Patent Publication Number: US-7581569-B2

Title: Screen for a vibratory separator having wear reduction feature

Description:
FIELD OF THE INVENTION 
   The invention relates to a screen for a vibratory separator comprising a woven wire cloth having a plurality of warp wires arranged substantially parallel to each other that define openings in the woven wire cloth and a plurality of weft wires that extend substantially perpendicular to the warp wires that are woven through the warp wires in groups at spaced intervals. 
   BACKGROUND 
   Screens mounted on vibratory separators are typically used by quarries to separate loose or suspended materials by grade and/or size. The screen typically consists of a woven wire cloth having a plurality of warp wires arranged and configured to form a plurality of openings therein. A plurality of fill or weft wires are woven through the warp wires to maintain the warp wires in spaced relation to each other. Each of the warp and weft wires has a substantially round cross-section. As the screen is vibrated, the material having a smaller size than the openings in the woven wire cloth is passed through the openings in the woven wire cloth, and the material having a larger size than the openings in the woven wire cloth are guided over and off of a top surface of the woven wire cloth onto a pile by the weft wires. 
   In the above described screen, problems occur in that the material that is to be separated gradually wears down the material of the warp and weft wires thereby altering the dimensions of the warp and weft wires. For example, when the dimensions of the warp wires are altered, the dimensions of the openings in the woven wire cloth are also altered causing the woven wire cloth to improperly separate the material passing through the openings. Additionally, when the dimensions of the weft wires are altered, the weft wires are unable to properly secure the warp wires in spaced relation to each other. 
   It is therefore desirable to provide a screen for a vibratory separator wherein wear of the warp and/or weft wires of the woven wire cloth is prevented so that the weft wires are able to properly secure the warp wires in spaced relation to each other and the volume of flow of the material through the openings in the woven wire cloth is not impeded. 
   BRIEF SUMMARY 
   A screen for a vibratory separator comprises a woven wire cloth extending in a substantially flat plane. The woven wire cloth has a plurality of warp wires and a plurality of weft wires. Each of the warp wires and each of the weft wires have a cross-section with a height extending substantially perpendicular to the plane of the woven wire cloth and a width extending substantially parallel to the plane of the woven wire cloth. The warp wires are arranged substantially parallel to each other and define openings in the woven wire cloth for the passage of material there through. The height of each of the warp wires is larger than the width of each of the warp wires. The weft wires extend substantially perpendicular to the warp wires. The weft wires are woven through the warp wires in groups at spaced intervals. The height of each of the weft wires is smaller than the width of each of the weft wires. 
   A screen for a vibratory separator further comprises a woven wire cloth extending in a substantially flat plane. The woven wire cloth has a plurality of warp wires and a plurality of weft wires. The warp wires are arranged substantially parallel to each other and define openings in the woven wire cloth for the passage of material there through. The warp wires are flattened substantially perpendicular to the plane of the woven wire cloth. The weft wires extend substantially perpendicular to the warp wires. The weft wires are woven through the warp wires in groups at spaced intervals. The weft wires being flattened substantially parallel to the plane of the woven wire cloth. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a screen for a vibratory separator according to a first embodiment of the invention. 
       FIG. 2  is a section view taken along line  2 - 2  of the screen of  FIG. 1 . 
       FIG. 3  is a section view taken along line  3 - 3  of the screen of  FIG. 1 . 
       FIG. 4  is a perspective view of a screen for a vibratory separator according to a second embodiment of the invention. 
       FIG. 5  is a perspective view of a screen for a vibratory separator according to a third embodiment of the invention. 
       FIG. 6  is a perspective view of a screen for a vibratory separator according to a fourth embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     FIGS. 1-3  show a screen  1  for a vibratory separator according to a first embodiment of the invention. As shown in  FIG. 1 , the screen  1  comprises a woven wire cloth  2 . The woven wire cloth  2  extends in a substantially flat plane and includes a plurality of warp wires  4  and a plurality of fill or weft wires  5 . The warp wires  4  are disposed substantially in a common plane and are arranged substantially parallel to each other. Each of the warp wires  4  has a substantially wave shape formed by a succession of substantially straight portions  7  connected together by oppositely bent portions  8 . The warp wires  4  are arranged such that the bent portions  8  of the warp wires  4  substantially oppose each other and every other one of the warp wires  4  is inverted by about 180 degree with respect to an adjacent one of the warp wires  4  in a direction of width W of the woven wire cloth  2 . The warp wires  4  thereby form openings  6  having a substantially diamond shaped configuration. 
   As shown in  FIG. 3 , each of the warp wires  4  has a substantially elliptical or oval cross-section. Each of the warp wires  4  has a height  9  extending substantially perpendicular to the substantially flat plane of the woven wire cloth  2  and a width  10  extending substantially parallel to the substantially flat plane of the woven wire cloth  2 . The height  9  of each of the warp wires  4  is greater than the width  10  of each of the warp wires  4 . The height  9  of the warp wires  4  is about 30-40% greater than the width  10  of the warp wires  4 . The height  9  of the warp wires  4  may be about 0.072-0.312 inches, and the width  10  of the warp wires  4  may be about 0.054-0.225 inches. The warp wires  4  may be, for example, shaped wires that have been flattened by rolling or by being drawn through a flattening die. For example, with regard to the warp wires  4 , sides  3  of the warp wires  4 , which extend substantially perpendicular to the plane of the woven wire cloth  2 , would be substantially flattened so that the height  9  of each of the warp wires  4  is greater than the width  10  of each of the warp wires  4 . Thus, a substantially round wire having a diameter of 0.105 inches could be flattened to have the height  9  of 0.125 inches and the width  10  of 0.092 inches. The warp wires may be made, for example, from ferrous or non-ferrous steel. 
   As shown in  FIG. 1 , the weft wires  5  are disposed substantially in a common plane and are arranged substantially parallel to each other. The weft wires  5  extend substantially perpendicular to the warp wires  4 . The weft wires  5  are woven through the warp wires  4  in groups  14  that are arranged at spaced intervals. The number of the groups  14  of the wefts wires  5  and the number of weft wires  5  in each of the groups  14  may vary depending on dimensions and desired configuration of the woven wire cloth  2 . The weft wires  5  may be woven through the warp wires  4 , for example, by a double or triple heddle loom. The weft wires  5  maintain the warp wires  4  in spaced relation to each other. Alternatively or in addition to the weft wires  5 , the warp wires  4  may be maintained in spaced relation to each other by molding the warp wires  4  together at spaced intervals. The warp wires  4  may be molded together, for example, with a polyurethane or rubber material. 
   As shown in  FIG. 2 , each of the weft wires  5  has a substantially elliptical or oval cross-section. Each of the weft wires  5  has a height  11  extending substantially perpendicular to the substantially flat plane of the woven wire cloth  2  and a width  12  extending substantially parallel to the substantially flat plane of the woven wire cloth  2 . The height  11  of each of the weft wires  5  is smaller than the width  12  of each of the weft wires  5 . The width  12  of the weft wires  5  is about 30-40% greater than the height  11  of the weft wires  5 . The width  12  of the weft wires  5  may be about 0.072-0.312 inches, and the height  11  of the weft wires  5  may be about 0.054-0.225 inches. The weft wires  5  may be, for example, shaped wires that have been flattened by rolling or by being drawn through a flattening die. For example, with regard to the weft wires  5 , sides  13  of the weft wires  5 , which extend substantially parallel to the plane of the woven wire cloth  2 , would be substantially flattened so that the height  10  of each of the weft wires  5  is smaller than the width  12  of each of the weft wires  5 . Thus, a substantially round wire having a diameter of 0.105 inches could be flattened to have the width  12  of 0.125 inches and the height  11  of 0.092 inches. The weft wires  5  may be, for example, made from ferrous or non-ferrous steel. 
   Holding members (not shown) are arranged on ends  15  of the warp wires  4 . The holding members (not shown) extend along the direction of width W of the woven wire cloth  2  and maintain the warp wires  4  under tension along a direction of length L of the woven wire cloth  2 . It will be appreciated by those skilled in the art that any holding member that is well known in the art that is configured to maintain the warp wires  4  under tension along the direction of length L of the woven wire cloth  2  may be used. 
   When the screen  1  is mounted on a vibratory separator (not shown), the vibratory separator (not shown) imparts vibrations on the screen  1  so that a material (not shown) that is to be separated either flows through the openings  6  in the woven wire cloth  2  or is guided over and off of a top surface of the woven wire cloth  2  onto a pile by the weft wires  5 . Because the surface of the warp wires  4  that is exposed to the most wear is the width  10  of the warp wires  4  and the width  10  of the warp wires  4  is reduced, the warp wires  4  are more resistant to wear. Thus, the separation of the material (not shown) passing through the openings  9  is less likely to be altered over the life of the screen  1 . Further, because the surface of the weft wires  5  that is exposed to the most wear is the height  11  of the weft wires  5  and the height  11  of the weft wires  5  is reduced, the weft wires  5  are more resistant to wear. Thus, the weft wires  5  are able to properly secure the warp wires  4  in spaced relation to each other. 
     FIG. 4  shows a screen  101  for a vibratory separator according to a second embodiment of the invention. As shown in  FIG. 4 , the screen  101  comprises a woven wire cloth  102 . The woven wire cloth  102  is identical to the woven wire cloth  2  of the first embodiment, except the warp wires  104  are arranged with respect to each other such that the bent portions  108  of the warp wires  104  substantially oppose each other to form openings  106  having a substantially wave shaped configuration. Because the assembly and method of use of the woven wire cloth  102  is the same as the assembly and method of use of the woven wire cloth  2  of the first embodiment, further description thereof will not be provided herein. 
     FIG. 5  shows a screen  201  for a vibratory separator according to a third embodiment of the invention. As shown in  FIG. 5 , the screen  201  comprises a woven wire cloth  202 . The woven wire cloth  202  is identical to the woven wire cloth  2  of the first embodiment, except that the warp wires  4  consist of a plurality of substantially straight warp wires  204   a  and a plurality of substantially wave shaped warp wires  204   b . The substantially wave shaped warp wires  204   b  are formed by a succession of substantially straight portions  207  connected together by oppositely bent portions  208 . The warp wires  204  are arranged such that the substantially straight warp wires  204   a  alternate with the substantially wave shaped warp wires  204   b  in a direction of width W of the woven wire cloth  204 . Every other one of the substantially wave shaped warp wires  204   b  is inverted by about 180 degrees with respect to an adjacent one of the substantially wave shaped warp wires  204   b . The warp wires  204  thereby form openings  206  having a substantially triangular shaped configuration. Because the assembly and method of use of the woven wire cloth  202  is the same as the assembly and method of use of the woven wire cloth  2  of the first embodiment, further description thereof will not be provided herein. 
     FIG. 6  shows a screen  301  for a vibratory separator according to a fourth embodiment of the invention. As shown in  FIG. 6 , the screen  301  comprises a woven wire cloth  302 . The woven wire cloth  302  is identical to the woven wire cloth  2  of the first embodiment, except the warp wires  304  are substantially straight with respect to a direction of length L of the woven wire cloth  302 . The warp wires  304  thereby form openings  306  having a substantially rectangular shaped configuration. Because the assembly and method of use of the woven wire cloth  302  is the same as the assembly and method of use of the woven wire cloth  2  of the first embodiment, further description thereof will not be provided herein. 
   The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. For example, although the woven wire cloth  2 ,  102 ,  202 ,  302  is shown and described herein as having openings  6 ,  106 ,  206 ,  306  with certain configurations, it will be appreciated by those skilled in the art that the concepts shown and described herein may be applied to woven wire cloths having other configurations. Additionally, the woven wire cloth  2 ,  102 ,  202 ,  302  may be formed such that just the weft wires  5 ,  105 ,  205 ,  305  or just the warp wires  4 ,  104 ,  204 ,  304  are configured to have the height  9 ,  11  and the width  10 ,  12  dimensions shown and described herein. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.