Abstract:
A disperser plate segment for removing contaminants from fiber stock, the segment comprising: radially inner and outer edges, multiple radially concentric rows of teeth, each row of teeth having multiple teeth defining multiple channels disposed intermediate the teeth, each of the channels having a lower channel base surface and each of the teeth having a top surface, at least one face surface extending from the channel base surface to the top surface, and wherein at least one of the face surfaces comprises at least two grooves.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority to and incorporates by reference U.S. Provisional Application Ser. No. 61/746,011, filed Dec. 26, 2012. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to disperser plate segments. 
       BACKGROUND OF THE INVETNION 
       [0003]    Recovered paper and packaging materials are known as “fiber stock” to those skilled in the art. Fiber stock is generally subjected to several processes designed to remove ink and toner in the case of copy paper. Contaminants such as plastics generally referred to as “stickies” by those skilled in the art. The removal processes are not completely efficient and the residual ink, toner, and stickies are typically dispersed to avoid the stickies adhering to parts of the paper machine, which can cause holes or weak spots in new paper. The agglomeration and accumulation of stickies on the paper machine can cause idle time thereby increasing the cost of the manufacturing process itself. Residual ink particles typically appear as specs in the reconstituted paper, which can lower its value considerably. 
         [0004]    A machine called a disperser (or a disperger) can be used to reduce the size of the ink and stickie particles so that in subsequent paper machine operations, paper qualities may be minimally impacted. Disperser machines generally have two circular discs facing each other. One disc, generally referred to as a rotor, can be rotated while the other disc, generally referred to as a stator, is generally stationary. Conical machines can also be used where a rotor cone can move while a stator cone generally remains stationary. 
         [0005]    On the faces of the discs or cones may be mounted plate segments having pyramids or teeth mounted in tangential rows. The rows are at radii generally chosen to allow the rotor and stator teeth to intersect a plane between the discs or cones so that the fiber passing from the center of the stator to the periphery of the discs or cones generally receives impacts from the rotor teeth as they pass close to the stator teeth. The clearance between rotor and stator teeth is on the order of about 1 to about 12 mm so that the fibers are generally not cut but rather are typically severely and alternately flexed. This action usually breaks the ink and toner particles into smaller particles and also breaks down the stickie particles. It is also generally thought that the fresh smaller sticky surfaces collect fine fiber particles and may be further passivated as smaller particles. Increasing the number of flexures the fibers experience has generally been shown to improve the unwanted particle reduction process. Adding more teeth generally improves the efficiency of the dispersion process but the size of the teeth that can be manufactured at reasonable costs limits this number. A conventional disperser plate is described in U.S. Pat. No. 7,172,148 where a single groove extends from the tooth top surface to a point intermediate the top surface and the channel base surface. 
         [0006]    For conical dispersers, where the cones contain the pyramids or teeth, the same action usually occurs and the designs of the teeth are substantially the same as those for flat discs. 
       SUMMARY OF THE INVENTION 
       [0007]    The efficiency of dispersion may be improved and the amount of ink, toner, and stickies entering a paper-making machine may be reduced by increasing the number of edges that contact the fiber stock. By configuring grooves into one or more sides of the teeth, the amount of contact edges may be increased while substantially maintaining the structural integrity of the teeth. The plane defined by sides of the teeth may be known as “face surfaces” throughout this disclosure. 
         [0008]    A disperser plate segment for removing contaminants from fiber stock, the segment comprising: radially inner and radially outer edges, multiple radially concentric rows of teeth, each row of teeth having multiple teeth defining multiple channels disposed intermediate the teeth, each of the channels having a lower channel base surface and each of the teeth comprising: an top surface, at least one face surface extending from the channel base surface to the top surface, and wherein at least one of the face surfaces comprises at least two grooves. 
         [0009]    At least one tooth may have multiple grooves on at least one of its surfaces. The additional grooves to the faces surfaces of the tooth may help to increase circumferential friction applied to the material in between the intermeshing row of teeth thereby improving separation of the contaminants from the desired material. By using a groove angled relative to the vertical axis of the face of the tooth surface, the angled groove may help to redirect material along the axis of the height of the teeth, as the teeth move material vertically between the channel base surface and the tooth top surface. 
         [0010]    The inner and outer surfaces of each tooth may extend at an acute angle from the channel base surface to the top surface, such that the tooth may have a truncated pyramid shape. With multi-grooved teeth, a segment of the top surface may separate the inner face and outer face surface grooves from each other when the grooves extend to the top surface of the tooth. Additionally, for multi-grooved teeth, a segment of the top surface may separate the grooves along a face surface; this face surface may be an inner face surface or outer face surface. In some example embodiments, the face surface may be the side surfaces of the teeth that define a channel between two teeth. 
         [0011]    In some exemplary embodiments, the grooves on the inner face surface and outer face surface may be tapered. For example, for at least one of the grooves, the width of the groove may taper outward on the face surface from the top surface toward the channel base surface. In another example embodiment, the depth of the groove may taper from the face surface into or inward to the tooth mass as the groove extends from the top surface toward the channel base surface. In example embodiments involving a tapered groove, a segment of the top surface may separates the inner face and outer face surface grooves from each other. 
         [0012]    In some embodiments the width of at least one of the grooves may change along its length. For example, at least one of the grooves may taper outwardly on the tooth face surface. In other exemplary embodiments, the depth of at least one of the grooves may change along its length. For example, the depth of at least one of the grooves may taper inward into the tooth face surface as the groove extends across the tooth face surface toward the channel base surface. In some exemplary embodiments, the grooves may not connect with each other through the teeth. In other exemplary embodiments, it is possible to have at least two of the grooves connect. 
         [0013]    Each of the teeth may also have oppositely disposed leading and trailing edges. The grooves of the inner face surface of each tooth and the grooves of the outer face surface of each tooth may define additional leading edges and additional trailing edges. 
         [0014]    In an exemplary embodiment of this disclosure, multiple grooves on the inner face or outer face surfaces of the teeth may extend the substantially similar lengths between the top surface and the channel base surface, that is from the top surface to a point intermediate the top surface and the channels base surface. 
         [0015]    In another example embodiment of this disclosure, multiple grooves on the inner face surface or outer face surface of the teeth may extend the same lengths between the top surface and the channel base surface; for example, at least one of the grooves may extend from the tooth top surface to or substantially to the channel base surface. 
         [0016]    In another example embodiment of the disclosure, multiple grooves on the inner face surface or outer face surface of the teeth may extend different lengths between the top surface and the channel base surface. For example, one or more grooves may extend from the top surface to the channel base surface, and one or more grooves may extend from the top surface to a groove lower most end point intermediate the top surface and the channel base surface, and one or more groves may extend from the channel base surface upward toward—but not to—the top surface, and one or more grooves can extend from below the top surface to a point intermediate the channel base surface. 
         [0017]    In yet another embodiment, widths of the individual grooves on the inner face surface or outer face surface of teeth may vary. The widths of the individual grooves on the inner face surface or outer face surface may also vary among any individual tooth. For example, one groove may have a wider width than the remaining grooves on the face surface of the tooth. The lengths of each of the grooves, whether wide or narrow may be any of the previously identified lengths, e.g. the entire length from the top surface to the channel base surface or the length from the top surface to a point intermediate the top surface and the channel base surface or the length from the channel base surface to a point below the top surface. Moreover, one or more grooves can extend from below the top surface to a point intermediate the channel base surface. 
         [0018]    In still another embodiment of the disclosure, the multiple tapered grooves of varying lengths (as described previously) may exist on the inner face surface or the outer face surface of the teeth. 
         [0019]    In another embodiment of the disclosure, the grooves on the inner face surface or outer face surface may be angled relative to the vertical axis of the face of the tooth surface and each groove may be the same length or may be different lengths. The angled grooves may be the same width or different widths and may have tapering. Both the width and depth of the groove may be tapered. Conversely, either the width or depth of the groove may be tapered. The angle of the grooves may be about 5 degrees to about 60 degrees. 
         [0020]    A disperser plate segment for removing contaminants from fiber stock has been conceived, the segment comprising: radially inner and outer edges and multiple of radially concentric rows of teeth; each row of teeth having multiple teeth defining multiple channels disposed intermediate the teeth; each of the channels having a lower channel base surface and each of the teeth comprising: a top surface, at least one face surface extending from the channel base surface to the top surface, the at least one face surface defining at least two grooves at an angle θ relative to the vertical axis of the face surface. 
         [0021]    It is also possible to have the inner face surface with one embodiment of the disclosure and the outer face surface with a different embodiment or both the inner face and outer face surfaces may use the same embodiment of the disclosure. In yet another embodiment, any combination of previously described grooves on any of the surfaces of the teeth may be used. 
         [0022]    A disperser plate comprising: multiple radially concentric rows of teeth, wherein each row may be configured to mesh between rows of teeth on an opposing plate; adjacent teeth of the radially concentric rows defining channels between the adjacent teeth, wherein the channels each are aligned with a respective row of teeth on the opposing plate, and multiple grooves on a face surface of each of the teeth in at least one of the concentric rows. 
         [0023]    Additionally, the disperser plate may be segmented into disperser plate segments. In some embodiments, the disperser plate may have the teeth in at least one of the concentric rows each having an upper surface and the grooves extend from one of the channels to the top surface of the respective tooth. In at least some of the embodiments of the disperser plate, the depth of at least one of the grooves on each of the teeth may vary along the length of the groove. In some embodiments, the groove extends only partially along the height of the tooth and the grooves may be parallel. In other embodiments the grooves are oblique to a plane of rotation of the disperser plate. In at least some embodiments, the width of at least one of the grooves on each tooth differs from the width of another one of the grooves on the tooth. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The foregoing will be apparent from the following more particular description of example embodiments of the disclosure, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, with emphasis instead being placed upon illustrating embodiments of the disclosed device. 
           [0025]      FIGS. 1   a ,  1   b , and  1   c  show a conventional disperser with plate segments. 
           [0026]      FIG. 2  shows an exemplary face view of a tooth with multiple grooves of similar length and width. 
           [0027]      FIG. 3  shows an exemplary face view of a tooth with multiple grooves having differing lengths. 
           [0028]      FIG. 4  shows an exemplary face view of a tooth with multiple grooves having differing widths. 
           [0029]      FIG. 5  shows an exemplary face view of a tooth having a groove with a tapered width. 
           [0030]      FIG. 6  shows an exemplary face view of a tooth having a groove with a tapered depth. 
           [0031]      FIG. 7  shows an exemplary top view of the tooth having an asymmetrical shape to the depth tapering. 
           [0032]      FIG. 8  is the mirror image of  FIG. 6 . 
           [0033]      FIG. 9  shows an exemplary top view of the tooth with multiple grooves having different shapes. 
           [0034]      FIG. 10  shows an exemplary face view of a tooth with angled grooves. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Increasing the number of contact edges available for the material may improve the breaking down of the contaminants and stickies in the fiber stock and may improve the efficiency of a disperser machine. 
         [0036]    A disperser plate segment according to any of the embodiments of the disclosure has at least one of the teeth of the inner face surface or outer face surface comprising at least two grooves. The teeth with at least two grooves can be any combination of groove lengths, groove widths, groove shape, tapered width grooves, tapered depth grooves, or angled grooves on the inner face surface or outer face surfaces. 
         [0037]    Although the grooves are depicted as ovular, cylindrical, or conical in the figures, the grooves may have triangular, pyramidal, or quadrilateral shapes in other embodiments. 
         [0038]      FIGS. 1   a ,  1   b , and  1   c  show a conventional plate segment  10  for a disperser. In  FIG. 1   a , the conventional plate segment  10  is a stator plate segment  15 . Each conventional plate segment  10  is typically a molded metal piece formed as a pie-shape, such as an annularly truncated wedge-shape, having a generally planar substrate. However, the conventional plate segment  10  may be circular or semi-circular and the substrate may be conical or partially conical. Each conventional plate segment  10  has an inner edge  22  towards the common center axis  19  of the disc to which the conventional plate segment  10  may be attached (disc not shown). Each conventional plate segment  10  also has an outer edge  24  near the periphery of the disc to which the conventional plate segment  10  may be attached (disc not shown). Each conventional plate segment  10  has concentric rows  26  of teeth  28 . People skilled in the art may refer to the teeth  28  as pyramids. The concentric rows  26  of teeth  28  are each at a common radial distance (see radii  32 ) from the common center axis  19 . 
         [0039]      FIG. 1   b  is a cross-sectional view of one of the stator plate segment  15 . As the fiber stock (not shown) contacts the stator plate segment  15  near the inner edge  22  of the stator plate segment  15 , the fibrous material may flow over concentric rows  26  of teeth  28  towards the outer edge  24  of the stator plate segment  15 . 
         [0040]      FIG. 1   c  is a cross-sectional view of a rotor disc  12  and a stator disc  13  arranged opposite to each other. The stator disc  13  has an annular array of the stator plate segments  15  and a rotor disc  12  has an annular array of rotor plate segments  14 . 
         [0041]    The teeth  28  on rotor plate segments  14  intermesh with the rows of teeth on the array of stator plate segments  15 , as is shown in  FIG. 1   c . The intermeshing teeth  28  intersect a radially extending plane in the gap  30  between rotor disc  12  and stator disc  13 . 
         [0042]    The array of rotor plate segments  14  on the rotor disc  12  and the array of stator plate segments  15  on the stator disc  13  generally rotate about a common center axis  19 . 
         [0043]    As the rotor disc  12  rotates, fiber stock (not shown) generally moves through the serpentine gap  30  between the arrays of stator plate segments  15  and rotor plate segments  14  as a pad of fiber material. The flexing and bending of the fiber stock as the pad moves over and between the teeth  28  dislodges stickies from fibers in the fiber stock. 
         [0044]    The rotation of the rotor disc  12  and the rotor plate segments  14  apply a centrifugal force that moves the fiber stock straight through the gap  30  between the opposing arrays of plate segments. As the fiber stock moves radially beyond the outer edges  24  of the rotor plate segments  14  and stator plate segments  15 , the fiber stock enters a casing  31  of the disperser. 
         [0045]    For similar elements, similar reference numbers are used for the remaining figures.  FIG. 2  shows a face surface  140  of a tooth  100  having grooves  110  of substantially the same length. The grooves  110  can extend from the top surface  120  of the tooth  100  to the channel base surface  130  The width  150  and depth  160  of each groove  110  may be similar or substantially the same. 
         [0046]      FIG. 3  shows a face surface  240  of a tooth  200  having grooves  210  of differing lengths. The grooves  210  may extend from the top surface  220  to the channel base surface  230  or from the top surface  220  to a point  255  intermediate the top surface  220  and the channel base surface  230  or from the channel base surface  230  to a point below the top surface  220 , or one or more grooves  210  can extend from below the top surface  220  to a point intermediate the channel base surface  230 , or any combination with at least one of the grooves  210  being a different length from the other grooves  210 , with the width  250  and depth of all grooves  210  being the same or substantially the same. 
         [0047]      FIG. 4  shows face surface  340  of a tooth  300  having grooves  310  of the same lengths. In other embodiments, the lengths of the grooves may be different. The grooves  310  may extend from the top surface  320  to the channel base surface  330  or from the top surface  320  to a point intermediate the top surface and the channel base surface  330  or from the channel base surface  330  to a point below the top surface  320 , or one or more grooves  310  can extend from below the top surface  320  to a point intermediate the channel base surface  330 , or any combination with at least one of the grooves being a different length from the other groove or grooves  310 , with at least one of the grooves  310  being a different width  350  from the other groove or grooves  310 . The depth  360  of the groove  310  into the tooth  300  may vary, e.g., linearly, in a direction towards the top of the tooth or in an opposite direction. Further, the depth  360  of the grooves  310  may vary from groove  310  to groove  310  on the same tooth  300 . 
         [0048]      FIG. 5  shows face surface  440  of a tooth  400  having a single groove  410 . Groove  410  may have a width  450 , which tapers from narrowest point at or near the top surface  420  and widest at or near the channel base surface  430 . There may be grooves  410  that have widths  450  tapering along the face surface  440 , while the depth  460  and lengths of the grooves  410  may remain constant or the depths  460  of the grooves may remain constant while the lengths of the grooves may vary. 
         [0049]      FIG. 6  shows face surface  540  of a tooth  500  having a single groove  510 . Groove  510  has a first depth  560  which tapers from the top surface  520  to a second depth  570  at the lowest point of the groove  510 . The first depth  560  may be measured as the distance between the face surface  540  and the top internal backside  580  of the groove  510  at the top surface  520 . The lowest point of the groove  510  may be the point closest to the channel base surface  530 . The second depth  570  may be measured as the distance from the face surface  540  and the lowermost internal backside  590  of the groove  510 . The tapering of the groove  510  may increase from the first depth  560  to the second depth  570  and can be for example about 1 mm to about 10 mm, or possibly about 2 mm to about 10 mm, or possibly about 1 mm to about 3 mm, or possibly about 2 mm to about 5 mm and any dimension in between. There may be grooves  510  with varying tapered depths where the first depth  560  and the second depth  570  can be the same for each groove  510  or can be different for each groove  510 . In addition to having different depths in the grooves  510 , the depth of each groove  510  may taper. Further, the length of the grooves  510  on the face surface  540  may vary as the first depth  560  and second depth  570  varies. There may be a lowest most point of the groove  510  at or near the channel base surface  530  while the upper end of the groove  510  may be located at any point between the channel surface base  530  and the top surface  520 , or the groove  510  may extend from the top surface  520  to a point intermediate the channel base surface  530 , or have the groove  510  located along the face surface  540  but not extend to either the top surface  520  or the channel base surface  530  while having at least one groove  510  with a first depth  560  and a second depth  570 . While not shown in  FIG. 6 , the depth of the groove may be greater in the top of a tooth  500  as compared to bottom of the tooth  500 . 
         [0050]      FIG. 7  shows a top view of a tooth  600  having an asymmetrical shape to the depth tapering. On the left side  612  of the opening  621 , the angle from the face surface  640  to the innermost point of the groove  655  may be shallow and sharp such as less than about 90 degrees. On the right side  613 , the angle from the face surface  640  to the innermost point of the groove  655  may be about 90 degrees. In some embodiments, the angles from the front surface  640  to the innermost point of the groove  655  may by symmetrical. In other embodiments, the angles from the front surface  640  to the innermost point of the groove  655  may be asymmetrical. 
         [0051]      FIG. 8  shows a top view of a tooth  700  having an asymmetrical shape to the depth tapering a mirror image of  FIG. 7 . On the right side  712  of the opening  721 , the angle from the face surface  740  to the innermost point of the groove  755  may be shallow and sharp, such as less than about 90 degrees. On the left side  713 , the angle from the face surface  740  to the innermost point of the groove  755  may be about 90 degrees. In some embodiments, the angles from the front surface  740  to the innermost point of the groove  755  may by symmetrical. In other embodiments, the angles from the front surface  740  to the innermost point of the groove  755  may be asymmetrical. 
         [0052]      FIG. 9  shows a top view of a tooth  800  when multiple grooves are used and may be any combination of the shapes shown in  FIGS. 7 and 8 . As shown in  FIG. 9 , opening  821  has the shape of the opening  621  (from  FIG. 7 ). On the first shallow side  818 , the angle from the face surface  840  to the innermost point of the groove  855  may be shallow and sharp such as less than about degrees. On the sharp side  813 , the angle from the face surface  840  to the innermost point of the groove  855  may be about 90 degrees. Opening  822  has the shape of opening  721  (from  FIG. 8 ). On the second shallow side  812 , the angle from the face surface  840  to the innermost point of the groove  855  may be shallow and sharp such as less than about 90 degrees. On the sharp side  813 , the angle from the face surface  840  to the innermost point of the groove  855  may be about 90 degrees. In other embodiments, grooves using at least one of the configurations from  FIG. 7  or  8  may be used for at least one of the teeth. 
         [0053]      FIG. 10  shows face surface  940  of a tooth  900  having a top surface  920 , a channel base surface  930 , and grooves  910 . The grooves  910  are positioned at an angle θ of between about 5 degrees and about 60 degrees. In other example embodiments, angle θ may be between about 10 degrees and about 60 degrees, or possibly about 30 degrees and about 60 degrees relative to the vertical axis of the face surface  940  of the tooth  900 . In some example embodiments, the angle θ may vary between at least one groove on the same tooth. In some example embodiments, the angle θ may vary among at least one groove on a different tooth on the disperser. The angle θ may allow edges of the grooves to engage fiber stock at different angles thereby increasing the number of edges that contact the fiber stock and altering the direction of the fiber stock in a manner that may improve dispersion. By contrast, the angle θ for conventional grooves in conventional disperser plate teeth is about zero degrees. Grooves  910  are shown as having differing lengths  965  and the same widths  950 . In some example embodiments, grooves  910  may also have the same depths (not shown). The grooves  910  may have differing widths  950  and the same lengths  965  and the same depths. In other example embodiments, the grooves  910  may have the same widths and differing heights. In another exemplary embodiment, the length of at least of the grooves may extend through the side face surface of at least one tooth. In some embodiments, the widths  950  of grooves  910  could taper from narrow to wide as grooves  910  move across the face surface  940 . In some embodiments, the depth may taper from shallow to deep as grooves  610  move across the face surface  940 . Combinations of the above embodiments are also possible. 
         [0054]    While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.