GB2123859A

GB2123859A - Fluid entanglement device for yarn

Info

Publication number: GB2123859A
Application number: GB08313940A
Authority: GB
Inventors: Yoshiyasu Maeda
Original assignee: Murata Machinery Ltd
Current assignee: Murata Machinery Ltd
Priority date: 1982-05-21
Filing date: 1983-05-19
Publication date: 1984-02-08
Also published as: FR2527235A1; DE3318494A1; DE3318494C2; GB2123859B; JPS58220839A; GB8313940D0; FR2527235B1; CH662587A5; JPS6110570B2

Abstract

A device for the effective manufacture of bulk yarn employing fluid and comprising two assembled blocks of simple geometric form has a first yarn path part (17) of polygonal cross-section which is defined by planes arranged in the yarn-travelling direction (19). A second part (25a) of the yarn path is provided with a fluid- jetting opening (23) and is formed with a different cross-section. The second, yarn-treating section is defined by curved faces and planes and has a cross-section greater than that of the polygonal part of the yarn path. The bottom portion of the yarn treating section (25a) has a curved face with said fluid-jetting opening (23) therein. A separate covering member encloses the yarn path to define a tunnel-like structure. <IMAGE>

Description

SPECIFICATION Fluid entanglement device for yarn The present invention relates to a device for producing bulked yarn by treating multifilament yarn with fluid.

Techniques for imparting compactness to a multifilament yarn in which the yarn is subjected to the action of a turbulent fluid are well-known.

Examples are to be found in U.S. Patents Nos.

2,036,838, 4,063,338, 3,823,449 and 4,251,904. The purpose of such a yarn treating device is to obtain a synthetic multifilament yarn which offers bulkiness, compactness and convenience for further processing. These qualities are best achieved if open thick yarn portions and compact entangled portions appear alternately. The greater the number of entangled portions per unit length, the stronger the final yarn product becomes.

An air or fluid jet device is preferably employed to obtain these qualities since alternative methods, such as twisting or sizing procedures, have several disadvantages. If the yarn is sized, it is necessary to wash the textiles fabricated therefrom in order to remote paste. If the yarn is twisted, a twisting machine will be required. In any event, the number of treating processes will be increased, a rewinding process will be required, and there will be a higher probability that the yarns will be damaged. The fluid jetting device avoids these procedures and produces the entanglements by fluid turbulence in the yarn path of the device. Such fluid jetting methods enable one to obtain a product of the same quality as twisted yarns with the separation of filaments being controlled in spite of being untwisted.

However, the treating of yarn with fluid has created several problems in connection with certain conventional devices. While the processability of the yarn may be enhanced by imparting compactness and cohesiveness to the yarn by interlacing individual filaments in the yarn, the bulkiness of the yarn decreases and the appearance of a fabric made with such yarn deteriorates as the processability is enhanced.

The relationship between bulkiness and processability is more advantageous if the entangled and not entangled portions appear regular and if the number of entangled portions per unit length is high. Although conventional devices try to achieve a more satisfying relationship between bulkiness, processability and cost, they have been less successful than the device of the present invention. One reason for the limited success of prior art devices may be that in almost all of such conventional devices the yarn path enclosure is cylindrical in form. The cylindrical enclosure is provided with an air jetting port for jetting air on to the yarn, e.g. U.S. Patents Nos. 4,188,692, 4,070,815,4,064,686, 4,063,338 and 4,138,840. The specific construction of such conventional devices differs.

For example, the length or diameter of the cylindrical enclosure may be changed, or a slit may be formed along the length of the cylindrical enclosure in order to make the passage of yarn easy. Nevertheless, they do have the problem that the consumption of air or fluid, and the necessary pressure, is too high compared with the number of entangled portions achieved and the strength of these portions. In addition, the entanglement is not solid enough, and tension and relaxation with only a small force extinguishes the entangled structure of the yarn and the gathering property is frequently lost.

It is an object of the present invention to solve the above-described problems and to obtain with a smaller quantity of fluid a yarn which has a high number of entangled portions of good quality and processability. The special, although simple, construction of the device of the present invention enables one to achieve these advantages.

In accordance with the present invention there is provided a device for entangling yarn comprising a yarn path having portions with at least two different cross-sections, one portion defining a yarn path channel having a first crosssection which is defined by one or more wall planes arranged in the yarn travelling direction and having a first cross-sectional area, and a second portion defining a yarn treating section which is continuous with the yarn path channel and is provided with at least one fluid jet opening, said second portion being defined by curved surfaces to form a second cross-section having a cross-sectional area which is greater than said first cross-sectional area, with at least one fluid jet opening being located in the vicinity of the bottom of said curved surfaces.

In one preferred embodiment the first crosssection is a triangular cross-section. This form of yarn path enclosure ensures a uniformly interlaced yarn because it avoids the unidirectional and continuous rotation during the interlacing procedures. One prior art device that employs a similar construction of the yarn path enclosure is U.S. Patent No. 4,251,904. However, in contrast to that, the yarn path component of the present invention is interrupted by an intersection which constitutes the yarn treating section and is defined by curved faces and planes having a cross-section larger than that of the polygonal part (e.g., triangular cross-section) of the yarn path component. The specific construction of that portion of the yarn path component effects the desired mode of entanglement as described below.

All other known prior art devices differ even more than the aforementioned patent from the present invention. For example, in U.S. Patent No. 4,064,686, the yarn treating portion of the yarn path is also larger than the other portions, but the whole yarn path is purely cylindrical.

A number of embodiments of device in accordance with the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 illustrates schematically a layout of a false twisting machine in which a device in accordance with the present invention can be used; Figure 2 illustrates schematically the yarn obtained from the machine shown in Figure 1 incorporating the device of the present invention; Figure 3 is a perspective view showing one preferred embodiment of a device for treating yarn with fluid according to the present invention; Figure 4 is a plan view of the lower block of the device of Figure 3; Figure 5 is a sectional front view of the device shown in Figure 3 taken along the line V--V; Figure 6 is a sectional side view of the device shown in Figure 3 taken along the line VI-VI;; Figure 7 is a sectional front view of another preferred embodiment of device for treating yarn with fluid according to the present invention; Figure 8 is a sectional side view of the device shown in Figure 7; Figure 9 is a sectional front view showing another preferred embodiment of device for treating yarn with fluid according to the present invention; Figure 10 is a sectional side view of the device shown in Figure 9; Figure 11 is a graph showing the relationship between the air pressure P and the number E of the entangled portions of yarn, comparing the use of a device for treating yarn with fluid as shown in Figures 5 and 6 with the use of certain conventional devices; and, Figure 12 is a graph showing the relationship between the air pressure P and the number E of entangled portions of yarn obtained from similar experiments to those shown in Figure 11, except that the type of yarn to be treated and the speed of the yarn has been changed.

The entanglement device of the present invention comprises a component in the yarn path having a polygonal cross-section (e.g., triangular shape) that is defined by planes lying in the yarn travelling direction. In the vicinity of its central portion, the yarn path component is provided with a fluid jet. The fluid jet has curved surfaces in proximity thereto which may be of part-spherical cross-section ("yarn treating section") with a cross-sectional area larger than that of the polygonal part of the yarn path component.

Individual filaments of a multifiliament yarn passing the yarn treating section are subjected to a different swirling action and disturbing action than those placed in the polygonal part of the yarn path component. Thus, while the multifilament yarn is subjected to the action of rapidly injected flow in the yarn treating section of the yarn path component, the yarn simultaneously collides with the side walls of the polygonal portion of the yarn path component which promote the formation of entanglements. The resulting bulk yarn is produced with a lower consumption of fluid, and its quality is better than the quality of bulk yarn produced by means of a conventional device.

Thus, the device of the present invention is remarkably more effective.

Figure 1 shows one example of the layout of a false twisting machine in which the device of the present invention can be used.

A yarn Y1 is pulled out from a yarn-feeding package 1 by means of a first feed roller 2 and travels vertically upwards through a heater 3, around direction-changing rollers 4 and 5, past a balloon-regulating plate 6 and through a cooling apparatus 7 to be cooled to the desired temperature. The yarn Y1 is then introduced to a conventional false twisting unit 8 of pin-type, belt-type, friction-type or the like, there to be false twisted. The drawn and false-twisted yarn Y1 then travels to a device 10 in accordance with the present invention by way of a guide and a second feed roller 9. After treatment with fluid, the multifilament yarn Y1 leaves the device 10 as an entangled bulky yarn Y2. It is pulled through a second heater 11 by means of a third roller 12 and is wound around a winding package 13.The result is a false-twisted bulk yarn as schematically shown in Figure 2. Open thick yarn portions Y3 and entangled portions Y4 appear alternately. The entangled portions Y4 guarantee convenience in further yarn processing, and the greater the number of entangled portions Y4 per unit length, the stronger the yarn becomes. Therefore, the single filaments can be effectively prevented from becoming separated in the subsequent processes.

Figures 3 and 4 show a preferred embodiment of device 10. The device has a simple geometrical construction; it consists of two blocks 14 and 1 5 and bolts 16 for joining block 14 to block 15. The block 14 forms the yarn path component having a polygonal cross-section which preferably is triangular and forms a triangular cross-section channel or passageway 1 7. The channel is defined by planes or walls extending in the yarn travelling direction. A curved yarn treating section 18 is formed within the length of the triangular channel 17. Block 15 has the function of closing the top side of the yarn path component 14 and of the yarn treating section 1 8 to form a yarn path enclosure or tunnel. Figure 4 is a plan view of the surface of block 14 of the device.

Figures 5 and 6 are sections of the same preferred embodiment of the present invention as is shown in Figures 3 and 4. Figure 5 is a sectional view of yarn path component 14 taken along the line V-V of Figure 3. Figure 6 is a sectional view of yarn path component 14 taken along the line VI--VI of Figure 4. Yarn path component 14 and block 15 form a triangular enclosure surrounded by three side walls 20,21 and 22 parallel to the yarn-travelling direction 1 9.

At its central portion, the yarn path is provided with an air jet 23. The exit of the air jet 24 is surrounded by curved surfaces 25a and 25b each part-spherical in shape and extending beyond the side walls 20 and 21.

The yarn path enclosure has a cross-section which is in the shape of an isosceles or regular triangle with the apex 26 positioned within the yarn path component 14. The diameter D of the part-spherical yarn treating section 1 8 is greater than the length L of the sides of said triangle; preferably, the diameter D is 1.25 to 2.1 times the length L. Preferably also, no side of the triangle has a length which is more than 50% greater than the length of any other side. Accordingly, the partspherical yarn treating section 18 of the yarn path component has a larger cross-section than the triangular channel 17.

Compressed air injected through the air jet 23 collides with the top wall 22 and spreads out towards both sides to generate a swirling or turbulent flow. This causes the entanglement of the bundle of filaments in the following way.

While the bundle of filaments Y is swirled along the part-spherical side walls 25a and 25b in the yarn treating section 18, and is disturbed at random in the region surrounded by said walls 25a and 25b and the top wall 22 by the action of the injected air, the entanglement of the filaments Y is promoted by forces acting on the filaments Y at the boundary portions 27, 27. The forces acting at the boundary portions 27, 27 between the triangular parts of the yarn path and the partspherical part of the yarn path are created by the triangular parts surrounding the part-spherical part and having a smaller cross-section than the cross-section of the part-spherical part of the yarn path.In addition, the routes of yarns are stabilised and the yarns are effectively guided while travelling since both ends of the triangular channel 17, 1 7 have a triangular cross-section.

The operation of the device of the present invention may also be explained as resulting from the filling of the entangled yarn treating section 18 with turbulent yarn until the feeding of the yarn into section 1 8 develops a force which expels the yarn from the section 18. The expelling of the yarn from section 1 8 may carry with it a section of yarn which has not been subjected to the same treatment. The precise nature of exactly what happens is not yet fully understood. It is only clear that the results from the device of the present invention are surprisingly superior to known devices.

Contrary to a conventional device, the device of the present invention does not require guide members for controlling the passage of the yarn at the input side and output side of the device and for achieving the desired results. The desired number of entangled portions, or the number of entangled portions per unit length, or the entangling strength, can be achieved regardless of the absence of guide members.

Figures 7 and 8 show another preferred embodiment of device in accordance with the present invention. Here, the yarn path component 14 has an inverse trapezoidal section or channel 28 and a yarn treating section 29. The section 29 is composed of a curved surface 30 forming a part-spherical section, and a top plane 31 formed by block 1 5 similarly to the above-described preferred embodiment of Figures 3 to 6. The cross-sectional area of the yarn treating section 29 again is larger than that of the polygonal yarn channel 28.

Figures 9 and 10 show still another preferred embodiment of device in accordance with the present invention. The yarn path component 14 has an almost pentagonal channel 32 and a yarn treating section 33 again composed from a curved surface yarn treating section forming a part-spherical section and a top plane 37 formed by block 15 with the air jet exit 24 at the bottom portion of section 33 similar to the abovedescribed embodiments.

In an alternative embodiment the channel for the yarn can be octagonal in cross-section.

The described embodiments of the present invention have in common the fact that the exit 24 of the airjet at the bottom of the partspherical section is positioned at the same level as the bottom line 26, 34 and 35 of the yarn passages 17, 28 and 32 in the different embodiments, and at least one corner of the polygon touches internally with a part of an imaginary circular arc corresponding to the shape of the yarn treating section. Further, in all the embodiments the yarn channels 17, 28 and 32 have a cross-sectional area which is less than that of the yarn treating section, and the walls of the channeis 1 7, 28 and 32 extend in the direction of yarn travel and form a trough to support the yarn.

Experimental examples of the use of a false twisting machine as shown in Figure 1 which incorporates a device in accordance with the present invention will now be described.

Example 1 Figure 11 shows the correlation between the air pressure P (kg/cm2) and the number of entangled portions E (n/m) for polyester yarn of SD (Semi-Dull) of 225/1 50/48 (treated yarns of 150 denier obtained from a bundle of filaments of 225 denier consisting of 48 filaments) treated by means of a device as shown in Figures 5 and 6.

The diameter of the outlet of the air jet is 1.4 mm, the diameter of the yarn treating portion is 2 mm, and angle 6 of the yarn path channel is 600, the speed of the yarn in the channel is 600 m/min, and the overfeed coefficient of the second feed roller 9 and the third feed roller 12 is at least 2%.

The line L1 signifies the relation between pressure P and number of interlaced portions E when using a device according to the present invention, while the line L2 shows the relation for the case when a conventional device with a cylindrical yarn path channel is used. The lines L1 and L2 demonstrate that the number of entangled portions E is 80/m at the air pressure P of 2 kg/cm2 for the case of a device of the present invention, while there are scarcely any entangled portions when using the conventional device at this pressure.In addition, it is clearly seen that the number of entangled portions E is 98/m when using the device of the present invention at an air pressure P of 3 kg/cm2, which is about twice the number of entangled portions E for the case of a conventional device, i.e. 48/m. Thus, for the same air pressure, the device of the present invention is capable of achieving a remarkably greater number of entangled portions than the conventional device. Furthermore, the device of the present invention requires an air pressure P of only 2 kg/cm2 in order to achieve the number of entangled portions E of 80/m, while the conventional device requires for the same number E an air pressure P of about 5 kg/cm2.

Consequently, the air consumption of the device of the present invention is about half that of the conventional device and therefore its efficiency is higher.

Example 2 Figure 12 shows the relationship between the air pressure P and the number of entangled portions E for a second experimental example in which yarns of 11 5/75/36 SD (Semi Dull) are treated by means of the same apparatus. The line L3 shows the relation between the air pressure P and the number of entangled portions E at a yarn speed of 600 m/min using a conventional device.

The lines L4, L5 and L6 show the relationship between the air pressure P and the number of entangled portions E at yarn speeds of 600 m/min, 700 m/min, and 800 m/min, respectively, using the device of the present invention.

With the device of the present invention the number of entangled portions E of 80 to 11 8/m can be achieved at an air pressure P of 2 to 5 kg/cm2 for every speed of yarn, which is remarkably higher than that in the case of the conventional device. In addition, it is found that the device of the present invention can achieve a sufficient number of entangled portions even at the increased speed of yarns. Thus, high speed treatment is possible.

It should be appreciated that the present invention may be implemented in various mechanical arrangements and forms. For example, while the embodiments have been shown using upper and lower block parts, it is possible to implement the invention with two blocks arranged side-by-side or with a single block which is suitably configured internally.

Claims

1. A device for entangling yarn comprising a yarn path having portions with at least two different cross-sections, one portion defining a yarn path channel having a first cross-section which is defined by one or more wall planes arranged in the yarn travelling direction and having a first cross-sectional area,and a second portion defining a yarn treating section which is continuous with the yarn path channel and is provided with at least one fluid jet opening, said second portion being defined by curved surfaces to form a second cross-section having a crosssectional area which is greater than said first cross-sectional area, with at least one fluid jet opening being located in the vicinity of the bottom of said curved surfaces.

2. A device according to claim 1, in which the yarn path channel and the yarn treating section have one wall defined by closure means enclosing the yarn path to form a tunnel-like structure.

3. A device according to claim 1 or 2, wherein the first cross-section is polygonal.

4. A device according to claim 3, wherein the polygon is a triangle.

5. A device according to claim 3, wherein the polygon is a trapezium.

6. A device according to claim 3, wherein the polygon is octagonal in shape.

7. A device according to any preceding claim, wherein the second cross-section is part-circular and forms a part-spherical yarn treating section.

8. A device according to claim 2, wherein the closure means is a separate member fastened to a yarn path component defining the yarn path.

9. A device according to claim 4, wherein the triangular cross-section has one corner thereof substantially aligned with said fluid jet opening.

10. A device according to claim 7 when dependent on claim 4, wherein the ratio of the diameter of the part-circuiar second cross-section to the length of the longest side of the triangular first cross-section is between 1.25 and 2.1 and wherein no side of the triangle has a length which is more than 50% greater than the length of any other side.

11. A device according to claim 7 when dependent on claim 4, wherein the yarn passing through the yarn path is subjected to swirling and disturbing action along the walls of the partspherical section while simultaneously the walls of the triangular channel of the yarn path promote entanglement by frictional force.

12. A device according to claim 1, wherein the wall planes are parallel to the yarn travel direction.

1 3. A device for entangling yarn substantially as hereinbefore described with reference to Figs.

3 to 6, Figs. 7 and 8, or Figs. 9 and 10 of the accompanying drawings.

14. A draw texturing apparatus comprising: a) a draw texturing means for draw texturing multifilament yarn having feed rollers at the output thereof; and b) an air entanglement device as claimed in any preceding claim, with said device receiving said multifilament yarn from said feed rollers.

1 5. An apparatus as claimed in claim 14, wherein the overfeed coefficient is at least 2%.