Patent Grant
7752723
The invention relates to a method for producing a ceramic nozzle core as part of a device to produce loop yarn, as well as a nozzle core for a device used for producing loop yarn.
The term “texturing” in part still relates to the finishing of spun bundles of filaments and/or the corresponding continuous yarns, with the goal of lending the yarn a textile character. In the following description, the term “texturing” relates to the production of a number of loops on individual filaments and/or the production of loop yarn. An older solution for texturing is described in EP 0 088 254. The continuous filament yarn is supplied to the yarn guide duct at the entry end of a texturing nozzle and textured at a trumpet-shaped outlet end by the impact forces of a supersonic flow. The yarn guide duct is cylindrical and has a constant diameter. The entry is slightly rounded to introduce the untreated yarn without any problems. There is a draw bar at the trumpet-shaped outlet end, with the formation of loops occurring between the trumpet form and the drawbar. The yarn is supplied to the texturing nozzle with excess delivery. The excess delivery is required for the formation of loops at each individual filament, which results in an increase of the titer at the output end.
EP 0 088 254 proceeded from a device for the texturing of at least one continuous yarn comprised of a plurality of filaments. The nozzle has a yarn guide duct as well as at least one feed for the pressure medium, which runs into the duct in radial direction. The generic nozzle had a duct outlet opening that tapered toward the outside and a spherical and/or semi-spherical draw bar that projected into the outlet opening, and formed a ring gap with the same. It was found that with textured yarns, retaining the properties of the yarn during the processing process as well and after the processing process on the finished product is an important criterion for the application of these yarns. Furthermore, the mixing of two or more yarns and the individual filaments of the textured yarns is of significant importance for obtaining a uniform product. The stability is used as criterion for quality.
To determine the instability I of the yarn, small strands of yarn with four coils of 1 meter circumference each are formed on a reel, as is explained with the example of multi-filament yarn on polyester with the titer 167f68 dtex. These small strands are then stressed for one minute at 25 cN, and then the length X is determined. This is followed for another minute with a stress of 1250 cN. After relieve, the strand is again stressed a minute later at 25 cN, and after another minute, the length y is determined. This results in the value of the instability:
The instability indicates the percentage of lasting elongation caused by the applied stress. EP 0 088 254 was then based on the problem to create an improved device of the type mentioned above, which can be used to obtain an optimum texturing effect that ensures a high stability of the yarn as well as a high degree of mixing of the individual filaments. As a solution, it was proposed that as optimum results the outer diameter of the convexly arched outlet opening of the duct is at least equal to four times the diameter of the duct and at least equal to 0.5 times the diameter of the spherical- and/or semispherical draw bar. Production speeds in a range of 100 to over 600 meters per minute were determined. What is interesting is the fact that the applicant was able to successfully market these nozzles for a period of more than 15 years. The quality of the yarns produced with said nozzles was considered very good for one and a half decades. However, there was a growing desire for greater performance. With the solution according to EP 0 880 611, the applicant was able to achieve a massive increase in performance up to far above 1000 meters per minute of yarn transport speed. The core idea for the increase in performance was in an intensification of the flow conditions in the expanding ultrasound duct, i.e., in the zone where the loops are formed. The tension of the yarn at the output of the texturing nozzle was recognized as special testing criterion. Many testing series revealed that with the solution according to EP 0 088 254, the yarn tension drops sharply after a yarn transport speed of approximately 600 m per minute. In the end, this is the explanation for the performance limitations of these types of nozzles. The recommendation in EP 0 880 611, to intensify the flow in the supersonic duct, results in an unexpected increase in the yarn tension, which allowed an increase of the transport speed to over 1000 m per minute. The quality of the yarn processed in this way was initially assessed as equal, if not even better, even at the highest transport speeds. In practice, however, there were some surprises afterwards because in many applications the quality of the yarn did not correspond to the desired demands after all.
In EP 0 880 611 it was realized that the first key for quality lies in the tension of the yarn following the texturing nozzle. Only if it is possible to increase the yarn tension, it is possible to improve the quality. The breakthrough was made possible when the flow of the blast jet was increased to above the range Mach 2. Many series of experiments have confirmed that not only is there an improvement in the quality, but that an increase in the production speed has surprisingly little negative impact on the quality. Even a slight increase of the Mach number above 2 already produced significant results. The best explanation for the corresponding intensification of the texturing process is seen in that the difference in speed is increased directly before and after the shock front, which has a direct effect on the corresponding air attack forces on the filaments. The increased forces in the area of the shock front cause an increase in the yarn tension. By increasing the Mach number, the events at the shock front are directly increased. In accordance with the invention, the following rule was recognized: higher Mach number=greater shock=more intensive texturing. The intensified supersonic flow takes hold of the individual filaments of the opened yarn on a wider front and with much more intensity so that loops cannot escape laterally through the effective zone of the shock front. Because generating the supersonic flow in the acceleration duct is based on the expansion, a higher Mach range, for example Mach 1.5, Mach 2.5, results in an increase and/or nearly a doubling of the effective output diameter. Various surprising observations were made and confirmed in combination with the new invention:
The comparative experiments, state of texturing technology according to EP 0 088 254, and the solution in the scope of EP 0 880 611, resulted in the following rule in a considerably wide area: The texturing quality is at least the same or better at a higher production speed compared to the texturing quality at lower production speed with a supersonic duct designed for the lower Mach range. With air speeds in the shock front of above Mach 2, for example at Mach 2.5 to Mach 5, the texturing process is so intensive that even at the highest yarn throughput speeds, nearly all loops are captured without exception and integrated well in the yarn. Generating an air speed in the high Mach range within the acceleration duct effects that the texturing no longer collapses even at the highest speeds. Secondly, the entire filament composite is guided evenly and directly into the shock front zone within clear outer duct limits.
In the acceleration duct, the yarn is pulled in by the accelerating air jet over the appropriate path, opened farther, and then transferred directly to the subsequent texturing zone. The blast air jet is then guided to the acceleration duct without redirection through a segment that widens unsteadily and strongly. One or a plurality of yarn threads can be inserted at the same or different delivery and textured at a production speed of 400 to 1200 meters per minute. The compressed air jet in the supersonic duct is accelerated to 2.0 to 6 Mach, preferably to 2.5 to 4 Mach. The best results are obtained if the end of the yarn duct at the output side is delimited by a deflector. The textured yarn is discharged through a gap at an approximately right angle relative to the yarn duct axis.
The entire theoretically effective expansion angle of the supersonic duct should be more than 10°, but less than 40°, preferably between 15° to 30° from the smallest to the largest diameter. According to the currently applicable roughness values, the uppermost limiting angle (total angle) relative to the series production is 35° to 36°. In a conical acceleration duct, the compressed air is essentially accelerated steadily. The nozzle duct segment directly before the supersonic duct is preferably designed approximately cylindrically, with the conveyer component being blown into the cylindrical segment in direction of the acceleration duct. The introduction force on the yarn is increased with the length of the acceleration duct. The nozzle enlargement and/or the increase of the Mach number results in the intensity of the texturing. The acceleration duct should have at least one cross-sectional enlargement area of 1:2.0, preferably 1:2.5 or greater. It is furthermore proposed that the length of the acceleration duct is 3 to 15 times greater, preferably 4 to 12 times greater, than the diameter of the yarn duct at the beginning of the acceleration duct. The acceleration duct can be designed to expand completely or in part steadily, it can have conical segments, and/or it can have a slightly spherical form. However, it is also possible to develop the acceleration duct in fine steps and it can have different acceleration zones, with at least one zone with great acceleration and at least one zone of small acceleration of the compressed air jet. If the aforementioned parameters for the acceleration duct were maintained, the aforementioned variations of the acceleration duct proved to be nearly equal in value or at least equivalent. Downstream of the supersonic duct, the yarn duct has a strongly convex, preferably trumpet-shaped yarn duct orifice that is enlarged by more than 40°, with the transition from the supersonic duct into the yarn duct orifice preferably being intermittent. A decisive factor was also found in that a deflector can positively influence and stabilize the pressure conditions in the texturing space. Another preferred embodiment of the texturing nozzle is characterized in that it has a continuous yarn duct with a cylindrical center segment into which the air feed runs.
All earlier experiments only confirmed that for the data determined with texturing nozzles with radial air blast into the yarn duct according to EP 0 088 254, the optimal injection angle for the treatment air is around 48°. As a compete surprise, it was found with the latest experiments that the enlargement of the injection angle with nozzles in accordance with EP 0 880 611 already led to an unexpected increase in the quality of the textured yarn in the first series of experiments. Thereafter, the inventors realized that the two process zones,
From the area of yarn interlacing, which is not an object of the present application, it is known that the yarn opening effect is greatest at an injection angle of 90°. The objective of the interlacing is to form regular knots in the yarn. For an example of interlacing, reference is made to DE 195 80 019. With textured yarn, however, knots are absolutely undesired. There is a limit for the injection angle for the two principally different processes of the formation of knots and the formation of loops. From the various functions for obtaining the highest yarn qualities, even at the highest yarn transport speeds, an unexpected increase was achieved, which is described in detail in the following. At least from the view of the applicant, it was seen as a huge disadvantage that the production of the so-called nozzle cores required high-effort production processes. All attempts with more economic procedures, such as the pressing or injection moulding, for example, failed. In the scope of the allowances, it was not possible to produce acceptable blanks, either in the press- or in the injection molding process. The reason for this was in the specifics of the material, i.e., ceramic. Ceramic is still one of the best materials in view of wear-and-tear and/or resistance.
The new invention was then based on attaining the objective to ensure, on the one hand, all of the known advantages of the described nozzle cores, while on the other hand, develop new production methods that allow an economical production of the nozzle cores.
The method in accordance with the invention is characterized in that the ceramic nozzle core is designed with nearly constant wall strength and its size is reduced to the central functions of the yarn treatment duct with air injection and yarn outlet for the formation of loops, and that it is produced in the molding process.
A very advantageous embodiment is characterized in that the ceramic nozzle core is injection molded in the high precision process.
The nozzle core in accordance with the invention is characterized in that it is developed as a ceramic nozzle core with approximately constant wall strength, that its size is reduced to the central functions of the yarn treatment duct with air injection and yarn outlet for the formation of loops, and that it can be produced in the molding process.
Until now, the applicant proceeded on the assumption that an important criterion for any new development is to develop the nozzle core as a replaceable core so that a nozzle core with other internal dimensions and air inlet angles can be inserted. This makes it possible, for example, to replace an existing state of the art nozzle core with only a few manipulations and to use all advantages of the new development. Only now has the inventor realized that this requirement, which in itself is a positive one, was taken too literal in past developments and strongly inhibited the further development. Consequently, any new nozzle core was developed with outer dimensions that were identical to the old nozzle cores. As a result, the blanks for the nozzle core increasingly could not be produced in the injection- or pressing process any more, and/or the conditions for a production in the molding process became increasingly less favorable. The new invention has let go of the literal urge to develop the ceramic nozzle core as a replacement core. Rather, the development is geared consequently toward the interior central functions. The entire structure can now be determined according to the requirements of injection molding technology and developed, for example, by a division into two, as a ceramic nozzle core in miniaturized fashion with an outer ceramic nozzle jacket. Only the outer jacket receives the dimensions of the nozzle cores of the state of the art, which also take over the function of the replacement core.
The new invention allows a number of especially advantageous embodiments, with reference being made to the claims 4 to 10. An especially advantageous embodiment is characterized in that the yarn treatment duct has at least one cylindrical segment as well as an enlarged segment, with the air injection being arranged within the cylindrical segment, preferably approximately in the center area of the longitudinal side of the ceramic nozzle core. According to EP 0 088 254, the enlarged segment can be developed completely in trumpet-shape, or according to EP 0 880 611 it can have a conical as well as a trumpet-shaped segment. The yarn duct has a center segment, which is preferably cylindrical and transitions into the conical enlargement in transport direction without jump, with the compressed air being blown into the cylindrical segment with sufficient distance to the conically enlarged supersonic duct. The experiments in connection with the new invention revealed several new findings:
With texturing nozzles with intensified supersonic flow according to EP 0 880 611, a quality improvement could be achieved with each yarn titer if the air injection angle was increased to over 48°. The increase in quality begins with a clear-cut rise when the angle is enlarged to over 50°. The yarn quality remains surprisingly stable at air injection angles greater than 52°, partially to 60° and even to 65°. However, the optimum injection angle also depends on the yarn titer.
Preferably, the compressed air is blown into the yarn duct through three borings offset by 120° on the circumference. In any case, what is important is that the opening of the yarn intensifies because of the compressed air being blown into the yarn duct, but that the formation of knots in the yarn is avoided. The opening of the yarn on the one side as well as the texturing of the yarn on the other side must be optimized individually. To optimize these two completely different functions, they have to be separated locally, but performed quickly one after the other so that the texturing follows directly after the opening, and/or that the ending of the yarn opening process directly transitions into the texturing. All central texturing functions for the production of a loop yarn can now be realized within a ceramic nozzle core in miniaturized fashion. The new ceramic nozzle core may be part of a device that has a spherical deflector which can be lowered into the enlargement segment, with the trumpet-shaped segment having a radius that is relative to the diameter of the deflector. Preferably, according to EP 0 088 254, the deflector and the trumpet-shaped segment form a ring gap, with the outer diameter of the convexly arched output opening of the duct being at least equal to four (4) times the diameter of the duct and at least equal to 0.5 times the diameter of the spherical- and/or semi-spherical drawbar.
It is in particular preferred if the nozzle core is designed in two parts and has an outer nozzle body into which the ceramic nozzle core can be inserted, with the outer nozzle body being made of synthetic material. The outer body made of synthetic material then has the function of a replacement body in the previous sense with the required installation dimensions and fastening means. Preferably, a nip is arranged between the outer nozzle body and the ceramic nozzle core to fasten the ceramic nozzle core in the outer nozzle body. Furthermore, an annular compressed air duct is arranged between the ceramic nozzle core and the nozzle body in the area of the cylindrical segment, through which the air is blown in by means of the blow-in borings. The annular compressed air duct has in both end areas of the cylindrical segment one each seal to seal the compressed air.
According to a further embodiment, the nozzle core is designed as a quick replacement element inside the device, so that it can be installed in and removed from the device quickly together with the ceramic nozzle core. The nozzle core can be designed in two parts, with an inner ceramic nozzle core and an outer nozzle body, with both parts being one device with rotary actuator, and the nozzle body being driven with the installed ceramic nozzle core.
In the two-part solution, the ceramic nozzle core and the outer nozzle body form an approximately planar surface at the yarn output end in assembled condition. According to an important requirement of the new solution, the design of the nozzle body is supposed to compensate variations in form and thickness. The structural requirements in view of the assembly and the installation into a machine can be compensated in this manner by the outer nozzle body. The ceramic nozzle core can be designed optimally with respect to the production of ceramic blanks. Especially preferably, the nozzle body is produced as an injection molded part and developed in the outer dimensions as a replacement part with respect to corresponding solutions in the state of the art.
The new invention proceeds from the generic texturing nozzles according to the radial principle. In the radial principle, the blast air is guided from the in-feed location in a cylindrical segment of the yarn duct directly into an axial direction at approximately constant speed up to the acceleration duct. As in the state of the art of EP 0 880 611, the new solution also allows the texturing of one or a plurality of yarn threads with varying delivery.
The invention is shown in detail in the following by means of several examples. Shown are:
In
In
In
In
in
In
In
In
In
In
The following refers to
An extension of the acceleration duct 11 with appropriate opening angle effects an enlargement of the shock front diameter DAE. Directly in the area of the formation of the shock front, the largest possible densification shock front 13 with subsequent abrupt pressure increase zone 14 is created. The actual texturing occurs in the area of the densification shock front 13. The air moves faster than the yarn by a factor of approximately 50. With many experiments, it was determined that the detachment location A3, A4 may also travel into the acceleration duct 11, i.e., specifically if the feed pressure is lowered. In practice, the optimal feed pressure for each yarn must therefore be determined, with the length (l2) of the acceleration duct being designed for the unfavorable case, i.e., it is selected a bit too long. MB denotes the center line of the injection boring 15, MGK denotes the center line of the yarn duct 4, and SM denotes the section of MGK and MB. Pd is the location of the narrowest cross-section at the beginning of the acceleration duct 11, l1 is the distance between SM and Pd, l2 is the distance from Pd to the end of the acceleration duct (A4). Löff denotes approximately the length of the yarn opening zone, Ltex approximately the length of the yarn texturing zone. The yarn opening zone is enlarged backwards in proportion to the size of the angle β.
The following now refers to
a, 4b and 4c show a solution in accordance with the state of the art corresponding to EP 0 088 254, with a long yarn guide duct 29 through which the yarn 30 to be textured runs. The yarn guide duct 29 is supplied with compressed air by a radial compressed air boring 15. With the axis of the yarn guide duct 29, the injection boring 15 encloses an angle α of approximately 48°. The diameter of the injection boring 15 is 1.1 mm. The yarn guide duct 29 has a diameter d1 of 1.5 mm and a convexly curved outlet opening that enlarges toward the outside. The convex curvature has the form of a circular arc with a radius R of 6.5 mm, with the end face 34 of the texturing nozzle 1 forming a tangential plane relative to said circular arc, and with the contact points of the curved arc and the tangential plane being located on a circle with the diameter D. The diameter D corresponds to the formula D=d1+2 R and is thus 14.5 mm. The deflector 10, which has a diameter d2 of 12.5 mm, partially projects into the duct outlet opening 35 and forms a ring gap 31 with the interior wall of the latter. The yarn 30* leaving the nozzle is removed through the edge of the outlet opening.
As shown in
On the lower left,
In practice, the textured yarn runs through a quality sensor after the second delivery system, such as the trademark name HemaQuality, called ATQ, for example, where the tensile force of the yarn 30* (in cN) as well as the deviation of the current tensile force (Sigma %) is measured. The measuring signals are supplied to a computer processor. The appropriate quality measurement is a condition for the optimum monitoring of the production. The values are also an indicator of the quality of the yarn. In the air blow texturing process, the determination of the quality is complicated in that there is no defined loop size. It is easier to determine the deviation from the quality that was assessed as good by the customers. This is possible with the ATQ system because the yarn structure and its deviation is determined by a thread tension sensor, evaluated, and displayed by a single number, the AT value. A thread tension sensor records as an analogue electrical signal in particular the tensile force of the thread after the texturing nozzle. The AT value is calculated continually from the mean value and the variance of the thread tensile force measuring values. The size of the AT value depends on the structure of the yarn and is determined by the user according to his own quality demands. If the tensile force of the thread or the variance (evenness) of the thread tension changes during the production, the AT value changes as well. The upper and lower limit values can be determined with yarn mirrors, knitting- and fabric samples. Depending on the quality demands, they will be different. The advantage of the ATQ measurement is that various types of problems in the process are determined simultaneously, such as, for example, equal positioning of the texturing, thread whetting, filament breaks, nozzle clogging, striking ball distance, hot pin temperature, differences in air pressure, POY plug zone, yarn feed, etc.
The following refers to the
a shows concretely that the cylindrical segment zyl. A. is about twice as long as the enlargement segment EA. Three radial angle of introduction borings 15 are offset backward by a distance ö.A, the opening segment, relative to the enlargement segment EA and are located in the center area of the cylindrical segment, which is illustrated according to the angle of introduction segment (Einbl. A). In the enlargement segment EA, the diameter D as well as the radius R are very important. The cylindrical segment has a diameter Gd. Another important characteristic of the solution according to
b shows two special characteristics compared to
The example according to
| Number | Date | Country | Kind |
|---|---|---|---|
| 946/03 | May 2003 | CH | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CH2004/000202 | 4/1/2004 | WO | 00 | 12/7/2006 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2004/106605 | 12/9/2004 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3389444 | Fletcher et al. | Jun 1968 | A |
| 4507833 | Simmen et al. | Apr 1985 | A |
| 4945718 | Stahlecker et al. | Aug 1990 | A |
| 5119623 | Fetzer et al. | Jun 1992 | A |
| 5326009 | Kobayashi et al. | Jul 1994 | A |
| 5423859 | Koyfman et al. | Jun 1995 | A |
| 5481787 | Sano et al. | Jan 1996 | A |
| 5640745 | Bertsch et al. | Jun 1997 | A |
| 6088892 | Bertsch et al. | Jul 2000 | A |
| 6134759 | Saijo et al. | Oct 2000 | A |
| 6564438 | Bertsch et al. | May 2003 | B1 |
| 7260875 | Stundl et al. | Aug 2007 | B2 |
| Number | Date | Country |
|---|---|---|
| 3927910 | Feb 1991 | DE |
| 195 80 019 | Sep 1996 | DE |
| 0 088 254 | Sep 1983 | EP |
| 0 088 254 | Sep 1983 | EP |
| 1022366 | Jul 2000 | EP |
| 0 880 611 | Aug 2001 | EP |
| 1 058 745 | Feb 2002 | EP |
| 3193905 | Aug 1991 | JP |
| 6200448 | Jul 1994 | JP |
| 11315440 | Nov 1999 | JP |
| 2001159044 | Jun 2001 | JP |
| 2006160446 | Jun 2006 | JP |
| WO 9730200 | Aug 1997 | WO |
| WO 9945182 | Sep 1999 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20070107410 A1 | May 2007 | US |
