Doctor Device For Fiber Web Machine And Doctor Arrangement In Fiber Web Machine

Abstract

A doctor device includes blade devices ( 19 ) supported on holder devices ( 23 ). The holder devices ( 23 ) are for arranging the blade devices ( 19 ) in a fiber web machine to be placed in connection with a doctor blade ( 18 ) equipped with a blade holder ( 38 ). The blade devices ( 19 ) are supported aligned in a circumferential direction with edge areas ( 20 ) of the doctor blade ( 18 ). The holder devices ( 23 ) are arranged to be fastened in connection with the blade holder ( 38 ) so that the blade devices ( 19 ) extend further out than the doctor blade ( 18 ) to reduce the wear of the doctor blade ( 18 ).

1 - 13 . (canceled) 
     
     
         14 . A doctor device for a fiber web machine having a roll with a cylindrical surface to be doctored which roll defines a circumferential direction along which the roll rotates, a doctor blade ( 18 ) engageable with the roll cylindrical surface, wherein the doctor blade ( 18 ) is mounted in a first doctor blade holder to a doctor beam which extends in a cross machine direction, the doctor blade having in the cross machine direction, a first end edge and a second end edge, and a middle between the first end edge and the second end edge, wherein an outward direction is defined between the middle and the first end edge and between the middle and the second end edge, the doctor device comprising:
 two blade devices ( 19 ), wherein each blade device is mounted to a holder device ( 23 ) which is arranged to fastened one of the blade devices to the first blade holder ( 38 ) of the doctor blade ( 18 );   wherein the holder devices ( 23 ) are arranged to be connected to the doctor beam ( 38 ) aligned with an edge area containing one of the first end edge and the second end edge of the doctor blade ( 18 );   wherein the holder devices ( 23 ) are arranged to be fastened to the blade holder ( 38 ) so that a portion of each blade device is further out in the outward direction than the doctor blade ( 18 ); and   wherein each blade device when mounted to the first blade holder extends further out than the doctor blade so that the blade devices are positioned to engage the roll before the doctor blade in the circumferential direction.   
     
     
         15 . The doctor device of  claim 14  wherein the each of the holder devices ( 23 ) includes a support structure ( 24 ) which has connecting devices for fastening to the doctor beam ( 17 ). 
     
     
         16 . The doctor device of  claim 14  wherein each of the holder devices has two ends, and further comprising a support structure ( 24 ) fastened to one end of the holder devices, wherein the support structure has connecting devices for fastening to the doctor beam ( 17 ). 
     
     
         17 . The doctor device of  claim 14  wherein the two holder devices ( 23 ) are symmetrical about a plane passing between said two holder devices. 
     
     
         18 . The doctor device of  claim 14  wherein the holder devices define a length of 800 to 1,200 mm in the cross machine direction. 
     
     
         19 . The doctor device of  claim 15  further comprising adjusting devices ( 31 ) between the holder devices ( 23 ) and the support structures ( 24 ). 
     
     
         20 . A doctor arrangement in a fiber web machine having a roll to be doctored, the roll defining an axis along which the roll is supported to rotate and along which the roll extends to define a roll width, the axis defining an axial direction, and the roll defining a circumferential direction of rotation of the roll, the doctor arrangement comprising:
 a doctor blade ( 18 ) which extends essentially across the entire roll width, wherein the doctor blade has in the axial direction a first end edge and a second end edge;   two blade devices ( 19 ) each of which is separate from the doctor blade ( 18 ), wherein each blade device is arranged aligned with an edge area containing one of the first end edge and the second end edge; and   wherein the blade devices and the doctor blade are arranged so that with respect to the cylindrical surface which the blade devices and doctor blade are arranged to engage, the blade devices ( 19 ) are arranged before the doctor blade ( 18 ) in the direction of rotation of the roll ( 16 ).   
     
     
         21 . The doctor arrangement of  claim 20  further comprising a doctor beam, and wherein the blade devices ( 19 ) are supported to the doctor beam ( 17 ) to which the doctor blade is supported by fastening devices. 
     
     
         22 . The doctor arrangement of  claim 20  wherein the fiber web machine has a coating station ( 22 ) and wherein the roll ( 16 ) is a drying cylinder ( 21 ) which is placed after the coating station in the fiber web machine. 
     
     
         23 . The doctor arrangement of  claim 20  wherein the blade devices ( 19 ) extend beyond the edge areas ( 20 ). 
     
     
         24 . The doctor arrangement of  claim 23  wherein the blade devices ( 19 ) define a length and 40 to 60 percent of the length of the blade devices ( 19 ) extends beyond the edge areas ( 20 ). 
     
     
         25 . The doctor arrangement of  claim 21  wherein each blade device ( 19 ) includes a support arm ( 28 ) which is fastened to the doctor beam ( 17 ) using at least some of the fastening devices ( 34 ) that support the doctor blade ( 18 ). 
     
     
         26 . A doctor arrangement for a fiber web machine having a coating station and a dryer roll having a cylindrical surface arranged after the coating station, the dryer roll defining a circumferential direction along which the dryer roll rotates; the doctor arrangement comprising:
 a main doctor blade ( 18 ), wherein the main doctor blade ( 18 ) is supported in a first blade holder ( 38 ) which is mountable to a doctor beam which extends in a cross machine direction;   wherein the main doctor blade has in the cross machine direction, a first end edge and a second end edge, and a middle between the first end edge and the second end edge, wherein an outward direction is defined between the middle and the first end edge and between the middle and the second end edge;   two short doctor blades each of which is shorter than the main doctor blade ( 18 ) and each short doctor blade is supported in a holder device which is arranged to fasten one of the short doctor blades to the doctor beam ( 18 );   wherein the short doctor blades and the main doctor blade are arranged so that with respect to the cylindrical surface to which the blade devices and doctor blade are arranged to engage, the short doctor blades ( 19 ) are arranged before the main doctor blade ( 18 ) in the circumferential direction of rotation of the roll ( 16 );   wherein the holder devices ( 23 ) are arranged supported on the doctor beam aligned with an edge area containing one of the first end edge and the second end edge of the doctor blade ( 18 );   wherein the holder devices ( 23 ) are arranged to be fastened to the doctor beam so that a portion of each short doctor blade is further out in the outward direction than the main doctor blade ( 18 ); and   wherein each short doctor blade extends further out than the main doctor blade so that the short doctor blades are positioned to engage the dryer roll before the main doctor blade in the circumferential direction.   
     
     
         27 . The doctor arrangement of  claim 26  wherein the main doctor blade is supported on the doctor beam by fastening devices. 
     
     
         28 . The doctor arrangement of  claim 26  wherein the short doctor blades extend beyond the edge areas in the outward direction. 
     
     
         29 . The doctor arrangement of  claim 26  wherein the short doctor blades define a length, and 40 to 60 percent of the length of the short doctor blade extends beyond the edge areas in the outward direction. 
     
     
         30 . The doctor arrangement of  claim 27  wherein each holder device includes a support arm which is fastened to the doctor beam using at least some of the fastening devices that support the main doctor blade.