Stabilizing apparatus for paper webs in the course of formation

Abstract

A stabilizing apparatus for paper webs, comprising at least a movable element ( 4 ) disposed in correspondence of a paper web ( 2 ); tho movable element ( 4 ) comprises a wedge-like portion ( 5 ) having a lower surface ( 7 ) for intercepting an entrained first fluid thread (F 1 ) in correspondence of a lower face ( 2 a ) of the web ( 2 ) and diverting said first thread (F 1 ) along a direction transverse to the advancement direction (A).

1 . Stabilizing apparatus for paper webs, comprising at least a movable element ( 4 ) disposed in correspondence of a paper web ( 2 ), characterized in that the said movable element ( 4 ) comprises a wedge-like portion ( 5 ) having a continuous upper surface ( 8 ) of contact with a lower face ( 2   a ) of web ( 2 ), and a lower surface ( 7 ) associated therewith for intercepting a first fluid thread (F 1 ) carried by said lower face ( 2   a ) and diverting said first thread (F 1 ) along a direction transverse to the feeding direction (A) of the web.  
   
   
       2 . Apparatus according to  claim 1 , characterized in that the said lower surface ( 7 ) of the wedge-like portion ( 5 ) exhibits an aerodynamic profile to divert said first fluid thread (F 1 ) and create a depression in correspondence of the lower face ( 2   a ) of web ( 2 ).  
   
   
       3 . Apparatus according to preceding  claim 2 , characterized in that the said aerodynamic profile has a substantially wavy pattern.  
   
   
       4 . Apparatus according to  claim 1 , characterized in that the said wedge-like portion ( 5 ) has also a flat upper surface ( 8 ) opposite to said lower surface ( 7 ), and a leading edge ( 6 ) disposed between said upper surface ( 8 ) and said lower surface ( 7 ); said lower surface ( 7 ), upper surface ( 8 ) and leading edge ( 6 ), all defining a continuous surface.  
   
   
       5 . Apparatus according to  claim 4 , characterized in that the said flat upper surface ( 8 ) can be associated with the lower face ( 2   a ) of web ( 2 ).  
   
   
       6 . Apparatus according to  claim 5 , characterized in that the said flat upper surface ( 8 ) has a first end ( 8   a ) associated with said leading edge ( 6 ), and a second end ( 8   b ) opposite to the first ( 8   a ) and bent away from the lower face ( 2   a ) of web ( 2 ); said second end ( 8   b ) defining, in cooperation with an outer surface ( 3   a ) of the transmission roller ( 3 ), a section ( 9 ) for the passage of a second fluid thread (F 2 ) carried by the same roller ( 3 ).  
   
   
       7 . Apparatus according to  claim 6 , characterized in that the said passage section ( 9 ) forms a neck for determining the expansion of the second fluid thread (F 2 ) and create a depression in correspondence of a portion of the external surface ( 3   a ) of roller ( 3 ) in contact with the lower face ( 2   a ) of web ( 2 ).  
   
   
       8 . Apparatus according to  claim 6 , characterized in that the said movable element ( 4 ) comprises also a support arm ( 10 ) having a first end ( 10   a ) associated with said wedge-like portion ( 5 ), and a second end ( 10   b ) opposite to the first ( 10   a ); said first end ( 10   a ) exhibiting a substantially unshaped development which defines a concave region.  
   
   
       9 . Apparatus according to  claim 8 , characterized in that the said first end  10   a ) of the support arm ( 10 ) exhibits an extension ( 11 ) shaped like a lamina and abutted against the external surface ( 3   a ) of the transmission roller ( 3 ) in order to divert the second fluid thread (F 2 ) towards the second end ( 10   b ) of said arm ( 10 )  
   
   
       10 . Apparatus according to  claim 8 , characterized in that it comprises also a linear actuator ( 12 ) associated with the second end ( 10   b ) of said arm ( 10 ) in order to drive the movable element ( 4 ) between an operating position in which it is moved close to the paper web ( 2 ), and an inoperative position in which it is moved away from said web ( 2 ).  
   
   
       11 . Apparatus according to  claim 1 , characterized in that it comprises also suction means ( 13 ) moved close to said movable element ( 4 ) and disposed in correspondence of the lower face ( 2   a ) of said web ( 2 ).  
   
   
       12 . Apparatus according to  claim 11 , characterized in that the said suction means ( 13 ) comprise a first mouth ( 13   a ) facing said wedge-like portion ( 5 ) to aspirate said first fluid thread (F 1 ) diverted by the lower surface ( 7 ), and a second suction mouth ( 13   b ) facing a yankee roller disposed upstream of said movable element ( 4 ).  
   
   
       13 . Suction box ( 13 ) for tissue paper-production plants which include a smooth cylinder and a pope roller, the box comprising a first suction mouth ( 13   a ) facing said pope roller, and a second suction mouth (i 3   b ) facing said smooth roller.