EP0412429B1 - Heating device - Google Patents

Description

The invention relates to a heating device for heating a running thread according to the preamble of claim 1.

In the known heating device according to GB-PS 890 057, the thread is guided at a distance from the surface by thread guides arranged at a distance from one another. The fact that the thread guides are arranged on a convex curved line ensures that the thread abuts the thread guides and that the thread runs smoothly.

In this known heating device and also in the heating device according to DE-OS 23 14 975, the thread is guided along a surface which has a temperature which is substantially above the target temperature of the thread. The target temperature of the thread is the temperature to which the thread is to be heated. The heating device is mainly used in false twist crimping machines for crimping synthetic threads. The target temperature of the thread is in the range between 150 and 230 °. The surface temperature is well above 300 °.

It has now been found that the wrap angle of the thread on each individual thread guide and the sum of the wrap angles are of decisive importance for the smoothness of the thread run and the height of the false twist to be introduced into the thread. In the known heater the distance of the thread from the surface is influenced by the specification of the wrap angle and the total wrap angle.

The object of the invention is to design the thread guide on the heating device according to the preamble of claim 1 so that the wrap angle on the thread guides and the total sum of the wrap angles on all thread guides can be freely selected without thereby also the distance of the thread path from the surface must be influenced.

The solution results from the characterizing part of claim 1. The solution has the further advantage that the zigzag-shaped thread guide along the hot surface also extends the thread path or further shortens the length of the heater with the same length of stay of the thread on the heating surfaces . The achievement of longer dwell times by zigzag-shaped guidance of fabric webs is known, e.g. from CA-PS 897 961. However, such fabric webs are not guided along a heating surface or heating plane, but through a heating or drying chamber. The teaching from CA-PS 897 961 is therefore not readily applicable to thread technology.

The thread guide along the radiator with changing spacing, which is known from the St.dT, has the following disadvantage in particular:
The heat transfer between the heating element and the thread is dependent on the distance of the thread from the heating element. However, this dependence is influenced by the temperature. A different course of the distance between the thread and the radiator would therefore have to be set for each desired radiator temperature. Thereby on the other hand, there would be a - possibly - harmful influence on the wrap angle. This disadvantage is avoided in the embodiment of the invention according to claim 2.

A precise setting of the distance of the thread running plane from the heating surface or heating plane of the radiator is achieved by the embodiment according to claim 3.

It is manufacturing technology and favorable for operation if the heating surface is a level, in particular a flat plate. As a result, the previously used curved heating rails can be dispensed with. Favorable heat conduction can be achieved by the configuration according to claim 4.

A plurality of thread guides arranged one behind the other at a distance can be introduced into this groove. The design of the groove and the thread guide results from claim 5 or 6. Either the insert guides symmetrical to the central plane of the groove and the fork-shaped thread guide asymmetrical or the insert guides asymmetrical to the central plane of the groove and the thread guide can be constructed symmetrically. This results in an offset of the flanks of the fork-shaped thread guides guiding the thread relative to the central plane such that the thread is guided in a zigzag line penetrating the central plane.

It has already been pointed out that the wrap angle on the individual thread guides and the sum of the wrap angles is of great importance for the quality of the textured thread. In order to achieve good qualities, a dimensioning rule is specified by claim 7 for the offset V between the thread guides. For synthetic threads in the titer range from 15 to 44 dtex, in particular nylon hosiery, the entire range for factor F must be taken into account. The total length of the heating device can, however, be selected to be short in accordance with the lower heat requirement. Longer heating devices are required for synthetic threads in the titer range between 55 and 500 dtex, in particular polyester yarns and nylon medium-titer yarns. However, the factor F is preferably between 0.8 and 0.15.

By selecting the factor F it can be achieved that the sum of the wrap angles, which are the individual Thread guides result, ie the total wrap angle is preferably greater than 7 ° and less than 40 °, preferably less than 30 °.

As already mentioned, it is an object of this invention to achieve smooth running of the thread and a high twist level. The design according to claim 8 serves this goal. Depending on the length of the entire heating device, it is sufficient if the heating device is composed of two or three radiators. The bend angle between the individual radiators is small and can preferably be 1 ° to 10 °.

The embodiment according to claim 9 ensures good heat management and avoids heat loss.

The embodiment according to claim 10 facilitates thread insertion. As a result of this configuration, the fork-shaped thread guides form an open V on their open side - in the direction of view of the thread path - into which the thread can be inserted well.

The embodiment according to claim 11 ensures that the thread cannot climb out of the thread guides. This embodiment is particularly advantageous if the measure according to claim 8 is not used.

The radiator described so far can e.g. be made from a high-temperature steel. Because of the low manufacturing effort, a ceramic plate is also suitable (claim 12).

The embodiment of the invention according to claim 13 offers the advantage that the offset of the thread guides and thus the amplitude of the zigzag line can be adjusted at any time. The tube can be closed and partially filled with a heat transfer fluid. The liquid will evaporate heated. This design ensures good temperature stability over the entire length of the radiator. Pressure control or temperature control of the heat transfer fluid can take place.

Due to the configuration according to claim 13, the heating device can be adapted to various process parameters, such as Thread speed, thread titer, desired target temperature, etc. adjust by simple maintenance work, without any intervention in the structure of the textile machine would be required.

Heating devices according to this invention are particularly suitable for heating the thread in the twisted zone of a false-wire texturing machine. It becomes possible to operate the false-wire texturing machine at high thread speeds with strong twisting and correspondingly strong crimping and to economically crimp even strong thread titers with good crimping.

The advantages claimed in the prior art, in particular the effect of self-cleaning of the heater, are also retained in the thread guide according to this invention.

An embodiment of the invention is described below.

Fig. 1

eine Falschzwirnkräuselmaschine (schematisch);

Fig. 2

das Ausführungsbeispiel in der Aufsicht;

Fig. 3

das Ausführungsbeispiel im Längsschnitt (vergrößert);

Fig. 4

Aufsicht eines Heizkörpers;

Fig. 5

Querschnitt durch einen Heizkörper;

Fig. 6

ein weiteres Ausführungsbeispiel mit einem Fadenlauf entlang einer Zickzack-Linie.

Show it:

Fig. 1

a false twist crimping machine (schematic);

Fig. 2

the embodiment in supervision;

Fig. 3

the embodiment in longitudinal section (enlarged);

Fig. 4

Supervision of a radiator;

Fig. 5

Cross section through a radiator;

Fig. 6

a further embodiment with a thread running along a zigzag line.

In the false twist crimping machine according to FIG. 1, the thread 7 is drawn off from the delivery spool 15 by the delivery mechanism 17 via thread guide 28. The thread then passes to the heater 1, which consists of two pieces. The first piece 19 is heated with the temperature T1. In the second part of the heater, which is referred to as end piece 20, the thread is brought to the target temperature. This end piece 20 is heated with a temperature T2. A deflection thread guide 21 is provided behind the heater 1, via which the thread reaches the cooling rail 22 and the false twisting unit 23. The thread is drawn out of the texturing zone by the delivery unit 24 and can then be guided via a second heater 25, deflection 26, delivery unit 27 for winding up with a bobbin 29, drive roller 30 and traverse 31.

In all exemplary embodiments, the heating device consists of a heating element 1 on which thread guides 2 are arranged. The thread guides 2 are webs which are arranged parallel to one another on the surface of the radiator 1. At the same time, the surface 3 forms the heating surface in the sense of this application. The thread guides are in heat-conducting contact with the radiator 1. The thread guides are arranged and dimensioned such that the thread is guided in a zigzag line over the heating surfaces 3 of the radiator. As a result, the thread comes into full contact with the thread guides.

Fig. 2 shows a schematic representation of the top view of a heating device in which a thread run in the form of a zigzag line is realized. Thread guides 2 are screwed onto the radiator 1, which is heated in an analogous manner to that in FIG. 1. The deflecting surfaces (heating surfaces) 35 of the thread guide 2 are arranged so that they deflect the thread 7 along a zigzag line 34, that is to say side-by-side and opposite deflecting surfaces mesh with one another and guide the thread so that it forms a zigzag line with the Thread guides 3 at the reversal points follows. The length of the heater is shortened or shortened by the thread path along the zigzag line Length of stay of the thread on the heater increased.

The thread is fed to the first or last deflecting surface 34 by means of input and outlet thread guides 37.

The guiding of the thread in a zigzag line means that the thread is stretched in a surface and preferably in one plane (running surface or running plane). This running surface is at a distance from the surface 3 of the radiator 1 at all points of the thread run. The thread guide 2, through which the zigzag line is spanned, have the most important feature, the deflection edge or deflection surface 35, which is shown and described in FIG. 2 and which penetrates the plane of the thread vertically.

The radiators described in the following according to FIGS. 3 to 5 correspond to the radiator shown only schematically in FIG. 1. In the following, Figures 3 to 5 are described together:

The heating device consists of two individual radiator pieces 19, 20. These radiators are constructed essentially the same. The following description refers to both radiators. Every radiator is a cuboid, elongated body. In a longitudinal surface, two rectangular grooves are cut in the longitudinal direction and parallel to each other. The heating element is penetrated by a heating cartridge 10 in the center plane between the two grooves. It is a resistance heater. The resistance heater of each piece 19, 20 is connected to a regulator 18 - as shown and described in FIG. 1. In the grooves 8, 9 several thread guides are inserted with the same distance, namely in the first piece 19 four thread guides 2 and in the second piece 20 five thread guides 2. Each thread guide is located at the entrance and exit of each piece 19 or 20. Die Thread guides 2 are flat plates. For installation in the grooves 8, 9, the grooves 8, 9 have insert guides for the thread guide 2, through which the thread guide 2 can be installed in planes transverse to the central plane 6. The insert guides in the example shown are insert grooves 5 running around the walls, the width of which in the longitudinal direction essentially corresponds to the thickness of the thread guide plates. Instead of the insert grooves, however, cylindrical bores can also be made in the groove, the diameter of which corresponds to the width of the thread guide.

In the case shown in FIG. 5, the depth of the insert grooves is symmetrical to the central plane 6 of the grooves. Therefore, the thread guides are constructed asymmetrically in their width. 5 for the grooves 8 and 9 differently designed thread guides are drawn. This is only used to describe various exemplary embodiments. In practice, one would probably only use one type of thread guide.

The thread guides shown on the right in FIG. 5 are each rectangular plates. In each of these plates, a slot 16 is made offset to the central plane 6. The slot extends parallel to the center plane 6 of the groove 9. However, it lies at a lateral distance from this center line. Successive thread guides 2 are each rotated about the central plane 6. Therefore, in the case of successive thread guides 2, the slot 16 alternately lies on one and the other side of the center plane 6. The flanks of the slot 16 facing the center plane 6 each form the deflection surface 35 on which the thread is deflected in a zigzag shape. The flanks of the slot 16 diverge in a V-shape on the open side of the slot. The opening width of the V is so large that the flanks of successive thread guides 2 facing the central plane 6 intersect - in the direction of view of the thread path - and in turn form an alignment of V-shaped openings into which the thread can be inserted in a straight line.

The thread guides 2, which are shown on the left in FIG. 5, have a climbing lock, by means of which the thread is prevented from climbing out of the groove. The thread guides are again designed as flat, rectangular plates. A slot is made in each of the plates from a broad side, asymmetrically to the center of the width. The flank facing the center of the width or center plane 6 of the groove ends in a bulge 32 which at the same time forms the deflection surface 35. The other side flank of the slot 16 runs more or less parallel to the central plane 6 of the groove. The flank facing the central plane 6, on the other hand, penetrates the central plane 6 of the groove. It should be added that the bulge is laterally offset with respect to the central plane 6. Successive thread guides 2 are each rotated about their axis during installation. For this reason, the bulges 32 of successive thread guides lie alternately on one and the other side of the central plane 6.

Each radiator 19, 20 is closed by a cover 13 and, moreover, each radiator is surrounded by suitable external insulation - which is not shown here. It is noteworthy that each groove 8, 9 is closed by its own cover. Therefore, only the affected groove needs to be opened for maintenance and operation.

As already mentioned, the heating device consists of two pieces 19 and 20. As shown in FIG. 3, these radiators 19, 20 are bent at an angle alpha to one another. This measure is also sufficient when designing the thread guide slots 16 without climbing locks, that is to say as shown on the right in FIG. 5, in order to ensure a smooth thread run. The angle alpha should be more than 1 ° and is preferably less than 10 °.

Darin bedeuten:

V =

Versatz der Fadenführer bzw. Umlenkflächen 35 relativ zueinander = Amplitude der Zickzack-Linie = 2 x Versatz der Umlenkflächen 35 relativ zur Mittelebene 6 der Nut;

F =

Faktor zwischen 0,1 bis 0,8;

L =

Länge des Heizkörpers;

N =

Anzahl der Fadenführer über die Länge des Heizkörpers.

In Fig. 4, which is the supervision of the radiator with the view in shows the grooves (the covers are not drawn for clarity), it is shown that the offset V of the zigzag line between successive thread guides is the distance between successive deflection surfaces 35, the distance being measured perpendicular to the central plane 6 of the groove. To measure this offset, total wrap angles at the deflection angles between 6 ° and 40 ° are specified. In order to achieve this, it is first determined what length L each of the radiators 19, 20 must have. This depends on the process parameters, in particular type of thread, thread thickness, thread speed, temperature of the radiator, dimensioning of the heating device. For example, assume that the total length is 1 m. This results in a length L of 500 mm for each of the radiators 19, 20. It has been found that four thread guides are expedient on the first section 19 and five on the second section. This results - if one calculates the second section 20 as an example - a distance A of the individual thread guides - measured in the longitudinal direction of the radiator - of 125 mm. If the above angular relationship is observed, the formula for the offset is obtained

$\text{V = F x L / (N-1)}$

Where:

V =

Offset of the thread guides or deflection surfaces 35 relative to one another = amplitude of the zigzag line = 2 x offset of the deflection surfaces 35 relative to the central plane 6 of the groove;

F =

Factor between 0.1 and 0.8;

L =

Length of the radiator;

N =

Number of thread guides over the length of the radiator.

Taking into account the specified factor with the adaptation to the thread type discussed at the beginning, the desired overall wrap angles result.

FIG. 6 shows a cross section through the heating device according to FIG. 5 on an enlarged scale. On a suitably beveled Carrier 36, the radiator 1 is screwed to the heaters 2 attached to it. The heater 1 is designed with a cavity 8 and a heating cartridge similar to that in FIGS. 1 to 3 and arranged in an insulating box 12 with a cover 13. The heating surface is formed in the heating element 2 as a V-shaped groove, which is off-center and into which the thread 7 can be inserted when the cover 13 is open. In the longitudinal direction of the heater 1, the successive heating pieces 2 can be arranged so that the thread 7 follows a zigzag line corresponding to FIG. 5.

Claims (13)

1. Heating device for heating a running thread (7) and in the case of which the thread is guided by a plurality of thread guides (2) along a heater (1) which is aligned in the general thread running direction (38), which comprises a heating surface or heating plane facing the thread (7), and which is heated to a temperature which is higher than the temperature (target temperature) to which the thread is to be heated, the thread guides (2) lying on a curved line which is at a distance from the heating surface or heating plane, characterized in that the curved line is a zig-zagged line (34) which is set in a surface (running surface or running plane) which is at a distance from the heating surface or heating plane over the entire length of the heating device.
2. Heating device according to Claim 1, characterized in that the running surface or running plane is parallel to the heating surface or heating plane.
3. Heating device according to Claim 1 or 2, characterized in that the thread guides (2) are secured to the heating surface of the heater (19; 20).
4. Heating device according to any one of Claims 1 to 3, characterized in that the thread (7) is guided in a groove (8; 9) which is provided in the heater (19; 20) in the thread running direction (38); and in that the zig-zagged line (34) set by a plurality of thread guides (2) lies in the groove (8; 9) at a distance above the base of the groove.
5. Heating device according to Claim 4, characterized in that the groove (8; 9) comprises a plurality of insertion guides (5) which are disposed behind one another, which extend substantially perpendicular to the groove (8; 9) and which are offset relative to the central plane (6) of the groove (8; 9) alternately to one side or the other of the central plane (6); and in that symmetrical, fork-shaped thread guides (2) can be inserted in the insertion guides (5).
6. Heating device according to Claim 4, characterized in that the groove (8; 9) comprises a plurality of insertion guides (5) which are disposed behind one another, which extend substantially perpendicular to the groove (8; 9), and which are disposed symmetrically relative to the central plane (6) of the groove (8; 9); and that asymmetric, fork-shaped thread guides (2) can be inserted in the insertion guides (5) such that they are offset alternately to one side or the other of the central plane (6) (half offset V).
7. Heating device according to any one of the preceding claims, characterized in that the number and offset (V) of the thread guides (2) relative to one another are selected such that a total looping angle (total of the looping angles resulting at the individual thread guides (2)) results at the thread guides (2), which total looping angle is greater than 6°, preferably greater than 7°, and smaller than 40°, preferably smaller than 30°.
8. Heating device according to any one of the preceding claims, characterized in that the heating device (1) is composed of two or more heaters (19; 20) of which the heating planes are slightly angled relative to one another; and in that the running planes are in each case parallel to the heating planes.
9. Heating device according to Claim 4, characterized in that parallel grooves (8, 9) are provided in a heater (19; 20); and in that each of the grooves (8, 9) can in each case be closed by a separate door (cover 13).
10. Heating device according to any one of Claims 4 to 9, characterized in that the fork-shaped thread guides (2) open in a wedge-shaped manner; and in that the largest opening width covers the central plane (6) of the groove (8; 9).
11. Heating device according to any one of Claims 4 to 10, characterized in that the flank facing the central plane (6) comprises a convexity (32) facing the central plane (6) in the vicinity of the fork base.
12. Heating device according to any one of the preceding claims, characterized in that the heater (19; 20) is a ceramic plate, preferably a ceramic plate with resistance heaters (10) provided therein.
13. Heating device according to Claim 1, characterized in that the surface is formed by a tube which is heated and to which the thread guides (2) are secured at a distance from one another such that they can be rotated and fixed, the thread guides (2) comprising thread guide slots (16) with deflection edges (35) aligned radially in each case.

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