GB2041019A

GB2041019A - Open End Spinning of Composite Yarn

Info

Publication number: GB2041019A
Application number: GB8004762A
Authority: GB
Original assignee: Elitex Zavody Textilniho; Elitex
Current assignee: Elitex Zavody Textilniho; Elitex
Priority date: 1979-02-14
Filing date: 1980-02-13
Publication date: 1980-09-03
Also published as: IT8019900A0; DE3004051A1; FR2449146A1; JPS55132720A; IT1140587B; CS210725B1

Abstract

A method of producing a composite yarn in an open-end spinning apparatus comprises in parting a false twist to a first fibrous system 2 by means of a rotating fluid current within a nozzle 1, providing the surface of the fibrous system 2 with discrete, staple fibres 15, the front ends of which become clamped onto fibrous system 2 and the rear ends of which are mutually intercrossed by means of a second- rotating fluid current in a second nozzle 8, 1' thus forming a fibrous envelope around the first fibrous system. The staple fibres 15 may enter the twisting zone 13 separately from or together with the first fibrous system. The advancing speed of the rotating pressure fluid through the twisting zone 13 is lower than the speed of passage of the false twisted fibrous system 2. The flared outlet end of nozzle 8, 1' opens into an expansion chamber 23 from which the fluid is withdrawn. <IMAGE>

Description

SPECIFICATION Method of Manufacturing Yarn and Device for Performing Said Method Description The present invention relates to a method of manufacturing yarn and a device for performing said method.

Various systems of spindleless spinning are known for already a long time, of which e.g. the rotor spinning method, the so-called open end spinning is the most popular. In this method, separated staple fibres are fed on to the sliding wall of the rotor which rotates at high speed. The said separated fibres slide about the sliding wall upon action of centrifugal force in the direction towards the maximum inner diameter where the parallelized fibres are deposited in the form of a fibre ribbon in the collecting groove of the spinning rotor and spliced to the open end of the yarn formed already before. Upon axial withdrawal, the fibre ribbon is imparted twist and the yarn is wound on to a cross wound bobbin.

The disadvantage of this method consists in that the yarn strength, in view of conventional yarn made in ring spinning machines, is lower for about 1 5 to 30 per cent.

A further disadvantage consists in that this spinning system is less suitable for higher yarn numbers and combed yarns cannot be produced by this method economically.

In a further well known spinning method of staple fibres by means of a twisting device acting upon the fibres, the spinning process is performed by an electrostatic field, which is formed between the supply of the separate staple fibres and the rotating inlet funnel. The said electrostatic field straightens the fibres and transfers them into the rotating, twist imparting inlet funnel.

In connection therewith, important disadvantages are observed, which have an unfavourable influence on the course of the spinning process and the yam quality. The electrostatic field is unfavourably influenced by varying relative humidity, which causes yarn breakage and interruption of the spinning process.

Furthermore, a spinning method is known, by which yarn with true twist is produced by means of an air vortex.

The main disadvantage consist in great air consumption, besides a considerably loss of twist caused by the air vortex. It is further disadvantageous that splicing of the separated fibres on the yarn end rotating in the air vortex is not always secured, a considerable part of the fibres being sucked off to waste.

A further known yarn forming system using true twist is the so-called DREF system, of which the disadvantage consists in that it can be used only to a limited extent, particularly for coarse yarn numbers and in that the yarn surface is relatively closed, thus causing an excessive rigidity of the products with insufficient draping quality.

Of the methods hitherto known, it is possible to mention the ROTOFIL system, in which a ribbon of untwisted or loosely twisted surface fibres is wound onto the surface of one fibre ribbon, which is false twisted by means of annuling the twist imparted thereto, in reverse turns, a fibre helix thus being formed on the substantially twistless core surface. By this method, it is possible to produce very successfully yarn of long staple fibres which, however, has a very low extensibility, which is necessary for its further processing. Fibres of shorter stable length do not secure a sufficient reinforcement of the yarn.

A further known method of forming spindleless yarn is the Gotzfried system, which withdraws by venting and directs from one or two presented staple fibre ribbons a part of the staple length of their front ends and diverts this part from the zone of false twist penetration to be imparted and, by a change of the twisting direction of this ribbon, wraps said separated front ends of the staple fibres in tensioned condition about the surface of the ribbon, which is thus converted into yarn. The main disadvantage of this system consists in that the length of the separated staple fibre front ends is too short to reinforce the yarn sufficiently, so that the principle of forming this yarn can be applied only for processing long staple lengths, this however being already the subject matter of the ROTOFIL system as mentioned above.A further disadvantage of this system consists also in the circumstance, that the tensioning of the front ends of staple fibres in a rotating pressure fluid flow can take place only, when the velocity of advancement of the rotating pressure fluid helix, which tensions the staple fibre front ends, is substantially higher than the velocity of passage of the yarn being formed, so that a too steep climb of the rotating pressure fluid flow is to be formed, which causes an insufficient twist, so that the yarn is not sufficiently reinforced by twist and does not, consequently, achieve even the minimum strength necessary for its further processing.

Of the methods hitherto known, a further method, called the REPCO yarn forming method, should be mentioned, which is prevailingly used by the wool industry and is applied prevailingly for knitted goods, and further known methods of forming multicomponent twistless yarn, of which the strength is achieved by bonding. The typical representatives of this group of yarns are the TWILO of the BOBTEX systems. However, the application of these yarns is very limited. An analogous system to the TWILO system is the PAVENA system with the only difference, that the PAVENA system applies an adhesive solution, and the TWILO system a PVA fibre. Even further yarn forming methods are known which are, however substantially various modifications of the systems specified above.

The purpose the present invention consists in creating a method of open end spinning of yarn consisting of two fibrous systems, and a device for performing said method, which mitigates the known disadvantages to a considerable extent and which forms a yarn of a new type, which can be continuously produced and directly wound on to a cross bobbin.

According to one aspect of the invention there is provided a method of producing yarn from two fibrous systems by means of a rotating pressure fluid flow, at least one of said fibrous systems consisting of staple fibres, wherein one of the two fibrous systems is continuously imparted false twist and its surface is provided with staple fibres from the second fibrous system, which are fed into the inlet zone of the yarn forming twisting zone, their front ends being partially clamped on the rotating surface of the false twisted fibrous system and partially directed in free condition in the direction of rotation of the pressure fluid flow and forming an interlaced interlayer clamped on the fibrous surface of the false twisted fibrous system, the rear ends of said staple fibres from the second fibrous system clamped by their front ends by the surface of the false twisted fibrous system, and directed by imparting false twist in the counter-direction of rotation of the pressure fluid, are redirected at a speed higher than the speed of false twist imparting from the false twist direction to the direction of true twist, and are simultaneously in the rotating pressure fluid flow mutually intercrossed and girdled, forming together with the remaining staple fibres a fibrous envelope surrounding freely the false twisted fibrous system, said fibrous envelope being tightened on the surface of the false twisted fibrous system by the following continuous annulment of torsional force of the imparted false twist in the form of a unidirectional, regular twist helix, and contracting the cross section of both fibrous systems.

The staple fibres of the second fibrous system may enter the yarn forming twisting zone in untwisted condition together with the fibres of the false twisted fibrous system, or the staple fibres of the second fibrous system may enter the yarn forming twisting zone separately from the false twisted fibrous system. The staple fibres might be either sucked into the entering zone of the yarn forming twisting zone, or blown in, while the staple fibres of the second fibrous system might be fed into the inlet zone of the yarn forming twisting zone even in the rotating pressure fluid flow, which is directed into the false twist imparting direction.The basic condition consists in that the advancing speed of the rotating helix of the pressure fluid flow through the yarn forming twisting zone is substantially lower than the speed of passage of the false twisted fibrous system, and that in the yarn forming twisting zone, at least partially a twist inversion of the imparted false twist is caused in at least the section of the staple length of the redirected staple fibres of the second fibrous system, the course of said twist inversion being either continuous, or in the inlet zone of the yarn forming twisting zone of impact character, and maintained in the further passage through the yam forming twisting zone substantially at a constant level, the twist inversion possibly taking place in the inlet zone of the yarn forming twist zone impact-like and being continuously increased by further passage through this zone, or -the controlled twist inversion taking place impactlike in at least two phases following one another - (see Figures 11 to 14). An important condition is, that the total reduction of the imparted false twist by twist inversion should not surpass 60% of its original value. It is also necessary that the withdrawing speed of the yarn be lower than the supplying speed of the false twisted fibrous system.

According to another aspect of the invention there is provided a device for performing the above specified method of producing yarn in which device the path of a first fibrous system is arranged a pre-twisting nozzle in the direction of its passage, which opens into a re-spinning twisting nozzle arranged in the same direction and operating with the same direction of rotation of pressure fluid which, as well as a further control element for false twist imparts continuously in the yarn forming twisting zone the required degree of false twist to the first fibrous system and a feeding channel for feeding staple fibres of a second fibrous system into the device is directed into the inlet zone of the yarn forming twisting zone of the spinning twisting nozzle.The pressure fluid enters either the pre-twisting nozzle and passes through the respinning twisting nozzle by being directed thereinto by the embodiment of the pre-twisting nozzle consisting of at least one pressure fluid feeding aperture opening in a tangential direction to the inner surface of the rotary chamber passing to an oppositely mounted central rotation directing element, which is provided in its axis by a suction opening and which reaches in the direction of yarn withdrawal at least as far as the level of the lower edge of the pressure fluid feeding opening, or the pressure fluid entering the respinning twisting nozzle by at least one pressure fluid feeding opening, connected in tangential direction to the inner surface of its directing chamber, in the centre of which is mounted a pre-twisting nozzle directing by its outer housing the rotating pressure fluid flow in the direction of yarn withdrawal, or possibly the pressure fluid entering independently in the same direction into the pre-twisting nozzle, as well as into the re-spinning twisting nozzle.

The feeding channel for the staple fibres of the second fibrous system is directed into the directing chamber of the respinning twisting nozzle which opens in an inlet annulus defined by the outlet annular cross section of the pretwisting nozzle and the inlet annular cross section of the yarn forming twisting zone of the respinning twisting nozzle, into the inlet zone of the twist inversion caused in the yarn forming twisting zone of the spinning twisting nozzle. The width of the input annulus can be adjusted, e.g. by attaching the pre-twisting nozzle.The feeding channel for the staple fibres of the second fibrous system can also be directed, injector-like, into the direction of rotation of the pressure fluid flow in the directing chamber of the respinning twisting nozzle, or possibly even in the direction of the rectilinear pressure fluid flow in the feeding aperture, which is directed in directing chamber of the respinning twisting nozzle, or inclined into the directing chamber of the respinning twisting nozzle, or possibly also into the directing chamber of the respinning twisting nozzle obliquely to the axis of the false twisted fibrous system.Upon spinning short fibre material it is advantageous when the spinning twisting nozzle is connected by its outlet to an expansion chamber for the pressure fluid, said chamber being provided with withdrawing vents and mounted in the collecting space of the suction chamber, said withdrawing vents of the pressure fluid expansion chamber being directed to the direction of rotation of the said pressure fluid. It is also advantageous when the expansion chamber of the pressure fluid is narrowed in the direction of yarn withdrawal.

Upon processing long fibre material, and withdrawing excessively short fibres apart from yarn forming, it is advantageous, when the respinning twisting nozzle opens with its yarn outlet into the collecting space of the suction chamber. For facilitating the initiation of the spinning process in the device, a yarn introducer is arranged oppositely to the outlet of the respinning twisting nozzle in the collecting space of the sucking chamber, of which the cross section is narrowed in the direction of withdrawal of the formed yarn, and which might form even a component of the pressure fluid expansion chamber.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through an exemplary arrangement of the spinning unit with a feeding channel for staple fibres, opening obliquely into the direction of rotation of the pressure fluid in the directing chamber of the respinning twisting nozzle; Figure 2 is a longitudinal section of the detail view of the arrangement of the rotation chamber for the pre-twisting nozzle; Figure 3 is a cross section of the same detailed view of the pre-twisting nozzle rotation chamber as in Figure 2; Figure 4 is a longitudinal section of the detailed view of the arrangement of the rotation chamber of the respinning twisting nozzle formed by attachment of the pre-twisting nozzle, in the arrangement of the staple fibre feeding by an adjustable annulus;; Figure 5 is a cross section of the same detailed view of the arrangement as shown in Figure 4; Figure 6 is a cross section of the injector staple fibre feeding into the respinning twisting nozzle, evoked by a rectilinear pressure fluid flow which is directed into a directing chamber of the respinning twisting nozzle; Figure 7 is a cross section of the injector staple fibre feeding into the directing chamber of the respinning twisting nozzle, evoked by rotation of the pressure fluid; Figure 8 is a cross section through the expansion chamber with marked inclination of the withdrawing apertures which are directed into the direction of rotation of the pressure fluid; Figure 9 is a longitudinal section through the device provided with the expansion chamber for the pressure fluid, provided with the withdrawing apertures in the embodiment as shown in Figure 8;; Figure 10 is a longitudinal section through the device with the expansion chamber narrowing in the direction of yarn passage; and Figures 11 to 14 show various modifications of the course of controlled twist inversion given by the shape of the respinning twisting nozzle.

An exemplary embodiment of the device in the embodiment of the above mentioned drawings consists of a pre-twisting pressure nozzle 1 arranged in the direction of the fibrous system 2 passing therethrough, consisting of a feeding aperture 3 for the pressure fluid connected thereto in tangential direction in the inner surface 4 of rotation chamber 5, passing over to an oppositely mounted rotation directing element 6, in the axis of which a suction opening 7 for passage of fibrous system 2 is provided. This pretwisting nozzle 1 engages adjustably respinning twisting nozzle 8, 1', which imparts simultaneously as a second false twisting element 1' the appurtenant false twist value to the system 2 passing therethrough by the rotation of the pressure fluid passing in the same direction as the rotation of the pressure fluid in the pretwisting nozzle 1.The respinning twisting nozzle 8, 1' consists of a directing chamber 9, to which pressure fluid is fed in tangential direction to its inner surface 10 through the feeding aperture 11.

In the centre of this directing chamber 9, the twisting nozzle 1 is arranged, which directs by its outer housing 12 the rotating pressure fluid flow into the yarn forming twisting zone 13 of the respinning twisting nozzle 8, 1'. The feeding channel 14 for the staple fibres of the second fibrous system 1 5 is directed into the directing chamber 2 of the respinning twisting nozzle 8, 1', said channel opening by the inlet annulus 16 into the inlet zone of the twist inversion caused in the yarn forming twisting zone 13 of the respinning twisting nozzle 8, 1', by a second false twisting element 1'.The inlet annulus 16 is defined by an outlet circular cross section 1 7 of pre-twisting nozzle 1 and the inlet circular cross section 1 8 of the yarn forming twisting zone 13 of the respinning twisting nozzle 8, 1' and is adjustable e.g. by attaching pre-twisting nozzle 1. When the excessively short staple fibres of the second fibrous system 1 5 should be rejoined by respinning to the formed yarn 19, the respinning twisting nozzle 8, 1' is connected with its outlet 20 to the expansion chamber 21 for the pressure fluid leaving the respinning twisting chamber 8, 1'.

The expansion chamber 21 of the pressure fluid is provided with withdrawing apertures 22 directed in the direction of rotation of the pressure fluid in the respinning twisting nozzle 8, 1'. The expansion chamber 21 is located in the collecting space 23 of suction housing 24, from which the pressure fluid, expanding in the opposite direction of rotation is centrally sucked off through opening 25 into a not represented filter and can be compressed again and used in a so-called closed circulation for the operation of the device.

In the case, when it is not necessary to attach excessively short fibres which where completely separated upon forming yarn 19, again to the formed yarn 19, the respinning twisting nozzle 8, 1' is connected by its outlet 20 directly to the collecting space 23 of suction housing 24. For facilitating the guiding of yarn 1 9 by the device as specified above, a withdrawer 26 of yarn 1 9 is arranged in the collecting space 23 of sucking housing 24, of which the cross section is narrowed in the direction of withdrawing yarn 1 9.

The produced yarn 1 9 is withdrawn by withdrawing rollers 27 and wound by means of winding rolier 28 on to yarn bobbin 29.

The operation of the device as specified above according to the present invention is as follows: The fibrous system 2, passing through the pretwisting nozzle and thereupon through the yarn forming twisting zone 1 3 of the respinning twisting nozzle 8, 1', is imparted false twist by pre-twisting nozzle 1, and its surface is provided, by influence of the difference caused in the unidirectional false twist imparting by pretwisting nozzle 1 and influenced by twisting element 1' in the respinning twisting zone 11, with staple fibres of the second fibrous system 1 5 fed through a feeding chanel 14, said fibres being connected by their front ends into the direction of imparting false twist, as well as into the direction of beginning twist inversion to the surface of the false twisted fibrous system 2, forming thereabout due to rotation of the pressure fluid in the respinning twisting nozzle 8, 1' independent fibre helices, of which the front ends are partially gripped on the rotating surface of the false twisted fibrous system 2, and partially being in free condition directed around said system to the direction of rotation of the pressure fluid, and thus to the direction of imparting false twist, the false twisted fibrous system 2 drawing them to its surface.Thus, they cannot be influenced by the rotating pressure fluid flow in the yarn forming twisting zone 1 3 of the respinning twisting nozzle 8, 1' in any way, while the rear ends of the same staple fibres, directed due to unidirectional rotation of the pressure fluid into the opposite direction, gripped by the twist inversion, i.e. a higher speed than the false twist imparting speed in the yarn forming twisting zone 13 by the rotating pressure fluid flow, and the tensioned fibres brought from their rear ends from the false twist direction into the true twist direction, the said rear ends reversed by rotation of the pressure fluid flow of the staple fibres from the second fibrous system 1 5 being, together with the rear ends of the staple fibres, gripped by their front ends on the surface of the false twisted fibrous system 2 being mutually crossed and girded in the rotating pressure fluid flow, thus forming an interlaced fibrous envelope of tensioned staple fibres, which freely surrounded the false twisted fibrous system 2 on the surface of which said fibrous envelope is anchored by the interlaced front ends of staple fibres, said envelope being by the following continuous annulment by the rest of torsional force of the imparted false twist, upon leaving the yarn forming twisting zone 1 3 of the respinning twisting nozzle 8, 1' unidirectionally drawn to the surface of fibrous system 2 in a resulting regular twist helix, contracting the cross section of both fibrous systems 2, 1 5 towards the axis of yarn 1 9 thus formed, which is withdrawn by withdrawing rollers 27 and wound on to yarn bobbin 29 by means of winding roller 28.The overall operation explained above proceeds in detailed manner as follows: The pressure fluid fed through opening 3 to the rotary chamber 5 of the pre-twisting pressure nozzle 1 causes inside said nozzle 1 rotation of the pressure fluid, which is directed by the central rotation directing element 6 to the direction of passage of fibrous system 2, thus causing also a sucking effect to appear in the suction opening 7, through which said fibrous system 2 is sucked into the pre-twisting pressure nozzle 1, where it is imparted the necessary false twist value which reinforces the section of this fibrous system 2 in front of the inlet to the pretwisting pressure nozzle 1. The rotating pressure fluid flow passes over, upon leaving the pretwisting pressure nozzle 1, into the yarn forming twisting zone 13, in which it causes a controlled twist inversion of the imparted false twist.

Even the independent feeding of the pressure fluid takes part in reinforcement of fibrous system 2 by false twist, including the exertion of sucking effect in opening 7 and in the whole pre-twisting pressure nozzle. The pressure fluid is fed through opening 11 into the directing chamber 9 of the respinning twisting mozzle 8, 1' in the centre of which is mounted the outlet 17 of the pretwisting pressure nozzle 1 , which directs by the surface of its outer housing 12 the rotating pressure fluid flow into the yarn forming twisting zone 13, in which the effect of controlled twist inversion of the imparted false twist is performed.

The rotating pressure fluid flow enters always, upon imparting false twist to the fibrous system 2, the yarn forming twisting zone 1 3 of the respinning twisting nozzle 8, 1', in which deceleration of its rotation comes about, causing a controlled twist inversion of a part of the false twist already imparted to fibrous system 2. The course of this twist inversion is given by the applied fluid pressure, as well as the course of the extending cross section of respinning twisting nozzle 8, 1', which might be either continuous, or impact-like, or possibly combined, thus corresponding to the character and properties of the processed fibres, i.e. their rigidity, length, fineness etc. (see Figures 11 to 14).The value of this twist inversion is given by the ratio of the inlet cross section 1 8 to the outlet cross section 20 of the respinning twisting nozzle 8, 1', when e.g. the inlet cross section 18=56 3mm and the outlet cross section 20=t,6 4.55 mm represent 50 per cent of twist inversion in the appurtenant course of the wall shape of the re-spinning twisting nozzle 8, 1' and the distance between those two cross sections. The length of the yarn forming twisting zone 11 depends of the staple fibrous system 1 5 and must correspond to at least the staple length of those fibres, but advantageously to their double.In this yarn forming twisting zone 13, the input speed of rotation of the pressure fluid flow is accordingly reduced in such a manner, that by a positive unidirectional imparting of a reducing false twist a controlled counterdirectional inversion of the false twisted fibrous system 2 is evoked, whereby the effect of redirecting the staple fibres of the second fibrous system 1 5 from the direction of imparted false twist to the direction of true twist is increased.

This effect as specified above of imparting false twist and the evoked twist inversion taking place in the yarn forming twisting zone 13 is used for forming yarn 1 9 according to the present invention in the following manner: By a suitably connected and directed feeding channel 14 fof staple fibres of the second fibrous system 1 5, said staple fibres are fed either by means of an injector, suction or blowing into the inlet annulus 1 6, which is directed towards the surface of the passing through, false twisted fibrous system 2 moving towards the respinning twisting nozzle 8, 1', at the boundary of transition of false twist imparting to its twist inversion.In separate cases of processing fine fibres to high yarn numbers, it is also possible, that said staple fibres of the second fibrous system 1 5 enter in untwisted condition, together with the false twisted fibrous system 2, the suction opening 7 of the pretwisting pressure nozzle 1 (as shown in Figure 10). In this case, however, it is suitable to use only one pressure fluid flow fed through feeding opening 11 via directing chamber 9 into the respinning twisting nozzle 8, 1'.

The continuously proceeding twist inversion performed by the operation as specified above, of a part of the false twist imparted to fibrous system 2, brings the front ends of staple fibres of the fibrous system 1 5 into a different effect of unidirectional false twist imparting of the fibrous system 2 passing therethrough, which is given by the differing effect of the appurtenant speed of pressure fluid rotation, whereby a differing connection of said staple fibre front ends of the fibrous system 1 5 to the surface fibres of the false twisted fibrous system 2 takes place.The front ends of the staple fibres form between one another various modifications of fibre connection and interlacing combinations, which are given by the following examples of basic connection modifications, by which an interlaced interlayer is formed which interconnects both fibrous systems 2, 15 in such manner, that (a) certain of the staple fibre front ends of the fed fibrous system 1 5 are gripped by the rotating surface of fibrous system 2 upon false twist imparting, then directed in the direction of this rotation of the pressure fluid flow and begun to be wound in the same direction by a part of their staple length on to the surface of fibrous system 2;; (b) the front ends of other staple fibres of the fed fibrous system 1 5 are gripped on the surface of fibrous system 2 by a beginning twist inversion and begin to be wound on to its surface in a direction opposite to false twist imparting, thus mutually becoming intercrossed and girded with the front ends of the staple fibres gripped as mentioned in point a), thus forming the basic interconnection with interlaced interlayer and the surface of fibrous system 2;; (c) still other staple fibres of the fed fibrous system 1 5 carried by the pressure fluid flow and not gripped by the surface of the false twisted fibrous system 2 are entrained in free condition by the rotating pressure fluid flow and directed into a helical shape around fibrous system 2 in such manner, that their front ends, directed in the direction of rotation of the pressure fluid are drawn towards the surface of said fibrous system 2, thus girding the connected front ends of the staple fibres from the fibrous system 15, gripped in the surface of the fibrous system 2 according to the examples as given under a) and b).

In this manner, an interlaced interlayer consisting of substantially differently gripped, intercrossed and girded front ends of staple fibres of the fibrous system 1 5 gripped on the fibrous surface of the false twisted fibrous system 2, is formed. In the yarn forming twisting zone 13 of the respinning twisting nozzle 8, 1', all rear ends of the staple fibres of the fed fibrous system 1 5, of vl)nich the front ends participate, as mentioned in points a), c), in forming an interlaced interlayer, are directed by false twist imparting of the rotating pressure fluid flow about the surface of the false twisted fibrous system 2 in the counterdirection of this pressure fluid rotation imparting false twist, and are gripped by twist inversion, i.e. a higher speed than the false twist imparting speed, and the staple fibres in tensioned condition are gripped by this rotating pressure fluid flow, and in the direction from their rear ends re-directed from the direction of imparting false twist to the direction of true twist, and together with said rear ends of the fibres gripped by their front ends on the surface of the fibrous system 2 forming the beginning twist inversion as stated in point c), bearing carried by the pressure fluid flow, independent helices of mutually intercrossed, girded and interlaced staple fibres, which are thus interlaced into a fibrous envelope which freely surrounds the false twisted fibrous system 2.By the various course of twist inversion in the yarn forming twisting zone 1 3 (Figures 11 to 14) it is possible to modify successfully the course according to various characters of staple fibres of the fibrous system 1 5, or possibly to influence together with the length of the yarn forming twisting zone 1 3, the character of yarn 1 9, e.g. its voluminosity, its crimpiness, extensibility etc.By mutual combinations of the length of the yarn forming twisting zone 1 3 with the course of twist inversion, it is always possible to determine the optimum processing conditions for processing different fibres of fibrous system 2, as well as of fibrous system 1 5 to a quality yarn 1 9. Upon determining any course of twist inversion, the relation of speed of rotation of the pressure fluid flow must be always respected in relation to the speed of forming yarn 19 in such manner, that the advancing speed of the rotating pressure fluid flow through the yarn forming twisting zone 13 in the section of twist inversion, i.e. the redirecting of the rear ends of the staple fibres of fibrous system 1 5 must be in the yarn forming twisting zone 13 always lower than the speed of the passage of the false twisted fibrous system 2, on the surface of which the front ends of said redirected staple fibres of the fibrous system 1 5 are clamped. In this manner, it is guaranteed that the redirecting of the twist of the fibrous system 1 5 takes place in tensioned condition, the interlaced fibrous envelope, formed by their mutual intercrossing and interlacing, consisting of tensioned staple fibres anchored in the surface of the false twisted fibrous system 2.This interlaced fibrous envelope of tensioned staple fibres is unidirectionally tightened due to the following continuous annulment of the rest of torsional force of the false twisted fibrous system 2, upon leaving the yarn forming twisting zone 13, on to its surface in a resulting, regular twist helix of staple fibres, contracting the cross section of both fibrous systems 2, 1 5 in the direction towards the axis of the yarn 1 9 thus formed, which consequently shows high strength and undetwistability.As the torsional force of the false twist of fibrous system 2 is almost used up and eliminated by tightening the interlaced fibrous envelope of staple fibres from fibrous system 1 5 on to the surface of fibrous system 2, as specified above, said yarn 19 shows either a minimum, or even no torsional movement causing loop forming, the yarn 1 9 thus not having to be stabilised relative to twist, e.g. by vapouring.

A further advantage of the method of producing this yarn 1 9 consists in the circumstance, that no masses rotate and that the whole yarn forming is performed only in a unidirectional controlled pressure fluid rotation, thus making possible to achieve a very high speed of production.

The yarn producing method according to the present invention makes it possible either to eliminate excessively short staple fibres in the course of connecting and forming an interlaced envelope of staple fibres from fibrous system 15, and to withdraw them from forming yarn 1 9, or to return them to the surface of the yarn 1 9 being formed and to connect them by tightening the interlaced fibrous envelope to the yarn 1 9.

The connection of the interlaced envelope to the surface of the false twisted fibrous system 2 as well as the connection of completely free, excessively short staple fibres from the fibrous system 1 5 from the rotating pressure fluid flow back on to the surface of yarn 1 9 can be influenced by the speed ratio between the velocity of feeding of the false twisted fibrous system 2 and the withdrawing speed of yarn 19, when the speed of this interlaced yarn 1 9 is always lower, than the feeding speed of the false twisted fibrous system 2, whereupon the effect of false twist imparting to fibrous system 2 is increased, as well as the releasing of the surface of said fibrous system in the yarn forming twisting zone 13 and the growing effect of connection of front ends of the staple fibres from the fed fibrous system 15, and thus also an increased effect of forming yarn 1 9.

In case that the excessively short staple fibres should be eliminated from forming yarn 19, the respinning twisting nozzle 8, 1' opens with its exit 20 directly into the collecting space 23 of the sucking box 24, which is provided oppositely to exit 20 of respinning twisting nuzzle 8, 1' by a withdrawer 26 of yarn 1 9, of which the narrowing cross section directs yarn 1 9 towards the withdrawing rollers 27 which withdraw yarn 19 from the sucking box 24.

In the case, when the completely free excessively short staple fibres from fibrous system 15, which have not been clamped by the surface of the false twisted fibrous system 2, are to be connected to yarn 19, the respinning twisting nozzle 8, 1' is connected with its exit 20 to the expansion chamber 23 for the pressure fluid, provided with withdrawing apertures for the pressure fluid which are directed to the direction of rotation of the pressure fluid flow, the rotating surface of the contracting fibrous system 2, 1 5 coming into contact with the inner surface of the expansion chamber 21 due to the expansion of the pressure fluid through the apertures 22, said surface of the contracting fibrous systems 2, 1 5 thus wiping said fibres into its envelope which contacts due to twist inversion, and said excessively short fibres thus being rejoined with the surface of yarn 1 9. The direction of connection of the withdrawing apertures 22 into the direction of rotation of the pressure fluid flow does not admit their escape into the collecting space 23 of sucking box 24.

The expansion chamber 21, which might have also an advantageous narrowing cross section for facilitating the withdrawal of yarn 1 9 in the direction towards the withdrawing rollers 27, is mounted in the collecting space 23 of sucking box 24, so that the released impurities and dust which cannot be spun are withdrawn from forming yarn 19.

The fibrous systems 2, 1 5 of this yarn 19 can influence in various combinations both the character and the appearance of that yarn 1 9 and cause even the formation of completely new yarn types. So e.g. it is possible to make a yarn 19, of which both fibrous systems 2, 1 5 are made of the same presented fibrous body, or a yarn 1 9 of which one fibrous system, advantageously system 2 consists of fibres of inferior quality, or a yarn 1 9 of which the fibrous system 2 is made particularly of one bundle of continuous, possibly even textured fibres, and the texturing might take place in one production step before spinning. Even an interlaced yarn 1 9 might be obtained, of which fibrous system 2 consists of both continuous and staple fibres. The application of various colour combinations in the separate systems 2, 1 5 makes it possible to obtain also various types of completely new fancy yarns.

Claims

1. A method of producing yarn from two fibrous systems by means of a rotating pressure fluid flow, at least one of said fibrous systems consisting of staple fibres, wherein one of the two fibrous systems is continuously inparted false twist and its surface is provided with staple fibres from the second fibrous system, which are fed into the inlet zone of the yarn forming twisting zone, their front ends being partially clamped on the rotating surface of the false twisted fibrous system and partially directed in free condition in the direction of rotation of the pressure fluid flow and forming an interlaced interlayer clamped on the fibrous surface of the false twisted fibrous system, the rear ends of said staple fibres from the second fibrous system clamped by their front ends by the surface of the false twisted fibrous system, and directed by imparting false twist in the counterdirection of rotation of the pressure fluid, are re-directed at a speed higher than the speed of false twist imparting from the false twist direction in the direction of true twist, and are simultaneously in the rotating pressure fluid flow mutually intercrossed and girdled, forming together with the remaining staple fibres a fibrous envelope surrounding freely the false twisted fibrous system, said fibrous envelope being tightened on the surface of the false twisted fibrous system by the following continuous annulment of torsional force of the imparted false twist in the form of a unidirectional, regular twist helix, and contracting the cross section of both fibrous systems.

2. A method as claimed in claim 1, wherein the staple fibres from the second fibrous system enter the yarn forming twisting zone in untwisted condition together with the fibres of the false twisted fibrous system.

3. A method as claimed in claim 1, wherein the staple fibres from the second fibrous system enter the yarn forming twisting zone separately from the false twisted fibrous system.

4. A method as claimed in claim 3, wherein the staple fibres of the second fibrous system are sucked into the inlet zone of the yarn forming twisting zone.

5. A method as claimed in claim 3, wherein the staple fibres from the second fibrous system are blown into the inlet zone of the yarn forming twisting zone.

6. A method as claimed in claim 4 or 5, wherein the staple fibres from the second fibrous system are fed to the inlet zone of the yarn forming twisting zone in the direction of imparting false twist in the rotating pressure fluid flow.

7. A method as claimed in claim 1, wherein the advancing speed of the rotating helix of the pressure fluid flow in the yarn forming twisting zone is substantially lower than the speed of passage of the false twisted fibrous system.

8. A method as claimed in claim 7, wherein the yarn forming, twisting zone a partial twist inversion of the imparted false twist is performed at least in the section of the staple length of the re-directed staple fibres of the second fibrous system.

9. A method as claimed in claim 8, wherein the course of the twist inversion is continuous.

10. A method as claimed in claim 8, wherein the course of the twist inversion is impact-like in the inlet zone of the yarn forming twisting zone, and is maintained in the further passage through the yarn forming twisting zone at a substantially constant level.

11. A method as claimed in claim 8, wherein the controlled twist inversion takes place in the inlet zone of the yarn forming twisting zone in impact-like condition, and is continuously increased upon further passage through said zone.

12. A method as claimed in claim 8, wherein the controlled twist inversion proceeds impactlike in at least two phases following one another.

13. A method as claimed in any one of claims 8 to 12, wherein the total reduction of the imparted false twist by the controlled twist inversion does not surpass 60 per cent of its original value.

14. A method as claimed in claim 1, wherein the withdrawing speed of the yarn is lower than the speed of feeding the false twisted fibrous system.

1 5. A device for performing the method as claimed in claim 1, wherein around the path of a first fibrous system is arranged a pre-twisting nozzle in the direction of its passage, which opens into a respinning twisting nozzle arranged in the same direction and operating with the same direction of rotation of pressure fluid which, as well as a further control element for false twist imparts continuously in the yarn forming twisting zone the required degree of false twist to the first fibrous system, and a feeding channel for feeding staple fibres of a second fibrous system into the device is directed into the inlet zone of the yarn forming twisting zone of the respinning twisting nozzle.

1 6. A device as claimed in claim 15, wherein the pre-twisting nozzle comprises at least one feeding aperture for the pressure fluid, connected in tangential direction to the inner surface of a rotary chamber passing over to an opposite central rotary motion directing elemerSprovided in its centre with a suction opening and engaging in the direction of withdrawal of yarn at least to the level of the lower edge of the feeding aperture for the pressure fluid.

1 7. A device as claimed in claim 1 5, wherein the respinning twisting nozzle comprises at least one feeding aperture for the pressure fluid, which is connected tangentially to the inner surface of its directing chamber, in the centre of which is placed the pre-twisting nozzle, which directs with its outer housing the rotating pressure fluid flow into the yarn forming twisting zone.

18. A device as claimed in claim 15, wherein the feeding channel for the staple fibres from the second fibrous system is directed into a directing chamber of the respinning twisting nozzle, opening by an inlet annulus into the inlet zone of twist inversion formed in the yarn forming twisting zone of the respinning twisting nozzle, the inlet annulus being defined by the outlet circular cross section of pre-twisting nozzle and the inlet circular cross section of the yarn forming twisting zone of the respinning twisting nozzle.

1 9. A device as claimed in claim 18, wherein the width of the inlet annulus is adjustable.

20. A device as claimed in claim 18, wherein the feeding channel for the staple fibres of the second fibrous system is directed injector-like in the direction of rotation of the pressure fluid flow in the directing chamber of the respinning twisting nozzle.

21. A device as claimed in claim 17, wherein the feeding channel for the staple fibres of the second fibrous system is directed injector-like into a rectilinear stream of pressure fluid in the feeding aperture directed to the directing chamber of the respinning twisting nozzle.

22. A device as claimed in claim 17, wherein the feeding channel for the staple fibres of the second fibrous system is directed obliquely in the direction of rotation of the pressure fluid in the directing chamber of the respinning twisting nozzle.

23. A device as claimed in claim 17, wherein the feeding channel for the staple fibres from the second fibrous system is directed to the directing chamber of the respinning twisting nozzle obliquely to the axis of the false twisted fibrous system.

24. A device as claimed in claim 15, wherein the respinning twisting nozzle is connected with its outlet to an expansion chamber for the pressure fluid, provided with outlet apertures and arranged in the collecting space of a suction box.

25. A device as claimed in claimed 24, wherein the outlet apertures of the expansion chamber for the pressure fluid are directed in the direction of rotation of said pressure fluid.

26. A device for performing the method as claimed in claim 25, wherein the expansion chamber for the pressure fluid is narrowed in the direction of withdrawal of yarn.

27. A device as claimed in claim 15, wherein the respinning twisting nozzle opens with its outlet directly into the collecting space of the suction box.

28. A device as claimed in claim 27, wherein oppositely to the outlet of the respinning twisting nozzle is arranged in the collecting space of the suction box a withdrawing element for the yarn, of which the cross section is narrowed in the direction of withdrawal of the yarn being formed.

29. A method of producing yarn from two fibrous systems by means of a rotating pressure flow, substantially as hereinbefore described with reference to the accompanying drawings.

30. A device for producing yarn from two fibrous systems by means of a rotating pressure flow, substantially as hereinbefore described with reference to Figures 1 to 6 of the accompanying drawings.

31. A device for producing yarn from two fibrous systems by means of a rotating pressure flow, substantially as hereinbefore described with reference to Figures 1 to 5 and 7 of the accompanying drawings.

32. A device for producing yarn from two fibrous systems by means ofa rotating pressure flow, substantially as hereinbefore described with reference to Figures 8 and 9 of the accompanying drawings,

33. A device for producing yarn from two fibrous systems by means of a rotating pressure flow, substantially as hereinbefore described with reference to Figure 10 of the accompanying drawings.

34. A device as claimed in any one of claims 30 to 33 but modified substantially as hereinbefore described with reference to any one of Figures 11- to 14 of the accompanying drawings.