Screen Basket with Replaceable Profiled Bars

Abstract

A screen basket with replaceable profiled bars and method of making such screen basket are described herein. The screen basket includes profiled bars evenly spaced circumferentially to form a plurality of continuous slots that covers the whole basket length. The profiled bars are fixed in place by a backing structure, including support rings. In pulp and paper industry, this type of basket is mainly used for pulp screening and is commonly referred to as wedge wire basket. As opposed to conventional wedge wire baskets, in which the profiled bars are permanently joined to the rings, the present invention allows replacing the profiled bars when required and to fully re-use the main structural elements. This is achieved with an assembly that allows to insert the profiled bars, preferably consecutively sled into each aligned ring grooves in a vertical movement. The ring grooves are profiled such that there is sufficient clearance for sliding in the profiled bars. The mounting clearance is then removed radially to hold the profiled bars in place. According to an illustrative embodiment, this is achieved by squeezing an element made of compressible material, and placed between each ring pair.

1 . A screen basket comprising:
 a plurality of profiled bars generally aligned along a longitudinal axis so as to define a slotted cylindrical wall having an inner side and an outer side extending between two longitudinal ends; each of the profiled bars having a radial profiled portion and a radial locking portion joined at an intermediate cross-section; the radial locking portion having an irregular cross-section including at least one radial cross-section wider than the intermediate cross-section; and   a plurality of support ring assemblies, each removably mounted to at least some of the plurality of profiled bars substantially transversally therefrom for assembling the plurality of profiled bars into the slotted cylindrical wall; each of the plurality of support ring assemblies including a stack of first and second support rings; at least one of the first and second support rings including a plurality of grooves; each groove being configured and sized for complementary receiving the radial locking portion of a respective one of the profiled bars; the first and second support rings being mounted to each other and to the plurality of profiled bars so as to yield a locking force towards the radial locking portion of the profiled bars, thereby locking the profiled bars thereonto.   
   
   
       2 . A screen basket as recited in  claim 1 , wherein each of the grooves has a contour; the locking force biasing the locking portions of the plurality of profiled bars towards the contours of the grooves. 
   
   
       3 . A screen basket as recited in  claim 2 , further comprising means for compressing the stack of the first and second support rings; at least one of the support ring assemblies further comprising at least one deformable insert mounted between the first and second support ring adjacent the locking portions of the profiles bars; 
     whereby, compressing the stack causes the at least one deformable insert to deform and to be forced radially towards the locking portions of the profiled bars, thereby providing the locking force to bias the locking portions of the plurality of profiled bars towards the contours of the grooves. 
   
   
       4 . A screen basket as recited in  claim 3 , wherein the at least one deformable insert is a compressible insert. 
   
   
       5 . A screen basket as recited in  claim 4 , wherein the compressible insert is in the form of an integral ring. 
   
   
       6 . (canceled) 
   
   
       7 . (canceled) 
   
   
       8 . (canceled) 
   
   
       9 . (canceled) 
   
   
       10 . A screen basket as recited in  claim 3 , wherein at least one of the support ring assemblies further comprising an intermediary non-grooved ring mounted between the first and second support rings, having a larger inside diameter than the first and second support rings and having a thickness; the at least one deformable insert being in the form of a compressible ring characterized by an uncompressed longitudinal width greater than the intermediary non-grooved ring thickness. 
   
   
       11 . A screen basket as recited in  claim 3 , wherein the deformable insert is in the form of an open ring; wherein compressing the stack causes the open ring to close and to be forced radially towards the locking portions of the profiled bars. 
   
   
       12 . A screen basket as recited in  claim 11 , wherein at least one of the first and second support rings has an edge adjacent the plurality of profiled bars provided with a chamfer for receiving the open ring. 
   
   
       13 . A screen basket as recited in  claim 3 , wherein the means for compressing the stack of the first and second support rings includes at least one clamping post for clamping the plurality of support ring assemblies. 
   
   
       14 . A screen basket as recited in  claim 13 , wherein the at least one clamping post is in the form of a clamping comb provided with longitudinal notches for receiving a respective one of the plurality of support ring assemblies. 
   
   
       15 . (canceled) 
   
   
       16 . (canceled) 
   
   
       17 . (canceled) 
   
   
       18 . A screen basket as recited in  claim 13 , wherein each support ring assembly has a first thickness when said each support ring assembly is not compressed; the at least one clamping post including sequentially alternating narrow and wide portions; each narrow portion having a first height which is slightly less than the first thickness when the first support ring assembly is uncompressed and generally equal to the first thickness when the first support ring assembly is compressed; each wide portion having a second height generally corresponding to a longitudinal interspacing between two adjacent of the support ring assemblies; each one of the plurality of support ring assemblies being provided with at least one aperture having a wider side for allowing passage for the at least one clamping post when the at least one clamping post has its wide portions oriented along the wider side of the at least one aperture; 
     whereby, in operation, rotating the at least one clamping post of 90 degrees after insertion thereof in the at least one aperture causes the at least one clamping post to engage and compress the stack of the first and second support rings. 
   
   
       19 . (canceled) 
   
   
       20 . (canceled) 
   
   
       21 . (canceled) 
   
   
       22 . (canceled) 
   
   
       23 . (canceled) 
   
   
       24 . (canceled) 
   
   
       25 . A screen basket as recited in  claim 3 , wherein the stack of first and second support rings further includes a third intermediary ring mounted between the first and second support rings; the at least one deformable insert including a first deformable insert mounted between the first and intermediary rings and adjacent to the locking portions of the profiled bars and a second deformable insert mounted between the second and intermediary rings adjacent to the locking portions of the profiled bars; the intermediary ring including the plurality of grooves. 
   
   
       26 . A screen basket as recited in  claim 25 , wherein the intermediary ring is made of a plurality of angular segments. 
   
   
       27 . A screen basket as recited in  claim 26 , further comprising at least one clamping post for receiving, longitudinally spacing and compressing the plurality of support ring assemblies. 
   
   
       28 . A screen basket as recited in  claim 25 , wherein each of the first and second support rings has a respective edge adjacent the plurality of profiled bars provided with a chamfer for receiving the at least one deformable insert. 
   
   
       29 . A screen basket as recited in  claim 3 , wherein the means for compressing the stack of the first and second support rings includes fasteners. 
   
   
       30 . The use of a screen basket as recited in  claim 1  for inward flow screening, wherein the plurality of support ring assemblies are removably mounted to at least some of the plurality of profiled bars on the inner side of the slotted cylindrical wall defined by the plurality of profiled bars. 
   
   
       31 . The use of a screen basket as recited in  claim 1  for outward flow screening, wherein the plurality of support ring assemblies are removably mounted to at least some of the plurality of profiled bars on the outer side of the slotted cylindrical wall defined by the plurality of profiled bars. 
   
   
       32 . A screen basket as recited in  claim 1 , wherein the plurality of grooves are generally equidistanced. 
   
   
       33 . A screen basket as recited in  claim 1 , wherein the radial locking portion is generally shaped like a dovetail. 
   
   
       34 . A screen basket as recited in  claim 1 , further comprising a plurality of clamping posts for receiving and compressing the plurality of support ring assemblies. 
   
   
       35 . (canceled) 
   
   
       36 . (canceled) 
   
   
       37 . (canceled) 
   
   
       38 . (canceled) 
   
   
       39 . (canceled) 
   
   
       40 . A screen basket as recited in  claim 1 , wherein each of the plurality of support ring assemblies are removably mounted to at least some of the plurality of profiled bars substantially transversally therefrom. 
   
   
       41 . (canceled) 
   
   
       42 . (canceled) 
   
   
       43 . A method for assembling a screen basket comprising:
 providing a plurality of support ring assemblies including first and second support rings; at least one of the first and second support rings including a plurality of grooves;   providing a plurality of profiled bars, each having a radial profiled portion and a radial locking portion joined at an intermediate cross-section; the radial locking portion having an irregular cross-section including at least one radial cross-section wider than the intermediate cross-section; the radial locking portion being configured for complementary insertion into one of the grooves of the first and second support rings;   inserting the locking portions of the profiled bars into the grooves of the first and second support rings so as to generally align the profiled bars along a longitudinal axis and to define a slotted cylindrical wall having an inner side and an outer side extending between two longitudinal ends; and   applying a locking force towards the radial locking portion of the profiled bars for releasably locking the profiled bars in the support ring assemblies.   
   
   
       44 . A method as recited in  claim 43 , wherein applying a locking force towards the radial locking portion of the profiled bars includes inserting deformable inserts between the first and second support rings and installing clamping combs onto the plurality of support ring assembly for receiving and compressing the plurality of support ring assemblies, thereby forcing the deformable inserts towards the locking portion of the profiled bars, yielding the locking force. 
   
   
       45 . A method as recited in  claim 44 , wherein the clamping combs have longitudinal ends; the method further comprising securing end flanges at the longitudinal ends of the clamping combs. 
   
   
       46 . (canceled)