EP0118024B1

EP0118024B1 - A method and a device for fibre parallelisation and specifically for cotton fibres and synthetics

Info

Publication number: EP0118024B1
Application number: EP84101002A
Authority: EP
Inventors: Alexios Mamassioulas
Original assignee: CAESAR ENGINEERING SERVICES Ltd
Current assignee: CAESAR ENGINEERING SERVICES LTD.
Priority date: 1983-02-03
Filing date: 1984-02-01
Publication date: 1988-04-27
Also published as: EP0118024A1; DE3470758D1

Description

The invention relates to a method and a device for the parallelization of fibres being fed rectilinearly, changing direction, and placed one on top of the other in a parallelized form.
Aiming to obtain a parallelization of fibres moving rectilinearly, the system is based on a simple geometric model without complex mechanisms and employing the principles and properties of electrostatic fields. Accordingly, the invented simple practical arrangement can be useful also for other uses.
The US-A-2 557 433 refers to a spinning method, whereby fibres are twisted one around the other because of frictional, rotational (inertial) and electrostatic forces. The electrostatic charging of the fibres, together with the acting centrifugal forces, effects the disassociating of the upper ends of the fibres from each other immediately, prior to being formed into the strand, whereby uneven tensions between individual fibres and the internal torsions within fibres are virtually eliminated and a stronger strand can be produced thereby.
It is the object of the present invention to improve a method for the parallelization of fibres of the kind mentioned above such that fibres completely separated from each other, in parallel to each other, and in a direction perpendicular to the fibre stream being fed are spun to a yarn which is characterized by high fineness, uniformity and strongness, and which is also suitable for spinning extremely fine yarns.
The features characterized in the main claim serve to solve this problem.
Subclaims 2 and 3 comprise a device for performing the method of claim 1. Claims 4to 7 relate to using the device according to claim 2.
Below is a description of the method and of the embodiments of the device according to the invention on the basis of the attached set of drawings.
Fig. 1 shows the method of fibre parallelization in a perspective view. Separated fibres 8 (for instance, cotton fibres) are fed through the feeder 1 into the semicylindrical area which isformed by a cylinder 2 made of insulating material (for instance, plexiglass) and the metallic semicylindrical apron 3 which is formed in the upper part in such manner as to allow the fibres to enter freely without being obstructed.
The fibres 8 with the help of an air-suction device 4 descend in parallel to the axis AA of the cylinder, gradually changing their direction to that perpen- dicularto the above axis because offorces generated by an electrostatic field which is formed by the friction of the body of the device and by means of the metallic apron 3 inside of the device. Thus, the fibres are accumulated in parallelized form at the groove 7 on the bottom of the metallic apron 3 and with the aid of air-suction drawn through the slot 5 underneath the bottom of the groove 7 of the above-mentioned apron 3. What happens thereafter depends on the specific use of the fibres.
The semicylindrical metallic part 6, which is suitably formed integrally with the metallic apron 3, is disposed to be substantially transverse to the metallic apron and serves in particular to center the metallic apron 3 inside the cylinder 2. The descending fibres come into contact with part 6. During the descent of the fibres an electrostatic field is formed at the metallic apron 3, which causes the fibres to twist, wherein the fibres, by their sliding along the straight portion of the metallic apron 3, are mechanically allowed only to perform twisting in the direction towards the groove 7.
Fig. 2 shows a section (through axis AA) with the fibre feeder 1, the metallic apron 3, the cylinder 2 made of insulating material, the groove 7 on the bottom of the apron 3, the semicircular part 6, the slot 5, and the air-suction device 4.
As it is known, the insulating properties of the fibres, cellulose in the case of cotton, give them the behavior of a bipole (polarization of a dielectric material).
That is, during their movement inside of the device shown in Figs. 1 and 2, the fibres, because of friction with the immediate environment develop electrostatic loads at their ends and therefore behave like bipoles. As the fibres move through the electrical field which is formed by the surface of the metallic apron 3 and the inner surface of the cylinder 2 made of insulating material, they are reoriented by the influence of forces of electrical repulsion and attraction and thus assumethe desired direction which is perpendicular to the one they originally had when they entered the interior of the device.
Certainly, the length and the type of the fibre, the type of insulating material, the relative humidity of the interior and exterior environments and the properties of the air-suction system compose the variables and parameters of the invention.
A use of the invention for ring spinning processes is shown in Fig. 3. As shown, the fibres 8 from the card sliver are separated and thrown by the fibre feeder 1 into the fibre parallelization system.
A suction system 4 which is installed on a perforated drum 9 causes the fibres to cohere on its external surface in a continuous and parallelized form.
When the perforated drum rotates it moves the web of parallel fibres towards the contact point with the pressure roll 10. The spinning of the yarn is thus effected by the well-known ring spinning process 11.
Another use of this invention for Open-End spinning processes is shown in Fig. 4 and is the result of research for yarn production by open-end methods to obtain the same, perhaps better characteristics, strength, and uniformity from those achieved with the ring spinning method.
The fibres 8 of the card sliver are separated and thrown by the fibre feeder 1 into the fibre parallelization system. Thus, with the aid of the air-suction hole 4 the fibres cohere in parallelized form in a perforated groove 7.
Initially, the sliver must be positioned onto the contact point of the delivery rollers 12 passing through a hole 13 and subsequently the system is put in rotary motion (in such a direction as to obtain an S or Z-yarn configuration as required).
Thus, when the system rotates and when the delivery rollers 12 pull the sliver, there is obtained a twisting of fibres that produces the yarn. This yarn is wound at 14 into either cheese or cone form.
The form and the inclination of groove 7 towards the hole 13 and the air-suction characteristics give the required friction on the area 15 for twisting and the yarn production.
A third use of the invention is the Open-End spinning process with twin parallelization of fibres explained in Fig. 5 and is the result of research to obtain improvements in mixing parallelized fibres during the spinning process. The fibres 8 from the card sliver are separated and thrown by the fibre feeder 1 into the parallelization system for twin fibre parallelization. Through the fixed protective shell 17 and the small holes in the groove 7 the air-suction device 4 forces the fibres to descend and be separated in two groups under the influence of the self-maintaining electrostatic field inside of the device where a twin partitioning apron is positioned the two parts 19, 20 of which are separated with an insulating material 18, but which have a common groove 7 and a common straight part 33.
When the fibres enter into the grooves 7 and the parallelization system rotates and when the delivery rollers 12 pull the sliver which originates from the two groups of paralleiized fibres into the grooves 7, yarn is produced and wound at 14 into either cheese or cone form.
The form and inclination of the two grooves 7, the air-suction as well as the friction of the fibres on the grooves lead to the twisting and to the production of Z or S-type yarn with the appropriate rotation of the system. Finally, the yarn produced is wound on a bobbin with the use of an appropriate system 14.
A fourth use of the invention, the Open-End spinning process employing a special rotor, is explained in Fig. 6 and consists of the fiber parallelizer, the rotor 21, the delivery system 12, and the cone formation 14.
The fibres being positioned in a parallelized form by the self-maintaining electrostatic field of the fibre parallelization system into the groove 7 aided by the air-suction device 4, are led through a tube 23 to the special rotor 21 which is constructed as illustrated in cross-section (Fig. 6). During the rotation of the rotor 21 and due to the centrifugal force that is developed the wound web touches the inner surface 24 of the steady friction cylinder 22.
Accordingly, the friction of the fibres in the area 24 forces them to twist. When the fibres are twisted together, the one to the left in the groove, then the twist slides and is losened and, when the others are twisted to the right towards the exit of the rotor 21, the twist remains forming by the pulling of the delivery cylinders a yarn of Z or S-type which depends on the direction of the rotation of the rotor 21.
A fifth use of the invention, the Open-End spinning system with two deliveries of yarn, is explained in Fig. 7 and consists of the fibre parallelizer having a thin slot 28 on its bottom and a pair of perforated cylinders 25 thereunder both rotating in the same direction. In addition to this, on the left and the right of them and on the same axis XX', the two pairs of cylinders 26 bearing the spinning equalizer-discs 27 also rotate in the same direction. These two pairs of cylinders 25, 26 are well-known from the machines of friction- spinning and core-spun production of yarn.
When the fibres change direction while descending because of the self-maintaining electrostatic field of the system, they pass through the thin slot 28 which is parallel to the axis XX' and accumulate by means of the air-suction device 4 in the area of the longitudinal slots 29 of the suction on the outer surface of the perforated cylinders 25.
When the fibres are led to the pairs of cylinders 26 rotating in the same direction, the production of yarn will be obtained when the delivery cylinders 12 pull the yarn. It is evident that the fibres will be allotted to both sides, developing a resistance (restraint) depending on the difference of the rotational speed of the pairs 25 and 26. The holes of the perforated cylinders 25 are cleaned by an external suction system which is not shown in Fig. 7.
As mentioned above, the equalizer discs 27 are intended for the regulation of the spinning process. With the change in the direction of rotation of the pairs of cylinders 25 and 26, a Z or S-type yarn is produced which, after passing through the delivery cylinders 12 is wound on a bobbin 14.

Claims

1. A method for transporting fibres made of cotton or synthetics in a manner adapted for producing yarn thereof, with which the said fibres while moving along a first direction are subjected to electrostatic charging, characterized in

that the said fibres (8) are moved forward in electrostatically charged state towards a metallic sheet member (3) extending along the said first direction parallel to each other and to said first direction,

that the said fibres while flowing along the said metallic sheet member are subjected to a self-maintaining electrostatic field generated through frictional interaction of the fibres with the metallic sheet member for exerting on the fibres a force aligning them along a second direction parallel to the plane of the said metallic sheet member and perpendicular to the said first direction and

that the fibres thus placed one on top of the other parallel to each other and to the said second direction are further flown along the said second direction for further processing.

2. A device for performing the method of claim 1, characterized by

a) a feeder (1) delivering a parallel flow of electrostatically charged fibres;

b) a metallic sheet member (3) arranged inside a cylinder (2) made of insulating material for free entrance of said fibres and extending substantially along the feeding direction of said feeder (1) from the upper part of said cylinder (2) to its bottom;

c) a semicircular metallic part (6) on the bottom of said cylinder (2) connected to said metallic sheet member (3); and

d) a longitudinal groove (7) on the bottom of said sheet member (3) extending parallel to the place of said sheet member (3) and perpendicular to the feeding direction of said feeder (1) connected to a suction device (4) for sucking air through said cylinder (2) and to withdrawing means for further conveying the fibres therefrom (Fig. 2).

3. A device for performing the method of claim 1 in an Open-End spinning method characterized in that fibres from a card sliver (8) are separated by the fibre feeder (1) and thrown into the device and with the aid of the air-suction device (4) cohere in parallelized form in the groove (7), and that the metallic sheet member (3) rotates and when the delivery rollers (12) pull the sliver a twisting of fibres is obtained with yarn being produced and wound in either cheese or cone form (Fig. 4).

4. A device for performing the method of claim 1, characterized by

(a) a feeder (1) delivering a parallel flow of electrostatically charged fibres;

(b) two metallic plates (19, 20) separated by a strip (18) of insulating material arranged inside a cylinder (2) of insulating material for free entrance of said fibres along the feeding direction of said feeder (1) from the upper part of said cylinder (2) to its bottom;

(c) a semicircular metallic part (6) on the bottom of said cylinder (2) connected to said metallic plates (19, 20), and

(d) two common perforated grooves (7) on the bottom of said metallic plates (19, 20) extending parallel to the plane of said metallic plates (19,20) and perpendicular to the feeding direction of said feeder (1) on which grooves (7) the fibres are gathered and accumulate in parallel form assisted by the air that is sucked at point (4) out of shell (17) and through the holes of the grooves (7) and for separating the fibres in two groups corresponding to the metallic plates (19, 20), and after the device has been put in appropriate rotation, the fibres are pulled through a hole (13) by delivery cylinders (12) and yarn is produced and wound on a bobbin (14), also aided by friction forces that are developed inside of the grooves (7) (Fig. 5).

5. The use of the device according to claim 2, in a ring spinning method, characterized in that fibres from a card sliver (8) are separated and thrown by the fibre feeder (1) into the device and after passing through the groove (7) realign in parallelized form and with the aid of the air suction device (4) cohere on the external surface of a rotating perforated drum (9) which moves the layer of parallel fibres towards the nip formed by said drum (9) and a pressure roller (10) and further processed by a well-known ring spinning device (11) (Fig. 3).

6. The use of the device according to claim 2, in a false twist spinning method, characterized in that, when the fibres are positioned in a parallelized form by the self-maintaining electrostatic field into the groove (7) assisted by the air-suction device (4), they are led through a tube (23) to a special rotor (21), whereby after the rotor is set in appropriate rotary motion the fibres are forced into false twist because of the friction of the fibres on the inner surface of a fixed friction cylinder (22) and the centrifugal force that is developed, whereby after the fibres are pulled by delivery cylinders (12), a Z- or S-type yarn is produced and wound on a bobbin (14), the twist sliding backwards into the groove (7) is loosened and the friction inside, producing the necessary restraint for spinning, leaves the twist towards the delivery cylinders (12) (Fig. 6).

7. The use of the device according to claim 2, in a friction spinning method, characterized in that the fibres parallelized by the self-maintaining electrostatic field after passing through a thin slot (28) which is parallel to an axis (XX) accumulate in the area of the longitudinal slots (29) of the air-suction device (4) on the outer surface of a pair of perforated cylinders (25), where on the left and right sides of said pair another pair of cylinders (26) is located, one of them being perforated and bearing in its inner part a system with a fixed longitudinal slot (29) of the air-suction device (4), being also supplied with a pair of stabilizer discs (27) for the regulation of spinning, and when the fibres are led into the cylinder clearances and the pairs of said cylinders are set in rotary motion in the same direction, said fibres present a restraint appropriate for the production of yarn being developed on the basis of a difference in the rotational speed of the cylinders (25) and (26) and on the basis of the friction of the fibres while sliding on both sides (Fig. 7).