EP0602190B1 - Heater for a moving yarn - Google Patents

Abstract

The invention concerns a heater (1) for a moving thermoplastic yarn which is passed along a heated surface over annular segments (2). The heat flow to the yarn can be controlled by modifying the geometrical heat-transfer parameters.

Description

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

Such a heater is known from EP 412 429 (IP-1720). It has the disadvantage that the curvature of the thread path is fixed and at the same time determines the distance of the thread from the heated surface.

Such a radiator finds e.g. Use on a false twist crimping machine.

But other applications are also possible.

Radiators for heating running thermoplastic threads (chemical threads) false twist crimping machines generally have elongated rails which are heated to a certain temperature and over which the thread is guided.

For stretching and thermal fixing of a chemical thread, a heated tube is described in DE-AS 13 03 384, which is wrapped in a steep helix by the thread. The tube is provided with a bead at the end of the thread to prevent movement in the circumferential direction.

Polyamide (PA6, PA6.6) or polyethylene terephthalate is particularly suitable as the thermoplastic material for the thread, but without being restricted to these materials.

It is an object of the invention to provide a thread heating device which is simple to assemble and which makes it possible to change the curvature of the thread track within wide limits and for each thread track and at all points of the thread track to a distance from the surface which is independent of the selected curvature guarantee.

This object is achieved by the features of claim 1.

In addition, in a further development of the invention, it should be possible to influence the heat transfer for the respective application.

In this radiator, the steepness of the helix with which the thread runs over the rings of the tube, and thus the curvature of the thread path, can be selected in the circumferential direction by adjusting the thread guides provided at the entrance and exit of the thread path. However, while the curvature of the thread path has a decisive influence on the heat transfer in the described and otherwise known radiators, this is not the case with the invention. Here the heat transfer is based exclusively on the temperature of the pipe and the height of the rings above the pipe. However, the steepness of the helix, i.e. H. The curvature and wrap angle of the thread path can be selected without influencing the heat transfer in such a way that the thread runs smoothly and stably and that - in the case of false twist crimping machines - the thread introduced into the thread can also propagate unhindered in the area of the thread length exposed to the radiator .

This also enables a clear setting of the temperature of the thread. Since the curvature of the thread path has no influence on the heat transfer, the thread temperature depends only on the height of the rings (see above) Temperature and the length of the pipe. The length and the wrap angle are not interdependent. The length can therefore be selected so that the tube can be operated in a temperature range which corresponds to the self-cleaning temperature of the heated surface, that is to say is above 300.degree.

A thread guide is arranged upstream and downstream of the heating tube according to this invention. Both thread guides are offset from one another in the circumferential direction of the heating tube, so that the thread is guided over the heating tube in a steep helical line. The heating tube is preferably straight. A curvature is not necessary, since the curvature of the thread line can be specified by adjusting the thread guides - as already described.

The heating pipe is heated from the inside. This can preferably be done by providing an electrical resistance heater in the interior of the heating tube which extends at least over part of the length of the heating tube. It is also possible to intensify the heating in certain areas, e.g. B. in the entrance area, on the length of the heating tube to provide several independently activated and adjustable resistance heater. You can then regulate different temperatures over the length of the heating tube.

It is envisaged and sufficient that the thread runs over the heating tube and the rings at a very acute angle - to the surface line of the heating tube. In view of the high temperature of more than 350 ° to which the heating tube can be heated, only a small length of the heating tube is required. As a result, the total wrap angle of the thread - based on the circumference and length of the heating tube - is relatively small. It is preferably less than 180 °. Therefore, the heating tube is in any case the section of a section Cylinders. The design as a circular cylinder has the advantage that the thread rests on the outer surfaces of the rings over its entire contact length with the same contact parameters, in particular the same screw angle. However, there are other cylindrical designs, e.g. B. elliptical designs of the heating tube possible, especially when - what will be discussed later - the ring height in the area of the thread path is not constant over the length of the heating tube. In the area of the heating tube which faces away from the thread run, the heating tube can be of any design. However, a symmetrical design of the heating tube cylinder, in particular a circular cylindrical configuration of the heating tube cylinder, is expedient if special emphasis is placed on uniform heat distribution over the circumference and / or length of the heating tube.

In any case, the rings extend over the area of the heating tube circumference which is adjacent to the thread running line. So you do not have to extend over the entire circumference of the heating tube and are therefore referred to in the context of this application as "ring segments". The possibility of good thermal insulation of the heating tube arises if the rings only extend over the partial circumference of the heating tube on which the thread lies. In this case, the heating pipe can be covered with an insulating layer on the flat side facing away. The partial circumference over which the rings extend can be reduced by the fact that successive rings are offset from one another in the sense of the thread running, that is to say are offset helically from one another in the sense of the thread line. A certain circumferential extent of the rings is advisable in any case so that the pitch of the thread line can be preset in the desired range.

As already mentioned, the radiator according to the invention is particularly advantageous to operate at temperatures in the Self-cleaning area. This is understood to mean that the temperature is so high that polymer residues which stick to the heating element or the webs during the heat treatment of the thermoplastic threads disintegrate and oxidize. A slight mechanical cleaning is then necessary at most. The temperatures for polyester and nylon are over 300 ° and can also be 800 °. The temperature limit at which damage occurs depends on the type of polymer, the thickness of the threads, but also on the length of the radiator, the chosen helix and the other parameters of the heating process.

The rings according to this invention can each lie in a normal plane of the heating tube. These are rings in the strict sense of the word.

However, the rings can also be inclined with respect to the circumferential direction. For example, the inclined rings can lie in a family of parallel planes. In this case there is an advantage that the inclination of the rings relative to the curved helical thread run can be chosen so that the thread overflows the outer surface of the rings as short as possible; This means: The inclination of the rings should be chosen so that it is opposite to the inclination of the thread run and that the thread hits each ring at an angle of 90 ° or an angle that deviates only slightly from it.

Such an advantageous embodiment of the radiator according to this invention results from the development according to claim 2. In this case, the slope is preferably selected in opposition to the slope of the thread course, both based on a surface line of the heating tube. It is hereby achieved that the thread touches the ring as short as possible. The helical or helical line Web - also called a spiral - can, for. B. in the form of a helical wire on the circular cylindrical heating tube and replaced when worn. The exchange of the wire support is easy to do, as is cleaning, if it is spring wire, which rests on the heating tube due to its resilient contraction and which widens in the longitudinal direction by compression so that the wire can be pulled off the tube.

In the known radiators, in which the thread is guided along a strongly heated surface by means of webs, there is a disadvantage in that the surface and part of the webs have the required self-cleaning temperature, but the webs are cooled so much by the running thread that the temperature drops below the self-cleaning range. The preferred embodiment according to claim 3 avoids this disadvantage. In this case, the webs over which the thread runs are formed by recesses which are introduced into the heating surface of the heating tube and between which in each case a web remains in the axial direction, which is located in Extends circumferentially or inclined to. These recesses can extend in the circumferential direction and over the entire circumference and appear in this case as grooves. However, they can also extend over a partial circumference of the heating tube, specifically over the partial circumference that is provided for the helical line of the thread run. In this case, the successive grooves are preferably also offset in the sense of the helix.

In this embodiment, too, the rings can be arranged in a normal plane or lie in a family of inclined and parallel planes or on a helix of the heating tube. In this case, what was said above applies to the direction of the helix.

In this embodiment, there is good heat transfer from the heating pipe to the overflow surfaces of the rings, so that it can be ensured that the overflow surfaces are always heated to the self-cleaning temperature.

It has surprisingly been found that there is no risk of burns for the thread even at high temperatures and thin threads if - furthermore proposed as advantageous - the ring height or depth of the recess is between 0.1 mm and 5 mm, preferably between 0 , 5 mm and 3 mm. The lower limit is determined by the radius of the heating pipe and the steepness of the helix in which the thread is guided or the curvature of the heating surface, as well as by the distance between the successive rings / webs and must be selected so that the thread is the heating surface not even touched.

The following should be emphasized: Both the fact that webs and the heating surface consist of one piece and therefore have particularly good thermal contact, as well as the fact that the webs have only a small height compared to the heating surface - each individually and collectively - A significant improvement over the prior art. These improvements can be used advantageously in any type of high-temperature heater in which the thread is guided in a curved thread line along a heating surface.

Wear plays a role in the thermal treatment of man-made fibers, in particular man-made fibers of low strength (titer, denier) the thread-guiding surfaces play a very important role in the quality of the product. This applies in particular to the false twisting machine, in which the thread in the area of the radiator rotates about its axis. To avoid wear on one side, it may be expedient to provide the heating tube of this radiator in a rotatable manner. The heating tube can then be rotated permanently or slightly at certain intervals, so that a new thread run occurs.

However, due to the advantageous use of its electric resistance heater, such further rotation is only possible within limits. The further development of the invention according to claims 4 and 9 provides a remedy here.

A relative rotation between the ring and the heating tube or between the sleeve and the heating tube is of course only possible if the heating tube is circular-cylindrical. However, this is not necessary if the primary concern is the interchangeability of worn rings.

According to claim 4, the rings can be designed as separate components and threaded onto the heating tube. The inner diameter of the rings is substantially equal to the outer diameter of the heating tube, so that there is good heat-conducting contact between the heating surface and the ring.

In the development according to claim 5, it is possible to replace the rings individually, the thread-carrying part of the rings only extending over a partial circumference of the heating tube. In the development according to claim 5 can be achieved that almost the entire scope is still available for the thread guide. With the design according to claim 6, a constant offset in the circumferential direction can always be set from ring to ring. In the embodiment according to claim 7, this offset can be chosen.

In order to ensure intimate thermal contact between the ring and the heating tube on the thread running side, each ring is pressed against the heating tube by a resilient bracket. This resilient bracket is supported on the one hand on the side walls of the slot and with its central region on the heating tube.

In the case of webs or rings placed thereon, it is particularly advantageous if the height relative to the heating surface is chosen between 0.1 mm and 5 mm, preferably between 0.5 mm and 3 mm. The lower limit is also determined here by the radius of the heating pipe and the steepness of the helix in which the thread is guided or the curvature of the heating surface, as well as by the distance between the successive rings / webs, and must be selected so that the thread does not touch the heating surface itself.

In the embodiment according to claim 9, at least the partial circumference of the heating tube, which is provided for the yarn path, is covered with a sheet (sleeve) which is closely adapted to the surface shape of the heating tube and is in close heat-conducting contact with the surface of the heating tube. It should therefore be emphasized that the sleeve does not have to extend over the entire circumference of the heating tube, but only over the part of the circumference of the heating tube that faces the thread path (heating surface).

However, the sleeve can also be designed as a tube with a thin wall. In this case, the inner cross section of the sleeve is closely matched to the outer cross section of the heating tube, but is preferably adapted to be rotatable. If the heating tube is circular-cylindrical, the sleeve is advantageously also designed as a circular-cylindrical tube, since this ensures the rotation of the sleeve.

Rings having the shape described above are formed on the outer jacket of the cuff. The cuff is preferably made of a thin sheet. The rings can be formed in that the sleeve is compressed in several normal planes in such a way that an annular bulge arises outwards.

This creates cavities that can hinder heat transfer. On the other hand, it is complex and technically difficult to apply massive rings to a thin-walled sheet with good thermal conductivity, e.g. B. to weld. These difficulties are avoided in the execution according to claim 10. According to this embodiment of the invention, a sleeve or cage is placed on the heating tube, which is provided with a substantially smooth surface, the inside diameter of which corresponds to the outside diameter of the heating tube and the jacket of which is penetrated by recesses of the same shape which are lined up axially in a row. Lines of uniform recesses preferably lie diametrically opposite one another in the cuff, lines with recesses of other shapes preferably lying next to these lines of recesses arranged in a row. The lines may run parallel to the axis. Between the recesses lined up in a row there are uniform, circumferentially extending webs corresponding to the shape of the recesses. The sleeve is secured on the heating pipe against axial displacement, but can be turned. On the one hand, this has the advantage that the thread can always be passed over a clean overflow point of the webs by periodically or gradually rotating the sleeve on the tube; on the other hand, the thread can be heated in wide temperature ranges due to the different design of the webs. Since uniform webs or recesses lie diametrically opposite one another in the cuff or are repeated at certain angular intervals, overflow paths become two or more threads are formed. Otherwise, the webs running between the rows in the longitudinal direction of the cuff are of no significance for the essence of the invention.

In this case, the sleeve is a sheet metal, into which several recesses are axially cut. These recesses are designed so that a web remains between axially adjacent recesses, which extends in the circumferential direction. In this embodiment, too, the webs do not have to lie in a normal plane of the heating tube, but can be inclined in relation to a normal plane. Furthermore, it is not necessary for the webs to extend over the entire circumference. Rather, it is desirable that the sleeve consists of one piece over the entire length of the heating tube and that the recesses therefore only extend over a partial circumference / partial width.

It has already been pointed out above that a low ring height is not only possible but is also advantageous for making the temperature transfer more uniform and for mastering the temperature transfer to the thread. For this reason, it is also particularly advantageous to choose the sheet thickness between 0.1 mm and 5 mm, preferably between 0.5 mm and 3 mm. Reference is made to the above limitations.

The embodiment according to claim 4 allows the distance of the rings to vary over the length of the heating tube, which will be discussed later. In order to enable such a design even when using a cuff, the design according to claim 11 is proposed. Here, the sleeve is broken down into individual axial sections, which can be telescopically pushed into one another in an advantageous embodiment. Each section has a ring on its outer circumference. By making the sections more or the distance between the rings can be varied.

The application of the webs for thread guidance to a sheet metal that covers the heating surface, as well as the formation of the webs by a sheet metal that has recesses, offers the advantages described for each radiator.

As already mentioned, a thread guide is arranged at the entrance of the heating tube and at the exit of the heating tube. The two thread guides are offset from one another in the circumferential direction of the heating tube, so that the thread is guided over the rings in a steep helical line. The steepness of this helix and the radius of the outer surface of the rings determine the curvature of the thread run. The curvature of the thread run is in turn decisive for the stability of the thread run. In order to be able to adjust the stability of the thread run in other parameters that have an influence on the stability of the thread run (e.g. thread tension, amount of twist in the false twist crimping process), it is proposed according to claim 12 that the thread guide and the heating tube in the circumferential direction of the heating tube are adjustable and positionable relative to each other.

As already mentioned, it is thermally advantageous to heat the heating tube symmetrically. A good thermal utilization of the heating tube is then obtained in the embodiment according to claim 13. It is possible that the threads loop around the heating tube in a helical line of the same direction. As long as the total wrap angle of each thread is less than 180 °, more than two threads can be heated on each heating tube in this way. Of course, this makes operation and especially threading more difficult. This is especially true because the radiator for insulation must be surrounded by an insulating housing that only allows limited access to the heating tube. Such an insulating housing advantageously surrounds the entire heating tube and only leaves as narrow a radial slot as possible, which lies on a surface line or parallel to a surface line of the heating tube. With such a configuration of the insulating housing, the application of several threads is only possible to a limited extent. In the advantageous embodiment according to claim 14, in which two threads with opposite slope are applied to the heating tube, these two threads can be applied in any order without difficulty. In this case, a thread guide is provided for each thread run at the entrance and at the exit. The thread guide on one side, e.g. B. at the exit of the heating tube, are close together and essentially on the radial plane of the insertion slot. The two thread guides on the other side, in this case at the entrance of the heating tube, have a large distance symmetrically to the radial plane of the insertion slot in the operating position. Appropriately, they can be adjusted for threading between the radial plane of the insertion slot and the operating position. Each thread can therefore be inserted in the radial plane of the insertion slot in the thread guide at the entrance and at the exit of the heating tube. Then one of the two thread guides is adjusted in the circumferential direction and the thread is thereby brought into its operating thread run. Both threads can be attached one after the other in this way in any order.

In the case of radiators for thermoplastic threads, in which the temperature of the heating surface is substantially above the target temperature to which the thread is to be heated, there is a particular problem in reaching the target temperature in any case, but not exceeding it. For this purpose, only the temperature of the heating surface and the thread speed can be adjusted as parameters. The thread thickness and the length of the Radiators, however, are fixed.

However, optimizing the heating effect on the thread is of great importance for the quality of the thread and its texturing in the false twist crimping machine. For this reason, it is proposed that the contact length of the thread guide is adjustable. This also allows the heating to be optimally adjusted to the thread speed and thread diameter (titer) desired in each case. For execution, it is advisable to design the radiator and thread guide so that the thread guides are interchangeable.

In order to optimize the heating effect and to adapt to the thread running speed and titer, it is furthermore proposed as advantageous to set the ratio of the contact length of the thread guide to the contact-free length of the heating element (contact length), in particular in the area of the control zone. The radiator can e.g. B. especially have the shape of a tube. A plurality of webs / ring segments that widen in the circumferential direction are therefore provided on the circumference of the heating tube. These webs can be successively offset on the circumference. It is thereby achieved that the thread which wraps around the tube in a screw-like manner successively touches the webs in regions in which the webs have essentially the same contact length.

In the development of the invention according to claims 15 to 18, a further setting parameter is therefore provided, by means of which the heat transfer to the thread and thus the target temperature of the thread can be influenced. It is about the ratio of contact length / non-contact length of the thread run along the heating surface (claims 15, 16) and the height of the rings / webs above the heating surface or the depth of the recesses through which the rings or webs are formed be (claims 17, 18). In these embodiments of the invention, the contact ratio and / or the height of the rings / webs changes over the circumference of the heating tube or the width of the heating surface transversely to the thread path.

The ring segments / webs therefore have a working width transverse to the thread running direction of the multiple thread diameter. The contact length (contact length) of the ring segments / webs in the thread running direction over the working width is different, and the thread running can be adjusted relative to the working width of the ring segments / webs.

The thread path can be laid relative to the circumference of the heating tube or the rings / webs attached to it or the sleeves resting thereon. For this purpose, the input and output thread guides can be adjusted synchronously in the circumferential direction in all embodiments of the invention. However, it is also possible to leave the position of the thread guides unchanged and instead to rotate the heating tube or the rings placed thereon (claims 4-8) or the sleeve placed thereon (claims 9-10) in the circumferential direction. In all these cases it is a question of a relative adjustment of the thread run on the circumference of the heating tube. This relative adjustment can be done by hand. The height and the width can change continuously or step by step.

The advantage of this relative adjustment is that it has a very direct influence on the heat transfer and therefore also on the target temperature of the thread. This makes it possible for the first time to continuously measure the thread temperature of the running thread and to regulate it by adjusting the thread relative to the circumference of the heating tube so that the target temperature remains constant at a predetermined setpoint (claim 22).

In the case of a radiator with an attached sleeve, this means that the recesses have an increasing or decreasing width transverse to the direction of the thread. It is also possible and advantageous that in the circumferential direction of the heating tube, ie. Transversely shaped recesses lie next to each other in the cuff transverse to the thread path, that the ring segments / webs have sectors with a constant radius / constant height, or that the width and / or the height of the ring segments / webs changes only for one of the thread heating zones, or that the width and / or height of the ring segments / webs changes differently for different thread heating zones. As a result, not only changes in the heat supply for each thread, but also relative changes in the heat supply for several threads guided along the heating element at the same time and thus a mutual adaptation of the target temperatures can be achieved.

The effective thread temperature and thus the target temperature is of particular influence on the quality of the thread in the false twist crimping process. For this quality, the thread tension, which is measured behind the friction false twister, was discovered as an important indicator. It is therefore also possible to regulate the thread tension and in particular the thread tension that is continuously measured between the friction false twister and the subsequent delivery unit by relative adjustment of the thread run on the circumference of the heating tube so that the deviation between the measured value and the nominal value of the thread tension does not exceed a certain tolerance size (claim 23).

The invention according to claims 15 and 17 and 22 and 23 is equally applicable to all radiators and advantageous, hence claims 16 and 18.

This happens when there are several thread runs on a heating tube Another problem is to design the rings in such a way that a desired identical change in the ring height or depth of the recesses results with the synchronous relative adjustment of both thread runs on the circumference of the heating tube. Suitable designs result from claims 19 and 20.

When running a thread over a radiator and in particular the heating tube according to this invention, two essential functions result: In the entrance area of the thread run, the necessary amount of heat must be transferred to the thread. In the exit area, it is important that the heat distribution in the cross-section of the thread is evened out, so that the target temperature is established in the entire cross-section of the thread. It follows from these two different functions that the intensity of the heat transfer can also be different in the different length ranges of the heating tube. This is achieved according to claim 24 in that the contact ratio and / or the ring height are designed differently.

The area of the tube length in which it is essentially a matter of achieving the target temperature over the entire cross section of the thread is referred to in this application as the end section. The section of the pipe length that is primarily concerned with heat transfer is referred to as the control section. The contact ratio in the end section is significantly smaller or the ring height in the end section is many times greater than the corresponding values of the control section.

The peculiarity is that the thread in the entrance area of the heater has little or no contact with thread guides, since the thread guides are arranged there only at a great distance. The input area is preferably equipped with only one input thread guide and one output thread guide. In addition, it turns out to be advantageous that the input thread guide remains cold. For this reason, it is suggested that the input thread guide has no thermal contact with the heating surface. As a result, the thread guide remains essentially cold, so that thermoplastic material can separate. The thread guide on the output side, on the other hand, should have self-cleaning properties. It is therefore preferably connected directly to the heating surface and lies at the beginning of the so-called "control section".

The control section is the section in which the thread receives its target temperature. It connects to the input section of the radiator. Several thread guides are arranged in the control section. These thread guides have the same or - as shown by the above-mentioned EP-A2 0 412 429 - variable distances.

The use of the thread guide in the control section ensures that the thread is guided at a precisely defined distance from the heating surface. In addition, to ensure that the thread in the input section does not come into contact with the heating surface, it is further proposed that the radiator be given a gradation between the input section and the control section such that the distance of the heating surface in the input section from the thread path is a multiple of that distance is that the thread run has in the control section of the heating surface.

This arrangement of the thread guides ensures that the thread guides are only arranged in the zone in which the temperature of the thread reached on one side and the heater temperature on the other side ensure self-cleaning. In this control zone, the temperature of the radiator is precisely controlled, preferably by control. Due to the precise guidance of the thread, relative to the Radiator, it is ensured here that the thread assumes the specified target temperature. Precise guidance of the thread is dispensed with in the entrance section. Use is made of the knowledge that in the input section the filament is heated with large temperature gradients between the radiator and the filament and therefore an exact temperature control of the filament is neither wanted nor possible.

The heating of the thread in the control area has the effect that the outer layers of the thread first assume the desired temperature. However, uniform heating of the thread over its entire cross-section is required. This goal is achieved in that an end section is arranged after the control section, in which thread guide is in turn arranged at a great distance or no thread guide is arranged. In order to avoid the thread coming into contact with the heating surface of the radiator, the distance between the thread path and the heating surface should preferably be a multiple of the distance between the thread path and the heating surface in the control range. This arrangement of the end section ensures that heat losses are prevented with only a small amount of heat transfer and that the heat supplied in the control section is evenly distributed over the entire thread cross-section.

In the entrance section, a large, unsupported length of thread can be accepted; it has been found that the tendency of the thread to oscillate is low in the input section. A length of 400 mm - 500 mm is possible. However, the length should be limited to what is necessary to achieve the desired preheating of the thread to limit the effort.

The end section is in any case shorter than the entrance section. The length of the end section is preferably limited to 300 mm and should preferably be shorter.

It was pointed out that an essential area of application for a radiator according to this invention is in the false twist crimping process and in particular in the false twist crimping process for the stretch texturing of thermoplastic threads, in particular polyester and nylon. In this process, an undrawn or pre-oriented (POY) yarn is presented as a delivery spool and drawn off by the delivery plant. The thread is then passed through the radiator and then over a cooling rail and then through a friction false twister. The thread is withdrawn from the friction false twister by a delivery plant and then wound up. There may be another radiator and another delivery plant before winding up. By means of the friction false twister, the thread receives a thread by the action of friction in the circumferential direction, which runs back from the friction false twister to the heating element and is dissolved again in the friction false twister (claim 25).

The thread can run through the heating element according to the invention at a thread speed of 1000 meters per minute and more, without friction problems or overheating problems occurring.

The versions with attached rings or sleeves also offer the option of rotating the thread heating zones under the running thread at certain intervals in order to achieve regular self-cleaning of the thread heating zones.

Embodiments of the invention are shown in the drawings and are described in more detail below.

Fig. 1

die Draufsicht auf einen Ring für einen Heizkörper nach Figur 3;

Fig. 2

einen Schnitt entlang Linie II-II in Figur 3;

Fig. 3

die Seitenansicht einer Ausführung des erfindungsgemäßen Heizkkörpers;

Fig. 4

die Seitenansicht einer weiteren Ausführung mit Ringen geringer Dicke;

Fig. 5, Fig. 6

Seitenansichten von Heizkörpern mit schraubenlinienförmigen Ringen;

Fig. 7, Fig. 8

Axialschnitt und perspektivische Ansicht einer Ausführung mit mehreren Heizzonen;

Fig. 9

die Seitenansicht eines Heizkörpers mit sich in Umfangsrichtung ändernden Kontaktlängen der Stege;

Fig. 10, Fig. 11

die perspektivische Seitenansicht sowie den Axialschnitt einer Ausführung mit sich in Umfangsrichtung ändernden Steghöhen;

Fig. 12

die Seitenansicht einer Ausführung mit sich in Umfangsrichtung ändernden Kontaktlängen und -höhen der Stege;

Fig. 13a, Fig. 13b,

Draufsicht und Ansicht eines Heizkörpers mit zwei Fadenläufen;

Fig. 14 bis Fig. 18

Draufsichten und Seitenansichten von Heizkörpern mit sich ändernder Steghöhe und zwei Fadenläufen;

Fig. 19

Seitenansicht eines Heizkörpers mit aufgesetzter Manschette und Ringen;

Fig. 20

Seitenansicht eines Heizkörpers mit Manschette und zwei Fadenläufen;

Fig. 21a, Fig. 21b

Ansicht einer Manschette und perspektivische Darstellung eines Heizkörpers, wobei die Manschette unterschiedliche Formen der Ausnehmungen hat;

Fig. 22a, Fig. 22b

Heizkörper mit teleskopartig verschiebbaren Manschetten;

Fig. 23, Fig. 24

schematische Darstellung einer Falschzwirnkräuselmaschine mit Fadenspannungsmessung und Temperaturmessung des Fadens.

Show it:

Fig. 1

the top view of a ring for a radiator according to Figure 3;

Fig. 2

a section along line II-II in Figure 3;

Fig. 3

the side view of an embodiment of the radiator according to the invention;

Fig. 4

the side view of another embodiment with rings of small thickness;

5, 6

Side views of radiators with helical rings;

7, 8

Axial section and perspective view of an embodiment with several heating zones;

Fig. 9

the side view of a radiator with changing contact lengths of the webs in the circumferential direction;

10, 11

the perspective side view and the axial section of an embodiment with web heights changing in the circumferential direction;

Fig. 12

the side view of an embodiment with changing contact lengths and heights of the webs in the circumferential direction;

13a, 13b,

Top view and view of a radiator with two thread runs;

14 to 18

Top and side views of radiators with changing web height and two thread runs;

Fig. 19

Side view of a radiator with attached sleeve and rings;

Fig. 20

Side view of a radiator with sleeve and two thread runs;

21a, 21b

View of a sleeve and perspective view of a radiator, the sleeve having different shapes of the recesses;

22a, 22b

Radiator with telescopic sleeves;

Fig. 23, Fig. 24

schematic representation of a false twist crimping machine with thread tension measurement and temperature measurement of the thread.

In the following description of the various embodiments of the invention, the same reference numerals are used for the same parts.

All the radiators shown are designed as tube 1, in the following heating tube. The heating tube is circular cylindrical and straight. The tube can be designed as a rotating body, rotating body section or rotating body segment in order to achieve a thread run along a helix line, as described later.

The heating tube 1 carries one or more heating resistors 6 running parallel to one another in its interior. The resistance heater is designed as a cartridge and extends over the entire length of the heating element. The heating resistors in the example shown extend over the entire length of the heating tube. The heating tube 1 consists of a highly thermally conductive metal, such as steel or preferably a copper-aluminum alloy. The electrical supply lines are designated by 6a. It should be mentioned that the radiator shown is enclosed in practice in an insulating cage which has a radial slot for thread insertion and which forms a circumferential gap with respect to the heating tube. The thread is guided in this circumferential gap.

A large number of webs are attached to the heating tube 1. The webs are designed as ring segments in the area of the thread run, also referred to as rings.

The circumference of the ring segments can be crowned. It is outward-looking, thread-friendly, wear-free in nature, i.e. that is, it exerts a negligible friction on the overflowing thread. The circumference of the rings serves to guide the thread 7, which is guided by an input thread guide 8 and an output thread guide 9 over the peripheral surfaces of the ring segments. The input thread guide is offset in relation to the output thread guide 9 in the circumferential direction of the heating tube. That is, the thread 7 wraps around the heating tube in a spiral line or helix, the slope of which depends on the circumferential offset of the thread guides 8 and 9 to one another. This helix has a curvature, which is dependent on the radius of the rings, the length of the heating tube or axial distance of the thread guides 8, 9 and the circumferential offset of the thread guides 8, 9. These sizes are chosen so that the radius of curvature of the thread line between 5 and 25 mm, preferably between 10 and 25 mm. However, it should be particularly emphasized that in no case does the thread affect the heating surface, i.e. H. touches the jacket of the heating pipe. The diameter of the tube, the height of the rings above the jacket of the heating tube and the pitch of the helix in which the thread is to be selected accordingly. At least one of the thread guides is movable relative to the other about the axis of the heating tube 1, preferably pivotable, so that the thread path over the disks 2 can be changed by changing the pitch of the helix formed by the thread 7.

The ring segments can extend as rings to the entire circumference of the heating tube. You can then use the entire circumference of the heating tube, either for multiple thread runs or / and to lay a thread run in less worn ones or dirty parts of the circumference.

The ring segments should extend at least over the angular range of the circumference, which the helix of the thread also occupies. This has the advantage that the thread can be put on straight away. If, in addition, the successive ring segments are offset on the circumference in the sense of the thread line, a relative displacement of the thread line into less worn and / or soiled areas of the ring segment circumference is also possible here.

If the successive ring segments are offset on the circumference with the pitch of the helix in which the thread is to be guided over the circumference of the heating tube, the length of the ring segments in the circumferential direction can be reduced to the length necessary for guiding the thread. In this way, the ring segments become elevations on the heating surface. Such a shortening has the disadvantage, however, that the thread can only be applied with great difficulty, that the helix of the thread is defined by the sequence of the shortened elevations and can no longer be changed and that it is no longer necessary if the thread path is dirty to switch to other circumferential areas.

Each ring segment lies in a normal plane of the heating tube, that is, a plane that intersects the axis of the heating tube perpendicularly. However, if other layers are also conceivable and easy to implement in terms of production technology, reference is made in particular to the embodiments according to FIGS. 4 to 6 and 20 and 21, which will be described later. In any case, the ring segments that belong to a thread run will always lie in a family of parallel planes. If the ring segments of a jacket line of the heating pipe are not in a normal plane, i.e. do not cut a jacket line below 90 °, so the pitch of the helix of the thread path should be chosen opposite to the pitch of the rings in relation to the surface line. The pitch of the helix is also defined as the angle between the helix or thread line and a surface line of the heating tube. Due to the opposite inclination or slope, a short contact length of the thread is achieved on each ring segment and a secure guidance on the ring segment.

The following applies to the exemplary embodiment shown in FIGS. 1 to 3: Here, the ring segments are designed as independent components in the form of disks and are threaded onto the heating tube 4. In the simplest form, the disks 2 shown in detail in FIGS. 1 and 2 have a circular cylindrical hole which is closely matched to the outside diameter of the tube. In this way, the washers can be "threaded" onto the heating pipe. They are then in good heat-conducting contact with the heating tube. In the preferred embodiment shown here, the disks are provided with a radial slot 5, the clear width of which essentially corresponds to the diameter of the heating tube 1 and the opposite edges of which are parallel to one another. The outer edge of the discs 2 is spherical. There is a recess or recess 4 in one end face of the disks. A pin 3 serving as a spacer protrudes from the opposite end face of the disk 2 and its distance from the axis of the disk corresponds to the distance of the recesses 4 from the disk axis. It is sufficient that such a recess 4 is made in each disk. However, it is advantageous if, as can be seen from FIG. 1, a multiplicity of recesses 4 lie on a circular line, concentrically to the axis of the heating tube, at the same distance from one another and to the axis of the disk 2.

The discs 2 are so on the heating tube 1 that the a disc 2 protruding pin 3 in one of the recess 4 of the axially adjacent disc. The disks 2 are preferably stuck in a regular angular offset to one another on the heating tube, so that the slots 5 and the pins 3 surround the heating tube in a helical line. If - as shown in Fig. 1 - a plurality of recesses are arranged on a circle, the spiral line on which the slots lie can be adjusted and the spiral line in which the thread overflows the heating tube (see below). In order to clamp the rings 2 on the tube 1, a wire-shaped spring clip 10 can be inserted into the slots 5, the ends of which are supported on the opposite slot walls and the central region resiliently abuts the tube 1.

By removing this bracket, each of the disks can be removed from the tube and replaced. This is particularly important if one of the panes is unduly damaged due to wear.

The positions of the thread guides 8 and 9 lie on both sides of the slits 5 and the helix of the thread 7 lies in the area of the disks 2 located outside the slits 5. The turning line on which the pins 3 and accordingly the slits 5 lie corresponds in their slope direction and essentially also in their slope of the helix line of the thread race. It can thereby be achieved that the entire circumference of the disks, which remains outside the slot 5, is available for the variation of the thread path.

Preferably, the disks are made of a heat and scale resistant material, e.g. B. aluminum oxide or titanium oxide. In order to increase the abrasion resistance of the pane edges, these can optionally be coated with a suitable metal and around To increase their thread friendliness, the disc edges can be ground or polished.

The embodiment shown in FIG. 4 corresponds to that in FIGS. 1-3 and has the following special feature: The rings 2 are firmly connected to the heating tube 1, for example by soldering, and are at the same distance from one another. The rings 2 can, however, also be formed by beads which are compressed into the heating tube at regular intervals. The rings can also be formed by circumferential grooves which are incorporated in the outer jacket of the heating tube 1. The radially protruding peripheral surface of the rings 2 is spherical and is thread-friendly in nature. The rings 2 serve to thread 7 at a distance above the heating surface, i. H. To guide the outer surface of the heated tube 1, the thread overflow loop wrapping helically around the tube 1. As shown schematically, the thread guides 8 and 9 are located at both ends of the heating tube 1, the offset of which with respect to one another determines the pitch of the helix line or helix of the thread path. At least one of the two thread guides can be adjusted with respect to the other in the circumferential direction of the heating tube.

In this way, the steepness of the helix line can be adjusted. For the rest, reference is made to the description of FIGS. 1-3. The essential difference from the design according to FIGS. 1-3 is that the rings are firmly connected to the heating surface or form part of the same. The rings can be produced in particular by initially producing the heating tube with a thicker wall. Then the areas of the heating tube, which should have a smaller diameter than the rings, are turned off and the rings are worked out of the surface. In all of these embodiments of the exemplary embodiment according to FIG. 4, there is very good heat-conducting contact. This leads to, that the overflow surface of the rings is at substantially the same temperature as the heating surface. Therefore, if the temperature of the heating surface is set in the self-cleaning range, i.e. above 300 ° C to 350 ° C, the effect of self-cleaning also results on the rings. This means that thread remnants disintegrate and are either easily wiped off as ash or even continuously carried away by the thread, so that there is no significant contamination of the surface or the thread.

In the embodiments of the invention mentioned so far, the rings lie in normal planes of the heating tube 4.

The embodiment according to FIGS. 5 and 6 has the peculiarity that the heating tube is surrounded over its entire length by a ring 2, which has the shape of a helical spring or a helical or - meaning - helix-shaped wire. This bead can be a wire that - e.g. B. is firmly connected to the tube 1 by soldering. However, the helical ring can also be formed by working it out of the wall of the heating tube by removing part of the wall of the heating tube. In this embodiment, there is a particularly good heat-conducting contact between the ring and the heating tube with the advantages described above.

In the embodiment according to FIG. 6, the helical bead consists of a wire made of flexible, elastic material. This spring wire is designed so that it can be drawn onto the outer surface of the heating tube 1 and the outer surface is resilient, close and with good thermal contact. The inside of the wire should therefore be flattened if possible.

The slope of the helical around the heating tube 1 Wire 2 can be changed by rotating one of its ends with respect to the other on the circumferential surface in the circumferential direction and displacing it in the axial direction. This changes the slope and length of the heating tube 1 over which the thread guide helix described here extends. Extensions or narrowing of the cylinder, which describes the thread guide helix described here and which should correspond to the outer jacket of the heating tube, can be eliminated again by relative adjustment of the two helical ends in the circumferential direction and / or axial direction of the heating tube, so that the helix is adapted to the diameter of the tube 1 remains. In Fig. 6, the helical thread guide 2 is shown in full lines in an extended and in dash-dotted lines 2a in a pushed together position. Extensions or constrictions resulting from this change in the coil are compensated for by relative adjustment of the coil ends in the circumferential direction of the heating tube 1.

5 and 6, too, the thread 7 is guided in a helix, the pitch of which is opposite to the pitch of the helical bead which forms the rings 2 here.

In both embodiments, this ensures that the contact area between the thread and the ring or bead or wire at the individual overflow points remains as short as possible. On the other hand, it can be seen that there is the advantage that a slight change in the thread run results in a strong change in the contact surfaces. Another advantage of the embodiment according to FIG. 6 is also that the occupancy density in which the thread comes into contact with rings or overflow surfaces of the spiral can be changed here. In particular, areas can be specified with a dense occupancy of rings. This is particularly important in the control section of the length of the heating tube. In other longitudinal sections, in particular the entrance section and the end section, no rings are then provided.

This can be achieved either by rotatably arranged input and / or output thread guides 8.9 in cooperation with a fixed heating tube 1 or with fixedly arranged input and / or output thread guides 8.9 together with a heating tube 1 rotatable about its longitudinal axis or with a rotatable input - And / or output thread guides 8.9 in cooperation with a rotatable heating tube 1.

In the exemplary embodiment according to FIG. 11, only the starting thread guide 9 can be rotated relative to the tube, while the input thread guide 8 is stationary.

In the exemplary embodiment according to FIG. 7, the starting thread guide 9, formed by the notch 16, sits coaxially and rotatably on the lower end of the heating tube 1 and can be rotated relative to the tube in the rotating region 15.

It can be seen that when the starting thread guide 9 is rotated relative to the tube, the running thread 7 describes a helix on the rings 2, the geometry (winding, pitch) of which depends on the rotational position of the notch 16 on the starting thread guide 9.

As already explained, the designs according to FIGS. 4 and 5 have the special feature that the jacket of the heating tube and the rings consist of one piece, ie either by soldering or welding, but also firmly connected to the jacket by appropriate shaping of the heating surface, or even are worked out from the coat. This peculiarity also applies to the designs according to FIGS. 7 to 18. This concept of the invention can in principle be applied to all radiators in which the thread is longitudinal by means of webs a heating surface, preferably in the thread running curved heating surface. In particular, however, this inventive concept can be applied to all heating bodies according to the invention. In addition, however, there is a further measure which can be used additionally or alternatively, and also in the embodiments according to FIGS. 3, 4 and 5. The following are involved: The rings have a very small height. In this respect, the representation in all figures 3 to 5 is exaggerated in the drawing. The height of the rings above the heating surface (jacket of the heating tube), which is equal to the difference between the radii of the ring and the heating tube jacket, is in the smallest case 0.3 mm and does not exceed 5 mm, preferably not 3 mm. A favorable range is between 0.5 mm and 3 mm. The lowest height is chosen so that the thread between the rings does not touch the heating jacket. The lowest height therefore depends on the distance between the rings and the radius of the heating tube jacket. This dimensioning ensures, on the one hand, good heat transfer to the outer circumference of the rings, so that there is always a self-cleaning temperature or in any case a very high temperature. On the other hand, it also ensures that the thread is guided in the sense of the edge region of the heating tube jacket in which there is no annoying air convection. The thread there is therefore only exposed to the heat radiation from the heating surface, ie the jacket of the heating tube. There are no air currents that lead to cooling or uncontrolled temperature control.

This idea of the invention can in principle be applied to all radiators in which the thread is guided along a heating surface by means of webs, preferably a heating surface curved in the direction of the thread. In particular, however, this inventive concept can be applied to all heating bodies according to the invention.

The exemplary embodiment according to FIGS. 7 and 8 also has the following special feature:

The thread 7 is first passed through the input thread guide 8 and then reaches the area of the circumference of the tube. The thread is guided along the tube with axial and peripheral components through the thread guide 9 on the outlet side. The thread guide 9 is a disk which can be rotated about the tube axis and has a thread guide notch 16. In FIG. 7, an aligned position of the input thread guide 8 and the notch 16 is shown in a simplified manner. Fig. 8 shows that the disc 9 is rotated so that the thread - as I said - with axial but also with circumferential components over the tube and thereby describes a steep helix. By adjusting the disc 9, the looping of the thread on the tube can be adjusted in the circumferential direction. The wrap is equivalent to a curvature of the thread. The loop can therefore be used to achieve full contact of the thread on the tube or on the thread guide rings attached to the tube.

The heater consists of three sections, namely the input section 11, the control section 13 and the end section 12. The thread is guided through the input thread guide 8 and the first ring of the control area 13 serving as thread guide 2.1 via the input section 11.

The input thread guide 8 has as far as possible no contact with the radiator. This ensures that the thread guide 8 does not heat up. The deposits that form when the thread is heated do not therefore form on the thread guide 8. As already mentioned, the exit thread guide of the input section 11 is designed as the first ring 2.1 of the control section 13.

The heating surface facing the thread, i. H. the jacket of the input section 11 from the thread a distance which is a multiple of the distance that the thread from the heating surface, i. H. that between the rings 2.1, 2.2, 2.3 lying jacket areas of the control section. The distance between the thread guide 8 and the first thread guide 2.1 of the control range is also a multiple of the distance between the thread guides in the control range. Lengths of up to 500 mm can be accepted here. The length is strongly dependent on the tendency to vibrate. The length of the input section 11 is preferably chosen to be shorter, at least in such a way that efficient preheating of the thread is possible.

The temperature control of the radiator comprises a temperature sensor, not shown, which detects the effective actual temperature of the control range 13. This temperature is regulated. The control range therefore has a very precise temperature control.

A large number of thread guides 31 are arranged in the control region 13. All of these thread guides 31, including the first thread guide 31.1, are designed according to the invention as rings which extend at least over a partial circumference of the control section. These rings have a certain, predetermined distance and a certain height above the remaining jacket area of the control area 13. The number of rings is determined by the tendency of the thread to vibrate and the heat transfer. The height of the webs compared to the jacket of the control range is chosen to be small and is preferably a maximum of 3 mm. It is preferably smaller than 1.5 mm, but larger than 0.3 mm.

These rings are worked out from the jacket of the control area. You therefore have good heat-conducting contact with the Radiator. Their low height ensures that the control temperature also prevails in the contact surfaces. This ensures that the heater temperature, which is above 300 ° C and is chosen so high that cracking and burning of the remaining thread remains, also exists in the contact surfaces of the webs 31.1, 31.2, 31.3. Therefore, these thread guides have good self-cleaning properties.

The width of the rings in the thread direction is - as with all versions - also decisive for the heat transfer.

In order to protect the thread, this contact length (contact length) is chosen to be short, a compromise with the requirements of heat transfer being necessary. The axial distance between two webs (thread guide distance) also has an influence on the heat transfer. Overall, a ratio of contact length / thread guide distance of up to 20% can be used, but this ratio is preferably smaller, preferably less than 10%.

The distance from the heating surface, i.e. H. of the jacket of the entrance area is 3 to 10 times the height of the rings 2 compared to the jacket of the control area. In this respect, the representations of the drawing are not to scale.

In the output section, the thread is in turn guided by only a few thread guides, namely here through the ring 2.3 of the control area serving as the end thread guide and the disk 9 already mentioned at the beginning with its thread guide notch 16. The distance between the thread run and the jacket of the end section 12 is again a Much larger than the height of the thread guide rings 4 compared to the jacket of the control area, the same dimensioning rules as for the input area 11 apply here. Overall, however, the distance between the thread guides in the end section is smaller than in Entrance section. The thread guide distance is 300 mm and is preferably smaller. The disc 4, which sits on the heating tube, is also heated to self-cleaning temperature by heat transfer.

For the rest, the formation of the rings corresponds to what has been said about Figures 1-6. In Figures 7 and 8 it is shown that the rings with the jacket of the heating tube are made in one piece.

The following applies to the embodiment according to FIGS. 9 and 10/11:

The radiators also - like the embodiment according to Fig. 7/8 - at the entrance of the heating tube 1 and / or at the exit of the heating tube 1 each have an input section 11 or end section 12, which is a greater radial distance from the passing thread 7 than the outer surface of the Heating tube 1 takes.

Between the input section 11 and the end section 12 sits the control section 13, which in the present case has a further special feature, which, however, does not only apply to the embodiment shown in FIGS. 7/8 or 9 to 11, but also has a special input section, control section and end section if the rings are evenly or otherwise unevenly applicable:

As can be seen from FIG. 9, the input thread guide 8 and the output thread guide 9 can be rotated relative to the heating tube 1 in the embodiment according to FIG. 10/11 and in the embodiment according to FIG. which can be covered by the thread 7 as a result of the rotational range 15. This creates an area of possible contact between the thread and the rings.

The thread 7 can consequently run at any point within the predetermined angular range, depending on the respective rotational position of the thread guides 8, 9 and the tube 1 relative to one another.

9 is the circumferential design of the rings 2.1, 2.2 serving as thread guides. and possibly 2.3. The webs have an increasing axial extent (width) in the circumferential direction. The narrowest point does not lie on exactly one surface line, as could be seen in FIG. 18, but essentially on a line which is essentially parallel to the overflow line of the thread. This thread overflow line can be changed. An overflow line corresponding to the normal operating conditions must be selected here. Then in Fig. 9 not only the starting thread guide in the form of the disk 9 with thread guide notch 16 but also the thread guide 8 can be rotated about the axis of the heating element. As a result, the thread path can be displaced on the circumference of the radiator, in an area in which the contact length of the thread guide rings 31 has a desired dimension and in which there is a desired ratio of contact length to free guide length between the webs. As a result, the heat transfer, but also the smooth running of the thread can be influenced. On the other hand, too long a contact length leads to high thread friction, which is undesirable to protect the thread.

The embodiments according to FIGS. 9 and 12 thus have rings which have a ring width which changes in the circumferential direction in the angular region which can be covered by the thread 7. This means that the width B of a ring changes depending on a circumferential coordinate u according to a function B (u), which can be predetermined in each case. Here the function is linear. Furthermore, FIG. 12 shows the special feature that the rings 2 have a height H which changes in the circumferential direction in the possible area of contact with the thread 7. This means that the height H is a function of the circumferential coordinate u, which is accordingly designated H (u).

9, the width B of the rings increases in the circumferential direction in which the height H of the rings decreases. It is therefore to be expected that with increasing contact time of the thread 7 on the rings due to the increasing ring width B, the heat flow on the thread also increases in the non-contacting longitudinal regions between the rings 2 due to the simultaneously decreasing distance between the thread 7 and the tubular jacket.

FIGS. 10 and 11 additionally show that the rings 2 can also have a height which changes in the circumferential direction in the angular region which can be covered by the thread, if the width of the rings 2, that is to say the web width, does not change in the circumferential direction. The same applies in reverse; for this purpose, reference is made in particular to FIGS. 14 and 18 described later.

It should therefore be expressly said that these two embodiments of the invention - that is, rings with changing width and rings with changing height - can occur both in combination with one another and separately from one another.

The width B of the rings can also change gradually. This means that the width B is piecewise constant and stepwise at certain circumferential coordinates, e.g. from a smaller width to a larger width.

What has just been said also applies analogously to a change in height H of the rings. This results in a slight lateral adjustment of the contact zone between the thread and the ring without influencing the heat transfer between the heated surface and the thread.

In the embodiments according to FIGS. 9-11, the rings are formed in that annular grooves are machined into the tubular jacket in such a way that the rings according to the invention, on which the thread 7 runs, remain. In the embodiment according to FIGS. 10, 11, the grooves on the circumference of the heating tube jacket have different depths, in FIG. 9 different widths.

About the function:

The heat transfer from the heating tube 1 to the thread 7 takes place on the one hand at the contact zones which form the rings 2 with the thread 7.

Furthermore, there is a heat flow on the thread 7 in the longitudinal areas between the rings 2 that are not touched by the thread. Since the base of the ring grooves between the rings 2 is at a distance of at most a few millimeters from the running thread, e.g. starting with about 0.3 mm and increasing to about 5 mm, in view of the heating temperature of the heating tube 1 of 300 degrees Celsius or more, in particular temperatures in the order of the self-cleaning temperature, it can be assumed that an effective heat flow also takes place in the contact-free longitudinal areas.

The total heat flow acting on the thread will consequently be a function of the thread path geometry set in relation to the tube geometry, because the contact lengths and the non-contact longitudinal areas, like the ring height, depend on the relative position of the input thread guide 8 or the starting thread guide 9 to the heating tube 1. The contact ratio and the height of the rings are therefore decisive parameters for the heat transfer. The contact ratio is understood to be the quotient of the contact length of the thread on each ring and the length of the subsequent contact-free distance to the next ring.

Rings with different heights over the circumference can, for. B. be produced in that the rings are circular cylindrical, but are arranged eccentrically to the tube axis. The rings can also be shaped elliptically or in some other way.

Such variations in heat transfer are described below in connection with FIGS. 14 to 18 and 21.

This allows the heat flow transferred to be set very delicately by laying the thread run on the circumference of the heating tube. Even the slightest changes in the rotational positions relative to each other cause noticeable changes in the overall heat flow and the thread temperature reached.

The invention makes use of this knowledge in the application example of a false twist texturing machine, which will be discussed in more detail below.

It has already been mentioned above that the thread is guided along the heating tube on a helical or helical thread line. If in the embodiments of the heating tube according to FIGS. 9-11, in which the rings have a changing contact width and / or a changing height above the jacket of the heating tube in the circumferential direction, it is important that the thread along the thread line the rings always touched only at points of the same contact width or height, the successive rings are offset in terms of their contact width or height in the circumferential direction in the sense of the helical thread line. If the steepness of the thread line can be adjusted by adjusting one of the thread guides 8 or 9, an offset between the successive rings in the sense of the mean value of the pitch to which the helical thread line can be adjusted is sufficient. It then emerges that the successive contact widths or heights are in any case approximately the same size.

Instead of a graphic representation, which is very difficult and confusing, it is assumed that the successive rings 2.1, 2.2, 2.3, etc. are each offset by a certain angular amount in the circumferential direction in FIGS. 9-11. This angular amount corresponds to the mean value of the adjustable pitch of the helix of the thread.

However, this circumferential offset of the rings can also be deliberately dispensed with and the rings arranged one behind the other in such a way that the points of the same width and / or the same height lie on a surface line of the tube. With such a measure, the contact ratio and / or the height of the rings along the thread path and thus also the heat transfer over the length of the thread path can be designed differently.

On all embodiments of the radiator according to the invention, at least one running thread can be heated. By arranging several pairs of input thread guides 8 and output thread guides 9 on the circumference, a correspondingly larger number of running threads can also be treated at the same time. For this purpose, it is advisable to open the starting thread guides 9 with respect to the input thread guides 8 in the same sense to move the scope. In this case, all threads are guided in the same direction along the circumference of the pipe. The processing according to FIG. 13, however, shows an embodiment in which two threads with opposite pitch are guided in their writing line.

FIGS. 13a and 13b are described below.

13a shows a normal section through such a heating element, the insulation 41 surrounding the heating tube also being shown. 13b shows a view of the heating element, shown as a development, which is directed onto the insertion slot 42 of the insulation.

The insulation 41 surrounds the heating tube 1 as a tubular body. This tubular body 41 has a longitudinal slot 42 on a surface line. This longitudinal slot has a width of a few millimeters to avoid heat loss. Of course, the insulating body 41 is also closed on its end faces by an insulating layer (not visible in FIG. 13a). The slot width 42 is exaggerated in Figure 13a and Figure 13b. The starting thread guides 9 are arranged in a stationary manner and lie within the slot width. However, they can also be displaceable between the position shown and a position further away from the center line 40 of the slot 42. In Figure 13b, the insulating body 41 is - as I said - shown as a development and recognizable by the lines with thick lines.

In each case, the input thread guides 8 can be displaced in the opposite direction (arrows) in their operating position (arrows) from their application position, which is shown in broken lines in FIG. 13b.

It is also the underlying one through the insulation 41, to recognize the invisible part of the surface of the heating pipe.

As can be seen from FIG. 13a, the insulation 41 forms a narrow gap with the heating tube or the rings resting thereon in the peripheral region in which the thread can be displaced. By shifting the input thread guides 8 in the opposite direction from the feed position aligned with the slot 42 into the operating position, the threads are guided on the circumference of the rings 2 in a helical line, the helical lines of the two threads having opposite pitches.

If the starting thread guides 9 can also be displaced from the opposite direction in alignment with the longitudinal slot 42 into an operating position, the incoming thread guides 8 must of course be moved all the more in order to obtain the helical thread line with the desired pitch for each of the threads. It should be noted that the two thread guides 8 and 9 can also be arranged stationary in the specified operating positions. This is all the more true since the starting thread guides 9 can also be physically replaced by the running grooves of the cooling rail 19 shown in FIG. 13b, but in any case should be aligned with the running grooves. In this case, the incoming thread, which is drawn off and guided by a suction gun, becomes first placed in the input thread guide, then passed through the longitudinal slot 42 and then laterally warped and placed in the output thread guide 9, which in any case is preferably aligned with the longitudinal slot or is close to the longitudinal slot 42.

Exemplary embodiments have already been described in which the contact ratio and / or the height of the rings changes in the circumferential direction of the heating tube 1, so that by laying the thread line in the circumferential direction is a change in the amount of heat applied. 14, 15, 16, 17, 18 schematically show possible embodiments for rings of this type, in which two threads are heat-treated on the heating tube.

In the embodiment according to FIG. 10, the rings 2 are eccentric with respect to the tube axis 17, the eccentricities of successive rings being offset from one another by 180 degrees.

This design has the advantage that the relative heights of the rings at the thread overflow points change symmetrically and in the same way due to the relative rotation between the heating tube and the thread runs 7.1 and 7.2.

FIGS. 15-17 also show designs with two filament heating zones 25 on the radiator 1.

In each of the thread heating zones 25a and 25b, several webs (ring segments 2) are fastened axially one behind the other in the direction of the thread running on the heated surface, the height of the rings projecting beyond the heated surface by at least 0.1 millimeter but not more than 5 millimeter.

It is therefore important that the height of the rings 2 above the heated surface is not more than about 5 millimeters in order to be able to take advantage of the advantages of this radiator according to the invention, in particular the self-cleaning and the sensitive controllability.

The width B of the rings 2 changes in the circumferential direction. It should be expressly said that this alone or in combination with a circumferentially changing height H of the rings can be advantageous according to the invention. In this The trap should decrease in height with increasing width if an intensification of the heating effect by laying the thread course in the area of greater width is desired.

In the embodiment according to FIG. 15, the width increases from one surface line of the heating tube 1 to both sides. If a thread 7 is guided on both sides of the surface line, then with a relative rotation of the tube in the same direction, there is an opposite change in the heating effect for the two threads with respect to these thread runs. This can be desirable. If it is not desired, it is provided that the input thread guides 8 and 9, which are each assigned to a thread run, can be adjusted separately from the thread guides of the other thread run in the circumferential direction of the heating tube. For this purpose, the thread guides 8 and 9 sit on thread guide levers which can be rotated about the axis of the heating tube. As FIG. 16 shows, it can also make sense to provide only one of the filament heating zones with rings whose width B changes in the circumferential direction, analogously to what was predicted, also the height H, while the ring width B and ring height H are constant in the other of the two filament heating zones is.

In this case, it is not necessary for the one (left) thread run to provide a relative adjustability between the input thread guide 8 or output thread guide 9 and the heating tube.

For the other (right) thread path, however, a relative adjustment between the heating tube and thread path is possible, e.g. B. by adjusting the associated thread guides 8 and 9. By this adjustment, the heating action on one thread of the heating action on the other thread can be adjusted.

In all embodiments of this invention, in which there is a relative adjustment between the heating tube and the thread path this relative adjustment in the circumferential direction is done on the one hand by rotating the tube with a fixed thread path. In false twist crimping machines, this is the more obvious solution, since the thread run is determined by the machine geometry and a change in the thread run has negative effects on the thread tension and other process parameters. In other cases, however, the relative adjustment can be brought about by assigning the thread guides each synchronously movable input thread guide 8 or output thread guide 9, which thread guides 8 or 9 z. B. sit in the end regions rotatable thread guide lever 26. A change in the heating effect is also possible by relative adjustment of the thread guide, ie by changing the pitch of the thread line.

To achieve synchronous rotatability, the thread guide levers can be connected via a gear. With the embodiment according to FIG. 16, it can be achieved that the thread qualities of two threads running over a heating element are identical to one another or deliberately set differently. In the case of the embodiment according to FIG. 17, reference can be made to the description of embodiment examples 15 and 16. The special feature here is that only the ring width increases in the circumferential direction with respect to the right thread run, while the ring height remains constant over the jacket of the heating tube 1. Concerning. of the left thread run increases the ring width B in the circumferential direction and in the opposite direction to the other side, while the ring height H decreases. In this version, it makes sense to adjust the right-hand thread path and the left-hand thread path independently of one another by appropriate adjustment of the input thread guide 8 and output thread guide 9, either in the sense of a change in the steepness of the helical line or a parallel laying of the helical line. This also applies to all designs with changing ring width or ring height. Through the Circumferential adjustment of the thread path changes the heating effect differently. So you can not only make an absolute change in the heating effect for each thread run, but also a relative change in the heating effect and - associated with this - a corresponding adjustment of the target temperature to be achieved.

FIGS. 18a-18e merely show schematically an axial view of a heating tube with rings 2, the height of which changes in the circumferential direction in relation to the jacket of the heating tube.

This is achieved in the embodiment according to FIGS. 16a to 16c in that the rings have the shape of an ellipse and are arranged concentrically with the circular-cylindrical heating tube. It is possible to arrange two thread heating zones 25a, 25b, diametrically opposite one another, and in this case to arrange the input thread guides 8 and output thread guides 9 on the respective thread guide levers 26 in such a way that the threads run to locations with the same operating conditions. The prerequisite for this is that both threads are guided in the same direction. In this case, a synchronous movement of the two input thread end guides 8 and output thread guide 9 causes a congruent change in the two thread lines and the operating conditions to which the thread line is exposed. The same applies to the synchronous adjustment of the two output thread guides 9. Therefore, the pair of input thread guides 8 and the pair of output thread guides 9 can each sit on the same lever, which is rotatable about the axis of the heating tube.

The thread path shown in FIG. 18c is particularly favorable. Each of the threads 7 runs exclusively within a quadrant spanned between the long semiaxis and the short semiaxis of the ellipse.

It can be seen that in the selected quadrant the heat transfer from the heating tube 1 on the thread rises continuously over the entire length of the thread between the input thread guide 8 and the output thread guide 9. Because with the thread guide in this quadrant, there is a large distance between the thread on the input thread guide 8 and the heating tube 1, which is reduced in the thread run in the direction of the output thread guide 9 and assumes its lowest value on the output thread guide 9.

The distribution of heat transfer over the entire thread length between the input thread guide 8 and output thread guide 9 is thus adjustable in all of these versions as well as the total amount of heat transferred.

In the case of the elliptical execution of the rings according to FIGS. 18a to 18c and the laying of the thread runs in the quadrants selected according to 18c with the selected inclined pitch of the thread line, the entire area of the rings 2 stands for this setting between the minimum distance in the area of the small semi-axis of the ellipse and the maximum distance in the area of the large semi-axis of the ellipse.

Within this possible thread contact line, the optimally possible heat transfer can therefore be expected with a certain relative position between the input thread guide 8 and the output thread guide 9, in which case there is a continuously increasing heat transfer from the tube to the thread in the thread direction.

In this exemplary embodiment, “two opposing locations of the ellipses” therefore mean two circumferential regions of the ellipse that are diametrically opposed with respect to the intersection of the long and short ellipse axes.

The embodiment according to FIGS. 18d and 18e has eccentrically arranged rings 2. The rings 2 are circular, the Circle center of the web 2 is offset by the eccentricity 27 with respect to the circle center of the heating tube 1.

In this case, the eccentricities of all the rings are located on the same radial side of the axis on a common axial plane of the heating tube 1.

Input thread guide and output thread guide are arranged separately for each thread on a thread guide lever 26, namely rotatable circumferentially with respect to the center of the ring 2 in the sense of the same effect on the heated thread.

The two threads 7.1 and 7.2 are thus guided in thread runs whose helical lines have opposite pitches.

In this way it is achieved that with a synchronous adjustment only the input thread guide 8 or only the output thread guide 9, the heat flow is influenced to the same extent on both threads, both the distribution of the heat flow over the thread length exposed to the heating tube and the total amount of heat .

As additionally shown in FIG. 18e, which shows a situation rotated by 180 degrees in accordance with FIG. 18d, the heat transfer from the heating tube 1 to the thread 7 can be optimally influenced in this way:

While in the case of FIG. 18d the incoming thread (in the area of the input thread guide 8 is at a relatively large distance from the heated surface of the heating tube 1 and the outgoing thread is at a relatively small distance, the situation in the case of FIG. 18e is exactly the opposite.

Here the incoming thread is heated relatively strongly in the area of the input thread guide 8, since it is heated by the Surface of the heating tube 1 takes a very small distance, while the thread running out takes a relatively large distance in the area of the starting thread guide 9 from the heated surface.

With the designs according to FIGS. 9 to 18, a sensitive heat effect on the thread, which is sensitive to the respective thread parameters, can be adjusted. Therefore, even with fine titers, you can always drive self-cleaning temperatures by adjusting the contact ratio and / or the thread spacing on the thread on the heating tube and the webs. Nevertheless, damage-free heating of any kind of thread is made possible.

Above all, the invention enables filament yarns of different titers, e.g. 20 den. or 40 den. to be processed with the same radiator and at the same time, provided the relative position between the running thread and the heated surface is set accordingly.

In all of these versions, different heat flows and target temperatures can therefore be achieved with one and the same radiator without changing or adjusting the temperature of the heated surface solely by selecting the relative position between the thread path and the radiator. This also allows adaptation to the respective thread size (titer, denier) and the material (polyester, nylon) or to the different thread quality desired in each case.

Up to this point, embodiments of the invention have been described in which the rings 2 are threaded onto the heating tube as individual structural elements or are firmly connected to the heating tube and are part of the heating tube. With reference to Figures 19 to 22, embodiments are described in which the rings in all of them are part of an independent component. The following applies to all the designs according to FIGS. 19 to 22: A sleeve 33 is placed over the circular cylindrical heating tube 1. The cuff 33 is a thin sheet which closely conforms to the contour of the heating tube, at least in the thread running and thread heating area. It can be the segment of a circular cylinder that is braced on the heating tube with springs or bands. In the embodiments according to FIGS. 19 to 22, the sleeve is designed as a circular cylindrical tube, the inside diameter of which corresponds to the outside diameter of the heating tube with a close tolerance. The sleeve carries the rings 2 according to the invention in the axial direction. The embodiments shown in FIGS. 19 to 22 differ with regard to the design of the rings. The cuff is axially fixed by a guide 45. However, it is rotatable. For this purpose, the cuff has holes 44 on its circumference, into which one can engage with a suitable tool and rotate the cuff. However, a permanent rotary drive can also be provided for the sleeve according to FIG. 19.

In the embodiment according to FIG. 19, the sleeve is bulged outwards in several normal planes, at least in the thread running area. Such a bulge can be z. B. by rolling and / or compressing the tube in the axial direction. As a result, several bulged rings 2 have formed on the circumference. One or more threads can be guided over the outer circumference.

This version has its particular advantage when the radiator is very dirty. In this case, the sleeve, which is symmetrical over the circumference, can be rotated continuously and slowly at intervals by hand or by a drive (not shown here). As a result, the thread constantly takes away deposits that form on the rings. This allows the time intervals, in which the radiator is cleaned, can be significantly enlarged. The impurities carried along by the thread are of no importance for the thread quality.

In the embodiment according to FIGS. 20 and 21, the sleeve is provided with rings in that a plurality of recesses 34 are made in the sheet metal of the sleeve following the desired thread course. The recesses 34 are holes that are made in the sheet metal. The embodiment is shown in Figure 20 as a settlement, which corresponds essentially to the representation of Figures 13a and 13b. In this respect, reference is made to the description there. However, while the rings are part of the heating tube in the embodiment according to FIGS. 13a, 13b, the rings are formed in the embodiment according to FIG. 20 by said recesses 34. The recesses 34 extend over a partial circumference of the cuff. The axially successive recesses 34 are - following the central intended thread line - offset by a certain angle in the circumferential direction of the sleeve. The recesses 34 are rectangles, the longitudinal edges of which point in the circumferential direction each lie on a normal plane. Web-like ring segments, which act as rings 2 in the sense of this invention, therefore remain between adjacent recesses 34. In the embodiment according to FIG. 20, two rows of recesses 34 are arranged one behind the other with an opposite axial offset symmetrically to the center line 40, so that two threads can be guided over the recesses or rings for the respectively assigned input thread guide 8 and output thread guide 9. The circumferential extent of the recesses is chosen so large that the desired thread runs can be set.

In the embodiment of the invention according to FIGS. 21a, 21b, the sleeve 33 is also shaped into a hollow cylinder and as such placed on the heating tube 1. The inner diameter of the hollow cylinder corresponds to the outer diameter of the heating tube with a narrow tolerance. The cylinder, hereinafter sleeve 33, is secured against axial displacement on the heating tube 1, but can be rotated thereon, the rotational movement possibly being dependent on the release - not shown - of the lock. In the illustration according to FIG. 2b, two threads are passed over the cuff on opposite sides. The assigned input thread guide 8 and output thread guide 9 are not shown here in order not to impair the clarity. Accordingly, the threads are not shown in their helical shape, which they assume during operation, but only schematically and axially parallel. However, what has already been described applies to the guidance of the threads. In this respect, reference is made in particular to the description of the embodiment according to FIG. 20.

The embodiment according to FIGS. 21a, 21b, on the other hand, have the following special features: the recesses 34 lie in a row parallel to the axis of the heating tube 1 and form ring segments 2 of the same width between them. The ring segments 2 serve as overflow webs for one of the threads 7 and are of equal width in the axial direction. Characterized in that the sleeve 33 can be rotated on the heating tube 1, it is possible to run the thread 7 in the circumferentially extending region of the webs 32 in each case over a clean location, as a result of which the given temperatures as such are given Self-cleaning effect of the ridges is increased. A series of identically shaped recesses 34 lies diametrically opposite the recesses 34 in the thread path for the second thread 7.

In the circumferential direction next to the row of rectangular recesses 34 there is another row of recesses 35 shown here trapezoidal. These form between them wedge-shaped ring segments, here designated 38. This row diametrically opposite is the same arrangement of trapezoidal recesses 35 or wedge-shaped ring segments for the second thread. This makes it possible to change the length of the heating surfaces in contact with the thread by simply turning the sleeve 33 on the heating tube 1.

In the circumferential direction next to your row of trapezoidal recesses there is another row of recesses 36 lined up. These are recesses that are relatively narrow in the axial direction, but leave wide ring segments 2 between them, which as thread overflow webs have a larger contact surface with thread 7 Offer. Corresponding to the other recesses, in the case of the recesses 36 there is also a diametrically opposite row of recesses 36 with corresponding ring segments which form the second thread overflow path.

19, the cuff is shown enlarged as a development. The recesses of a respective row are of the same shape and are at the same distance from one another. The ring segments, which run in the circumferential direction, are located between the recesses. The connecting webs which remain in the circumferential direction of the sleeve 32 between the respective rows of recesses are important for the solid structure of the sleeve, but beyond that only have an influence on the uniform heat distribution.

The sleeve jacket has a thickness of 0.1 mm (practically 0.3 mm) to 5 mm, preferably 0.5 mm to 3 mm. This ensures that the radial distance between the outer surface of the heating tube 1 and the surface of the ring segments also corresponds to the dimensions of the ring height mentioned above and in the preferred ranges discussed in this embodiment 0.1 mm (practically 0.3 mm) - 5 mm, preferably 0.5 - 3 mm.

The cuff 33 can be provided with recesses of a different shape which satisfy working conditions and which satisfy other desired working conditions.

The cuff is an inexpensive component that can be easily installed, removed and replaced. The shape of the recesses and thus the formation of the rings or ring segments is unlimited within the structure of the sleeve. Therefore, it is to be regarded as a particular advantage with this design that the design of the sleeve with regard to the contact ratio (width of the ring segments / width of the recesses in each case in the thread running direction), number and distribution of the rings for each application (thread titer, thread running speed, thread material, target temperature, thread height, etc.) can be adjusted.

The embodiments of the invention according to FIGS. 22a and 22b have in common that the sleeve which carries the thread overflow webs or rings 2 is composed of tubular sections 33.

The sections following one another in the axial direction can be telescopically pushed into one another in both versions. For this purpose there are two successive sections with section pieces, in which the outer diameter of one section piece corresponds essentially to the inner diameter of the other section piece with a close tolerance. The sections are threaded onto the heating tube 1.

In the case of the embodiment according to FIG. 22a, the sections 33 each consist of an axial section 33a larger Diameter and an axial section 33b of smaller outer diameter, the latter corresponding to the inner diameter of the axial section 33a with a larger outer diameter. Expediently, threads G are cut into the inner lateral surface of the axial section 33a with the larger outside diameter and into the outer lateral surface of the axial section 33b with the smaller outside diameter, with which the individual pipe sections 1 'can be connected to one another. If necessary, the screw connections can be secured by lock nuts K, whereby the position of the sections relative to one another can be set precisely.

A ring 2 is provided on the outer circumference of the section parts 33a with the larger diameter. The embodiment shown in FIG. 22b differs from that according to FIG. 22a in that successive sections alternately have a small and a larger diameter. The outer diameters of the inner sections correspond to the inner diameters of the outer sections. The sections are screwed together via external or internal thread G and, if necessary, secured in their position with respect to one another with lock nut K. The large sections are each provided on their outer surface with a ring 2 serving as a thread guide, the rings 2 being shown increasing in width in the longitudinal direction of the sleeve.

Otherwise, what has been said in relation to the other embodiments also applies to these designs of the radiator and their thread guide rings. In particular, the rings can be designed in accordance with the exemplary embodiments of FIGS. 9 to 12 described above.

The heater of this invention is preferably used in a false twist crimping machine. Such a false twist crimping machine is e.g. B. in DE-PS 37 19 050 described and consists of a plurality of supply spools, from each of which a thread is withdrawn, from a heating device over which each thread is guided, from a cooling device over which each thread is guided, from a false twister, through which each thread has a temporary twist receives and from input and output supplying plants that pull the thread from the delivery spools or pull out of the false twister. Then each thread is wound on a winding spool. All the radiators according to this invention can be used in particular as the heater arranged in the false twist zone.

Furthermore, FIGS. 23 and 24 show that the input thread guide 8 and the output thread guide 9 can be adjusted relative to one another or synchronously in the circumferential direction of the heating tube 1. The thread guides are adjusted by stepper motors 23. Alternatively, the heating tube can also be rotated. The heating tube has rings which are designed in accordance with FIGS. 9 to 12. Alternatively, the heating tube can also be surrounded by a sleeve according to FIGS. 20 or 21. In any case, the configuration of the rings is such that the contact ratio and / or the height of the rings above the heating surface changes in the circumferential direction to the same extent or to different degrees for all rings.

In the false twist crimping machine according to FIG. 23, the input thread guide 8 and output thread guide 9 are rotated by the stepping motor 23 as a function of the thread temperature measured at the outlet of the heating element.

For this purpose, a temperature sensor 22 arranged in the output region of the heating tube 1 is used, which supplies an output signal by means of which the stepping motors 23 are activated and the input thread guide 8 and output thread guide 9 are adjusted depending on the temperature.

It should be expressly said that the measuring signal of the temperature sensor 22 can also be superimposed on a thread tension signal which is generated by the tensile force measuring device 24, specifically - here - behind the radiator.

Alternatively, the embodiment according to FIG. 24 can be chosen. In this false twist crimping machine, the thread tension is measured behind the friction false twister 20 by a tensile force measuring device 24. The stepping motors by which the input thread guide 8 and the output thread guide 9 are controlled are controlled by the output signal of the tensile force measuring device 24 and adjusted in the circumferential direction of the heating tube. It has been found that the thread tension that exists during the process downstream of the friction false twister is a yardstick for all product parameters that determine the quality of the crimped thread. By laying the thread run on the circumference of the heating tube to influence the heat transfer and the target temperature of the thread, it can be achieved - within limits - that the thread tension behind the friction false twister remains constant. If these limits are exceeded, other process parameters must be adjusted or corrected. With regard to the designs according to FIGS. 23 and 24, the false twist crimping machines with the heaters according to the invention have the advantage that the effective heat transfer from the heating element to the thread can be set extremely sensitively in the sense of a process optimization, and that in addition a very precise control or setting the thread temperature can take place in order to achieve an optimal thread quality over the entire length of the thread.

Claims (25)

1. Heater for heating a moving thermoplastic yarn (7), wherein the yarn (7) is conveyed along and at a distance from a heated surface via webs which are seated on the heated surface,
   characterized in that

   the heated surface is the outer jacket, curved at right angles to the longitudinal direction, of a tube (heating tube 1),

   that the webs are formed by ring segments (2), which are fastened on the heating tube (1) and extend at least over part of the periphery of the heating tube (1),

   and that associated with the beginning and end of the heating tube are yarn guides (8, 9), which are offset in a peripheral direction of the heating tube relative to one another and by means of which the yarn is guided along the heating tube in a steep helical line in contact with the external contour of the ring segments but without contact with the outer jacket of the heating tube.
2. Heater according to claim 1,
   characterized in that
   the ring segments (2) take the form of a bead wrapped helically around the heating tube (1).
3. Heater according to claim 1,
   characterized in that

   the ring segments are formed by a plurality of indentations,

   which are worked in the heated surface,

   which extend in a peripheral direction over at least part of the periphery of the heating tube and

   which have a limited length and succeed one another in an axial direction,

   there remaining between two axially adjacent indentations a web serving as a ring segment for yarn guidance

   and the indentations preferably having a depth between 0.1 and 5 mm, preferably between 0.5 and 3 mm.
4. Heater according to claim 1 or 2,
   characterized in that
   the ring segments are formed by annular structural elements, the internal contour of which corresponds with an exacting tolerance to the external contour of the heating tube and which are threaded with axial clearance (spacers 3) onto the heating tube, the thickness of the structural elements, by which they project beyond the heated surface, being at least 0.1 mm but not more than 5 mm, preferably at least 0.5 mm but not more than 3 mm.
5. Heater according to claim 4,
   characterized in that
   the annular structural elements (2) between their inner periphery and outer periphery are provided with a radial slot (5), which radial slot (5) has at least the width of the diameter of the heating tube (1), the slots of axially adjacent structural elements preferably being offset by a fixed angular amount on the periphery of the heating tube in the direction of the helical line, with which the yarn is guided along the heating tube.
6. Heater according to claim 5,
   characterized in that
   as a spacer (3), each structural element (2) has at one end an axially extending pin and at the other end a recess (4), cooperating pins and recesses of axially adjacent structural elements preferably being offset relative to the radial slot (5) by a fixed angular amount on the periphery of the heating tube such that the radial slots (5) of successive structural elements (2) lie substantially on a helical line which corresponds to the helical line of the yarn (7).
7. Heater according to claim 6,
   characterized in that
   the spacers (3) of two axially adjacent structural elements (2) cooperate in the manner of a grid, the grid being formed in that on each structural element (2) a plurality of indentations (4) are disposed with a fixed angular offset on a circle concentric with the heating tube.
8. Heater according to one of claims 5 to 7,
   characterized in that
   a resilient clip (10) is slidable between the flanks of the slot (5), which spring clip lies with its middle region resiliently against the outer jacket of the heating tube (1) and clamps the ring (2) firmly on the heating tube.
9. Heater according to claim 1,
   characterized in that
   a sheet-metal collar (33), which is congruent with the heated surface of the heating tube, is clamped onto the heated surface, and that the ring segments (2) are formed by bulges abutting in an axial direction with clearance on a collar, the collar preferably being rotatable in a peripheral direction of the heating tube.
10. Heater according to claim 1,
    characterized in that

    a sheet-metal collar (33), which is congruent with the heated surface of the heating tube, is clamped onto the heated surface, and that the ring segments are formed by recesses (34), which are worked in the wall of the collar and abut in an axial direction with clearance, which extend in a peripheral direction over at least part of the periphery of the heating tube and which have a limited length and succeed one another in an axial direction, there remaining between two axially adjacent recesses a web serving as a ring segment for yarn guidance,

    the thickness of the sheet metal of the collar being at least 0.1 mm but not more than 5 mm, preferably at least 0.5 mm but not more than 3 mm.
11. Heater according to claim 9 or 10,
    characterized in that
    the collar comprises a plurality of portions (33a, 33b), which are adjustably connected to one another and preferably engage telescopically one into the other.
12. Heater according to claim 1,
    characterized in that
    the yarn guides (inlet yarn guide 8, outlet yarn guide 9), which are associated with the yarn inlet and the yarn outlet of each yarn heating zone and by means of which the yarn (7) is guided on a helical line over the ring segments, are displaceable and positionable relative to one another in a peripheral direction of the heating tube.
13. Heater according to claim 1,
    characterized in that
    a plurality of yarns are guided over the heated surface of the heating tube, one inlet yarn guide (8) and one outlet yarn guide (9) being associated with each yarn course.
14. Heater according to claim 13,
    characterized in that

    two yarns are guided in opposite directions of wrap and with a clearance varying in a peripheral direction at an angle of wrap smaller than 180° over the heating tube,

    the heating tube preferably being surrounded by an insulating wrapper having a narrow insertion slot, which extends parallel to the axis of the heating tube and - viewed in a peripheral direction - lies between the two yarn courses.
15. Heater according to one of claims 1 to 14,
    characterized in that

    the ring segments in the region of potential contact with the yarn have a width varying in a peripheral direction,

    that the heating tube as well as the yarn guides (inlet yarn guide 8, outlet yarn guide 9), which are associated with the yarn inlet and the yarn outlet of each yarn heating zone and by means of which the yarn (7) is guided on a helical line over the ring segments, are displaceable relative to one another in a peripheral direction of the heating tube and positionable in such a way that the contact ratio, namely the ratio of contact length of the yarn at a ring segment to contactless yarn length adjoining the ring segment, is adjustable at the ring segment.
16. Heater for heating a moving thermoplastic yarn (7), wherein the yarn (7) is conveyed along and at a distance from a heated surface via webs which are seated on the heated surface (yarn heating zone),
    characterized in that

    the webs in the region of potential contact with the yarn have a width varying at right angles to the direction of movement of the yarn,

    that the heater as well as the yarn guides (inlet yarn guide 8, outlet yarn guide 9), which are associated with the yarn inlet and the yarn outlet of the yarn heating zone and by means of which the yarn (7) is guided over the webs (2), are displaceable relative to one another at right angles to the direction of movement of the yarn and positionable in such a way that the contact ratio, namely the ratio of contact length of the yarn at a web to contactless yarn length adjoining the web, is adjustable at the web.
17. Heater according to one of claims 1 to 16,
    characterized in that

    the ring segments in the region of potential contact with the yarn have a height varying in a peripheral direction,

    that the heating tube as well as the yarn guides (inlet yarn guide 8, outlet yarn guide 9), which are associated with the yarn inlet and the yarn outlet of each yarn heating zone and by means of which the yarn (7) is guided on a helical line over the ring segments, are displaceable relative to one another in a peripheral direction of the heating tube and positionable in such a way that the distance of the yarn course from the heated surface is adjustable at the ring segment.
18. Heater for heating a moving thermoplastic yarn (7), wherein the yarn (7) is conveyed along and at a distance from a heated surface via webs which are seated on the heated surface,
    characterized in that

    the webs in the region of potential contact with the yarn have a height varying at right angles to the direction of movement of the yarn,

    that the heater as well as the yarn guides (inlet yarn guide 8, outlet yarn guide 9), which are associated with the yarn inlet and the yarn outlet of the yarn heating zone and by means of which the yarn (7) is guided over the webs, are displaceable relative to one another at right angles to the direction of movement of the yarn and positionable in such a way that the distance of the yarn course from the heated surface is adjustable at the web.
19. Heater according to claim 17,
    characterized in that
    the external contour of the ring segments at least in areas is substantially elliptical, the centre of the ellipse lying on the axis of the heating tube, and preferably in that two yarns are guided at opposing points of the ellipse at uniformly directed helix angles.
20. Heater according to claim 17,
    characterized in that
    the ring segments lie eccentrically in relation to the heating tube axis, and preferably in that two yarns are guided one on either side of the axial plane of the heating tube, on which the centre of the ring segments lies, at oppositely directed helix angles and axially adjacent ring segments are offset by 180° relative to one another.
21. Heater according to one of claims 15 to 20,
    characterized in that
    the ring segments axially succeeding one another on the heating tube are offset in a peripheral direction approximately in the direction of the yarn overflow line.
22. Heater according to one of claims 15 to 21,
    characterized in that
    the heating tube and the inlet yarn guide (8) and the outlet yarn guide (9) are adjustable relative to one another in dependence upon the yarn temperature measured at the outlet of the heater in such a way that the yarn temperature as a result of varying and adjusting the contact ratio and/or the yarn distance from the heated surface substantially remains constant at a desired setpoint value.
23. Heater according to one of claims 15 to 22,
    characterized in that
    the heating tube and the inlet yarn guide (8) and the outlet yarn guide (9) are adjustable relative to one another in dependence upon the yarn tension measured downstream of the heater in such a way that the yarn temperature as a result of varying and adjusting the contact ratio and/or the yarn distance from the heated surface substantially remains constant at a desired setpoint value.
24. Heater according to one of claims 1 to 23,
    characterized in that
    the heating tube along its axial length comprises heating zones with a different contact ratio or height of the ring segments, preferably an inlet and/or outlet portion, in which yarn is guided at an increased distance greater than 5 mm from the outer jacket of the heating tube and/or with a sharply reduced contact ratio of less than 0.1 compared to the middle control region.
25. Heater according to one of claims 1 to 24,
    characterized in that
    the heater is installed in a false twist crimping machine, a delivery mechanism being disposed upstream and a cooling zone, in particular a cooling rail, an element for imparting friction false twist and a delivery mechanism being disposed downstream of the heater.

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