EP0880611B1 - Method of aerodynamical texturing, texturing nozzle, nozzle head and use thereof - Google Patents

Description

Technical field

The invention relates to a method for aerodynamic texturing of yarn with a Texturing nozzle with a continuous yarn channel, at one end of which the yarn is fed and is discharged at the other end as a textured yarn, with a middle Section compressed air with a feed pressure of more than four bar fed into the yarn channel and in a widening acceleration channel the blast air jet to supersonic is accelerated. The invention further relates to a texturing nozzle, a nozzle core Nozzle head and its use, with a continuous, a compressed air supply having yarn channel, on one side of the yarn can be fed, and on the other side the texturing is feasible.

State of the art

Two types of texturing nozzles have largely become available in air-jet texturing technology enforced. These can be differentiated according to the type of compressed air supply to the yarn channel become. One is the air-jet texturing nozzle based on the radial principle. Doing so the compressed air is supplied via one or more, mainly radially arranged air channels, e.g. according to EP-A-0 088 254. Texturing nozzles according to the radial principle have their Area of application above all for yarns that tend to have lower overdeliveries of less than 100% require. In special cases, with so-called fancy yarns, up to 200% Tradition are allowed. The second type has the axial principle. The Compressed air is fed into an expanded chamber of the yarn channel via axially directed channels guided. Such a solution is shown in EP-A-0 441 925. Texturing nozzles after up to 300% of the axial principle are used, especially with very high traditions even used up to 500% successfully. Differentiate between the two corresponding practical solutions also particularly due to the configuration of the nozzle opening in the area of the nozzle outlet. The solution according to EP-A-0 441 925 has a nozzle opening before the exit end corresponding to a Laval nozzle. The Laval nozzle is characterized by a very small opening angle of about 8 ° to a maximum of 10 °. Is the opening angle equal to or smaller than the so-called ideal Laval angle, the air speed in the nozzle opening can be raised bump-free above the sound limit, provided the air pressure is on the narrowest part of the Laval nozzle above a critical pressure ratio. Laval already had recognized that when the air pressure is reduced, even in an ideal nozzle, the border zone the speed increase in the nozzle. It can be a bump front form with the known shock waves. In most fields of fluid engineering compression shocks are avoided if possible. The texturing process is more complex in that not only a supersonic flow with a gas is required, but at the same time, the yarn is fed through the middle of the nozzle and processed through the butting front becomes. In order to compensate for all flow losses, texturing with air pressures is used from over 4 bar mostly worked over 6 bar. The theoretical maximum speed the air (at a temperature of 20 ° C, an infinite upstream pressure and an ideal Laval angle of less than 10 °) is around 770 m / sec. In reality lies the maximum possible air speed at 12 bar between 500 and 550 m / sec under Mach 2. For this, a scientific investigation in "Chemical fibers / Textile industry May 1981 ". GB-A 2 287 256 shows an older solution the applicant in so far as a mixed yarn consisting of staple fibers and a filament is produced. This was done by nozzle designs known per se assumed, which were designed as Laval nozzles, i.e. with an angle <10 °. The possibility of an increase in performance was not determined. According to the most The texturing process as such on the effect of compression shocks is widespread returned, which are a phenomenon of supersonic flow. The one Texturing nozzle, with ideal Laval angle, textured yarn with a maximum opening angle of 10 ° has long been considered a quality benchmark. Because of this given quality, others could Nozzle shapes are sought. The applicant succeeded, in accordance with EP-A-0 088 254, actually an alternative nozzle shape with a trumpet-shaped nozzle mouth, to develop the so-called Hemajet nozzle. The trumpet shape only appears at first View lying outside the Laval laws. A second investigation (International Textile bulletin yarn production 3/83) showed that even with the trumpet shape a supersonic flow is generated with maximum air velocities in the range of about 400 m / sec. were measured. The practice of yarn finishing has also shown that in special applications the trumpet shape is more advantageous. The Hemajet nozzle is based on a convex exit opening with a simple radius is writable. If you check the extension immediately afterwards to the closest one Position, it follows that this is initially a very short piece in the area of the ideal Laval opening angle is. This is an essential reason why both types of nozzles partly give similar texturing results. Both have been used in different applications Standard nozzles prevailed.

GB-A 839 493 proposes a very special nozzle structure with at least two Pipe inserts. The first tube insert has a slightly smaller diameter than the inside diameter of the second one, such that one between the two pipe inserts Inlet gap for the compressed air is created. The second tube insert extends up to one expanding occasion. This will make the transition between the second pipe insert and the expanding outlet creates an abrupt cross-sectional expansion and a Supersonic flow prevented. The supersonic speed would be one at this point condition continuous course. The pressure of approx. 2 bar is very low and would also question reaching supersonic flow.

Although texturing nozzles based on the radial principle, especially with deep traditions The texturing nozzles according to the axial principle are superior, the article mentioned shows that the Thread tension in the radial principle drops sharply with increasing tradition. It is one Experience shows that the thread tension immediately after the texturing nozzle Quality feature for the texturing is. A good quality comparison (higher / lower values) will be easier if at least 50 m / min. better 100 m / min. Differences in Production speeds are compared. Under quality you can do all sorts Yarn quality criteria are understood. Production conditions are also included, which are not directly as quality criteria on the textured product are measurable, but experience has shown that they must be taken into account. E.g. is strong or slight slagging of the incoming threads a criterion or a value that is above a certain value is no longer permissible. For a direct measurement comparison According to the teaching of the invention, the tensile force on the yarn is preferred after Texturing (in cN, or mean cN) as well as the percentage deviation of the current one Traction (sigma%) selected. The two values can be recorded separately or as a total (AT value). For this purpose, the ATQ measurement and evaluation principle of Applicant in cooperation with the company Retech AG, Switzerland. Yarn speeds below 400 m / min. don't pose any difficulties today. At individual practical applications is at yarn speeds of 400 to 600 m / min. still get a qualitatively accepted texturing. In contrast, one further increase in yarn take-off speed to over 600 m / min. a qualitative Deterioration noted. This is expressed, for example. so that for no explainable reason textured yarn individual loops protrude more from the textured yarn. The Known texturing nozzles, especially with compact yarns, can be of the highest quality Texturing required, only below 400 m / min. Production speed be used. The discharge speed of the Understood yarns from the texturing nozzle. When it comes to texturing, you are therefore familiar with this on the production speed in addition to the quality limit an absolute Texturing limit at which the texturing e.g. due to excessive slagging collapses.

Presentation of the invention

The object of the invention was now either the texturing quality at a increase the given speed or the production speeds e.g. in the range from 400 to 900 m / min. and increase more and also at higher ones Production speeds that are equally good or at least approximately equally good To achieve quality, such as at lower production or yarn speeds. On Another aspect of the task was to create existing systems with minimal effort, be it in terms of quality and / or performance.

The method according to the invention is characterized in that the yarn tension at a product speed of over 400 m / min. increases and the thread tension ratio is optimized to yarn speed in that the blown air jet in the Acceleration channel is accelerated to a speed greater than Mach 2, with the yarn tension of a given yarn quality over a large production speed range is about constant.

The invention further relates to a texturing nozzle, a nozzle core or nozzle head with a continuous yarn channel with an accelerating channel widening on the outlet side and a compressed air supply (P) into the yarn channel, on one side of which yarn can be fed and on the other side of which textured yarn can be drawn off, and is thereby characterized in that the acceleration-effective section adjoining the compressed air bores of the acceleration channel is designed continuously as a supersonic channel, and a length (ℓ ₂ ) of more than 1½ times the diameter (d) at the start of the acceleration channel and a total opening angle (α ₂ ) greater than 10 ° and less than 40 °.

• bei der Anwendung eines für den höheren Machbereich ausgestalteten Überschallkanales trat bei gleicher Produktionsgeschwindigkeit in jedem Fall eine qualitative Verbesserung der Texturierung ein, im Vergleich zum Stand der Technik;
• bei den Texturierdüsen des Standes der Technik stellt man bei Steigerung der Produktionsgeschwindigkeit immer wieder einen starken, graduellen Qualitätsverlust fest. Mit den neuen Texturierdüsen tritt zwar auch ein Qualitätsverlust ein, nur trat dieser bei allen Versuchen in nur kleinem Ausmass und je nach Garntiter erst bei sehr hohen Produktionsgeschwindigkeiten von z.Bsp. über 800 m/min. auf;
• Testversuche mit einzelnen Garntitern wurden bis zu einer Produktionsgeschwindigkeit von 1'000 bis 1500 m/min. durchgeführt, ohne Zusammenbruch der Texturierung.
• Messtechnisch fiel sofort auf, dass die Garnspannung im Durchschnitt um gegen 50 % gesteigert werden konnte. Der gesteigerte Wert blieb zudem über einen grossen Geschwindigkeitsbereich von z.Bsp. 400 bis 700 m/min. nahezu konstant.
• Es hat sicher ferner gezeigt, dass auch in der Wahl des Speisedruckes der Druckluft ein wesentlicher Einflussfaktor liegt. Zur Sicherstellung der höheren Machzahlen wird in vielen Fällen ein höherer Speisedruck benötigt. Dieser liegt etwa zwischen 6 bis 14 bar, kann aber auf 20 und mehr bar gesteigert werden.

It was recognized that the first key to quality was yarn tension after the texturing nozzle. The quality can only be improved if the thread tension is increased. The real breakthrough was only made possible when the flow of the blown air jet was increased over the Mach 2 area. Contrary to the obvious prejudice, this was achieved structurally throughout the specialist world by the design of the acceleration channel according to the invention. Surprisingly, it was possible to confirm with many test series that not only the quality is improved, but that, according to the invention, this is adversely affected to an astonishingly small extent by an increase in the production speed. The inventor recognized that the task can only be solved by intensifying the texturing process. However, the task was only solved with the discovery that the Mach number is a central influencing factor. So far, experts have been too fixated on the flow velocity. However, the speed cannot be increased in the given textile practice over the range mentioned above (below Mach 2). In the prior art, one was guided either by the regularities of the Laval nozzles or by purely empirically determined nozzle shapes that were found to be good. Even a slight increase in the Mach number above 2 already gave significant results. The best explanation for the corresponding intensification of the texturing process is seen in the fact that the speed difference is increased immediately before and after the impact front, which has a direct effect on the corresponding attack forces of the air on the filaments. The increased forces in the area of the butt front cause an increase in the yarn tension. By increasing the Mach number, the action on the front is immediately increased. Accordingly, the yarn tension could be increased significantly with the new invention, and the quality could be ensured to an extent not previously possible. According to the invention, the law was recognized: higher Mach number = stronger impact = more intensive texturing. The intensified supersonic flow covers the opened yarn on a wider front and much more intensely. This ensures that no loops can move sideways across the effective zone of the butt front. Since the generation of the supersonic flow in the acceleration channel is based on the expansion, a higher Mach range, e.g. instead of Mach 1.5 Mach 2.5 also an increase or almost a doubling of the effective outlet cross-section. Various surprising observations could already be made with the first series of experiments:

• when using a supersonic duct designed for the higher Mach range, the quality of the texturing improved in each case at the same production speed compared to the prior art;
• With the texturing nozzles of the prior art, a strong, gradual loss of quality is repeatedly observed when the production speed is increased. With the new texturing nozzles there is also a loss of quality, but this only occurred to a small extent in all tests and, depending on the yarn titer, only at very high production speeds of e.g. over 800 m / min. on;
• Test trials with individual yarn titers were carried out up to a production speed of 1,000 to 1,500 m / min. performed without breakdown of texturing.
• From a measurement point of view, it immediately became apparent that the yarn tension could be increased by around 50% on average. The increased value also remained over a large speed range of e.g. 400 to 700 m / min. almost constant.
• It has also shown that the choice of feed pressure for the compressed air also has a significant influence. In many cases, a higher feed pressure is required to ensure the higher Mach numbers. This is approximately between 6 and 14 bar, but can be increased to 20 and more bar.

The comparison tests, the state of texturing technology and the new invention resulted in one the following regularity: the texturing quality is at a higher production speed compared to the texturing quality at lower Production speed with one designed for the lower mach area Supersonic duct at least the same or better. The texturing process is at Air speeds in the shock front of over Mach 2, e.g. at Mach 2.5 to Mach 5 so intense that almost at the highest yarn throughput speeds without exception, all loops are sufficiently gripped and well integrated in the yarn. The Generation of an air speed in the high Mach range within the Acceleration channel does two things. First, the individual filaments become stronger opened and torn into the nozzle with greater force. The texturing breaks up to maximum speeds no longer together. Second, the whole Filament composite evenly and directly into the inside of clear outer channel boundaries Frontal zone led.

The new invention also allows for both the method and the device whole number of particularly advantageous configurations. It will also refer to the Claims 2 to 10 and 12 to 17 referenced. In the acceleration channel that is Yarn from the accelerating air jet over the corresponding distance drawn in and opened, and handed over to the subsequent texturing zone. On An essential point in texturing technology is that the end processor once for well-received quality can be maintained unchanged in further production. The constancy the same quality is often the top priority. This will be particularly good with the new solution achieved because the factors determining the texturing are more manageable than in the state of the art. The main point for this is mastering the yarn tension especially with regard to the constancy of the thread tension and the constancy of the Texturing quality. The compressed air is preferably in the acceleration channel via a Length of at least 1.5, preferably at least 2 times the narrowest diameter accelerated, the ratio of outlet to inlet cross section of the Acceleration channel is greater than 2. The total opening angle of the blowing air jet should be larger than 10 °, i.e. larger than the ideal Laval angle. So far the best The result is achieved when the acceleration of the blast air jet has been steady. There were but also examined different variants with different accelerations. The Results were almost as good as steady acceleration with one continuous conical acceleration channel. The blow air jet is then connected to the Acceleration channel without redirection, through a discontinuous and strongly expanding Section led. There can be one or more yarn threads with the same or different Tradition introduced and with a production speed of 400 to over 1200 m / min. be textured. The compressed air jet in the supersonic duct is reduced to 2.0 to 6 Mach preferably accelerated to 2.5 to 4 mach. The best results were achieved if the exit end of the yarn channel is delimited by an impact body, such that the textured yarn passes through a gap approximately perpendicular to the yarn channel axis is dissipated.

Furthermore, the blowing air is particularly preferably guided from the feed point into a cylindrical section of the yarn channel directly in an axial direction at an approximately constant speed up to the acceleration channel, the compressed air being introduced into the yarn channel via one or more, preferably three or more, bores or channels is such that the compressed air is blown in at an angle (β) with the delivery component in the direction of the acceleration channel. Surprisingly, very good results have enabled air-jet texturing nozzles to be modified according to the radial principle in accordance with the new invention, that is to say texturing nozzles according to EP-A-0 088 254, which is explained as part of this application for their technical designs. The compressed air is preferably introduced into the yarn channel via three bores, such that the compressed air is blown in at a corresponding angle with the conveying component in the direction of the supersonic channel. As in the prior art, the new solution can also be used to texturize one or more yarn threads with a wide variety of traditions. The entire theoretically effective expansion angle of the supersonic channel should be from the smallest to the largest diameter above 10 °, but below 40 °, preferably within 12 ° to 30 °, particularly preferably 12 ° to 25 °. According to the current roughness values, there is an upper limit angle (total angle) of 35 ° to 36 °, above which there is always one to prevent the supersonic flow from breaking off. In a conical acceleration duct, the compressed air is accelerated essentially continuously. The nozzle channel section immediately upstream of the supersonic channel is preferably approximately cylindrical, with the delivery component being blown into the cylindrical section in the direction of the acceleration channel. The pulling force on the yarn is increased with the length of the acceleration channel. The expansion of the nozzle or the increase in the Mach number results in the intensity of the texturing. The acceleration channel should have at least a cross-sectional expansion range of 1: 2.0, preferably 1: 2.5 or greater. It is further proposed that the length of the acceleration channel is 3 to 15 times, preferably 4 to 12 times larger than the diameter of the yarn channel at the start of the acceleration channel. The acceleration channel can be completely or partially continuously expanded, have conical sections and / or have a slightly spherical shape. However, the acceleration channel can also be formed in stages and have different acceleration zones, with at least one zone with high acceleration and at least one zone with low acceleration of the compressed air jet. The exit area of the acceleration channel can also be cylindrical or approximately cylindrical and the entry area can be greatly expanded, but expanded less than 36 °. If the boundary conditions for the acceleration channel have been complied with according to the invention, the aforementioned variations of the acceleration channel have proven to be almost equivalent or at least equivalent. The yarn channel then has a strongly convex, preferably trumpet-shaped, more than 40 ° widened yarn channel mouth, the transition from the supersonic channel into the yarn channel mouth preferably being discontinuous. A decisive factor was found in the fact that the impact conditions in the texturing space can also be positively influenced and kept stable with an impact body. A preferred embodiment of the texturing nozzle according to the invention is characterized in that it has a continuous yarn channel with a central cylindrical section into which the air supply opens, and in the thread running direction a preferably conical acceleration channel directly adjoining the cylindrical section with an opening angle (α ₂ ) greater than 10 ° , and has a subsequent extension section with an opening angle (∂) greater than 40 °, the extension section being conical or trumpet-shaped.

The invention further relates to a nozzle head with a texturing nozzle with a yarn channel, which has an inlet section in the yarn conveying direction, a cylindrical central section with the compressed air supply, and an expanded air acceleration section and a preferably deliverable impact body on the outlet side, and is characterized in that the acceleration-effective section subsequently adjoins the compressed air bores (15) of the acceleration channel are continuously designed as supersonic channels, and have a length (ℓ ₂ ) of more than 1½ times the diameter (d) at the beginning of the acceleration channel and a total opening angle (α ₂ ) greater than 10 ° and less than 40 ° . The yarn channel is preferably formed with the central section and the air acceleration section in a nozzle core that can be installed and removed.

The invention was also based on the object of improving the quality and / or the production speed in an existing system. The solution according to the invention is characterized by the use of a nozzle core, as a replacement for an existing nozzle core (or an entire nozzle head with a nozzle core) for increasing the production speed and / or for improving the texturing quality according to claim 21. The nozzle core or the entire nozzle head have identical fitting dimensions as the nozzle cores or the nozzle heads of the prior art. The new replacement nozzle core has an air acceleration section with a length (ℓ ₂ ) of more than 1.5 times the diameter (d) at the beginning of the acceleration channel (11) and a total opening angle (α ₂ ) greater than 10 °.

The tests carried out to date have also shown that moistening of the yarn brings better results before texturing with the new invention. But it was still not possible, the influence of the condensation surge known in the professional world to clarify finally.

Brief description of the invention

die Figur 1

die Mündung einer Düse des Standes der Technik;

die Figur 2

ein Beispiel für eine erfindungsgemässe Gestaltung des Beschleunigungskanales;

die Figur 3

ein erfindungsgemässer Düsenkern gemäss Figur 2;

die Figur 4

eine Texturierdüse bzw. ein Düsenkopf mit eingebautem Düsenkern im Einsatz mit einer Qualitätsmessung;

die Figur 4a

ein Messverlauf des AT-Wertes während einer kurzen Messzeit;

die Figur 5

ein Düsenkern des Standes der Technik gemäss EP-PS Nr. 88 254;

die Figur 6

ein erfindungsgemässer Düsenkern mit gleichen äusseren Einbauabmessungen;

die Figur 7

einige vorteilhafte Ausgestaltungen für den erfindungsgemässen Beschleunigungskanal;

die Figur 8

eine Texturierdüse bzw. Düsenkopf teilweise im Schnitt;

die Figur 8a

einen Teilvergrösserung der Figuren 8 in dem Austrittsbereich der Texturierdüse;

die Figur 9

ein Vergleich von texturiertem Garn gemäss Stand der Technik/neue Erfindung in Bezug auf Garnspannung;

die Figur 10

Qualitätsmesswerte im Vergleich Stand der Technik und verschiedener erfindungsgemässer Düsen in tabellarischer Form;

die Figur 11

Vergleichsaufnahmen von texturiertem Garn, Stand der Technik (rechts);

die Figur 11a

erfindungsgemäss verarbeitetes Garn (links);

die Figur 12

Messdispositiv für Vergleichsmessungen, Stand der Technik/ neue Erfindung;

die Figur 13, 13a und 14

Einzelkraft-Dehnung als Vergleich Stand der Technik (Figur 13, 13a) sowie neue Erifndung Figur 14;

The invention will now be explained in more detail by means of some examples. Show it:

the figure 1

the mouth of a prior art nozzle;

the figure 2

an example of an inventive design of the acceleration channel;

the figure 3

an inventive nozzle core according to Figure 2;

the figure 4

a texturing nozzle or a nozzle head with built-in nozzle core in use with a quality measurement;

the figure 4a

a measurement curve of the AT value during a short measurement time;

the figure 5

a nozzle core of the prior art according to EP-PS No. 88 254;

the figure 6

a nozzle core according to the invention with the same outer installation dimensions;

the figure 7

some advantageous configurations for the acceleration channel according to the invention;

the figure 8

a texturing nozzle or nozzle head partly in section;

the figure 8a

a partial enlargement of Figures 8 in the outlet area of the texturing nozzle;

the figure 9

a comparison of textured yarn according to the prior art / new invention in relation to yarn tension;

the figure 10

Quality measurement values in comparison with the prior art and various nozzles according to the invention in tabular form;

the figure 11

Comparative pictures of textured yarn, state of the art (right);

the figure 11a

yarn processed according to the invention (left);

the figure 12

Measuring device for comparative measurements, state of the art / new invention;

Figures 13, 13a and 14

Single force expansion as a comparison of the prior art (FIGS. 13, 13a) and new invention in FIG. 14;

Ways and implementation of the invention

In the following, reference is now made to FIG. 1, which represents only the area of the nozzle mouth of a known texturing nozzle, in accordance with EP-A-0 088 254. The corresponding texturing nozzle 1 has a first cylindrical section 2, which at the same time also has the same corresponds to the narrowest cross section 3 with a diameter d. From the narrowest cross-section 3, the yarn channel 4 begins to expand in a trumpet shape, the shape being able to be defined with a radius R. On the basis of the supersonic flow that occurs, a corresponding impact front diameter DAs can be determined. On the basis of the butt front diameter DAs, the detachment or tear-off point A ₁ can be determined relatively precisely, which is slightly larger than the clear diameter of the nozzle. If a tangent is now created on both sides in the area of the removal point A ₁ , an envelope cone with an opening angle α ₁ of approximately 22 ° results. This means that in the case of the mentioned nozzle shape with a corresponding surface texture, the butt front detaches at an opening angle of 22 °. For the peculiarities of the shock front, reference is made to the scientific studies mentioned at the beginning. The acceleration range of the air can also be defined by the length ℓ ₁ from the point of the narrowest cross-section 3 and the tear-off point A ₁ . Since it is a real supersonic flow, the air speed can be roughly calculated from this. VDa is the highest air speed. Vd is the speed of sound at the narrowest point 3. In the present example, the following values were calculated: The d ≅ 1.225; FA F3 ≅ 1.5; ℓ 1 d <1.0;

If at Vd an air speed of 330 m / sec. is present (Mach 1), then Mach 1.8 (M _Da ) results at the exit A from the supersonic area. These values are close to the measured values according to the textile bulletin. The actual acceleration distance within the supersonic channel is very short and, as was recognized on the basis of the new invention, too short. F ₃ or F _A means the area at the point in question.

FIG. 2 now shows an example of an embodiment of the acceleration channel 11 according to the invention, which corresponds to the length ℓ ₂ . The texturing nozzle 10 according to the invention corresponds in the example shown up to the narrowest cross section 3 to the nozzle core according to FIG. 1, but is then different. The opening angle α ₂ is specified at 20 °. The drainage point A ₂ is located at the end of the supersonic duct, where the yarn duct merges into a discontinuous, strongly conical or trumpet-shaped extension 12 with an opening angle ∂> 40 °. Due to the geometry, there is a butt front diameter DAE which is significantly larger than in FIG. 1. The following relationships result in FIG. 2: L2 / d = 4.2; Vd = 330 m / sec. (Mach 1); DAE d ∼ 2.5 → M DE = Mach 3.2

According to the new invention, an extension of the acceleration channel 11 with a corresponding opening angle increases the butt front diameter D _AE . Various studies have shown that the previous assumption, for example according to textile practice, that the texturing is a result of multiple knock-out penetrations of the yarn is at least partially incorrect. Immediately in the area of the shock front formation is the largest possible compression shock front 13 with subsequent abrupt pressure increase zone 14. The actual texturing takes place in the area of the compression shock front 13. The air moves about 50 times faster than the yarn. Many tests have shown that the detachment point A ₃ , A _{4 can} also migrate into the acceleration channel 11, namely when the feed pressure is reduced. In practice, it is now a matter of determining the optimum feed pressure for each yarn, the length (ℓ ₂ ) of the acceleration channel being designed for the worst case, that is to say it is chosen somewhat too long. In contrast, an increase in the feed pressure in the solution of the prior art does very little, since the separation point is almost unaffected by the pressure.

In the following, reference is now made to FIG. 3, which is a preferred one Embodiment of an entire nozzle core 5 shows in cross section. The outer fit is preferably adapted exactly to the nozzle cores of the prior art. This affects before all the critical installation dimensions, the bore diameter BD, the total length L, the Nozzle head height KH, as well as the distance LA for the compressed air connection P '. The attempts have show that the previous optimal injection angle β can be maintained, as can the Location of the corresponding compressed air bores 15. The yarn channel 4 has in the inlet area of the yarn, arrow 16, a yarn insertion cone 6. By in the yarn transport sense (Arrow 16) directed compressed air via the oblique compressed air bores 15, after backward exhaust air flow reduced. The dimension "X" (FIG. 6) indicates that the Air drilling preferably at least about the size of the diameter of the narrowest Cross section 3 is set back. Seen in the direction of transport (arrow 16), the Texturing nozzle 10, or the nozzle core 5 a yarn insertion cone 6, a cylindrical middle section 7, a cone 8, which is simultaneously the acceleration channel 11 corresponds, as well as an expanded texturing space 9. The texturing room becomes transverse to Flow limited by a trumpet shape 12, which is also an open conical funnel can be trained.

FIG. 4 shows an entire texturing head or nozzle head 20 with a built-in one Nozzle core 5. The unprocessed yarn 21 is fed to the texturing nozzle via a feed mechanism 22 fed and transported as textured yarn 21 '. In the exit area 13 of the There is an impact body 23 for a texturing nozzle. A compressed air connection P 'is on the side of the Nozzle head 20 arranged. The textured yarn 21 'runs at a transport speed VT via a second delivery unit 25. The textured yarn 21 'is via a quality sensor 26 led e.g. with the market name HemaQuality, called ATQ, in which the Tensile force of the yarn 21 '(in cN) and the deviation of the instantaneous tensile force (sigma%) is measured. The measurement signals are fed to a computer unit 27. The Appropriate quality measurement is a prerequisite for optimal monitoring of the Production. Above all, the values are also a measure of the yarn quality. in the Air bubble texturing process is difficult to determine quality in that no defined one Loop size exists. There is much better deviation from that of the customer as good quality. This is possible with the ATQ system because the Yarn structure and its deviation determined via a thread tension sensor 26 evaluated and the AT value can be displayed by a single key figure. On The thread tension sensor 26 detects in particular the analog electrical signal Thread tension after the texturing nozzle. The mean and variance are the Thread tension measured values continuously calculated the AT value. The size of the AT value is from The structure of the yarn depends on the user and his own Quality requirements determined. The thread tension changes during production or the variance (uniformity) of the thread tension, the AT value also changes. Where the upper and lower limits can be with yarn mirrors, knitting or Tissue samples can be determined. They differ depending on the quality requirements. The A very special advantage of the ATQ measurement is that different types of interference from the Process can be recorded simultaneously. E.g. Equality of texturing, Thread wetting, filament breaks, nozzle contamination, impact ball spacing, hotpin temperature, Air pressure differences, POY plug-in zone, thread pattern, etc. Figure 4a is a Display pattern for the course of the AT value during a short measurement time.

Figures 5 and 6 show a multiple magnification compared to the actual size of the nozzle cores; 5 shows a nozzle core of the prior art, FIG. 6 shows a nozzle core according to the invention. Since the new invention succeeded in solving the problem inside the nozzle core, the new nozzle core could be designed as an exchange core for the previous one. In particular, the dimensions B _d , E _L as the installation length, L _A + K _H and K _H are therefore preferably not only produced in the same way, but also with the same tolerances. The trumpet shape in the outer exit area is also preferably produced in the same way as in the prior art, with a corresponding radius R. The impact body can have any shape: spherical, spherical flat or even in the form of a spherical cap (FIG. 8a). The exact position of the impact body in the exit area is maintained by maintaining the outer mass, corresponding to an equal withdrawal gap S _p1 . The texturing space 18, which is denoted by 17 in FIG. 5, remains unchanged on the outside, but is now defined in the backward direction by the acceleration channel 11 according to the invention. Depending on the level of the selected air pressure, the texturing space can also be enlarged into the acceleration channel, as indicated by two arrows 18 in FIG. 6. As in the prior art, the nozzle core is made from a high-quality material such as ceramic, hard metal or special steel and is actually the expensive part of a texturing nozzle. It is important with the new nozzle that the cylindrical wall surface 21 and the wall surface 22 are of the highest quality in the area of the acceleration channel. The nature of the trumpet extension is determined with regard to the yarn friction.

FIG. 7 shows differently designed supersonic channels. Sometimes only that Opening angle specified for a section of the supersonic duct. Against everyone The variations between the test results were not very large. As The best forms were obtained from purely conical acceleration channels with an opening angle over 12 ° between 15 ° and 25 ° (far left in the picture). The vertical column a shows pure Cone shapes, for rows b and c a combination of cone shape and short cylindrical sections, whereas the row d a parabolic acceleration channel according to the invention having. The minimum total opening angle of the acceleration channel is defined here as the angle between the tangents to the parabola at the transition to the straight-line part of the nozzle channel. Row c shows a combination of cone and trumpet shapes. At In rows f and g, the first section of the acceleration channel is greatly expanded and goes then into a cylindrical part. Tests with all types have remarkably good ones Results were brought, with best results so far being determined with rows a and d. For understanding it is not unimportant that the central cylindrical section unites Has diameter in the range of millimeters or even less than 1 mm. The length of the Accelerating section is in the range of about 1 cm or less.

FIG. 8 shows an entire nozzle head 20, with a nozzle core 5 and one Impact body 14, which is anchored via an arm 23 in a known housing 24 is. For threading the impact body 14 with the arm 23 in a known manner drawn away from the working area 13 of the texturing nozzle according to arrow 25 or swung away. The compressed air is from a housing chamber 27 through the Compressed air holes supplied. The nozzle core 5 is a clamp 28 on the Housing 24 firmly clamped. Instead of a spherical shape 30, the impact body can also be a Dome shape 31 have.

FIG. 8a shows the combination of a texturing nozzle according to the invention with some variations in the shape of the impact body 14. The impact ball 14 easily penetrates into the trumpet-shaped opening of the nozzle. A normal working position is shown with a dashed line in FIG. 6, dash-dotted lines, the impact ball touching the trumpet shape 12. The dash-dotted position can be used as a starting position for the exact position in the working position. Due to the trumpet shape 12 on the one hand and that of the impact body 14 on the other hand, there is an internal texturing space 18, as well as a free gap Sp ₁ for the flowing texturing air and for the removal of the textured yarn. The gap Sp ₁ is determined empirically based on the yarn quality, optimized and determined for production. The texturing space 18 is given a shape and size that can be influenced, depending on the ball diameter and shape of the impact body. The inventor has determined that the pressure ratios for the acceleration channel can be set primarily with the size of the trigger gap. By reducing the discharge gap Sp ₁ , the flow resistance and the static pressure in the texturing space change. Gap width changes on the order of tenths of a millimeter are decisive for the pressure setting. For the previous experiments, circular cross sections and supersonic channels formed symmetrically in the longitudinal section were used. The new solution can also be used for asymmetrical cross-sections that differ from the circular shape, for example with regard to the supersonic duct. be formed with a rectangular cross section or with an approximate rectangle or approximately oval shapes. It is also possible to design a nozzle so that it can be opened for threading. Reference is made to the international application PCT / CH96 / 00311, which is explained for the technical content as an integral part of the present application.

FIG. 9 shows the texturing of the prior art in a purely schematic manner at the bottom left. Two main parameters are highlighted. An opening zone Oe-Z1 and a butt front diameter DAs, starting from a diameter d, corresponding to a nozzle as shown in FIG. 1. In contrast, the new texturing is shown in the top right. It is very clear that the values Oe-Z2 and DAE are significantly larger. Another interesting aspect was also identified. The yarn opening begins before the acceleration channel in the area of the compressed air supply P, that is to say already in the cylindrical section, which is denoted by V ₀ as the pre-opening. The dimension Vo greater than d is preferably selected.

The essential statement of FIG. 9 lies in the diagrammatic comparison of the State-of-the-art yarn tension (curve T 311) with Mach <2 and one Texturing nozzle according to the invention (curve S 315) with Mach> 2. In the vertical of the The diagram is the thread tension in cN. In the horizontal is the production speed Pspeed shown in m / min. Curve 311 leaves this clear The yarn tension collapses at a production speed of 500 m / min. detect. Above about 650 m / min. the texturing broke down. In contrast to curve S 315 shows with the nozzle according to the invention that the yarn tension is not only is much higher, but in the range of 400 to 700 m / min. is almost constant and also falls slowly in the higher production area. Increasing the Mach number is one of the main "secrets" for progress with the new invention.

FIG. 10 shows a printout of an ATQ quality test. The top table gives that mean tensile stress (cN), the mean the percentage deviation of the current Tensile force (sigma%) and the table below shows the corresponding AT values. On the first horizontal line of each table are the values of a standard T nozzle, that is a texturing nozzle of the prior art. Are from top to bottom then the values of S nozzles according to the invention with different Opening angles from 19 ° to 30.6 °. All of the nozzles according to the invention had the same Length of the supersonic duct. The values 0.00 indicate that either the texturing is not was possible or the experiment was not carried out.

Figures 11 and 11a show a visual comparison using textured yarn. Figure 11 (right half of the picture) shows a texturing with a nozzle of the state of the Technology, at 400, 600 and 800 m / min. Production speed. At 800 m / min. has been also increased the pressure to 12. The result can be up to 400 m / min. as well and at 600 m / min. can be described as conditionally good. On the left half of the picture (Figure 11a) are the results of 5 experiments with a nozzle according to the invention are shown accordingly. It can be seen that even at 800 m / min. Production speed still on conditionally good result is achieved. In contrast, the comparative example (right besides) rejected by the customer according to the state of the art, although a feed pressure of 12 bar was used.

In FIGS. 11 and 11a there was an identical yarn quality and the same conditions tested. Core: PA dtex 78f66x1; Effect: PA dtex 78f66x1; OF 12/30%. Figure 12 shows the Test arrangement for the comparative tests according to FIG. 11. The following were found Measured values determined (setting data and measurement data): (see table state of the art / new Invention)

The analogous statements relating to FIGS. 11 and 12 can also be seen from FIGS. 13, 13a as well as 14. On the left in the picture is a graphic representation of a large number of threads each with the individual force F cN / dtex (vertical) over the elongation E in% (horizontal). Figure 13 belongs to Table 12a, Figure 13a to 12b and Figure 14 to Table 12c. The graphical representation is a single force / Elongation curve.

• anstelle eines Düsenkernes des Standes der Technik ohne irgend welche Änderungen der übrigen Prozessparameter einen erfindungsgemässen einzubauen, mit dem Ergebnis, dass die Qualität stabiler und besser wird;
• oder der Kunde möchte die Produktionsgeschwindigkeit leicht erhöhen. - Der Einbau eines neuen Düsenkernes gestattet die Erhöhung der Produktionsgeschwindigkeit ohne Qualitätseinbusse;
• oder der Kunde möchte die Produktionsgeschwindigkeit stark erhöhen. - Hier kann durch Erhöhung des Speisedruckes der Luft die Qualität ebenfalls sichergestellt werden;
• in jedem Fall kann entweder nur der Düsenkern oder aber der ganze Düsenkopf ersetzt werden.
  

With a relatively small measure, in particular due to the inventive design of the area of the acceleration channel, the new invention has produced many surprising effects. This allows, for example:

• instead of installing a nozzle core of the prior art without any changes to the other process parameters, the result being that the quality becomes more stable and better;
• or the customer would like to increase the production speed slightly. - The installation of a new nozzle core allows an increase in production speed without loss of quality;
• or the customer would like to increase the production speed significantly. - The quality can also be ensured here by increasing the supply pressure of the air;
• in any case, either only the nozzle core or the entire nozzle head can be replaced.
  

The best texturing nozzle to date has a continuous yarn channel with one on the outlet side, the acceleration channel and a compressed air supply (P) into the yarn channel one end of which can be fed with yarn and at the other end of which textured yarn can be removed is on and is characterized in that it has a continuous yarn channel with a middle, cylindrical section, into which the air supply opens, and in

Thread running direction has a conical acceleration channel preferably directly adjoining the cylindrical section with an opening angle (α ₂ ) greater than 10 ° and a subsequent extension section with an opening angle greater than 40 °, the extension section being conical or trumpet-shaped.

The texturing nozzle can be used as a nozzle core, which can be installed and removed in a nozzle head, and forms a nozzle head when installed, or as a nozzle head with built-in nozzle core can be formed, with an outlet side, deliverable on the nozzle core arranged impact body through which the texturing space can be limited.

Claims (17)

1. Process for the aerodynamic texturing of yarn with a texturing nozzle (10) with yarn through-passage (4), at one end of which the yarn (21) is supplied and at the other end of which the textured yarn (21') is discharged, compressed air with a feed pressure (P) higher than four bar being supplied in a middle portion (7) into the yarn passage (4) and the blast air stream being accelerated to supersonic speed in an accelerating passage (11) which widens at the outlet side and the yarn tension being increased at a production rate of above 400 m/min, characterised in that the yarn tension to yarn speed ratio is optimised in that the blast air stream in the accelerating passage (11) is accelerated to a speed higher than Mach 2, the yarn tension of a given yarn quality being approximately constant over a large production rate range.
2. Process according to claim 1, characterised in that at predetermined feed pressure (P) of the compressed air between 6 and 14 bar or higher, the yarn tension of a given yarn quality is approximately constant at a production rate of 400 to 700 m/min.
3. Process according to claim 1 or 2, characterised in that the blast air from the supply point into the yarn passage (4) is conveyed directly in an axial direction at approximately constant speed up to the accelerating passage (11), the compressed air (8) being introduced via one or more holes (15) into the yarn passage (4) in such a way that the compressed air is blown in at an angle (β) with a component in the direction of the accelerating passage (11).
4. Process according to one of claims 1 to 3, characterised in that one or more yarn threads are introduced with identical or different delivery according to the core/sheath principle and are textured at a production rate of 400 to 1500 m/min or higher.
5. Process according to one of claims 1 to 4, characterised in that the compressed air stream is accelerated in the supersonic passage to 2.0 to 6 Mach, in particular to 2.5 to 4 Mach.
6. Process according to one of claims 1 to 5, characterised in that the outlet end of the yarn passage (4) is delimited by an impact element (23) in such a way that the textured yarn (21') is discharged approximately at right angles to the yarn passage axis through a gap (Sp1).
7. Texturing nozzle (10) with a nozzle core (5) with a yarn through-passage (4) with an accelerating passage (11) widening at the outlet side and holes for compressed air (15) into the yarn passage (4), to one side of which yarn (21) can be supplied and at the other side of which textured yarn (21') can be taken off, the accelerating portion adjoining the holes for compressed air (15) of the accelerating passage (11) being formed right-through as a supersonic passage, and having a length (l ₂) greater than 1½ times the diameter (d) at the start of the accelerating passage (11) and an overall angle of aperture (α₂) greater than 10° and smaller than 40°.
8. Texturing nozzle according to claim 7, characterised in that the effective angle of enlargement (α₂) of the accelerating passage (11) is 12° to 30°.
9. Texturing nozzle according to claim 7 or 8, characterised in that the accelerating passage (11) has at least a cross-section which widens from 1 to 2.0 or greater and an overall angle of aperture (α₂) greater than 10°.
10. Texturing nozzle according to one of claims 7 to 9, characterised in that the accelerating passage (11) is conical and in particular passes into a much further widened trumpet-like opening (12).
11. Texturing nozzle according to one of claims 7 to 10, characterised in that the length (l ₂) of the accelerating passage (11) is at least twice as great as the diameter (d) of the yarn passage at the start of the accelerating passage.
12. Texturing nozzle according to one of claims 7 to 11, characterised in that the inlet region of the accelerating passage (11) is cylindrical or approximately cylindrical (VO) and the outlet region is widened by more than 40° at the end of the yarn passage.
13. Texturing nozzle according to one of claims 7 to 12, characterised in that the air bulking texturing nozzle (10) has a compressed air supply (P) according to the radial principle.
14. Nozzle head (20) with a texturing nozzle (10) with a yarn through-passage (4) which in yarn conveying direction has an inflow portion, a cylindrical middle portion with the compressed air supply, and an air acceleration portion (11) widening at the outlet side and an impact element (23) on the outlet side, wherein the yarn can be supplied at the inflow portion and taken off at the impact element side, the accelerating portion (11) adjoining the holes for compressed air (15) of the accelerating passage (11) being formed right-through as a supersonic passage, and having a length (l ₂) greater than 1½ times the diameter (d) at the start of the accelerating passage (11) and an overall angle of aperture (α₂) greater than 10° and smaller than 40°.
15. Nozzle head (20) according to claim 14 with a texturing nozzle (10) with a yarn passage (4) which in yarn conveying direction has an inflow portion, a cylindrical middle portion with the compressed air supply (8) and widened air accelerating portion and an impact element on the outlet side which can preferably be advanced, characterised in that the yarn passage (4) with the middle portion and the air accelerating portion is formed in an attachable/detachable nozzle core (5).
16. Nozzle head (20) according to one of claims 14 or 15, characterised in that the nozzle core (5) has a yarn through-passage (4) with a middle cylindrical portion (7) into which the air supply discharges via holes for compressed air (15) and a conical enlargement portion with an angle of aperture greater than 10° directly adjoining the cylindrical portion (7) in the direction of travel of the thread and an adjoining conical or trumpetshaped widening portion with an angle of aperture (χ) greater than 40°.
17. Use of a texturing nozzle (10) as a nozzle head (20) or nozzle core (5) with a yarn through-passage (4) with an accelerating passage (11) widening at the outlet side and holes for compressed air (15) into the yarn passage (4), to one side of which yarn (21) can be supplied and at the other side of which textured yarn (21') can be taken off, for the aerodynamic texturing of yarn (21), the accelerating portion of the accelerating passage (11) being formed right-through as a supersonic passage and having a length (l ₂) greater than 1½ times the diameter (d) at the start of the accelerating passage (11) and an overall angle of aperture (α₂) greater than 10° and smaller than 40°, in such a way that a supersonic flow of higher than Mach 2 can be achieved in the accelerating passage (11).

Images