspension device from the cutter outlet. and is suspended in the fiber suspension device into fiber strands, which are subjected to further processing, wherein the transport of the fibers from the outlet of the cutter to the fiber suspension device takes place in the device according to the invention.

Here, the residence time of the fibers in the liquid delivery device is preferably equal to 2 seconds to 40 seconds, more preferably equal to 10 seconds to 30 seconds. The flow velocity of the fibers in the siphon-shaped portion is preferably equal to 0.15 m/s-2 m/s, more preferably equal to 0.3 m/s-1.5 m/s.

In a preferred embodiment of the method according to the invention realized by means of a device with downwardly extending segments, the fibers in the downwardly extending segments are preferably accelerated to 1 m/s-5 m/s The speed of second, is better the speed of 2 m/s-3 m/s.

The apparatus and method according to the invention are especially suitable for the manufacture of solvent-spun cellulose staple fibers. These fibers are also called "Lyocell fibers" and are produced from cellulose solutions in tertiary amine oxides (amine oxidation method).

Description of drawings

Below, describe preferred embodiment of the present invention in detail by drawing and example, wherein:

Fig. 1 schematically represents the basic structure of the above-mentioned type of device;

Fig. 2 schematically represents a preferred embodiment of the device according to the invention;

Figure 3 shows details of a preferred embodiment with respect to the downwardly extending segments.

Detailed ways

FIG. 1 shows a cutting device 1 , a liquid delivery device 2 and a fiber suspension device 3 . The fibers cut into short fibers in the cutting device 1 are flushed with liquid into the liquid delivery device 2 and sent to the fiber suspension device 3 . According to the prior art, the liquid delivery device 2 is configured as a tank which is not completely filled with liquid. The fiber strands are formed in the fiber suspension device 3 and in a subsequent stage the fiber strands are cleaned and reprocessed (not shown).

According to a preferred embodiment of the device according to the invention, as shown in FIG. 2 , the liquid delivery device 2 has a siphon-shaped part 4 which is configured with two branches 5 , 6 . Between the two branches of substantially equal length there is provided a substantially horizontally extending intermediate portion 7 whose length is equal to a multiple of the length of the downwardly extending branch 5 .

At the outlet of the siphon 4 there is a further part 8 leading to the fiber suspending device 3 . The part 8 has a section 9 which extends substantially vertically downwards and merges into a further section 10 which extends substantially horizontally and is also advantageously tubular. The vertical height of the section 9 is substantially equal to the vertical height of the two branches 5 , 6 of the siphon 4 . However, the section 10 could possibly also be open, ie be grooved, for example.

In the preferred embodiment shown in FIG. 3 , at the transition point between the downwardly extending segment 9 and the further segment 10 , a bend 11 is provided downwardly.

Furthermore, in the embodiment shown in FIGS. 2 and 3 , a substantially horizontally extending segment 12 is provided between the outlet of the siphon 4 and the segment 9 . At the transition point between segment 12 and segment 9, air holes (not shown) may be provided on the top surface of the tube.

The function of the device according to Figures 2 and 3 is as follows:

The short fibers cut in the cutting device 1 are blown by means of the liquid out of the cutting device 1 into the part 4 of the liquid delivery device 2 , which part 4 is in the form of a tube, and from there onwards. Since the part 4 is siphon-shaped, the tube is completely filled with liquid before the outlet of the siphon. The fibers are thus conveyed floating and completely surrounded by liquid, so that the short fibers can be wetted freely and unravel better.

After leaving the siphon 4, the fibers fall into the downwardly extending section 9 and are thus accelerated. When the transition point between segment 9 and segment 10 is hit, further unraveling of the short fibers takes place. This effect can even be enhanced by means of the curved portion 11 shown in FIG. 3 . Thereafter, the fibers in the section 10 are fed to the fiber suspending device 3 and formed there into fiber strands in a manner known per se. In section 10 the tube is filled eg about 50% with liquid.

example

In a continuously operating test plant for the production of solvent-spun cellulose staple fibers, the fibers were cut and conveyed in the device according to FIG. 3 .

Thus, the length of the branches 5, 6 of this siphon tubular part 4 is equal to 0.5 meters and the length of the middle part 7 is equal to 10 meters. The flow velocity of the fibers in the siphon tubular portion 4 is approximately equal to 0.45 m/s. In this downwardly extending segment 9 the fiber is accelerated to a velocity of about 2.5 m/s. The total residence time of the fibers in the liquid delivery device 2 is approximately equal to 20 seconds.

To assess the effectiveness of the device, samples were taken of the fiber strands formed in the fiber suspension device. The number of unopened short fibers per 50 ^cm2 fiber strand cross-section is determined. In addition, staple fibers are grouped according to size classes. The amount of unopened short fiber found in each size class is multiplied by a conversion factor as follows:

Size class Conversion factor

＞20mm ×20

20-10mm ×10

10-5mm ×5

5-3mm ×3

(Short fibers with a size less than 3mm are not included in the calculation)

The values thus obtained are added up. From this, the calculation relationship results in a staple length index, which provides information about the mass of the formed fiber strands containing unopened staple fibers.

The short fiber length index of the fiber sliver consisting of fibers conveyed by means of the device according to the invention was 39. In contrast, a fiber strand made of fibers produced in the same way but fed according to the prior art has a short fiber length index equal to 67.

Claims (19)

1, a kind of manufacturing installation of short fiber of cellulose, it comprises that a shearing device (1), that cellulosic filaments is cut into staple fibre carries the liquid transporting apparatus (2) of this staple fibre, it is characterized in that this liquid transporting apparatus (2) has a part that becomes siphon pipe (4) form.

2, device as claimed in claim 1, it also comprises a fiber suspension device (3) that is used for this staple fibre is suspended into fiber strip.

3, device as claimed in claim 1 or 2 is characterized in that, this liquid transporting apparatus (2) leads to this fiber suspension device (3) from the outlet of this shearing device (1).

4, device as claimed in claim 3 is characterized in that, this siphon pipe (4) is close to this shearing device (1).

5, as the described device of one of previous claim, it is characterized in that, this siphon pipe (4) to inferior division with between top set (5,6), be provided with the mid portion (7) that a best basic horizontal is extended.

As the described device of one of previous claim, it is characterized in that 6, the length of this mid portion (7) equals the length to inferior division (5) of this siphon pipe (4) at least, preferably is its 10 times and especially preferably its 30 times at least.

As the described device of one of previous claim, it is characterized in that 7, the length of two branches of this of this siphon pipe (4) (5,6) equates basically.

As the described device of one of previous claim, it is characterized in that 8, this liquid transporting apparatus (2) has one and preferably constitutes tubulose and another part (8) lead to this fiber suspension device (3) from this siphon pipe (4).

9, device as claimed in claim 8 is characterized in that, this another part (8) comprises a segmentation (9) under leading to.

10, device as claimed in claim 9 is characterized in that, this segmentation (9) perpendicular is extended downwards.

As claim 9 or 10 described devices, it is characterized in that 11, the vertical height of the segmentation (9) that this extends is substantially equal to the vertical height of the branch (5,6) of this siphon pipe (4) downwards.

As the described device of one of claim 9-11, it is characterized in that 12, this segmentation (9) of extending is transited into another segmentation (10) of leading to this fiber suspension device (3) downwards.

13, device as claimed in claim 12 is characterized in that, this another segmentation (10) substantial horizontal is extended.

14, as claim 12 or 13 described devices, it is characterized in that, in this segmentation (9) and the transition point between another segmentation (10) of extending, down be provided with a sweep (11) downwards.

15, a kind of manufacture method of short fiber of cellulose, wherein, the cellulosic filaments that newly is spun into is cut off into staple fibre in a cutting machine (1), these staple fibres are sent to a fiber suspension device (3) and are suspended into fiber strip in this fiber suspension devices (3) from the outlet of this cutting machine (1), described fiber strip is accepted further to handle, it is characterized in that, in liquid transporting apparatus (2), carry out of the conveying that be exported to this fiber suspension device (3) of described fiber from this cutting machine (1) according to one of claim 1-3 described filled with fluid.

16, method as claimed in claim 15 is characterized in that, the time of staying of described fiber in this liquid transporting apparatus (2) equals 2 seconds-40 seconds, preferably equals 10 seconds-30 seconds.

As claim 15 or 16 described methods, it is characterized in that 17, the flow velocity of described fiber in the part (4) that becomes the siphon pipe form equals 0.15 meter per second-2 meter per second, preferably equals 0.3 meter per second-1.5 meter per second.

As the described method of one of claim 15-17, it is characterized in that 18, the fiber in this segmentation (9) of extending is accelerated to the speed of 1 meter per second-5 meter per second, the preferably speed of 2 meter per seconds-3 meter per second downwards.

19, as the described method of one of claim 15-18, it is used to make the short fiber of cellulose that the solvent spinning forms.

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