EP0796935A2 - Heating device for a running yarn - Google Patents

Abstract

Yarn is heated, esp. on a false twist texturing machine, by a heater with a contact heating surface consisting of a series of spaced ridges which carry the yarn at a distance from the heater surface and which are arranged to reach the temperature of the heater, pref. a sufficiently high temperature to be self cleaning. A heating tube is heated by resistance heaters and carriers a series of rings or discs of wear and heat resistant material, e.g. Al or Ti oxide, which are sepd. by spacers. Adjustable inlet and outlet guides guide the yarn across them along a helix. The relative position of the guides is adjustable to control the helix angle and contact length. The spacing length and height of the yarn carriers can be varied to control the contact length. The yarn carrier can be made of a single shape, perforated cuff placed on the heating tube.

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 enables the course of the thread path to be varied within wide limits.

In addition, a further object of the invention is to enable the heat transfer to be influenced.

This object is achieved by the features of claim 1.

According to the embodiment of the invention, a sheet-like sleeve is placed on the essentially smooth heating surface, the inner contour of which corresponds to the outer contour of the heating surface and the outer contour of which has rows of axially aligned webs. The sleeve is secured on the heating surface against displacement in the thread running direction, but can be moved transversely to the thread running direction. 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 moving the sleeve on the heating surface; on the other hand, the thread can be heated over a wide temperature range due to the different design of the webs. The shape of the sleeve, which is congruent to the heating surface, ensures intimate thermal contact between the sleeve and the heating surface. According to the invention, at least the section of the heating surface which is provided for the thread path is covered with the sleeve which is closely adapted to the surface shape of the heating tube and is in close, heat-conducting contact with the heating surface.

In the thermal treatment of man-made fibers, especially man-made fibers of low strength (titer, denier), the wear on the thread-guiding surfaces plays 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 advisable to move the sleeve of this radiator to provide. The cuff can then be moved permanently or slightly at certain time intervals, so that a new thread run occurs.

Bars are formed on the outer contour of the cuff. The cuff is preferably made of a thin sheet. The webs can be formed in that the cuff is compressed in several normal planes in such a way that a bulge arises outwards.

This creates cavities that can hinder heat transfer. On the other hand, it is complex and difficult from a manufacturing point of view to apply massive webs with good thermal conductivity to a thin-walled sheet, e.g. B. to weld. These difficulties are avoided in the execution according to claim 3. According to this embodiment of the invention, a sleeve or a cage is placed on the radiator, which is essentially provided with a smooth surface, the inner contour of which corresponds to the outer contour of the heating surface and the outer contour of which is penetrated by recesses of the same shape which are axially lined up in rows. Rows of uniform recesses preferably lie opposite each other in the cuff, with rows of recesses of other shapes preferably lying next to these rows 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. Since uniform webs or recesses lie opposite one another in the sleeve or are repeated at certain angular intervals, overflow paths for 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 version, too, the webs do not have to lie in a normal plane of the heating surface, but rather can be inclined in relation to a normal plane. It is desirable that the sleeve be made of one piece over the entire length of the heating surface and that the recesses therefore only extend over a partial width.

A low web height is not only possible here, but is advantageous for making the temperature transfer more even and for controlling the temperature transfer on the thread. For this reason, it is proposed to be particularly advantageous to choose the sheet thickness between 0.1 mm and 5 mm, preferably between 0.5 mm and 3 mm.

In a particularly advantageous embodiment of the invention, the heating surface is formed by the jacket of a heating tube. 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.

In this radiator, by adjusting the thread guides provided at the entrance and exit of the thread path in the circumferential direction, the steepness of the helix with which the thread runs over the webs of the sleeve, and thus the curvature of the thread path, can be selected. 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 here. Here the heat transfer is based exclusively on the temperature of the pipe and the height of the webs above the cuff. The The steepness of the helical line, on the other hand, i.e. the curvature and wrap angle of the thread path can be selected without influencing the heat transfer so that the thread runs smoothly and stably and that - in the case of false twist crimping machines - the thread introduced into the thread also extends in the area of the thread length corresponding to the radiator exposed, can reproduce unhindered.

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 not only on the height of the webs (see above) but also on the temperature and the length of the heating surface. 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 surface is preferably heated by an electrical resistance heater which is introduced in the interior of the heating element and extends at least over part of the length of the heating surface. It is also possible to intensify the heating in certain areas, e.g. B. in the entrance area to provide several independently activated and adjustable resistance heaters on the length of the heating surface. You can then regulate different temperatures over the length of the heating surface.

Given the high temperature of more than 350 °, to which the Heating surface can be heated, only a small length of the heating surface is required.

As already mentioned, the radiator according to the invention can be operated particularly advantageously at temperatures which are in the self-cleaning range. 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 embodiment according to claim 7 allows the distance between the webs to vary over the length of the heating surface, which will be discussed later. 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 web on its outer circumference. The distance between the webs can be varied by pushing the sections into each other to a greater or lesser extent.

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. However, the thread thickness and the length of the radiator are fixed.

The optimization of the heating effect on the thread is however from 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 widening in the circumferential direction are therefore provided on a sleeve 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 8 and 9, therefore, a further setting parameter is provided, by means of which the heat transfer to the thread and thus the target temperature of the thread can be influenced. These are the ratio of the contact length / non-contact length of the thread run along the heating surface and the height of the webs above the heating surface and the depth of the recesses by which the webs are formed. In these embodiments of the invention, the contact ratio and / or the height of the webs changes across the width of the heating surface transversely to the thread path.

The webs therefore have a working width of multiple thread diameters transversely to the thread running direction. The touch length (contact length) the webs in the thread running direction over the working width are different, and the thread running can be adjusted relative to the working width of the webs.

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 relative adjustment of the thread on the heating surface in such a way that the target temperature remains constant at a predetermined target value (claim 10).

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 differently shaped recesses lie next to one another transversely to the thread running in the sleeve, that the webs have sectors with a constant height in each case, or that the width and / or the height of the 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 adjust the thread tension, and in particular the thread tension, between the friction false twister and the subsequent delivery unit is measured by relative adjustment of the thread running on the heating surface so that the deviation between the measured value and the target value of the thread tension does not exceed a certain tolerance size (claim 11).

If there are several thread runs on a heating surface, there is the further problem of designing the webs in such a way that a desired identical change in the web height or depth of the recesses results with synchronous relative adjustment of both thread runs on the heating surface.

When a thread runs over a radiator 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 surface. This is achieved according to claim 12 in that the contact ratio and / or the web height are designed differently.

The range of the heater length, which essentially involves reaching 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 heater length, which is primarily about heat transfer, is called the control section. The contact ratio is much smaller in the end section. the web 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 will. The input area is preferably equipped with only one input thread guide and one output thread guide. In addition, it proves 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. The temperature of the radiator is precisely controlled in this control zone, and preferably by regulation. The precise guidance of the thread relative to the heating element ensures 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 31).

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 also offer the possibility 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

Seitenansicht eines Heizkörpers mit aufgesetzter Manschette und Ringen;

Fig. 2

Seitenansicht eines Heizkörpers mit Manschette und zwei Fadenläufen;

Fig. 3, 4

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

Fig. 5, 6

Heizkörper mit teleskopartig verschiebbaren Manschetten;

Fig. 7, 8

schematische Darstellung einer Falschzwirnkräuselmaschine mit Fadenspannungsmessung und Temperaturmessung des Fadens.

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;

Show it:

Fig. 1

Side view of a radiator with attached sleeve and rings;

Fig. 2

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

3, 4

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

5, 6

Radiator with telescopic sleeves;

7, 8

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

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;

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

All of the radiators shown are designed, for example, 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.

The invention is basically applicable to all radiators in which the thread is guided along a heating surface by means of webs. In particular, however, this inventive concept can be applied to all heating bodies according to the invention.

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.

The following applies to all designs according to FIGS. 1 to 6: 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 webs 2 according to the invention in the axial direction. The designs shown according to FIGS. 1 to 6 differ with regard to the design of the webs. 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 cuff according to FIG. 1.

In the embodiment according to FIG. 1, 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 arched webs 2 were formed on the circumference. One or more threads can be guided over the outer circumference.

This version has its special advantage if with heavy contamination of the radiator is to be expected. 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 webs. As a result, the time intervals in which the radiator is cleaned can be significantly increased. The impurities carried along by the thread are of no importance for the thread quality.

In the embodiment according to FIGS. 2 and 4, the sleeve is provided with webs 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 execution is shown in Figure 2 as a settlement. In the embodiment according to FIG. 2, the webs are formed 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. Therefore, web-like ring segments remain between adjacent recesses 34, which act as webs 2 in the sense of this invention. In the embodiment according to FIG. 2, two rows of recesses 34 are arranged one behind the other with an opposite axial offset symmetrical to the center line 40, so that two threads can be guided over the recesses or webs 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 Figures 3, 4, the sleeve 33 is also formed 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. 2, 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. 2.

The embodiment according to FIGS. 3, 4 have the following special features: The recesses 34 lie in a row parallel to the axis of the heating tube 1 and form webs 2 of the same width between them. The webs 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 wedge-shaped ring segments between them, 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 the row of trapezoidal recesses there is another row of recesses 36 lined up. These are recesses which are relatively narrow in the axial direction, but leave wide webs 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.

In Fig. 2 the cuff is shown enlarged as a settlement. The recesses 34 of a respective row are of the same shape and are at the same distance from one another. Between the recesses 34 are the ring segments which run in the circumferential direction. 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 webs also corresponds to the dimensions of the web height mentioned above in this embodiment and in the discussed preferred ranges of 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 that meet the working conditions, the other desired working conditions are enough.

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 webs 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 webs / width of the recesses in each case in the thread running direction), number and distribution of the webs in 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. 5 and 6 have in common that the sleeve which carries the thread overflow webs or webs 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. 5, the sections 33 each consist of an axial section 33a with a larger diameter and an axial section 33b with a smaller outside diameter, the latter corresponding to the inside diameter of the axial section 33a with a larger outside 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 made using lock nuts K are secured, whereby the position of the sections can be adjusted to each other exactly.

A web 2 is provided on the outer circumference of the section parts 33a with the larger diameter. The embodiment shown in FIG. 6 differs from that according to FIG. 5 in that successive sections alternately have a small and 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 web 2 serving as a thread guide, the webs 2 being shown to increase 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 webs. In particular, the webs can be designed in accordance with the exemplary embodiments of FIGS. 9 to 12 described later.

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 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 a false twist, which gives each thread a temporary twist, and from input and output delivery systems that pull the thread from the delivery spools or pull it out of the false twist. 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.

FIGS. 7 and 8 also 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 webs which are formed on a sleeve according to FIGS. 2 to 4. In any case, the configuration of the webs is such that the contact ratio and / or the height of the webs above the heating surface changes in the circumferential direction to the same extent or to a different extent for all webs.

In the false twist crimping machine according to FIG. 7, 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. 8 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 down the thread from the false twister is a yardstick is 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. 7 and 8, 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.

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

The radiators also each have an input section 11 and / or end section 12 at the input of the heating tube 1 and / or at the output of the heating tube 1, which has a greater radial distance from the passing thread 7 than the outer surface of the heating tube 1.

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. 9 to 11 with a special input section, control section and end section but also with a more uniform or different one Uneven distribution of the webs can be used:

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. that due to the range of rotation 15 of the thread 7 is paintable. 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 webs 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 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 webs 2.1, 2.2, 2.3 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 designs according to FIGS. 9 and 12 thus have webs 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 web 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 webs 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 webs increases in the circumferential direction in which the height H of the webs decreases. It is therefore to be expected that with increasing contact time of the thread 7 on the webs due to the increasing web width B, the heat flow on the thread also increases in the non-contacting longitudinal regions between the webs 2 due to the simultaneously decreasing distance between the thread 7 and the tubular jacket.

FIGS. 10 and 11 additionally show that the webs 2 can also have a height that changes in the circumferential direction in the angular region that can be covered by the thread if the width of the webs 2, that is to say the web width, does not change in the circumferential direction. The same applies in reverse.

It should therefore be expressly stated that these two embodiments of the invention - that is to say webs with changing widths and webs with changing heights - can occur both in combination with one another and separately from one another.

The width B of the webs can also change in stages. 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 the height H of the webs. This results in a slight lateral adjustment of the contact zone between the thread and the web without influencing the heat transfer between the heated surface and the thread.

In the embodiments according to FIGS. 9-11, the webs could be formed on the outer contour of a sleeve.

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 webs 2 with the thread 7.

Furthermore, there is a heat flow on the thread 7 in the longitudinal areas between the webs 2 that are not touched by the thread. Since the base of the web grooves between the webs 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 web height, depend on the relative position of the input thread guide 8 and the output thread guide 9 to the heating pipe 1. The contact ratio and the height of the webs are therefore decisive parameters for heat transfer. The ratio of the contact length of the thread on each ring and the length of the subsequent contact-free distance to the next web is understood as the contact ratio.

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

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 was discussed previously.

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 webs 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 webs Always touched only at points of the same contact width or height, the successive webs 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 webs in the sense of the mean value of the pitch is sufficient, to which the helical thread line can be adjusted. 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 webs 2.1, 2.2, 2.3 etc. in the circumferential direction are each offset by a certain angular amount in FIGS. 9-11. This angular amount corresponds to the mean value of the adjustable pitch of the helix of the thread.

However, one can also consciously dispense with this circumferential offset of the webs and arrange the webs one behind the other in such a way that the locations 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 webs along the thread path and thus also the heat transfer over the length of the thread path can be designed differently.

REFERENCES

1

Heating pipe, heating surface

2nd

Bridge, ring segment

3rd

Spacers

4th

deepening

5

slot

6

resistance

6a

Electrical supply

7

thread

8th

Input thread guide, thread guide

9

Starting thread guide, thread guide

10th

Spring clip

11

Entrance section

12th

End section

13

Rule section

14

Thread running direction

15

Running direction

16

score

17th

Pipe axis

18th

Delivery plant

19th

Cooling rail

20th

False twister

21

Delivery plant

22

Temperature sensor

23

Stepper motor

24th

Traction measuring device

25a, 25b

Thread heating zone

26

Thread guide lever

27

eccentricity

30th

radiator

31

Thread guide, bridge, ring

32

blank

33

cuff

33a, 33b

Axial section of the cuff

34

Recess

35

Recess

36

Recess

37

web

38

web

39

web

40

Center line

41

insulation

42

Long slot, slot, feed slot

43

Groove

44

hole

45

axial guidance

Claims (13)

Radiator for heating a running thermoplastic thread (7), in which the thread (7) is guided along and at a distance from a heated surface (heating surface) (1) via webs (2) which sit on the heated surface,
characterized in that
a sheet-like sleeve (33), which is congruent to the shape of the heating surface (1), is stretched onto the heating surface (1) and that the webs (2) are formed on the sleeve (33), the sleeve (33) preferably is movable on the heating surface. Radiator according to claim 1,
characterized in that
the webs (2) are formed by bulges which are lined up at a distance in the axial direction on the sleeve (33). Radiator according to claim 1,
characterized in that
the webs (2) are formed by recesses (34), which are incorporated into the wall of the sleeve (33) and are lined up at a distance in the axial direction, which have a limited length in the direction of thread travel and follow one another, with two recesses adjacent in the axial direction ( 34) a web (37) for thread guidance remains. Radiator according to one of claims 1 to 3,
characterized in that
the thickness of the sheet of the sleeve (33) is at least 0.1 mm but not more than 5 mm, preferably at least 0.5 mm but not more than 3 mm. Radiator according to one of claims 1 to 4,
characterized in that
the heating surface (1) is the outer jacket of a heating tube which is curved transversely to the longitudinal direction, the sleeve (33) preferably being rotatable in the circumferential direction of the heating tube (1). Radiator according to claim 5,
characterized in that
the beginning and end of the heating tube (1) thread guides (8, 9) are assigned, which are offset from one another in the circumferential direction of the heating tube (1) and through which the thread (7) in a steep screw line in contact with the outer contour of the ring segments Web (2, 34) is guided along the cuff. Radiator according to claim 1 to 6,
characterized in that
the cuff consists of a plurality of sections (33a, 33b) which are adjustably connected to one another and which are preferably telescopically inserted into one another. Radiator according to one of claims 1 to 7,
characterized in that
the webs (2, 38) in the possible area of contact with the thread (7) have a width (contact length) that changes transversely to the thread running direction,
that the sleeve (33) and the thread guide (input thread guide 8, output thread guide 9) assigned to the thread input and the thread output of the thread heating zone, through which the thread (7) is guided over the webs (2), can be displaced relative to one another transversely to the thread running direction and positioned in this way are that the contact ratio (quotient of the contact length of the thread on a web / non-contact thread length subsequent to the web) is adjustable on the web. Radiator according to one of claims 1 to 8,
characterized in that
the webs (2) in the possible area of contact with the thread have a height which changes transversely to the thread running direction,
that the cuff (33) and the thread guide (input thread guide 8, output thread guide 9) assigned to the thread input and the thread output of the thread heating zone, through which the thread (7) is guided over the webs (2), can be displaced relative to one another transversely to the thread running direction and positioned in this way are that the distance of the thread path from the heating surface on the web is adjustable. Radiator according to one of claims 1 to 9,
characterized in that
the sleeve (33) and the input thread guide (8) and the output thread guide (9) can be adjusted relative to one another depending on the thread temperature measured at the outlet of the radiator in such a way that the thread temperature by changing and adjusting the contact ratio or the thread distance from the heating surface in remains essentially constant at a desired setpoint. Radiator according to one of claims 1 to 10,
characterized in that
the sleeve (33) and the input thread guide (8) and the output thread guide (9) can be adjusted relative to one another in dependence on the thread tension measured behind the heating element in such a way that the thread temperature is essentially changed and the contact ratio or the thread distance from the heating surface is changed and adjusted remains constant at a desired setpoint. Radiator according to one of claims 1 to 11,
characterized in that
the sleeve (33) has, along its axial length, heating zones with a different contact ratio or height of the webs, preferably an input and / or output section, in the thread with an increased distance (greater than 5 mm) to the heating surface and / or greatly reduced contact ratio compared to the central control range (less than 0.1) is performed. Radiator according to one of claims 1 to 12,
characterized in that
the radiator is installed in a false twist crimping machine, the radiator being arranged upstream of a supply unit and a cooling zone, in particular a cooling rail, a friction false twist generator and a supply unit being arranged downstream.

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