IE69038B1

IE69038B1 - Spinning nozzles

Info

Publication number: IE69038B1
Application number: IE428990A
Authority: IE
Inventors: Stefan Zikeli; Hermann Koberger; Dieter Eichinger; Karin Weinzierl; Raimund Jurhovic; Bernd Wolschner; Heinrich Firgo; Stefan Astegger
Original assignee: Chemiefaser Lenzing Ag
Priority date: 1989-11-29
Filing date: 1990-11-28
Publication date: 1996-08-07
Also published as: NO176445C; YU217990A; FI92845B; ATE127542T1; AU6657690A; ATA272489A; KR0157408B1; PL287957A1; PT8495U; IL96314A0; AT397392B; NO176445B; JPH03174006A; EP0430926A3; EP0430926A2; PT96019A; KR910009969A; PL165105B1; FI905437L; RO108011B1

Abstract

In a spinneret, the spinning plate having the spinning capillaries (9) consists, according to the invention, of a carrier plate (2) having holes (7), especially stepped bores, into which are inserted or pressed small plates (8) containing the capillaries (9). The carrier plate (2) can therefore be of any thickness and consist of material of any strength, in order to achieve a high pressure resistance, without making it difficult to produce closely arranged capillaries (9), since the capillaries can be made in the softer small plates (8).

Description

The invention relates to a spinning nozzle, with a nozzle head and a spinning plate which consists of a stable carrier plate in which holes are provided, inserts being inserted or pressed into the holes, in which inserts the capillaries are formed.

Spinning nozzles are required for the production of fibres, the starting material of the spinning stock consisting of organic or inorganic material. The material, which is capable of flowing and of being pumped and which generally has a very high viscosity, is forced through nozzle capillary tubes which vary in form and is then, depending on the process, hardened into fibres in spinning and after-treatment steps specifically arranged for this.

Characteristics of quality are expected of a good spinning nozzle, such as the quality of the holes (exactness of measurement), the smoothness of the walls of the holes, the sharpness of the edges at the exit from the hole, the smoothness of the floor of the nozzle, corrosion-resistance and specially designed spinning channels. Not least, the requisite strength of the spinning nozzle must be mentioned, - 2 as the spinning nozzle is subjected to enormous compression load while spinning the stock. The use of spinning nozzles or spinning nozzle materials which have high strength is especially necessary when spinning cellulose stocks of high viscosity, as spinning pressures of up to 200 bar can occur.

These problems arise particularly with cellulose solutions which are produced in accordance with the NMMO-process. This process is known for instance from the examples given in DE-OS 29 13 589.

NMMO stands for N-methylmorpholine-N-oxide, a tertiary amine-N-oxide, which has the effect of a solvent on cellulose. Because of the high spinning viscosities, spinning nozzles have to be provided with reinforced spinning plates.

On the other hand, there is a tendency to increase the density of the capillary tubes of the spinning nozzles, in order to increase the performance per unit of surface of the spinning position. The problem then occurring is that the threads tend to stick together.

In order to be able to increase the density of the capillary tubes despite this, the adhesiveness of the threads has to be reduced. This can be realised by a non-soluble liquid being applied to the surface of the newly-extended threads, in order to reduce the effect of the solvent (see DE-AS 28 44 163). Additionally, a polyalkylene ether, particularly polyethylene glycol, may be added to the tertiary amine oxide (see DD-PS 218 121).

There is therefore a demand for a spinning nozzle with a relatively large diameter and high capillary tube density and consequently a large number of capillary tubes, in order to spin the cellulose solution economically. At the same time, the spinning nozzle is to be capable of withstanding high pressures (up to 130 bar). * The known spinning nozzles to an extent have high capillary densities, but cannot withstand high spinning pressures : the spinning I - 3 plate buckles or cracks. Such nozzles are employed in the viscose process.

./ On the other hand, spinning nozzles are known, which are made 5 of special types of steel and which are capable of withstanding high loads. Spinning nozzles of this kind are used in the dry spinning process for plastics. The disadvantage of this nozzle construction is however that as a result of the complex arrangement of the nozzle holes in the nozzle plate, pre-drilling is required in the relatively hard but strong material for the individual spinning capillary tubes, in order to be then able to mount the capillary tubes which have a precise diameter. As a result of the larger diameter of the pre-drilling, only a relatively small number of spinning capillary tubes are possible in the nozzle plate, which in turn results in a reduced capillary tube density. In this regard, it is also already known (DE-A-808872) to bore the pre-bore right through (at the end with a taper) and then to press in a gold insert, in which a capillary is then mounted.

However, with nozzles of this kind, it is also not possible to increase the hole density.

According to GB-PS 1126609, nozzles with interchangeable inserts may be provided. The material of the insert is as hard as or even harder than the material of the carrier plate (see page 1, righthand column, lines 61-63), and the insert has practically the same thickness as the carrier plate (see Figure 1). It is therefore clear that the hole density achieved by this can in no way be greater than when the capillaries are formed directly in the carrier plate.

It is an object of the present invention to provide a spinning nozzle which, on the one hand, withstands high spinning pressures and, on the other hand, has a high capillary tube density (capillary tubes/mm ). .

This object is achieved according to the invention by means of a spinning nozzle of the type initially described, in that platelets - 4 are inserted or pressed in, in which in each case a multiplicity of capillary tubes is formed. It is expedient for this that the carrier plate consist of high-grade steel and that the platelets consist of a material which is less hard than steel, in particular, a precious metal. At present gold, silver and tantalum are preferred.

According to the invention therefore, a carrier plate is used, the strength of which is designed to be sufficiently great for it to withstand high spinning pressures. It can also be made of material of any strength, as it does not itself have any spinning capillary tubes. Platelets, made for example from precious metal, are inserted into or pressed into the holes of the carrier plate, into which platelets, depending on the softness of the metal, the requisite number of spinning capillary tubes may be introduced without pre-drilling.

The holes in the carrier plate are preferably stepped holes, in which the step is located near the external surface of the carrier plate and the smaller diameter is at the external surface of the carrier plate. Consequently, the platelets which are inserted or pressed in are held to an additional extent and are able to withstand very high spinning pressures.

Finally, it is expedient for a perforated plate to be provided on the inside of the carrier plate and for a filter to be positioned between the carrier plate and the perforated plate. The holes of the perforated plate accord with the positioning of the platelets so that the cellulose solution or the polymeric melt is distributed as appropriate. Particles of dirt or undissolved polymeric fragments are retrained by the filter.

The invention is explained in more detail by way of example with reference to the accompanying drawings.

Fig. 1 shows a spinning nozzle according to the invention, in section; - 5 Fig. 2 shows the carrier plate of the spinning nozzle according to Fig. 1, somewhat enlarged compared to Fig. 1 and partially in section; and Fig. 3 shows a platelet to be inserted into the carrier plate according to Fig 2, somewhat enlarged compared to Fig. 2 and partially in section.

The nozzle head 1 (Fig. 1) suitably consists of corrosionresistant high-grade steel. It has heating channels 6 for warming and it forms the upper section of the spinning nozzle, into which the cellulose solution is fed and where it is continually warmed during the spinning.

A perforated plate 3, a filter 4 and a carrier plate 2 are located in the nozzle head 1. These three elements are pressed onto the nozzle head 1 by a threaded nut 5. Soft packing (not illustrated) can be used for sealing.

The carrier plate 2 (see Fig. 2) has several holes, formed as stepped holes 7. (For simplification, only a single hole 7 is illustrated in Fig. 2). Platelets 8 (see Fig. 3) which are made of relatively soft material are pressed into these holes. In this soft material, many capillary tubes 9 can easily be made, close to one another. (For simplification only a single capillary tube 9 is illustrated in Fig. 3).

The holes of the perforated plate 3 are positioned exactly as the holes of the carrier plate 2, the filter 4 lying between them. Depending on the cellulose solution or the polymeric melt, the filters 4 may have pores of widely varying widths and may consist of different materials. Corrosion resistant non-woven metal is preferred. The spinning stock is distributed over the perforated plate 3, is filtered, then enters the holes or stepped openings and from there enters the capillary tubes 9 of the platelets 8. - 6 Despite the high resistance to pressure, a spinning nozzle formed according to the invention can achieve high capillary tube densities. Thus, for example, a spinning nozzle was developed, which has 1147 capillary tubes for a diameter of 45 mm (which is equivalent o to 0.72 capillary tubes/mm ) and which is able for an operating pressure of ca. 85 bar. Another spinning nozzle had 1.19 capillary tubes/mm and was able for an operating pressure of 55 bar.

The construction of the nozzle as a whole from component parts enables individual exchange of carrier plates with precious metal platelets, in which the capillary tubes have varying diameters, lengths and cross-sections.

Claims

1. A spinning nozzle with a nozzle head (1) and a spinning plate which consists of a stable carrier plate (2) in which holes (7) are provided, small plates (8) of a material less hard than steel being inserted or pressed into the holes (7), in which small plates in each case a plurality of capillaries (9) is formed, and the capillary density of the spinning nozzle being at least 0.72 capillaries/mm .

2. A spinning nozzle according to Claim 1, in which the carrier plate (2) consists of high-grade steel.

3. A spinning nozzle according to Claim 1 or Claim 2, in which the small plates (8) consist of a precious metal.

4. A spinning nozzle according to Claim 3, in which the small plates (8) consist of gold or silver.

5. A spinning nozzle according to Claim 3, in which the small plates (8) consist of tantalum.

6. A spinning nozzle according to one of Claims 1 to 5, in which the holes (7) in the carrier plate (2) are stepped bores, the steps being located close to the outer surface of the carrier plate (2) and the smaller diameter being at the outer surface of the carrier plate (2).

7. A spinning nozzle according to one of Claims 1 to 6, in which a perforated plate (3) is provided on the inner side of the carrier plate (2), and in which a filter (4) is disposed between the carrier plate (2) and the perforated plate (3). 8. A spinning nozzle according to one of Claims 1 to 7, in which the nozzle head (1) is provided with heating channels (6) for tempering.

8. - 8

9. A spinning nozzle as defined in Claim 1, substantially as described herein with reference to and as shown in the accompanying drawings.