Abstract:
The disclosure relates to a device for cleaning a functional surface for guiding or treating a material web, preferably a non-woven wed. The device includes a pivotably mounted roller body, a plurality of hollow cylindrical brush segments being disposed on the circumference thereof and positively connected to each other and tensioned between two adjusting rings disposed at the circumference of the roller body. According to various embodiments, in order to ensure secure tensioning of the brush segments regardless of the surrounding conditions, at least one of the adjusting rings is axially flexibly retained at the circumference of the roller body and a compression ring rotationally fixed to the flexible adjusting rings is axially tensioned against the roller body by means of at least one spring element, such that an axial force acting on the brush segments is generated.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application is a Continuation of PCT International Patent Application No. PCT/EP2010/061400 filed on Aug. 5, 2010, entitled “DEVICE FOR CLEANING A FUNCTIONAL SURFACE FOR GUIDING OR TREATING A MATERIAL WEB,” which claims priority to German Patent Application No. 10 2009 037 126.5 filed on Aug. 11, 2009, the contents and teachings of each of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a device for cleaning a functional surface for guiding or treating a material web. 
       BACKGROUND 
       [0003]    In the manufacture of fibrous nonwoven webs, in particular in an airlaid process in which a plurality of fiber pieces are shaped on a laydown belt to form a nonwoven web, fairly pronounced soiling appears on the functional surfaces for guiding or treating the nonwoven web due to the adherence of unbonded short fibers or dust particles. These types of functional surfaces, which may be provided on laydown belts, transport belts, calenders, or individual guide rollers, must therefore be continuously or intermittently cleaned to ensure product quality. It is generally known to use rotating brush segments for cleaning the functional surfaces. Such a device is known from DE 197 26 970 A1, for example. 
         [0004]    In the known device for cleaning a functional surface, multiple hollow cylindrical brush segments are adjacently situated on a roller body. The brush segments are connected to one another in a positive-fit manner in the axial direction and braced against one another at the ends of the roller body by attached adjusting rings. Thus, multiple brush segments may be situated on a roller body, resulting in a brush roller. 
       SUMMARY 
       [0005]    However, significant problems occur with the known device when it is used for cleaning a functional surface in an airlaid process. On the one hand, multiple brush segments for transmitting torque must be securely braced at the periphery of the roller body by means of the adjusting rings. On the other hand, the harsh operating conditions, in particular for use at fairly high surrounding temperatures, for example on a calender, result in differing expansions of the materials of the brush segments and roller bodies which are combined with one another within the device. Conditions thus occur which cause the adjusting rings to drift apart during operation, resulting in loosening of the individual brush segments. 
         [0006]    It would be desirable to provide a generic device for cleaning a functional surface for guiding or treating a material web, in which the brush segments may be securely held at the periphery of the roller body under all operating conditions. 
         [0007]    It would further be desirable to provide a device for cleaning a functional surface for guiding or treating a material web, in which multiple brush segments may be situated on a roller body in order to form a large working width. 
         [0008]    Thus, embodiments are provided for a device in which at least one of the adjusting rings is mounted in an axially movable manner at the periphery of the roller body, and a clamping ring which is connected to the movable adjusting ring in a rotationally fixed manner is axially braced against the roller body by means of at least one spring element in such a way that an axial tension force is generated which acts on the brush segments. 
         [0009]    Additional advantageous refinements are also provided. 
         [0010]    Embodiments have the advantage that during operation, relative motions between the roller body and the brush segments are possible due to differing material expansions. Loss of the tension force generated on the brush segments in the axial direction is thus avoided by means of the adjusting rings. Depending on the field of application, fairly high pretensioning may be produced for fixing the brush segments as a function of the selection of the spring element. As a result of the spring element, the brush segments remain in their predefined location at the periphery of the roller body. 
         [0011]    To allow the largest possible working widths using an appropriate plurality of brush segments, in one embodiment, the roller body has one of multiple spring-loaded clamping rings on both end faces, which are connected in a rotationally fixed manner to the movably mounted adjusting rings and which generate axial tension forces which act oppositely on the roller body. Even fairly large relative motions may thus be compensated for in order to hold the brush segments fixed in position at the periphery of the roller body. 
         [0012]    Since the torque is to be transmitted solely via the axial bracing between the adjusting rings and the brush segments, some embodiments offer the particular advantage that multiple coupling sites may be achieved between the roller body and the clamping ring in order to transmit the torque from the roller body toward the adjusting rings and the brush segments. Thus, the spring elements are formed by multiple disk spring assemblies or by multiple compression springs which are uniformly distributed at the end face of the roller body. The bracing and the connection of the clamping ring to the roller body are thus achieved by multiple fastening elements. 
         [0013]    To achieve transmission of the torque between the roller body and the clamping ring with as little play as possible, in one embodiment, the fastening elements are designed as screws for the rotationally fixed fastening of the clamping ring to an end wall of the roller body, the clamping ring having multiple drill bushings for accommodating the screws. Thus, high wear resistance during the transmission of torque is also achieved. 
         [0014]    The positive-fit connection between the brush segments and the adjusting rings as well as among the brush segments themselves may be established by toothing on each end face. The so-called Hirth serration has proven to be particularly suitable. 
         [0015]    Particularly large working widths may thus be achieved, so that, according to one embodiment, the brush segments at the periphery of the roller body are arranged together to form a brush width in the range of 2000 mm to 4000 mm. Such brush widths are particularly suitable for uniformly cleaning the functional surface of laydown belts and calender rollers over the entire working width in the manufacture of nonwovens. 
         [0016]    For accommodating and driving the roller body, the roller body may have stub axles, projecting at each end face, which are mounted on a roller support. At least one of the stub axles may be directly coupled to a drive. 
         [0017]    Depending on the application, and whether continuous or intermittent cleaning of the functional surface is desired, according to one embodiment, the roller support may have a movable design, so that the roller body is guidable between an operating position and a neutral position. This is particularly advantageous for the intermittent cleaning of functional surfaces. 
         [0018]    To obtain high stability in the holding and guiding of the brush segments over large working widths, the roller body may be formed by a double-tube shell having an inner tube and an outer tube which are connected to the stub axles at both end faces. A particularly lightweight design having high stability may be achieved in this way. 
         [0019]    The brush segments may be accommodated at the periphery of the roller body by a holding sleeve which has a surface that is adapted to the characteristics of the brush segments, so that, for example, individual brush segments may be quickly replaced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The invention is explained in greater detail below by means of several example embodiments of the device according to the invention, with reference to the accompanying figures, which show the following: 
           [0021]      FIG. 1  schematically shows an example device for manufacturing a nonwoven web, having multiple functional surfaces for guiding or treating a nonwoven web. 
           [0022]      FIG. 2  schematically shows a cross-sectional view of a first example embodiment of the device. 
           [0023]      FIG. 3  schematically shows a cross-sectional view of another example embodiment of the device. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]      FIG. 1  illustrates an example device for manufacturing a nonwoven web as used in an airlaid process. Such a device has multiple functional surfaces, which, in each case, are cleaned by the device according to various embodiments.  FIG. 1  shows only a small portion of the unit for manufacturing and treating the nonwoven web. Thus, a nonwoven web  2  formed from short fiber pieces is produced on the functional surface of a laydown belt  3 . For this purpose, a forming station  1  which lays the fiber pieces on the laydown belt  3  is associated with the laydown belt  3 . A suction unit  4  on the underside of the laydown belt  3  is associated with the forming station  1 . The laydown belt  3  is continuously driven, and is guided over the guide rollers  7 . The surface of the laydown belt  3  forms a functional surface  9  which is cleaned using the device according to various embodiments. In this regard, the cleaning device  8 . 1  is shown. The cleaning device  8 . 1  has a roller support  11  on which a roller body  10  is guided. By use of the roller support  11 , the roller body  10  may be guided into an operating position (as depicted in  FIG. 1 ) and into a neutral position which is provided at a distance from the laydown belt  3  (not depicted). In the operating position, the roller body  10  is mounted for cleaning the functional surface  9  of the laydown belt  3 . 
         [0025]    The nonwoven web  2  is led to a calender station  5  for bonding of the nonwoven web. In the present example embodiment, the calender station  5  is formed by two calender rollers  6 . 1  and  6 . 2 , between which a roller nip is formed for guiding and treating the nonwoven web  2 . At the sides opposite from the roller nip, cleaning devices  8 . 2  and  8 . 3 , according to various embodiments, are associated with the calender rollers  6 . 1  and  6 . 2 , respectively. In this case, the functional surfaces  9  are formed at the periphery of the calender rollers  6 . 1  and  6 . 2 , and are continuously cleaned by the cleaning devices  8 . 2  and  8 . 3 . 
         [0026]    The cleaning devices  8 . 1  through  8 . 3  illustrated in  FIG. 1  have an essentially identical design, which is explained below with reference to several specific example embodiments.  FIG. 2  schematically illustrates a first example embodiment of the device in a cross-sectional view, as would be usable, for example, as a cleaning device  8 . 1 ,  8 . 2 , or  8 . 3 . 
         [0027]    The device illustrated in  FIG. 2  has a roller body  10  which has a hollow cylindrical design, and which at each end is fixedly connected to a stub axle  12 . 1  and  12 . 2 , respectively. The ends of the stub axles  12 . 1  and  12 . 2 , which are not illustrated here in greater detail, are used for the rotatable bearing of the roller body  10  on a roller support, and for transmitting a torque which is generated by a drive which is coupled to at least one of the stub axles  12 . 1  and  12 . 2 . One of the stub axles  12 . 1  and  12 . 2  is therefore connected to a drive, not illustrated here. 
         [0028]    A cylindrical holding sleeve  15  is attached at the periphery of the roller body  10 . Multiple hollow cylindrical brush segments  13  are mounted at the periphery of the holding sleeve  15 . The brush segments  13  have an identical design, and include a circular brush  28  and a brush holder  29 . The brush holders  29  each have end-face toothing  16  at their end faces. The toothings  16  of the brush holders  29  intermesh, so that a positive-fit connection is present between the brush segments  13 . 
         [0029]    A first adjusting ring  14 . 1  is situated at the periphery of the holding sleeve  15  at the left end of the roller body. The adjusting ring  14 . 1  is fixedly connected to the roller body  10  via a fixing means  17 . The adjusting ring  14 . 1  likewise has toothing  16  on the end face facing the brush segment  13  which establishes a positive-fit connection to the adjacent brush segment  13 . 
         [0030]    An axially movable adjusting ring  14 . 2  is situated at the opposite end of the holding sleeve  15 . The adjusting ring  14 . 2  has toothing  16  on its end face facing the brush segment  13  which connects the adjusting ring  14 . 2  to the brush segments  13  in a positive-fit manner. A clamping ring  19  is situated at the opposite end of the adjusting ring  14 . 2 . The adjusting ring  14 . 2  is connected to the clamping ring  19  situated at the end face of the roller body  10 . For this purpose, via a shoulder the clamping ring  19  is fixedly connected directly to the adjusting ring  14 . 2  by multiple joining means  18 . The clamping ring  19  is axially adjustably held against an end wall  30  of the roller body  10  via multiple fastening elements  23 . A spring element  20  is clamped between the fastening element  23  and the clamping ring  19 , so that the clamping ring is pushed in the direction of the brush segments  13  as the result of an axially directed elastic force. In the present example embodiment, the fastening elements  23  are formed by multiple screws which are uniformly distributed at the end wall  30  of the roller body  10 . The spring elements  20  are formed by multiple compression springs  22  which, in each case, are clamped between a head of the screw  23  and a shoulder of the clamping ring  19 . As a result of the compression springs  22 , which are uniformly distributed at the face of the clamping ring  19 , an axial tension force is generated which acts on the adjusting ring  14 . 2  via the clamping ring  19 , and which thus braces the entire brush assembly of brush segments  13  against the opposite adjusting ring  14 . 1 . 
         [0031]    In the operating state, the roller body  10  is driven by the stub axles  12 . 1  and  12 . 2 . The torque is transmitted toward the adjusting rings  14 . 1  and  14 . 2  at both end faces of the roller body  10 , so that the entire assembly of brush segments  13  is rotationally driven. 
         [0032]    The transmission of torque to the adjusting ring  14 . 1  is ensured by the fixing means  17 . On the opposite side, the torque is transmitted to the adjusting ring  14 . 2  by the clamping ring  19  and the screws  23 . 
         [0033]    To allow cleaning of the largest possible working widths, preferably using a roller body and brush segments fastened thereto, the pretensioning produced by spring elements for fixing the brush segments is preferably provided at both end faces of the roller body  10 . In this regard,  FIG. 3  schematically shows one example embodiment of the device according to the invention in a cross-sectional view. The example embodiment according to  FIG. 3  has a double-tube shell  25  as a roller body  10  which is formed by an inner tube  26  and an outer tube  27  which encloses the inner tube  26  at a distance therefrom, the inner tube and the outer tube being connected at their free ends to the stub axles  12 . 1  and  12 . 2 . A holding sleeve on which the brush segments  13  are mounted is situated at the periphery of the double-tube shell  25 . The brush segments  13  have a design which is identical to the preceding example embodiment, so that no further explanation in this regard is provided here. 
         [0034]    For axially bracing the brush segments  13 , axially movable adjusting rings  14 . 1  and  14 . 2  are respectively situated at each end of the roller body  10 . A clamping ring  19 . 1  and  19 . 2  is associated with each of the adjusting rings  14 . 1  and  14 . 2 , respectively. The clamping ring  19 . 1  is coupled to the adjusting ring  14 . 1  in a rotationally fixed manner via a shoulder. For this purpose, multiple joining means  18  are distributed at the periphery of the clamping ring and fixedly connected to the adjusting ring  14 . 1 . 
         [0035]    The oppositely situated clamping ring  19 . 2  is coupled to the adjusting ring  14 . 2  in the same way. 
         [0036]    For the axial bracing, in the present example embodiment the spring elements are formed by multiple disk spring assemblies  21  which are held via multiple screws  23  for axially bracing the clamping ring  19 . 1 . The screws  23  are screwed into the end wall  30 . 1  of the roller body  10 , the disk spring assemblies  21  being tensioned in each case between a head of the screw  23  and a shoulder of the clamping ring  19 . 1 . 
         [0037]    A drill bushing  24  passes through the clamping ring  19 . 1 , concentrically with respect to the disk spring assemblies  21 , for accommodating the screw  23 . A drill bushing  24  in the clamping ring  19 . 1  is thus associated with each screw  23 . Thus, an essentially play-free connection for transmitting torque may be established between the roller body  10  and the clamping ring  19 . 1 . 
         [0038]    The clamping ring  19 . 2  is likewise coupled to the opposite end wall  30 . 2  via multiple screws  23  and drill bushings  24 . A disk spring assembly  21  is likewise associated with each of the screws  23 , so that an axially acting pretensioning force likewise results at the clamping ring  19 . 2  due to the disk spring assemblies  21 . 
         [0039]    As a result of the clamping rings  19 . 1  and  19 . 2 , the oppositely acting axial tension force is introduced at the adjusting rings  14 . 1  and  14 . 2 , respectively, which brace the brush segments  13  at the periphery of the holding sleeve  15 . It is important that relatively high torques are transmittable to the brush segments  13  due to the connection of the clamping rings  19 . 1  and  19 . 2  by multiple uniformly distributed fastening elements  23 . In this regard, the example embodiment according to  FIG. 3  is particularly suited for removing especially stubborn soiling on the functional surfaces. 
         [0040]    The example embodiments of the device according to the invention illustrated in  FIGS. 2 and 3  are particularly suited for continuously or intermittently cleaning the functional surfaces illustrated in  FIG. 1 . The characteristics of the brush segments, in particular of the circular brushes, are individually selectable, depending on the type of soiling or the type of functional surfaces that are present. Thus, such devices may even be used for cleaning screen cloth strips in dryers, where the surrounding temperature is approximately 90° C., and the brush segments are held in continuous linear contact with a screen cloth strip surface having a surface temperature of 200° C. Similar conditions are also present during cleaning of the functional surfaces on calender rollers, which typically have a surface temperature of above 100° C. Self-heating of the roller body has no effect on the bracing and torque transmission of the individual brush segments. 
         [0041]    While various embodiments of the invention have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. 
         [0042]    It should be understood that all embodiments which have been described may be combined in all possible combinations with each other, except to the extent that such combinations have been explicitly excluded. 
         [0043]    Finally, nothing in this Specification shall be construed as an admission of any sort. Even if a technique, method, apparatus, or other concept is specifically labeled as “prior art” or as “conventional,” Applicant makes no admission that such technique, method, apparatus, or other concept is actually prior art under 35 U.S.C. §102, such determination being a legal determination that depends upon many factors, not all of which are known to Applicant at this time. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           1  Forming station 
           2  Nonwoven web 
           3  Laydown belt 
           4  Suction unit 
           5  Calender station 
           6 . 1 ,  6 . 2  Calender rollers 
           7  Guide rollers 
           8 . 1 ,  8 . 2 ,  8 . 3  Cleaning device 
           9  Functional surface 
           10  Roller body 
           11  Roller support 
           12 . 1 ,  12 . 2  Stub axle 
           13  Brush segments 
           14 . 1 ,  14 . 2  Adjusting ring 
           15  Holding sleeve 
           16  Toothing 
           17  Fixing means 
           18  Joining means 
           19 ,  19 . 1 ,  19 . 2  Clamping ring 
           20  Spring element 
           21  Disk spring assembly 
           22  Compression spring 
           23  Fastening element, screw 
           24  Drill bushing 
           25  Double-tube shell 
           26  Inner tube 
           27  Outer tube 
           28  Circular brush 
           29  Brush holder 
           30 . 1 ,  30 . 2  End wall