Abstract:
A crimping apparatus for crimping a filament bundle in a melt spinning process includes a conveyor nozzle and a stuffer box which is associated with the conveyor nozzle. For thermal processing, a processing unit, which includes a rotatable processing drum which, for guiding and temperature control of a thread plug, has a rotating drum wall, is disposed downstream of the stuffer box. In order to be able to carry out as gentle a processing of the thread plug as possible, the stuffer box is disposed axially parallel to the processing drum in such a manner that the thread plug can be infed in a straight run from a plug outlet of the stuffer box to the circumference of the drum wall. This allows the naturally acting weight force of the thread plug to be advantageously used for guiding the thread plug.

Description:
This application is a continuation-in-part of PCT/EP2013/054126 filed Mar. 1, 2013, which claims priority to German Application No. 10 2012 004 747.9 filed Mar. 8, 2012; the entire contents of each are incorporated herein by reference. 
    
    
     BACKGROUND 
     The invention relates to a crimping apparatus for crimping a multifilament bundle in a melt spinning process. 
     In the manufacturing of crimped threads in a melt spinning process crimping of the threads is caused by stuffing the filament bundles to form in each case a thread plug. In this known process, on account of stuffing the filament bundles, the filaments are deposited as loops and arcs and compressed to form the thread plugs, such that, after disintegration of the thread plug, a thread having crimped filaments is produced. The shape of the crimp contained in the filaments here essentially depends on the thermal processing of the thread plug. In order to enable dwelling times for temperature-control of the thread plug that are as long as possible, processing units in which the thread plug produced after stuffing is guided with multiple enlacements on a processing drum have been successful in the prior art. 
     A crimping apparatus of such type is known from DE 26 32 082, for example. In the known crimping apparatus, a conveyor nozzle, a stuffer box and a processing unit with a processing drum are disposed below one another. In principle, two different positions of the processing drum for receiving and guiding a thread plug guided out of the stuffer box are known here. In a first variant, the axis of the processing drum is oriented substantially horizontally, such that, in the case of multiple enlacements on the circumference of the processing drum, the thread plug has to be guided substantially in the horizontal direction. In this arrangement of the processing drum the windings of the thread plug on the circumference of the drum wall have to be displaced in order to obtain a helical profile of the thread plug on the circumference of the processing drum. Depending on the properties of the drum wall, entanglements of adjacent windings of the thread plug that are more or less intense may arise here. In addition, indexing means are used. In order to axially displace the windings of the thread plug. 
     In a second variant of the arrangement of the processing drum, the latter, with its axis, is substantially vertically oriented, such that the helically guided thread plugs on the circumference of the processing drum experience natural support of their indexing movement on the circumference of the drum wall. To this extent, comparatively slight indexing forces are required in order to guide the helical profile of the thread plug from the upper end of the processing drum to a lower end of the processing drum. Here, infeeding of the thread plug takes place by an upstream deflection between the stuffer box and the processing chamber. Deflections of this type typically represent a zone which, for temperature control of the thread plug, is uncontrolled and, wherever possible, they should be implemented as short as possible. 
     SUMMARY 
     It is an object of the invention to provide a crimping apparatus for crimping a multifilament bundle in a melt spinning process of the generic type in which the thread plug, for thermal treatment, is guidable with multiple enlacements in a gentle manner on the circumference of a processing drum. 
     A further object of the invention lies in refining the crimping apparatus of the generic type in such a manner that guiding of the thread plug on the circumference of the processing drum can substantially take place without an indexing unit. 
     This object is achieved according to the invention in that the stuffer box is disposed axially parallel to the processing drum in such a manner that the thread plug can be infed in a straight run from a plug outlet of the stuffer box to the circumference of the drum wall. 
     The invention is distinguished in that the natural weight force of the thread plug may be used to infeed the thread plug, without deflection, to the processing drum. The change of direction of the thread plug on the circumference of the processing drum is caused only by the relative speeds of the thread plug and the drum wall. The processing drum which, with its axis, is vertically oriented here ensures indexing of the individual windings of the thread plug without any comparatively large indexing forces. 
     Guiding of the thread plug on the circumference of the processing drum may still be improved in that, according to an advantageous refinement of the invention, the drum wall, at a short distance therefrom, is associated with an outer cylinder which encompasses the cooling drum in a sleeve-like manner and in that, for guiding the thread plug, an encircling annular chamber is configured between the outer cylinder and the drum wall. Here, the thread plug may be guided immediately from the plug outlet directly to the annular chamber, such that dynamic friction existing between the thread plug and the drum wall can be reduced to a minimum. 
     In order to facilitate filling of the annular chamber on the circumference of the processing drum, on the one hand, and to obtain setting of the thread plug on the circumference of the drum prior to disintegration of the thread plug, on the other hand, the refinement of the invention is preferably implemented in which the annular chamber includes an inlet opening to an upper end of the outer cylinder and, between the drum wall and the outer cylinder, includes an outlet opening to a lower end of the outer cylinder, and in that the annular chamber includes a chamber cross section which tapers off in the axial direction toward the outlet opening. In this manner, the chamber cross section may be implemented so as to be preferably larger in the inlet region of the annular chamber than a diameter of the thread plug. This enables the thread plug to be directly deposited in the annular chamber immediately after stuffing and without any compression. On account of the subsequent tapering of the chamber cross section it is achieved that positive setting of the thread plug is possible in the lower region of the annular chamber. To this end, the chamber cross section, in the region of the outlet opening, includes a size that is substantially smaller than the diameter of the thread plug. 
     In order to obtain secure guiding within the annular chamber in the case of fine counts and correspondingly low thread weights, it is furthermore provided that the inlet opening of the annular chamber is associated with a segment-shaped holding-down element which partially covers the inlet opening. In this manner, secure guiding of the plug layers within the annular chamber is achieved even in the case of a tapering chamber cross section. 
     In order to obtain slight relative speeds of the processing drum and the outer cylinder, a particularly advantageous embodiment is one in which the outer cylinder is configured so as to be rotatable and is coupled to a rotational drive which drives the cylinder wall in the same direction of rotation as the drum wall of the processing drum. In this manner, the cylinder wall can be driven in the same direction of rotation as the drum wall at a circumferential speed in such a manner that no speed differential exists between the walls of the annular chamber. In order to produce special effects when guiding the thread plug, there is, in principle, however also the possibility of setting desired speed differentials between the cylinder wall and the drum wall. 
     In the case of a synchronous drive of the processing drum and of the outer cylinder the refinement of the invention in which the processing drum is driven by an electric motor which is coupled to the rotational drive of the outer cylinder has proven successful. In this manner, both walls can be collectively driven in the same direction of rotation by way of one electric motor. 
     For temperature control of the thread plug on the circumference of the processing chamber the invention offers high flexibility in the choice and implementation of the temperature-control means. In a first variant, the drum wall of the processing chamber is configured so as to be gas-permeable, wherein the processing drum is coupled to a blower for generating a flow of cooling air. In this manner, the blower in the interior of the processing drum could produce negative pressure, for example, such that the available ambient air is sucked in via the drum wall and may be used for cooling the thread plug. Alternatively, however, there is also the possibility for the blower in the interior of the processing chamber to produce positive pressure, such that a flow of cooling air from the inside to the outside is established. 
     Irrespective of the properties of the blower, the thread plug may also be advantageously cooled within the annular chamber, in that the outer cylinder includes a gas-permeable cylinder wall. 
     However, in principle there is also the possibility for a fluid to be used as a temperature-control means which, for temperature control of the drum wall, is guided through fluid ducts within the processing chamber. Cold as well as hot fluids may be used here in order to implement temperature control of the thread plug. 
     The invention will be explained in more detail in the following with reference to the appended figures and by means of a plurality of exemplary embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows schematically a cross-sectional view of a first exemplary embodiment of the crimping apparatus according to the invention. 
         FIG. 2  shows schematically a side view of the exemplary embodiment of  FIG. 1 . 
         FIG. 3  shows schematically a cross-sectional view of a further exemplary embodiment of the crimping apparatus according to the invention. 
         FIG. 4  shows schematically a cross-sectional view of a further exemplary embodiment of the crimping apparatus according to the invention. 
         FIG. 5  shows schematically a detail of a cross-sectional view of a further exemplary embodiment of the crimping apparatus according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIGS. 1 and 2  a first exemplary embodiment is illustrated schematically in a plurality of views. Both illustrations show the exemplary embodiment in operation, wherein  FIG. 1  shows a partial cross section of the complete apparatus and  FIG. 2  shows a side view. In as far as no reference is made to any of the figures, the following description applies to both figures. 
     The exemplary embodiment as shown in  FIGS. 1 and 2  includes a conveyor nozzle  1  which, via a fluid connector  2 , is coupled to a fluid source (not illustrated here). The conveyor nozzle  1  contains a continuous guide duct  30  which is illustrated with dashed lines in  FIGS. 1 and 2 . The guide duct  30  penetrates the conveyor nozzle  1  and, in this manner, forms an inlet on the upper end. The lower end of the guide duct  30  of the conveyor nozzle  1  opens into a stuffer box  3 . The stuffer box  3  is likewise illustrated with dashed lines in  FIGS. 1 and 2  and configured in a housing  31 . The housing  31 , on its lower side, includes a plug outlet  4  which is connected to the stuffer box  3  in the interior of the housing  1 . 
     A processing unit  7  is disposed below the plug outlet  4 . The processing unit  7  includes a rotatable processing drum  8  which, via a drive shaft  16 , is connected to a rotational drive (not illustrated here). 
     As can be understood from the illustration in  FIG. 1 , the processing drum  8  is configured as a hollow cylinder, the drum wall  9  of which includes a plurality of openings. The end sides of the processing drum  8  are closed and, via a suction duct  32 , coupled to a blower  17 . 
     The processing drum  8  is vertically oriented in relation to the drum axis, such that the drum wall  9  extends in the vertical direction from an upper end down to a lower end. The upper end of the drum wall  9 , at a short distance therefrom, is associated with the plug outlet  4  of the stuffer box  3 . The stuffer box  3  here is disposed axially parallel to the processing drum  8  in such a manner that a thread plug  6  is guided in a straight run between the plug outlet  4  of the stuffer box  3  and the circumference of the drum wall. 
     As can be seen from the illustration in  FIG. 2 , the thread plug is only deflected after striking the circumference of the drum wall  9 , on account of the rotational movement of the drum wall  9  in the circumferential direction of the processing drum  8 . Here, temperature-control produced by the processing drum  8  already sets in. The thread plug  6  is deposited on the circumference of the drum wall  9  in multiple windings as the rotational movement on the drum wall  9  continues. Disintegration of the thread plug  6  to form a crimped thread  18  only takes place at the lower end of the drum wall  9 . 
     In the exemplary embodiment illustrated in  FIGS. 1 and 2 , a filament bundle  5  is continuously conveyed by the conveyor nozzle I via a preferred hot fluid, for example heated compressed air, into the stuffer box  3  and there stuffed to form a thread plug  6 . For the purpose of further temperature control and setting of the crimp in the filaments, the thread plug  6  is subsequently directly infed into the processing unit  7 . In this exemplary embodiment the processing unit  7  has cooling air as a temperature-control means. To this end, the blower  17  produces negative pressure in the interior of the processing drum  8 , such that a suction flow from the outside to the inside is produced via the gas-permeable drum wall  9 . For temperature control, in particular for cooling the thread plug  6 , ambient air is used in this exemplary embodiment. By way of the suction flow, a positive grip of the windings of the thread plug  6  on the circumference of the drum wall  9  is simultaneously achieved. 
     In the exemplary embodiment illustrated in  FIGS. 1 and 2 , the flow of cooling air is used for temperature control as well as for providing a grip for the thread plug on the circumference of the drum wall  9 . In order to be able to use the cooling air exclusively for temperature control, a further exemplary embodiment of the crimping apparatus according to the invention is shown in  FIG. 3 . The exemplary embodiment as shown in  FIG. 3  is substantially identical to the exemplary embodiment as shown in  FIG. 1 , such that only points of differentiation will be explained in the following and reference is otherwise made to the aforementioned description. 
     For guiding the thread plug on the circumference of the drum wall  9 , the processing drum  8  is associated with an outer cylinder  10 . The outer cylinder  10  includes a gas-permeable cylinder wall  11  which is implemented in an enclosing manner, having a small spacing in relation to the drum wall  9 . An annular chamber  12  for receiving the thread plug  6  is formed between the drum wall  9  and the cylinder wall  11 . The annular chamber  12 , on the upper end of the processing drum  8 , includes an inlet opening  13  and, on the lower end of the processing drum  8 , includes an outlet opening  14 . The inlet opening  13  is associated with a segment-shaped holding-down element  15  which acts on the windings of the thread plug  6  that have been deposited in the annular chamber  12 . The outer cylinder  10  is rotatably held by way of a bearing unit  19  on an upper support  20 . 
     The processing drum  8  and the stuffer box  3  and the conveyor nozzle  1  are implemented in an identical manner to the aforementioned exemplary embodiment as shown in  FIG. 1 , such that no further explanation is offered at this point in order to avoid any repetition. 
     In the exemplary embodiment illustrated in  FIG. 3 , the thread plug  6  is guided in a straight run from the plug outlet  4  of the stuffer box  3  into the annular chamber  12  on the circumference of the drum wall  9 . Setting of the windings of the thread plug on the circumference of the drum wall  9  here is substantially handled by the cylinder wall  11  of the outer cylinder  10 . The outer cylinder  10  here is driven via the processing drum  8  in the same direction of rotation. For temperature control, positive pressure is produced via the blower  17  in the interior of the processing drum  8 , such that a flow of cooling air permeates the windings of the thread plug  6  from the inside to the outside. 
     In the exemplary embodiment illustrated in  FIG. 3 , the rotational drive of the outer cylinder  10  takes place via the driven processing drum  8 . To this end, it is necessary for the windings of the thread plugs that are guided in the annular chamber  12  to be used for transmission of rotation. In order to be able to perform guiding of the thread plugs that is as unencumbered as possible, a further exemplary embodiment of the crimping apparatus according to the invention is shown in  FIG. 4 . In this exemplary embodiment of the crimping apparatus that is schematically shown in a cross-sectional view, the outer cylinder includes a dedicated rotational drive, such that both the drum wall  9  and the cylinder wall  11  are drivable in the same direction of rotation. 
     The exemplary embodiment in  FIG. 4  includes a conveyor nozzle  1  and a stuffer box  3  which are implemented in an identical manner to the aforementioned exemplary embodiments. 
     The processing unit  7  in this exemplary embodiment is disposed between an upper support  20  and a lower support  21 . The lower support  21  supports a processing drum  8  which has a cup-shaped drum wall  9 . The drum wall  9  is associated with an inner annulet  22  which, on the circumference, has a plurality of fluid ducts  23 . The fluid ducts  23  may be helically configured so as to be one groove or so as to be a plurality of grooves having connecting grooves. The fluid ducts  23  are coupled to a fluid infeed (not illustrated here). A temperature-controlled fluid, preferably a liquid, is guided within the fluid ducts  23 , such that the inside of the drum wall  9  is directly temperature controlled by way of the fluid. 
     The inner annulet  22  and the drum wall  9  are connected to the drive shaft  16 . The drive shaft  16 , on one free end, is coupled to an electric motor  27  via a rotational drive  25 . 
     On the upper support  20 , an outer cylinder  10  is rotatably held by way of a bearing unit  19 . The outer cylinder  10 , with one cylinder wall  11 , extends sleeve-like toward the drum wall  9  and, with the drum wall  9 , forms an annular chamber  12 . The annular chamber  12  includes an upper inlet opening  13  and a lower outlet opening  14 . The inlet opening  13 , over part of the circumference, is covered by a holding-down element  15 . To this end, the holding-down element  15  is held in the upper region of the annular chamber  12 . 
     A rotational drive  24  which is coupled to the electric motor  27  acts on the circumference of the outer cylinder  10 . In this exemplary embodiment, the rotational drive  24  is formed by an encircling crown gear  33  and a gear wheel  34  which is held on a motor shaft  26 . 
     The rotational drive  25  of the processing drum  8  is formed by a gear pair  35  which connects the drive shaft  11  with the motor shaft  26 . To this end, the motor shaft  26  extends axially parallel to the processing drum  8 . The electric motor  27  is disposed on the upper support  20  and directly coupled to the motor shaft  26 . 
     The rotational drives  24  and  25  are adapted in such a manner that, when rotating the motor shaft  26 , the cylinder wall  11  of the outer cylinder  10  and the drum wall  9  of the processing drum  8  can be operated without any speed differential. In this manner slippage-free guiding of the windings of the thread plug within the annular chamber  12  is possible. 
     For temperature control, a heating radiator  28  which enables temperature control, in this case being heating of the thread plug, in the region of the outlet opening  14  of the annular chamber  12  is associated with the lower end of the cylinder wall  11  on the lower support  21 . Thermal post-processing of this type may facilitate in particular setting of the crimp in the filaments. 
     The function of the exemplary embodiment as shown in  FIG. 4  is substantially identical to that of the exemplary embodiment as shown in  FIG. 3 . However, the exemplary embodiment as shown in  FIG. 4  is particularly suited to performing crimping at comparatively high speeds. On account of the synchronous drive in the drum wall  9  and the cylinder wall  11  gentle plug processing is also possible in the case of comparatively high speeds. 
     The exemplary embodiments illustrated in  FIGS. 3 and 4  include in each case an annular chamber  12  on the circumference of the processing drum  8  that is substantially formed by walls  9  and  11  which run parallel to one another. However, there is, in principle, also the possibility of configuring the annular chamber  12  having variable chamber cross sections on the circumference of the processing drum  8 . 
     A further exemplary embodiment of the crimping apparatus according to the invention is shown schematically in  FIG. 5  by means of a detail of a cross-sectional view of the processing unit  7 . In the exemplary embodiment illustrated in  FIG. 5  of the processing unit  7 , on the circumference of the processing drum  8  an annular chamber  12  is formed between the drum wall  9  and the cylinder wall  11  of the outer cylinder  10 . The cylinder wall  11  of the outer cylinder  10  here is configured so as to be a slightly truncated cone, such that a chamber cross section in the annular chamber  12  that tapers off in the axial direction is established. The annular chamber, in the region of the inlet opening  13 , includes a chamber cross section which is preferably larger than a diameter of the thread plug  6 . On the lower end of the outer cylinder  10  the annular chamber  12  preferably includes a chamber cross section which is smaller than the diameter of the thread plug. In this manner, it is possible, in particular, to perform a setting which is required for the disintegration of the thread plug. 
     It may be furthermore derived from the illustration in  FIG. 5  that the drum wall  9  and the cylinder wall  11  include in each case a plurality of fluid ducts  23  which in each case guide a temperature-controlled fluid for temperature control of the walls  9  and  11 . The possibility also exists here for the fluid ducts to be subdivided into a plurality of zones such that, for example, cooling of the thread plug sets in in an upper region of the annular chamber and heating of the thread plug sets in in a lower region of the annular chamber. 
     The exemplary embodiment illustrated in  FIG. 5  moreover offers the particular advantage that the windings of the thread plug  6  are guided on a smooth drum wall  9  and a smooth cylinder wall  11 . In this manner, undesirable drawing-in of individual filaments into sleeve openings is not possible. To this extent, the exemplary embodiment as per  FIG. 5  is, in particular, particularly suited to yarns having fine counts. 
     REFERENCE LIST 
     
         
           1  Conveyor nozzle 
           2  Fluid connector 
           3  Stuffer box 
           4  Plug outlet 
           5  Filament bundle 
           6  Thread plug 
           7  Processing unit 
           8  Processing drum 
           9  Drum wall 
           10  Outer cylinder 
           11  Cylinder wall 
           12  Annular chamber 
           13  Inlet opening 
           14  Outlet opening 
           15  Holding-down element 
           16  Drive shaft 
           17  Blower 
           18  Thread 
           19  Bearing unit 
           20  Upper support 
           21  Lower support 
           22  Inner annulet 
           23  Fluid ducts 
           24  Rotational drive of outer cylinder 
           25  Rotational drive of processing drum 
           26  Motor shaft 
           27  Electric motor 
           28  Heating radiator 
           29  Bearing 
           30  Guide duct 
           31  Housing 
           32  Suction duct 
           33  Crown gear 
           34  Gear wheel 
           35  Gear pair