FIELD OF THE INVENTION

The present invention relates to an improved apparatus for spun yarn/thread forming from bundle of textile staple fibres. Particularly, the invention deals with yarn forming apparatus for use in air jet spinning machines. More particularly, the invention is concerned about an air nozzle block of air jet spinning machines.

BACKGROUND OF THE INVENTION

In the existing air jet spinning machines, the fibre bundle such as roving or sliver is introduced into and drafted by drafting device comprising of back rollers, middle rollers and front rollers and then it is introduced into an air nozzle block where air nozzles inject air towards the fibre bundle. Thereby free fibre ends (tail ends) begin to expand due to the whirling force of the jet air stream and they twine over the hollow spindle. While drawing the fibers through the hollow spindle this twined fibers are whirled around the core fibers and made into vortex yarn. A yarn thus fabricated is wound onto the bobbin to form yarn package. Spinning device of the type mentioned above is known from United States patent number 5,211,001 filed by Murata Kikai Kabushiki Kaisha, Japan.

All air jet spinning apparatus as mentioned above are mounted with an air nozzle block at the fibre bundle introductory part. Said nozzle block is equipped with plurality of air injecting nozzles, which supplies the compressed air tangentially onto the inner wall of the nozzle block. An empty hollow space is provided, where the compressed air meets the fibre bundle hereafter called as chamber. This chamber provides the yarn formation zone in which around the combined air vortex takes place. This optimizes the compressed air required for spin wrapping fibres around the core fibres. Such arrangements are well known from United States patent numbers 4,480,434 filed by Kabushiki Kaisha Toyoda, Japan and 5,398,493 by Koyo Seiko Co. Ltd, Japan.

In general and all of the aforesaid prior arts, the nozzle block uses a circular inner wall profile to which the injecting air is made tangent. By this arrangement, the free fiber ends while spinning are not sufficiently cohere to the core fibre bundle. And plenty of free fibres are pulled out from the core due to escaping velocity of injected air and centrifugal force of the spinning fiber bundle. Such pulled out fibers are eliminated from spinning zone as waste. Since the free fibre ends serves the function of wrapping around the core fibres, their loss leads to insufficient wrapping and results into poor yarn strength. Moreover the usage of circular inner wall profiled nozzle block, directs more wastage of fibres and instantly affects the yarn quality.

Thus, there is a need to overcome the disadvantages of the prior art.

Therefore, the present inventors have provided an improved apparatus for air jet spinning, particularly a unique profiled nozzle block which would ensure the fibers are held firmly with the yarn core during spinning which reduces the fiber lose in staple spinning.

OBJECTS OF THE INVENTION

An object of the present invention is to overcome the problems/disadvantages of the prior art.

Another object of the present invention is to provide an improved apparatus for air jet spinning.

Another object of the present invention is to provide a unique profiled air jet nozzle block which can generate high tangential velocity with more shrinking air vortex.

Another object of the present invention is to inject the escaping and swirling fibres towards the yarn core and thereby increased locking force and twisting efficiency on fibres.

Another object of the present invention is to prepare high strength vortex yarn

Yet another object of the present invention is to minimizing the flying away fibres by fully or partially compensating the centrifugal force of the fibre bundle and thereby reducing the fibre loss.

One more object of the present invention is to reduce the yarn hairiness by enhancing the wrap of fibres around yarn core and thereby increasing the yarn quality.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided an improved apparatus for use in air jet spinning machine for forming yarn/thread from staple fibres, said apparatus comprising:

a unique shaped profiled nozzle block having plurality of substantially circumferential air nozzles, said nozzles being placed equidistantly along the circumference of said nozzle block where air is supplied tangentially towards inner wall of nozzle block; wherein said inner wall of nozzle block is having a substantially eccentric profile for each nozzle.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention there is provided an improved apparatus for air jet spinning. The improved apparatus comprises a unique profiled nozzle block wherein the inner wall is made into eccentric profile cross section. So that the plurality of air nozzles are made to have an eccentric path with the body diameter of the nozzle block. These nozzles axes are configured to be eccentric with center axis of the nozzle block. Moreover said air nozzles are axisymmetrical about the center axis of the nozzle block, which provides a yarn formation zone at the central axis of the chamber where the yarn is spun.

The injected air from the air nozzle is passed tangentially to the eccentric profiles which make the air to flow towards the center portion of the chamber. Here an united air vortex is formed because of the continuous flow of air stream from each nozzle. While forming the united air vortex, the air stream from every nozzle travels inward and gets combined there together. Consequently this motion of air, further injects the escaping fibers towards the yarn core and minimize the flying away fibers by compensating the centrifugal force of the fiber.

Thus according to the present invention the fibers are held firmly in the yarn core during spinning which reduces the fiber loss in staple spinning. This unique shaped profiled nozzle block provides more shrinking air vortex with higher tangential velocity which results in more spinning efficiency and simultaneously provides enough space for wrapping fibers.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 illustrates the schematic representation of basic system of the air jet spinning.

Figure 2 illustrates the schematic representation of functional aspects and constructional details of the air jet spinning zone.

Figure 3 illustrates the cross sectional view of the existing nozzle block.

Figure 4 illustrates the cross sectional view of nozzle block according to the present invention.

Figure 5 illustrates the isometric representation of nozzle block of the present invention.

Figure 6 illustrates the sectional isometric view of nozzle block of the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 and Figure 2 represent the basic functional aspects and constructional details of air jet spinning system. The schematic illustration of basic system of the air jet spinning is shown in figurel. Feeding fibre material such as roving (1) is supplied from the roving bobbin (2) into the drafting zone (4) through a condenser (3). Drafting zone (4) comprising a pair of back drafting rollers (5), pair of apron mounted middle drafting rollers (6) and a pair of front rollers(7). The roving (1) coming out of condenser (3) is then passed through the said drafting zone (4) and drafted to the required amount. On referring to the figure2 of the drawings, the drafted fibre bundle (8) is then entered into the nozzle block (9) through a fibre inlet (13). Nozzle block (9) comprises plurality of air nozzles (10), which are placed equidistantly in its circumference. Said nozzles (10) are being supplied with compressed air (shown by dotted lines) through their corresponding inlets (10a, 10b & 10c). While the compressed air injected through the nozzles (10), it emerges out into the chamber (15) through the nozzle outlets (10a', 10b' &10c') and flows tangentially towards the inner wall (14). Herein chamber (15) the fibre bundle (8) is processed by air vortex (16) produced by plurality of air nozzles (10) and then enters into the rotating spindle (11). Due to swirling motion of air vortex (16) and frictional force of rotating spindle (11), a false twist is being created in the fibre bundle (8). By this action, the tail end of fibres present in the periphery of fibre bundle (8) wraps the core fibres present inside it and forms yarn. A yarn(12) thus fabricated is being carried through the spindle (11), as shown in direction of arrow and wound on yarn package which is not shown.

Figure 3 represents elevated the cross sectional view of existing nozzle block (9) in which plurality of air nozzles (10) are provided equidistantly in the circumference. The inner wall (14) of the nozzle block (9) is of having circular profile to which the air nozzle's outlets (10a', 10b' &10c') meets the chamber (15). While the compressed air injects through the nozzles (10), it emerges out through the nozzle outlets (10a1, 10b' &10c') and flows tangentially towards the inner wall (14). Due to this, a united air vortex (17) (shown by dotted circle) is formed in the chamber (15). Since the inner wall (14) is having circular profile, said united air vortex (17) follows a circular path and flows adjoin with respect to inner wall (14). It has been noted that, an equidistant (D) (which is necessary to provide room for wrapping fibers) is maintained between united air vortex (17) and yarn formation zone (18) in the chamber (15). Because of lofty equidistant (D), it is not much capable of keeping the air vortex strongly to the fibre bundle that are being spun. Since the air expansion occurs at the space of equidistant (D), the loose fibres present in the circumference of fibre bundle (8) would fell down and goes as waste fibres. Moreover plenty of free fibres are pulled out from the core due to escaping velocity of injected air and centrifugal force of the spinning fiber bundle (8) which is more disadvantageous.

According to the present invention, the constructional details of improved nozzle block is shown in figure 4 of the drawings. Whereas the isometric and cross sectional isometric views of nozzle block of the present invention shown in figure 5 and figure 6 respectively. The inner wall (14) of the nozzle block (9) is made into an substantially eccentric profile (19) for each nozzle (10). i.e., an eccentric profile (19) is made along the inner wall which lies in between two successive nozzle outlets for Eg. (10a') & (10c1). Said nozzles(lO) axis are configured to be curved eccentrically with respect to center (X) of the nozzle block. Moreover these air nozzles are axisymmetrical about the center (X) of the nozzle block. For the ease of understanding, three number of nozzles (10) are shown, which can be increased to more than three (4,5,6,7,8nos etc.) or reduced to less than three (2nos or at least 1) according to the requirement.

While the compressed air injected through the nozzles (10), it emerges out through the nozzle outlets (10a', 10b' &10c') and flows tangentially towards the inner wall (14). Because of the axisymmetrical construction and continuous flow of air stream from each nozzle (10), a united air vortex (17) (shown by dotted circle) is formed around the yarn formation zone (18) in the chamber (15). Since the inner wall (14) is having eccentric profiles (19), the air flow travels inward into the chamber (15) while forming the united air vortex (17). Said inward deviation of air with respect to united air vortex (17) is shown by arrows (20). Thus a compact equidistant (d) is created between united air vortex (17) and yarn formation zone (18) which results in more shrinking air vortex with higher tangential velocity. This makes the air vortex (17) to flow more steeper to the yarn formation zone (18) and ensures effective utilization of air to spin the yarn. Due to the effect of inward deviation of air and compact equidistant (d), the escaping fibers are being injected further towards the yarn core or at least it stops or minimizes the flying away of fibers by fully or partially compensating the centrifugal force of the fiber bundle (8). Moreover the presence of adequate clearance between hollow spindle (11) and inner wall (14) of the nozzle block (9) due to eccentric profile (19), gives freedom to the fibres rotation and in turn leads to increased locking force and twisting efficiency on fibres. Hence the fibers are held firmly with the yarn core during spinning which reduces the fiber lose in staple spinning.

ADVANTAGES OF THE INVENTION

1. Enhanced spinning efficiency
2. Minimize the flying away fibers
3. Reduces the fiber loss in staple spinning
4. Increasing the yarn quality

The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The spindle and rollers as stated do not limit the scope of the present invention. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

WE CLAIM

1. An improved apparatus for use in air jet spinning machine for forming yarn/thread from staple fibres, said apparatus comprising:

a unique shaped profiled nozzle block having plurality of substantially circumferential air nozzles, said nozzles being placed equidistantly along the circumference of said nozzle block where air is supplied tangentially towards inner wall of nozzle block;

wherein said inner wall of nozzle block is having a substantially eccentric profile for each nozzle.

2. Apparatus as claimed in claim 1 wherein the eccentric profile lies along the inner wall between two successive nozzles.

3. Apparatus as claimed in claim 1 wherein air nozzles are being axissymmetrical about center of nozzle block.

4. Apparatus as claimed in claim 1 wherein nozzles axis is being configured to be curved eccentrically with respect to center of nozzle block.

5. Apparatus as claimed in claim 1, wherein said air nozzle means being adapted to provide air flows substantially tangential to the eccentric profiles so as to make the air jet moving into the chamber means forms shrinking united air vortex around the yarn formation zone resulting in higher tangential velocity thereby ensuring effective utilization of air to spin the yarn.

6. Apparatus as claimed in claim 1 further comprises a hollow spindle.

7. Apparatus as claimed in claims 1 and 6 wherein said spindle being adapted to have adequate clearance with said inner wall means so as to provide increased locking force and twisting efficiency on fibres.

8. Apparatus as claimed in claim 1, wherein said air nozzle means being adapted to provide air flow substantially tangential to the eccentric profiles so as to make the air flow moving towards the center portion of the chamber means.

9. Apparatus as claimed in claim 1, wherein said air nozzle provides continuous air flow.

10. An improved apparatus for use in air jet spinning machines for spun yarn/thread/fibre forming as herein substantially described and illustrated with the accompanying drawings.