The present invention relates to a device for the production of cellusoic staple fibres and process of production thereof,
In conventional process for the production of celluosic staple fibres, freshly spun cellulosic continuous filaments are cut into staple fibres in a cutting machine. From the outlet of the cutting machine, the staple fibres are transported along and treated further. For instance, the staple fibres are suspended to a fleece in a suspension means. Thereafter, said fleece is subjected to further treatment steps such as washing and finishing stages.
Devices known from the state of the art comprise a cutting device for cutting the continuous filaments into staple fibres and a liquid-transport device for transporting the staple fibres.
According to the state of the art, the liquid-transport devicce usually is configured as a groove the beginning of which is arranged, for instance, underneath the cutting device. A bundle of continuous filaments to be cut enters the cutting device and is cut there into fibres of a particular length usually by means of rotating knives. After cutting, the cut fibres from a bundle or staple, respectively. The cut fibres are flushed from the cutting device into the groove by means of a liquid such as water and are transported along in the groove by means of the liquid, (or instance, towards a suspension means.
In those known processes or devices, respectively, the problem arises that the staples formed during cutting fail to dissolve into individual fibres by the time the fibre fleece is formed in the suspension means.
Undissolved staples in the fibre fleece cause non-homogeneities with respect to the wash-out and exchange behaviour in the stages ofaftertreating the fleece. Usually, the staples are washed out worse, bleached less, cross-linked worse, finished worse etc ..
Furthermore, undissolved staples often cause quality problems during the subsequent treatment and processing of the fibres.
The object of the present invention is to provide a device as well as a process by means of which the above mentioned drawbacks are avoided and especially the number of undissolved staples and their sizes (i.e. the number of fibres per staple) in the fibre fleece is to be reduced

That object is achieved by the aid of a device which comprises a cutting device for cuttin« ceilulosic continuous filaments into staple fibres and a liquid-transport device for transporting the staple fibres and which is characterized in that the liquid-transport device is provided with a portion shaped as a syphon.
[t was found that by replacing the groove known from the state of the art by a syphon, surprisingly, a better dissolution of the staples during transport may be achieved.
The syphon is filled to capacity by the liquid emerging from the cutting device together with the fibres. Because of that, the transport of the fibre staples is no longer effected in a streaming but in a freely floating manner. The tendency to agglomeration occurring in the known streaming process and the tumbling staple movement are avoided.
Furthermore, the staples are able to swell freely since they are wetted with liquid from all sides.
Preferably, the device according to the invention furthermore comprises a suspension means for suspending the staple fibres to a fleece. The liquid-transport device preferably leads from the outlet of the cutting device to the suspension means.
Preferably, the syphon is immediately adjacent to. the cutting device.
In a further preferred embodiment of the device according to the invention, an intermediate portion preferably running essentially horizontally is provided between the downward and upward limbs of the syphon.
The length of said intermediate portion is at least equal to, preferably at least 10 times as long as, particularly preferably at least 30 times as long as, the length of the downward limb of the syphon.
In the intermediate portion, which preferably is a few times as long as the length of the downward limb of the syphon, the flow of the staples 'n the tube may develop further and the staples are opened up even better.
The lengths of the two limbs of the syphon may essentially be equal.

Txi a further preferred embodiment it is provided that the liquid-transport device has a further portion preferably also configured as a tube and leading from the syphon to the suspension means.
Said further portion preferably comprises a downward partial section, which, furthermore, nrcftrab!'" leads downward m nn .^soritiaily vertical way. Ih^ "snica! dirrr.ns.ior: of &••*. downward partial section advantageously is essentially equal to the vertical dimension of one of the limbs of the syphon.
By providing a downward partial section, the potential energy of the fibre staples may be utilized even better at the outlet of the syphon-type portion. During the downward movement, the fibre staples are accelerated. To this end, it has proven to be beneficial if an aperture for airing the tube is provided at a high point of the syphon.
Preferably, the downward partial section changes into a further partial section leading to the suspension means, which further partial section preferably runs essentially horizontally.
With the accelerated fibre staples impinging in the passage leading from the downward partial section to the further partial section, a further opening of the staples occurs.
To this end, preferably a downward bulge may be provided at the transitional point between the downward partial section and the further partial section, by means of which bulge the effect of that impact is increased even further.
According to a further aspect, the object of the present invention is achieved by means of a process wherein freshly spun, cellulosic filaments are cut into staple fibres in a cutting machine, the staple fibres are transported from the outlet of the cutting machine to a suspension means and are suspended to a fleece in the suspension means and the fleece is subjected to further treatment steps, which process is characterized in that the transport of the fibres from the outlet of the cutting machine to the suspension means is carried out in a device according to the invention.
In doing so, the retention time of the fibres in the liquid-transport device preferably amounts to from 2 to 40 s, preferably from 10 to 30 s. The flow rate of the fibres in the portion shaped in the manner of a syphon preferably amounts to from 0.15 to 2 m/s, preferably from 0.3 to 1.5 m/s.

In a preferred embodiments of the process according to the invention, which is realized sing a device provided with a downward partial section, the fibres in the downward partial section preferably are accelerated to a speed of from 1 to 5 m/s, preferably from 2 to 3 m/s.
The device according to the invention as well as the process according to the invention are particularly suitable for the manufacture of solvent, spun, cellulose staple fibres. These fibres are also known under the generic name "Lyocell fibres" and are produced from a solution of cellulose in a tertiary amine oxide (amine-oxide process).
Statement of Invention
A device for the production of cellulosic staple fibres comprising a cutting device (1) for cutting cellulosic continuous filaments into staple fibres, a liquid-transport device (2) for transporting the stable fibres, characterized in that the liquid-transport device (2) is provided with a portion shaped as a siphon (4).

In the following, preferred embodiments of the present invention are explained in more detail by way of the figures as well as the examples:
Thereby, Fig. 1 schematically shows the basic structure of the device according to the genus. Fig. 2 schematically shows a preferred embodiment of die device according to the invention. Fig. 3 shows a detail of a preferred embodiment with respect to the downward partial section.
Fig. 1 shows a cutting device 1, a liquid-transport device 2 and a suspension means 3. By means of a liquid, the fibres cut into staple fibres in the cutting device 1 are flushed into the liquid-transport device 2, which, in the state of the art, is configured as a groove not completely liquid-filled, and are transported therein towards the suspension means 3. In the suspension means 3, a fibre fleece is formed, which is washed and aftertreated in further stages (not shown).
According to a preferred embodiment of the device according to the invention, the liquid-transport device 2, as seen in Fig. 2, is provided with a portion 4 which, as a tube shaped as a syphon, is configured with two limbs 5,6. Between the two limbs of essentially equal lengths, an intermediate portion 7 running essentially horizontally is provided, the length of which amounts to a few times the length of the downward limb 5.
At the outlet of the syphon 4, a further portion 8 leading to the suspension means 3 is provided. The portion 8 is provided with a partial section 9 leading downward in an essentially vertical way and changing into a further partial section 10 running essentially horizontally and advantageously being tubular as well. The vertical dimension of the partial section 9 is essentially equal to the vertical dimensions of the two limbs 5,6 of the syphon 4. Optionally, however, the partial section 10 might also be open, i.e., shaped as a groove, for instance.

fn the preferred embodiment shown in Fig. 3, a downward bulge 1 1 is provided at the transitional point between the downward partial section 9 and the further partial section 10
In the embodiment shown in Fig. 2 and 3, furthermore, a partial section 12 running Li:c puri;ui section 9. At the transitional point between the partial section 12 and the partial section 9, air holes (not shown) may be arranged at the top surface of the tube.
The functioning of the device according to Fig. 2 and 3 is as follows:
The staple fibres cut in the cutting device 1 are flushed by means of a liquid from the cutting device 1 into the portion 4 of the liquid-transport device 2, said portion being shaped as a tube, and are transported along from there. Due to the syphon-type configuration of the portion 4, the tube is completely liquid-filled up to the outlet of the syphon. Thus, the fibres are transported in the floating state and are completely surrounded by liquid, whereby tne staples are enabled to swell freely and better opening will occur.
After leaving the syphon 4, the fibres fall down in the downward partial section 9 and hence are accelerated. With the impact on the transitional point between partial section 9 and partial section 10, a further opening of the staples occurs. That effect may even be increased by means of the bulge 11 shown in Fig. 3. Thereafter, the fibres are transported in partial section 10 to the suspension means 3, where a fleece is formed in a manner known per se. In partial section 10, the tube is liquid-filled by about 50%, for instance.
Example
In a continuously operating pilot plant for the production of solvent-spun, cellulosic staple fibres, the fibres were cut and transported in a device according to Fig. 3.
Thereby, the length of the limbs 5,6 of the syphon-type portion 4 amounted to 0.5 m, the length of the intermediate portion 7 amounted to 10 m. The flow rate of the fibres in the syphon-type portion 4 amounted to about 0.45 m/s rn fhe downward partial section 9, the fibres were accelerated to a speed of about 2.5 m/s. The entire retention time of the fibres in the liquid-transport device 2 amounted to about 20 s.

fn order to assess the effect of the device, samples of the fleece formed in the suspension means are taken. The number of undissolved staples per 50 cm2 of fleece cross-section is determined. Furthermore, the staples are grouped according to their size ranges. The number of undissolved staples encountered according to the respective size ranges is multiplied by a conversion factor such as follows:

(Table Removed)(Staples of a size of less than 3 mm are not included in the calculation.)
The values thus obtained are summed up. From this calculation, a characteristic staple number results, which supplies information about the quality of the formed fleece with respect to the undissolved staples contained therein.
The characteristic staple number of the fleece made up of fibres transported by means of the device according to the invention amounted to 39. In contrast to that, the characteristic staple number of a fleece made up of fibres produced in the same way but transported in accordance with the state of the art amounted to 67.

We Claim:
1. A device for the production of cellulosic staple fibres comprising a cutting device (I) for cutting cellulosic continuous filaments into staple fibres, a liquid-transport device (2) for transporting the staple fibres, characterized in that the liquid-transport device (2) is provided with a portion shaped as a syphon (4.).
2. A device as claimed in claim 1, comprising a suspension means (3) for suspending the staple fibres to a fleece.
3. A device as claimed in claim 1 or 2, wherein the liquid-transport device (2) leads from the outlet of the cutting device (1) to the suspension means (3).
4. A device according to claim 3, wherein the syphon (4) is immediately adjacent to the cutting device (1).
5. A device according to any of the preceding claims, wherein an intermediate portion (7) preferably running essentially horizontally is provided between the downward and upward limbs (5,6) of the syphon (4). -

6. A device as claimed in any of the preceding claims, wherein the length of the intermediate portion (7) is at least equal to, preferably at least 10 times as long as, particularly preferably at least 30 times as long as, the length of the downward limb (5) of the syphon (4).
7. A device as claimed in any of the preceding claims, wherein the lengths of the two limbs (5,6) of the syphon (4) are essentially equal.
8. A device as claimed in any of the preceding claims, wherein the liquid- transport device (2) has a further portion (8) preferably configured as a tube and leading from the syphon (4) to the suspension means (3).
9. A device as claimed in claim 8, wherein the further portion (8) comprises a downward partial section (9).
10 A device as claimed in claim 9, wherein the partial section (9) leads downward in an essentially vertical way.
11. A device as claimed in claim 9 or 10, wherein the vertical dimension of the downward
partial section (9) is essentially equal to the vertical dimension of one of the limbs (5,6)
of the syphon (4).
12. A device as claimed in any of the claims 9 to 11,wherein the downward partial
section (9) changes into a further partial section (10) leading to the suspension means (3).

13 A device as claimed in claim 12, wherein the further partial section (10) runs essentially horizontally.
14. A device as claimed in claim 12 or 13, wherein a downward bulge (11) is provided at
the transitional point between the downward partial Section (9) and the further partial
section (10).
15. A process for the production of cellulosic staple fibres, wherein freshly spun,
cellulosic filaments are cut into staple fibres in a cutting machine (1), the staple fibres are
transported from the outlet of the cutting machine (1) to a suspension means (3) and are
suspended to a fleece in the suspension means (3) and the fleece is subjected to further
treatment steps, characterized in that the transport of the fibres from the outlet of the
cutting machine (1) to the suspension means (3) is carried out in a liquid-filled liquid-
transport device (2) according to any of claims 1 to 13.
16 A process as claimed in claim 15, wherein the retention time of the fibres in the liquid-transport device (2) amounts to from 2 to 40s, preferably from 10 to 30s.
17. A process as claimed in claim 15 or 16, wherein the flow rate of the fibres in the portion (4) shaped in the manner of a syphon amounts to from 0.15 to 2 m/s, preferably from 0.3 to 1.5 mis.
18. A process as claimed in any of claims 15 to 17, wherein the fibres in the downward partial section (9) are accelerated to a speed of from I to 5 m/s, preferably from 2 to 3 m/s..
19. A process as claimed in any of claims 15 to 18 for the production of solvent-spun, cellulosic staple fibres.
20. A device for the production of cellulosic staple fibres substantially as herein described with reference to the foregoing example and accompanying drawing.
21. A process for the production of cellulosic staple fibres substantially as herein described with reference to the foregoing examples and accompanying drawing.