EP0659221B1 - Heating rail - Google Patents

Description

The invention relates to a heating rail for use in a False twist crimping machine according to the preamble of claim 1.

A synthetic thread of a zigzag thread path subjecting heating device is known from EP 0 412 429 A2. It enables the wrap angle during construction on the thread guides and the total sum of the wrap angles to choose on all thread guides without this at the same time the distance of the thread run from the heating surface influence.

The thread guides of the known heating device touch the thread with a curved contact surface. The thread guides have not just the job of calming the thread flow and all in one to define the defined distance to the bottom of the groove. Rather, they are Thread guide also of great importance for heat transfer.

It is an object of this invention in a false twist crimping machine the heat transfer of the heating rail through the special design to optimize the thread guide.

The solution results from claim 1.

A conventional distinction is made between so-called "contact heaters" and "contactless heaters".

D = Durchmesser der Kontaktflächen bzw. mittlerer Durchmesser zweier aufeinanderfolgender Kontaktflächen

U = Überlappung der aufeinanderfolgenden Fadenführer bzw. Amplitude der Zickzacklinie

A = Abstand zweier aufeinanderfolgender Fadenführer

T = Titer, ausgedrückt in dtex, d. h.: Gramm/10.000 m eine Rolle für die angegebene Dimensionierung.

The invention is based on the knowledge that in a false twist crimping machine for crimping a synthetic thread, a heater with a large number of thread guides, with a suitable design of the thread guides, is a contact heater and has its properties. In the false twist crimping machine, the heating rail is arranged directly in front of the swirl device in a zone of the thread run in which the synthetic thread running also rotates very quickly. As a result, the thread receives the twist, which is dissolved again in the twister. This rotation surrounds the thread with an air layer that hinders heat transfer. The invention is therefore based on the fact that the thread guides in the known heating device, when used in a false twist crimping machine, have the consequence that the heating rail is a contact heater and that the design of the contact surfaces is of particular importance for heat transfer. The invention avoids, on the one hand, that the spreading of the twist against the thread running direction is impeded; on the other hand, the invention results in a sufficiently close contact with a sufficient thread length on the contact surface of the thread guide. The formation of an air jacket preventing heat transfer is prevented and an air jacket which has already formed is effectively peeled off at the contact surfaces. The thread guides are designed so that the heating rail has sufficiently good properties for all thread titers to be processed by false twist crimping and is ideally designed in the lower titer range of approx. 20 dtex. The formula is playing here D = 0.0355 x A / U x root T with the following meaning:

D = diameter of the contact surfaces or average diameter of two successive contact surfaces

U = overlap of the successive thread guides or amplitude of the zigzag line

A = distance between two successive thread guides

T = titer, expressed in dtex, ie: grams / 10,000 m a role for the specified dimensioning.

Independently and in addition to the thermal solution solved by claim 1 Task specific to the use of the heating rail in a false twist crimping machine results for such Heating rails the further problem that the temperature control on the thread of crucial importance for the quality of the is curled thread. It is therefore necessary to run the thread very precise and reproducible.

This is done according to the invention by the design of the heating rail according to claim 2 and claim 3. The use permits circular cylindrical thread guide not only a very accurate and reproducible dimensioning of the thread guide but also the equally important exact dimensioning of the recesses, in which the thread guides with close tolerance but without press fit are included. The thread guides can be essentially free of play be fitted into these recesses. It's just one more axial fixation required.

Such a fixation that can be easily removed and inserted and therefore the exchange of worn or damaged ones without effort Thread guide allowed, follows from claim 10.

It should be ensured that the thread is simply inserted can be without having to put your hands on the over 200 ° C reaches into the heated heater. It must therefore be ensured that the Thread is tensioned when inserting and forms a straight line. This is made possible by the solution according to claim 5.

For better heat utilization, a heating rail is at least suitable for two threads. With the configuration according to claim 6 can then you save a substantial amount of material and effort achieve.

It has already been pointed out that the design of the Thread guide according to claim 1 thermally, especially the meaning has that an air jacket insulating the thread cannot arise or is peeled off. This goal will also be achieved if only some of the thread guides this goal completely, others this goal achieve less fully. This will make the constructive Solution according to claim 7 achieved.

It has already been indicated that it is necessary to Thread with great accuracy in its zigzag line but also relative lead to the heating surface. This problem is addressed by the Thread guides formed guide edge according to claim 8 or by solved the spacer according to claim 9.

The even heating of the thread by the heating rail is only then possible if the heating rail and the one formed on it Heating surface sufficient and over the length of the heating rail uniform amount of heat is supplied. This is done for simplicity for the sake of an elongated, rod-shaped resistance heater. The problem here is that these electric heater rods on the one hand, an intimate, good heat-conducting contact with the heating rail must have, but on the other hand also be easily interchangeable should. This problem is solved by the configuration according to claim 11 solved.

The heating device according to EP 412 429 consists of two heating rails, which are inclined relative to each other in a roof shape such that the form an obtuse angle between the two heating rails. Also this positioning must be done with great accuracy, the Positioning should be easily adjustable and reproducible. The The solution results from claim 12. When configured according to claim 13, the proposed U-profile acts simultaneously in the sense of a Temperature equalization over the length of the heater.

Fig. 1

eine Draufsicht auf eine erfindungsgemäße Heizvorrichtung mit einer doppelten Nut;

Fig. 2

eine Vorderansicht der in Fig. 1 gezeigten Heizvorrichtung mit sie umgebendem Isolierkasten in schematischer Darstellung;

Fig. 3a und 3b

Längsschnitte durch bevorzugte Ausführungsformen der in der erfindungsgemäßen Heizvorrichtung verwendeten Fadenführer;

Fig. 4

Querschnitt und Aufsicht auf ein modifiziertes Ausführungsbeispiel;

Fig. 5

Querschnitt und Längsschnitt durch eine Heizeinrichtung mit zwei Heizschienen;

Fig. 6

eine schematische Darstellung von 3 aufeinander folgenden Fadenführern zur Darstellung der Abmessungen.

The invention is described below using exemplary embodiments. Show it:

Fig. 1

a plan view of a heating device according to the invention with a double groove;

Fig. 2

a front view of the heater shown in Figure 1 with surrounding insulating box in a schematic representation.

3a and 3b

Longitudinal sections through preferred embodiments of the thread guides used in the heating device according to the invention;

Fig. 4

Cross section and top view of a modified embodiment;

Fig. 5

Cross-section and longitudinal section through a heating device with two heating rails;

Fig. 6

is a schematic representation of 3 successive thread guides to illustrate the dimensions.

The heating device 10 shown in Figures 1 to 5 consists of a provided with two longitudinal grooves 12 rail 14 from one Material that is heat and scale resistant, such as a copper alloy, and temperatures in the range above 450 ° C endures longer periods without significant changes. The Rail 14 consists of a substantially flat lower part 16, which represents the heating surface. With the bottom are three walls 18, 20, 22, connected, between which the longitudinal grooves 12 are located. Of the Lower part 16 can also have two or more than three upstanding Walls are provided, between which then accordingly there are fewer or more grooves. The outer walls 18 and 22 can be connected to the lower part 16, for example by screwing be. Between the walls 18 and 22 and the lower part 16 there is a heating element 24, 26, preferably in the form of a rod-shaped, electrical resistance, which extends over the entire Length of the rail 14 extends or in length also in several Sections can be divided to allow targeted heating profiles. The heating elements 24, 26 are with plug contacts, not shown provide a power source for connection.

The located between the outer walls 18, 22 and from the lower part There are 16 vertically projecting middle wall 20 with this either from one piece or is like the outer walls 18, 22 with connected to the lower part 16.

Alternatively, the rail 14 can be made from an extruded profile similar cross-section exist, with the lower part 16 and walls 18, 20, 22 are formed in one piece and which for receiving Heating elements in a known manner with recesses, bores, bendable cloth or the like is provided.

In the rails 18, 20, 22 are A at regular intervals Recesses or bores 28 with essentially the same Recessed depth, namely those located in the middle wall 20 Recesses 28 with respect to the recesses 28 in the side walls 18 and 22 offset by a distance A. The recesses have a circular cylindrical shape. The recesses 28 are each cut secantially from the longitudinal grooves 12 so that the walls 18, 20, 22 a slot 30 located on the longitudinal grooves 12, i. H. a rectangular opening. In the illustrated embodiment the recesses are perpendicular to the groove base and correspond in depth the height of the walls 18, 20, 22 receiving them. In certain circumstances it may be advantageous to use the recesses to slant.

In each of the recesses 28 there is a thread guide 32 Cross-sectional shape size and cross-section of the recess conforms in terms of form and which stipulates in order to maintain close tolerances but with play on the recess wall. The one from the Drawing recognizable distance between the wall of the holes and the outer surface of the thread guide is only for the sake of Clarity exaggerated. In the area of the respective slot 30 a part of each thread guide 32 projects into the longitudinal grooves 12, in such a way that on opposite sides of the grooves 12 successively arranged thread guides 32 to a certain extent, e.g. 0.1 to 1 mm, over a parallel to the walls 18, 20, 22 Middle plane. Otherwise, the width of the slots 30 each less than the largest cross-sectional dimension, d. h .: than that Diameter of the thread guide 32 so that it does not come out of the recesses 28 can slide out.

In the illustrated exemplary embodiments, both the recesses are 28 as well as the thread guides 32 of circular cylindrical cross section. Other angular and rounded shapes, such as ellipses, rhombuses, Triangles, etc. are conceivable. The embodiment according to FIGS. 1, 2 has one that is kept within tight tolerances Fit between recesses 28 and thread guides 32. Therefore there is no need for separate fasteners to secure the thread guides 32 against axial and radial displacements, which makes it a special one Effort that would result from the use of fasteners, is avoided. 4 and 5 match fits are selected. On the one hand, these game fits are narrow enough so that the thread guides are immobile in their recesses lie. On the other hand, the game fits are also wide enough chosen that the thread guides easily from their recesses can be pulled out and replaced. To hold on to Sheet metal caps 52 serve in the axial direction. For this purpose, the side walls have 18, 20, 22 at their upper edge retaining grooves 54 or a head 56, which is wider than the respective wall. The sheet metal caps 52 have in cross section a cup-shaped profile, so that in the case of Project the central wall 20 into the retaining grooves 54 or in the case of the Side walls 18, 22 encompass the wall head 56. For the rest are the sheet metal caps formed as elongated profiles, the length of which Length of the heating rail corresponds. The thickness of the wall heads 56 or the position of the holding grooves 54 and the corresponding dimensioning the sheet metal caps is such that the sheet metal caps are the thread guides in Set the axial direction.

The thread guides consist of the usual materials such as Silicon, titanium, or aluminum oxides or from nitrided or hard chromed steel, or the like

The thread guides 32 are preferably in the area in which they come from protrude the recess slot 30 on their from the lower part 16 opposite ends beveled as shown at 34. Thereby form those in opposite walls 18 and 20, or 22 and 20 one behind the other thread guide 32 in the cross-sectional direction of the Heater 10 each have a V-shaped groove 36 which enables a thread 38 in the stretched state without any special measures or arrangements between the successive thread guides 32 in one with respect to the heating surface 12 and the lower part 16 substantially vertical movement between the thread guides 32 too to lead. There forms the thread 32 resting on the contact surfaces then a zigzag thread path (see Fig. 1).

At the ends (as in Fig. 1) or at several other locations (as in 4, 5) of the heating rail 14 with substantially the same There is a spacer each bridging the groove 12 40, of which only one is shown in FIG. 1. This thread guide have an upward thread guide surface, which serves the distance between a thread 38 and the groove bottom to protect. These rod-shaped spacers 40 are in transverse bores anchored in the walls 18, 20, 22.

As shown in FIG. 5, the heating device 10 can consist of two in Thread running direction one behind the other rail sections 14a and 14b exist. These are of different lengths, but otherwise same cross-sectional shape. Purpose of such a two-part arrangement it may be the heater 10 in different length ranges heat differently to the thread 38 at one to treat its properties in accordance with its thermal profile. That means: You can also do more than the two sections shown be applied. It is of particular importance that the Angle that the two heating rails form to each other, at each Processing point of the false twist crimping machine set identically threads of the same quality on all processing points be generated. One is used to attach the two heating rails Mounting rail 58. This is a rail that the Has length of the two heating rails. The mounting rail has one U-shaped cross section. The heating rails are on the bottom of the Fastening rail fastened with spacers 60. By dimensioning the spacer and its position relative to the heating rail, is the inclination of the heating rail in relation to the straight Fixing rail 58 set. The two have Heating rails of opposite inclination and together form one obtuse angle. The mounting rail 58 thus serves on the one hand exact fastening of the two heating rails. Because the mounting rail 58 has a U-shaped profile, but also encompasses the two heating rails. Therefore, the mounting rail 58 also serves Temperature equalization over the length and width of the heating rails. The mounting rail is surrounded with insulation.

It has already been noted that rod-shaped spacers 40 can be provided, the longitudinal groove 12 on the groove bottom, d. H. bridge the heating surface and the thread run in an exact Specify the distance to the base of the groove. Alternatively or additionally you can some or all of the thread guides 32 with a circumferential leading edge, e.g. B. a circumferential groove 42, the height of the groove bottom with the height of the thread path predetermined by the guide bodies 40 is coordinated. In this way, the thread that is in the Groove is guided through the side edges of the groove. The circumferential grooves have the same depth over the circumference, so they are concentric to the thread guides 32 are formed. However, it is also possible that To form circumferential grooves of varying depth over the course of the circumference, e.g. B. in that the groove base is circular cylindrical but is cut eccentrically to the thread guides 32. In this Trap is possible by twisting the thread guide Fine adjustment of the contact between thread 38 and thread guides 32 and given the zigzag thread run. To do this, the Thread guide 32, for example, via a linkage connecting them (not shown) twist together and to the same extent.

Otherwise, the heating device 10 is in an insulating box 44 (Fig. 2) housed in a thermal insulation material, e.g. Glass fibers, is embedded. The insulating box 44 can with a Flap (not shown) may be provided, which makes it possible to open to provide access to the heater 10 and the Insert thread. The insulating box 44 also serves in the exemplary embodiment 2 with its laying on the heater 10 Parts for axially fixing the thread guides 32 in the rail 14. The insulating box 44 is provided with slots 48 which with the Center plane 50 and the bevels 34 of the thread guide 32 are aligned and make it possible to thread 38 to be treated between the Thread guide 32 to bring. The slots are on their side walls provided with wear-resistant insulating plates 46.

Also the electrical required for the heating elements 24, 26 Contacts are optionally housed in the insulating box 44.

It can be seen from all the design examples that the contact surfaces, with which the thread guides touch the thread, a relative have a large diameter. In contrast, the Zigzag line in which the thread through the overlap U of the successive Thread guide is a relatively small Amplitude, with a relatively large distance A between two neighboring thread guides. This ensures that the wrap angle, with which thread the thread guides or the wrapped around them, even small in total is. Therefore, the rotation of the thread in the false twist zone becomes one False twist crimping machine not hindered. Nevertheless, as a result of large diameter the contact length of the thread large enough that a thread of small titer (e.g. 20 dtex) overflows turns a thread guide once around its axis and thus Air jacket that surrounds the thread and the heat transfer disabled, completely stripped.

A thread of larger titre needs the for a complete rotation Overflow over two or three thread guides. However, since the number of Thread guides distributed over the length of the heating rail and in particular the number of thread guides distributed over several heating rails is at least twice, it is guaranteed that during the run the thread through the heating device in any case a two-fold complete The air jacket surrounding the thread is stripped off. In Figure 6 shows that thread guides of different diameters D1 and D2 can be used. The thread guides are in the same Distance A arranged. A zigzag line of the thread run forms out. The amplitude of this zigzag line is labeled U. This size U is identical to the overlap of two successive ones Thread guides, which results from the successive Thread guides each protrude above the central plane 50.

If, within the scope of this application, the diameter of the thread guides or contact surfaces is mentioned, the mean diameter of two thread guides following one another in the thread path is meant. It can be seen from FIG. 6 that the overlap U results from the formula: (D1 / 2 - B1) + (D2 / 2 - B2).

In the exemplary embodiment according to FIGS. 4 and 5, the heating rail has on its side facing away from the longitudinal groove 12, two grooves, which are substantially below the thread guide grooves 12. In these grooves are heating elements 24 and 26 inserted. The heating elements are by a mounting rail 58 that extends over the entire Length of the heating rail extends, clamped. In addition, the Fastening rail grooves which surround the heating elements 24, 26. By loosening the fastening rail 58, the heating elements 24, 26 can be easily replaced.

Claims (13)

1. Heating rail for heating the moving yarn (38) in a false twist crimping machine for crimping a synthetic yarn (38),
   having a heating surface, which is heated up to more than 250° C, and a plurality of yarn guides (32),

   which are disposed on alternate sides of a common centre plane perpendicular to the heating surface,

   which with a curved contact surface project beyond the centre plane from alternate sides in such a way that the successive contact surfaces guide the yarn (38) by means of their curved contact surfaces along a zigzag course having the amplitude U and the yarn guide spacing A,

   characterized in that

   the amplitude U is 6 to 15%, preferably 9-14% of the spacing A,

   the diameter of the contact surfaces is 8 to 25 mm, preferably 10 to 20 mm.
2. Heating rail according to claim 1,
   characterized in that
   the heating rail has a longitudinal groove, the bottom of which forms the heating surface and the side walls (18, 20, 22) of which have recesses (28), into which are let the yarn guides which project into the groove, that the yarn guides are cylinders (32), the jacket of which forms the curved contact surface and which are disposed offset relative to one another on either side of their common centre plane (50).
3. Heating rail according to claim 2,
   characterized in that
   the recesses (28) have a cylindrical cross section which is adapted to the cross section of the yarn guides, the recesses in the walls forming a gap (30), through which the respective yarn guide (32) projects into the groove (12) with a part of its cross-sectional surface which is smaller than the part of the yarn guide situated in the recess (28).
4. Heating rail according to claim 3,
   characterized in that
   the yarn guides (32) and the recesses (28) have a circular-cylindrical cross section.
5. Heating rail according to one of claims 2 to 4,
   characterized in that
   the yarn guides (32) are conically (34) bevelled at their end remote from the heating surface.
6. Heating rail according to one of claims 1 to 5,
   characterized in that
   the heating rail has two parallel grooves (12) and that the dividing wall (20) situated between the two grooves is greater than the radius and smaller than the diameter of the recesses, which are formed in said dividing wall and in which the yarn guides (32) are inserted.
7. Heating rail according to claim 6,
   characterized in that
   the diameter of the yarn guides (32) inserted in the dividing wall (20) is greater than the diameter of the yarn guides inserted in the side walls (18; 22).
8. Heating rail according to one of claims 1 to 7,
   characterized in that
   at least some of the yarn guides are provided at a distance from the groove bottom with a guide (43) which axially defines the yarn course.
9. Heating rail according to one of claims 1 to 8,
   characterized in that
   provided in a longitudinal direction of the longitudinal groove (12) is a plurality of groove spacers (40) which bridge the groove at a distance from the groove bottom.
10. Heating rail according to one of claims 1 to 9,
    characterized in that
    placed onto each of the side walls is a sheet metal cap, which extends in a longitudinal direction of the heating rail and which rests on the end faces of the yarn guides and covers at least part of the end faces of the yarn guides which project beyond the side wall.
11. Heating rail according to one of claims 1 to 10,
    characterized in that
    the rail at its underside has longitudinal grooves, into which resistance heaters (24) are inserted, and that the resistance heaters (24) are clamped to the heating rail and covered by means of a clamping element.
12. Heating apparatus having two heating rails according to one of claims 1 to 11,
    characterized in that
    the heating apparatus comprises an elongate, straight fastening rail, to which the heating rails are fastened by means of spacers, preferably with an - in yarn course - ascending and descending slope.
13. Heating apparatus according to claim 12,
    characterized in that
    the fastening rail takes the form of a channel section, the side flanks of which embrace the heating rails.

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