The invention relates to an air spinning device having a spindle according to the preamble of the independent claims.
The air spinning device in the sense of the present invention is understood to be a yarn spinning device or a roving spinning device, such that the proposed device may be used for all spinning methods that operate with air.
A spinning device which serves to produce a yarn with the help of a stream of air comprises a slubbing or fiber band feed, a drawing mechanism, an air spinning device and a winding mechanism. A fiber band is guided by the fiber band feed from an upstream fiber band storage to a drawing mechanism. In the drawing mechanism, the fiber band is drawn at a certain deformation and is sent onto the air spinning device. The drawn fiber band is sent to an eddy zone via a fiber guide element in the air spinning device. The eddy zone is a space between the fiber guide element and the inlet opening into a spindle opposite the fiber guide element. The eddy zone is arranged in a nozzle body into which the fiber guide element is inserted from the one side and a spindle is inserted from the opposite side. In the eddy zone, compressed air is introduced through appropriately arranged boreholes, leading through the arrangement of boreholes to form an eddy which is dissipated along the spindle on the outside. Some of the fibers of the fiber band introduced into the air spinning device are separated from the fiber band by the eddy current of compressed air introduced and wrapped around the tip of the spindle. The ends of the fibers remain captured in the fibers of the fiber band that have not been separated out and are drawn into the spindle with the so-called core fibers. During the retraction of these loosened fibers, also known as winding fibers, into the spindle opening, the winding fibers are wound around the core fibers due to the eddy current. Various properties of the spinning operation can be influenced through the design of the individual components and the settings of the eddy air. For example, the number of winding fibers may be altered in comparison with the number of core fibers or the number of windings per length or the yarn twist of the finished yarn can be adjusted. The yarn twist is understood to be the angle at which the winding fibers are wrapped around the core fibers in relation to the longitudinal axis of the yarn. It is possible in this way to produce yarns with different properties in the air spinning method, for example, even roving. Roving is understood to be an intermediate product which is used as the starting product for the final spinning methods, for example, ring spinning or rotor spinning. In the production of roving, it is important for the yarn twist, on the one hand, to be low enough that it can be loosened again in the final spinning process and, on the other hand, for it to be great enough to ensure a reliable transport and a trouble-free feed to the final spinning device.
Various types of air spinning devices are known from the state of the art. EP 2 009 150 A1 discloses an air spinning device having a nozzle body and a hollow spindle. The spindle protrudes with its spindle tip into the nozzle body. A ring-shaped outlet channel is formed between the outside surface of the tip of the spindle and the inside surface of the nozzle body. The eddy air is removed along the spindle through the outlet channel. The outlet channel has a cylindrical shape and the distance between the inside surface of the nozzle body and the outside surface of the spindle is constant. This gap width is constant over the course of the longitudinal axis of the spindle so that the cross-sectional area normal to the longitudinal axis of the spindle is constant over the course of the longitudinal axis of the spindle. Furthermore, a certain range for the dimension of the gap width and the inside diameter of the nozzle body is disclosed in EP 2 009 150 A1. Apart from the dimensions of the spindle tip and the nozzle body and thus the definition of the outlet channel, the shape of the outlet channel is crucial for the behavior of the eddy air flow. Due to the cylindrical shape of the outlet channel, the eddy air can flow unhindered along the spindle tip. Short fibers are then picked up by the flow and transported away by the air flowing out along the spindle tip. This forms a so-called discharge, which contains fibers that have not been bound into the resulting yarn due to the process and are separated out of from the spinning process. The amount of the discharge therefore has a significant influence on the yarn production cost because it reduces the utilization of raw materials. Another disadvantage of the air spinning device as disclosed in the related art is that the yarn twist can be influenced only by reducing the eddy air, which results in a reduction in the eddy air leading at the same time to a reduction in the number of winding fibers, while the discharge quantity usually increases because the fibers are not bound adequately.
The object of the invention is to avoid the disadvantages of the state of the art and create an air spinning device, which makes it possible to minimize the discharge and thus allow better utilization of raw materials while simplifying the setting of the yarn twist.
This object is achieved by an air spinning device having the characterizing features of the independent claims. This object is achieved by providing an air spinning device with a nozzle body and a hollow spindle having a spindle tip and a longitudinal axis, wherein the spindle tip protrudes into the nozzle body and forms an outlet channel with a ring-shaped cross-sectional area between and outside surface of the spindle tip on an inside surface of the nozzle body, and a gap width, seen normal to the longitudinal axis of the spindle, is constant over the circumference of the spindle at a certain location in the outlet channel. The outside surface of the spindle tip and/or the inside surface of the nozzle body is/are shaped in such a way that at least two constrictions are formed in the outlet channel in its course in the direction of the longitudinal axis of the spindle, the outlet channel having a ring-shaped cross-sectional area at each of these constrictions in its course in the direction of the longitudinal axis of the spindle, the cross-sectional area being smaller than the ring-shaped cross-sectional area of the outlet channel upstream and downstream from each of these at least two constrictions.
The invention may be used with basically any air spinning machine, regardless of the type of yarn or roving to be produced, in which at least some of the fibers have a twist in the cross section of the process products, and the machine therefore has an air spinning device with a hollow spindle and a nozzle body.
In air spinning to produce a yarn or roving by winding core fibers with winding fibers, air spinning devices which encompass a hollow guide spindle and a nozzle body are used. A yarn guide channel which opens with a spindle opening in the spindle tip is provided in the spindle. A fiber band to be spun is introduced into the nozzle body through a fiber guide element upstream from the spindle. The spindle protrudes at its tip into the nozzle body, an outlet channel with a ring-shaped cross-sectional area being formed between an outside surface of the spindle tip and an inside surface of the nozzle body. An eddy zone is formed between the fiber guide element and the spindle tip. Compressed air is injected into the eddy zone through appropriately arranged boreholes, resulting in an eddy flow due to the arrangement of boreholes. The compressed air is removed from the eddy zone through the outlet channel, resulting in a rotating stream of air guided along the spindle. The fibers introduced into the air spinning device by the fiber guide element are divided by the eddy flow into core fibers, winding fibers and discharge, wherein the core fibers are introduced directly into the spindle opening, the winding fibers are gripped at one end in the core fibers and are wrapped around the spindle tip at the other end, and the discharge is removed from the air spinning device by the air flow guided along the spindle. The fibers wrapped around the spindle tip move in a helical line around the spindle tip, forming a so-called fiber cluster. The area of the spindle in which the wrapped fibers move is referred to as the spindle tip. The outflow of air going beyond this area of the spindle has no direct influence on the movement of the fibers. The number of winding fibers is determined by the distance of the spindle tip from a last clamping point of the fiber band. Before reaching the fiber guide element, the fiber band is guided through a pair of rollers which forms a clamping point. Because of the length of the individual fibers, the distance between this clamping point and the tip of the spindle is selected. At a constant fiber length, the proportion of winding fibers increases with an increase in the distance between the clamping point and the spindle tip. However, at the same time, this increase in the number of winding fibers results in an increase in the discharge. By making the outlet channel narrower, the discharge can be reduced again but that has a negative effect on eddying and turbulence of the winding fibers.
According to the invention the outlet channel is designed in its geometric shape so that fibers in the discharge are captured by the winding fibers before being removed and then they are bound into the yarn or roving. This has the advantage that the discharges reduced without influencing the eddy effect on the winding fibers. The shape of the outlet channel changes the path of the fibers around the spindle tip. When considered over the length of the fibers, individual sections of the fibers are subject to acceleration, deceleration or eddying in their rotating helical movement because of the design of the outlet channel. The type of movements induced by the fibers around the spindle tip also influences the yarn twist. Due to the reduction in the circumferential velocity, there is a lower twist so that the air and flow conditions in the eddy zones need not be changed for example, by reducing the eddy air.
In a first embodiment the air spinning device comprises a novel body and a hollow spindle having a spindle tip and a longitudinal axis, wherein the spindle tip protrudes into the nozzle body and forms an outlet channel having a ring-shaped cross-sectional area between an outside surface of the spindle tip and an inside surface of the nozzle body. A gap width at a certain location in the outlet channel, as seen normal to the longitudinal axis of the spindle, is constant over the circumference of the spindle. The outside surface of the spindle tip is shaped so that at least two constrictions are formed in the outlet channel in its course in the direction of the longitudinal axis of the spindle, wherein the outlet channel has a ring-shaped cross-sectional area at each of these constrictions in its course in the direction of the longitudinal axis of the spindle, this being smaller than the ring-shaped cross-sectional area of the outlet channel upstream and downstream from each of these at least two constrictions. The inside surface of the nozzle body has a cylindrical shape, which results in the same gap width at each location of the outlet channel over the circumference and forms a ring-shaped cross section. The flow pattern of the eddy air flowing out is influenced by the constrictions created in the outlet channel. The constrictions produce a change in the eddying of the air flowing out. The velocity of the air flowing out is influenced by the constrictions. The velocity is reduced upstream from a constriction, is increased by the constriction of the outlet channel and is reduced again by the subsequent widening of the outlet channel. By creating a breakaway edge due to the shape at the constriction, backflow or eddies rotating perpendicularly to the air flow along the spindle are created, and this additionally contributes toward a reduction in the discharge.
The formation of backflows downstream from a constriction is increased by a second following constriction. The backflow and the resulting eddies cause the fibers, which would normally be carried away as discharge along the spindle, to be pressed at least partially pressed against the spindle. In the vicinity of the outside surface of the spindle, these fibers are captured by the fibers which are within the fiber ring and are thereby tied into the yarn. The eddies resulting from the backflow rotate about an axis which stands essentially perpendicular to the axis of the spindle and is on a concentric circle with the inside contour of the nozzle body. The eddy rotates on its own, on the one hand, and on the other hand, the eddy is rotated in a circular pattern about the spindle due to the stream of air which rotates the fiber cluster.
A constriction may be formed by providing a ring-shaped bulge on the outside surface of the spindle tip. The development of the bulge is limited in its geometric shape only by the fact that the aforementioned cross-sectional area results in a uniform gap width over the circumference of the spindle. The integrally molded bulge may be round or wavy or may also have edges. In one embodiment having a plurality of constrictions, they may be formed by multiple bulges such that the bulges can be differentiated due to different geometric shapes as well as different dimensions.
To promote the formation of the backflows and/or eddy currents normal to the spindle axis, for example, asymmetrical wave forms or bulges and/or barreling which is/are provided with an undercut in the direction of the course of the yarn.
The spindle is preferably embodied in two parts. The spindle tip with the bulge formed on it forms a first part of the spindle and is attachable to the second part of the spindle. “Attachable” is understood to mean that the first and second parts of the spindle are coordinated to fit exactly with one another at a contact point. The parts of the spindle may be joined together at the contact point without creating a mechanical or chemical bond. Because of the pressure conditions prevailing in the nozzle body, the two parts of the spindle are held together. In addition, a mechanical connection of the first part to the second part of the spindle may also be provided, and may be a plug connection or a screw connection, for example. In another embodiment, the first part of the spindle is formed by the outside surface of the spindle tip, this being attachable to the second part of the spindle, for example, in the form of a spindle tip sleeve. The fastening may be accomplished by plug connection or by some other type of fastening, for example, by screwing. The advantage of the two-part embodiment lies in a simple replaceability of the part of the spindle which is subject to the greatest wear. In addition, there is the possibility of changing the shape of the outside surface of the spindle tip without having to replace the entire spindle. A change in the eddy zone is also possible simultaneously with the replacement of the spindle tip if the spindle tip protrudes more deeply into the nozzle body, for example, than the spindle tip replaced.
It has been found that the ratio of the largest outside diameter of the bulge to the smallest outside diameter of the spindle tip is preferably 1.05 to 1.5 for the structural embodiment of the bulge or the sum of the bulges.
In a second embodiment, the spindle tip is designed with a cylindrical shape and the inside surface of the nozzle body is shaped so that at least two constrictions are formed in the outlet channel in its course in the direction of the longitudinal axis of the spindle such that the outlet channel has a ring-shaped cross-sectional area at each of these constrictions in its course in the direction of the longitudinal axis of the spindle, this cross-sectional area being smaller than the ring-shaped cross-sectional area of the outlet channel upstream and downstream from each of these at least two constrictions. The constriction may be formed by a barreling in the nozzle body, which protrudes in a ring shape into the interior of the nozzle body. Various geometric shapes are also conceivable for the embodiment of such a barreling. The integrally molded barreling may be round or may also have edges. In an embodiment having a plurality of constrictions, they may be formed by a plurality of rolls of barreling, such that the rolls of barreling may be differentiated by different geometric shapes as well as different dimensions. The nozzle may also be embodied in two parts, such that the inside surface of the nozzle body is formed by a nozzle body insert, the latter being insertable into the nozzle body.
Due to the change in the position of the nozzle body in relation to the spindle in the direction of the longitudinal axis of the spindle, the formation and size of constrictions within the outlet channel can be adjusted. Due to the fact that the spindle or the nozzle body is movable in the direction of the longitudinal axis of the spindle, the outlet channel is adjustable in its shape along the spindle tip. The same effect is achieved by a nozzle body which is movable in the longitudinal direction of the spindle because the relative displacement of the spindle and nozzle body toward one another leads to a change in the setting. Thus, for example, with an increase in the size of the distance of the spindle with the spindle opening from the fiber guide element, an increase in the size of the eddy zone may be created. At the same time the gap width may be reduced if bulges on the spindle tip are brought into alignment with barreling formed on the inside surface of the nozzle body. The same adjustments can be achieved by replacing a spindle tip sleeve or a nozzle body insert.
A combination of the first embodiment with the second embodiment is also conceivable. The design of the inside surface of the nozzle body and the outside surface of the spindle are, however, to be coordinated with one another, such that the cross-sectional area of the outlet channel is ring-shaped and yields in a certain cross-sectional area a gap width which is the same over the circumference of the spindle. Another embodiment can be achieved if barreling in the nozzle body does not reduce the inside diameter of the nozzle body but instead increase it. Such grooves or channels are to be understood under the term “barreling” if a constriction of the outlet channel is created in conjunction with the spindle tip.
Regardless of the embodiment of the outlet channel, the spindle tip of the inside diameter of the yarn guide channel can be altered by inserting a yarn guide insert into the yarn guide channel of the spindle tip. At the same time, the shape of the spindle opening is also variable by such a yarn guide insert. By creating constrictions in the outlet channel, a backflow in the yarn guide channel may be formed, which results in air being drawn through the spindle into the eddy zone against the direction of yarn conveyance. The stream of air, which is drawn along the fiber guide element into the eddy zone, is diminished accordingly. The air flowing along the fiber guide element is important for the fiber band separation and for the transport of the fiber band to the spindle opening. This circumstance may be taken into account by a constriction of the yarn guide channel with the insert of the yarn guide insert in the area of the spindle tip.
The invention is explained in greater detail below on the basis of exemplary embodiments and is illustrated by drawings:
1 Air spinning device
2 Nozzle body
3 Spindle
4 Fiber guide element
5 Roll pair
6 Yarn guide channel
7 Longitudinal axis of the spindle
8 Spindle tip
9 Spindle opening
10 Fiber
11 Outside surface of the spindle tip
12 Inside surface of the nozzle body
13 Outlet channel
14 Fiber band
15 Bulge
16 Barreling
17 Nozzle body insert
18 Spindle tip sleeve
19 Yarn guide insert
20 Boreholes
21 Stop
22 Undercut
23 Direction of yarn travel
24 Backflow
D Movement of the spindle
S Gap width
L Distance between roll pair and spindle tip
Number | Date | Country | Kind |
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1115/09 | Jul 2009 | CH | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CH2010/000178 | 7/9/2010 | WO | 00 | 1/13/2012 |