Cylindrical screen, particularly for paper pulp

Abstract

Cylindrical screen, particularly for paper pulp, of the type comprising at least one filtering element ( 10 ) positioned between two flanges ( 1, 2 ) by means of a number of bars ( 3 ). The filtering element is composed by wires ( 10 ) placed side by side and held by rings ( 11 ). This filtering element is rigid in the axial direction and is placed upstream from the above mentioned bars ( 3 ), in relation to the direction of flow of the pulp. The filtering element is held against the bars ( 3 ) through the rings ( 11 ) that are in contact with the bars without being attached to them, so as to maintain its shape by withstanding the pressure exerted by the pulp.

1. A cylindrical screen, particularly for paper pulp, of the type comprising at least two flanges ( 1 , 2 ) connected to each other by means of bars ( 3 ), and at least one thin filtering element ( 10 ) rigid in the axial direction, said filtering element being held by support rings ( 11 ) and placed upstream from the above mentioned bars ( 3 ), in relation to the direction of flow of the pulp, wherein said filter element ( 10 ) is made up of wires placed side by side and being parallel in a cylindrical configuration, and the support rings ( 11 ) are at an internal or external edge thereof welded to the filtering element ( 1 ), whereas at the other edge thereof, they are in contact with the bars ( 3 ), without being attached to them, in a floating mounting between the rings and the bars. 
     
     
       2. The screen as claimed in  claim 1 , wherein the screen furthermore comprises at least one strengthening ring ( 20 ) placed between two filtering elements ( 10 A,  10 B,  10 C) following one after the other so as to receive the bars ( 3 ) and fixe them together in order to prevent bending of the same. 
     
     
       3. The screen as claimed in  claim 1 , wherein the bars ( 3 ) are attached to the two flanges ( 1 ,  2 ) and are held against the flanges, abutting in arrangements ( 6 ,  7 ) so that the distance between the two flanges is invariable. 
     
     
       4. The screen as claimed in  claim 3 , wherein thickness adjustment shims ( 12 ) are interpositioned between the filtering element ( 10 ) and one or other of said flanges ( 1 ,  2 ). 
     
     
       5. The screen as claimed in  claim 1 , wherein a distance of about 25 mm is arranged between two support rings ( 11 ) that are placed one after the other. 
     
     
       6. A cylindrical screen, particularly for paper pulp, of the type comprising at least two flanges (   1 ,  2   )  connected to each other by means of bars  (   3   ) , and at least one thin filtering element  (   10   )  rigid in the axial direction, said filtering element being held by support rings  (   11   )  and placed upstream from the above mentioned bars  (   3   ) , in relation to the direction of flow of the pulp, wherein said filter element  (   10   )  is made up of wires placed side by side and being parallel in a cylindrical configuration, and the support rings  (   11   )  are at an internal or external edge thereof attached to the filtering element  (   1   ) , whereas at the other edge thereof, they are in contact with the bars  (   3   ) , without being attached to them, in a floating mounting between the rings and the bars.   
     
     
       7. The screen as claimed in  claim 6 , wherein the screen furthermore comprises at least one strengthening ring (   20   )  placed between two filtering elements  (   10 A,  10 B,  10 C )  following one after the other so as to receive the bars  (   3   )  and fix them together in order to prevent bending of the same.   
     
     
       8. The screen as claimed in  claim 6 , wherein the bars (   3   )  are attached to the two flanges  (   1 ,  2   )  and are held against the flanges, abutting in arrangements  (   6 ,  7   )  so that the distance between the two flanges is invariable.   
     
     
       9. The screen as claimed in  claim 8 , wherein thickness adjustment shims (   12   )  are interpositioned between the filtering elements  (   10   )  and one or other of said flanges  (   1 ,  2   ) .   
     
     
       10. The screen as claimed in  claim 6 , wherein a distance of about  25  mm is arranged between two support rings (   11   )  that are placed one after the other.