Method for producing a rotationally symmetrical, in particular cylindrical screening device

Abstract

Method for producing a rotationally symmetrical screening device with a plurality of profile bars and screen basket for a pressurizable screen. The method includes producing bent bar holders having a radius of curvature of smaller than a radius of curvature of a finished screening device and having cut-outs open at an edge of an exterior circumference of the bent bar holders. The method also includes inserting profile bars parallel to one another into the cut-outs, and forming rings from the bar holders with inserted profile bars by enlarging the radius of curvature of the bar holders, thereby narrowing the cut-outs and clamping the profile bars. The forming of rings includes transferring bending forces to at least two locations on sides of the bar holders not provided with the cut-outs. The method also includes fixedly connecting respective ends of the bar holders to one another.

1 . A method for producing a rotationally symmetrical screening device with a plurality of profile bars, comprising: 
 producing bent bar holders having a radius of curvature of smaller than a radius of curvature of a finished screening device and having cut-outs open at an exterior circumference edge of the bent bar holders;    inserting profile bars parallel to one another into the cut-outs;    forming rings from the bar holders with inserted profile bars by enlarging the radius of curvature of the bar holders, thereby narrowing the cut-outs and clamping the profile bars, wherein the forming of rings includes transferring bending forces to at least two locations on sides of the bar holders not provided with the cut-outs; and    fixedly connecting respective ends of the bar holders to one another.    
     
     
         2 . The method in accordance with  claim 1 , wherein the rotationally symmetrical screening device is cylindrical.  
     
     
         3 . The method in accordance with  claim 1 , wherein the profile bars include base portions, and the cut-outs are shaped to essentially correspond in a complementary manner to the base portions of the profile bars.  
     
     
         4 . The method in accordance with  claim 1 , wherein a location for introducing the bending forces essentially extends over an axial extension of the screening device.  
     
     
         5 . The method in accordance with  claim 4 , wherein the location is fixed on the bar holders during the forming.  
     
     
         6 . The method in accordance with  claim 1 , wherein the bending forces act both radially outwardly and in the circumferential direction.  
     
     
         7 . The method in accordance with  claim 1 , wherein, during the forming, no forces influencing the forming are transferred to the exterior circumference of the bar holder being formed.  
     
     
         8 . The method in accordance with  claim 1 , wherein no mating shape is used during the forming.  
     
     
         9 . The method in accordance with  claim 1 , further comprising applying the bending forces during the connecting of the respective ends of the bar holders.  
     
     
         10 . The method in accordance with  claim 9 , wherein complete rings are formed by the connecting of the respective ends of the bar holders.  
     
     
         11 . The method in accordance with  claim 1 , further comprising clamping the bar holders during the forming in bending devices applying the bending forces.  
     
     
         12 . The method in accordance with  claim 1 , wherein the bending forces are introduced at a maximum of four locations.  
     
     
         13 . The method in accordance with  claim 12 , wherein four bending devices are used to introduce the bending forces at the maximum of four locations.  
     
     
         14 . The method in accordance with  claim 12 , wherein respectively two bending devices form a bending group which, in interaction, transfers a bending moment to the bar holders.  
     
     
         15 . The method in accordance with  claim 1 , wherein the bending forces are introduced at six locations.  
     
     
         16 . The method in accordance with  claim 15 , wherein four bending devices and two backing rolls are arranged to introduce the bending forces at the six locations.  
     
     
         17 . The method in accordance with  claim 15 , wherein respectively two bending devices and one backing roll form a bending group which, in interaction, transfers a bending moment to the bar holders.  
     
     
         18 . The method in accordance with  claim 1 , wherein the respective ends of the bar holders are fixedly connected to one another by welding.  
     
     
         19 . The method in accordance with  claim 1 , wherein the forming and the fixedly connecting of the bar holders are carried out with a same machine.  
     
     
         20 . The method in accordance with  claim 1 , wherein the bar holders are assembled from segments before the forming.  
     
     
         21 . A screen basket for a pressurized screen usable in the paper-producing industry, produced by the method of  claim 1.