Suction or Ventilation Roll

Abstract

The invention relates to a suction or ventilation roll of a machine for producing and/or finishing a paper, cardboard, tissue or other fibrous material web ( 2 ). Said roll comprises a rotatable, perforated roll jacket ( 1 ) and at least one pressure zone ( 9 ), which only extends over part of the roll circumference and is formed by a fixed pressure compartment ( 6 ) located in the interior of the roll and open towards the roll jacket ( 1 ). The pressure compartment ( 6 ) is connected to a negative- or excess-pressure source and is sealed in relation to the roll jacket ( 1 ) by means of at least one sealing element ( 7 ). One aim of the invention is to reduce the noise emissions. To achieve this, a substantially air-tight cover ( 5 ), which runs in the direction of the circumference and is located outside the pressure compartment ( 6 ), adjoins a sealing element ( 7 ), said cover making contact with the roll jacket ( 1 ), or being placed at a distance of less than 100 mm to the latter.

1 - 19 . (canceled)  
   
   
       20 . A roll for a machine comprising: 
 a rotatable perforated roll shell having at least one pressure region that extends over a first portion of a roll circumference;    a stationary pressure box in the interior of the roll which is open toward the roll shell forming the at least one pressure region, the pressure box being connected to one of a negative and a positive pressure source;    at least one sealing element, the at least one sealing element sealing off the pressure box is sealed off with respect to the roll shell; and    at least one substantially air-impermeable cover;    wherein the at least one sealing element and the at least one substantially air-impermeable cover running in the circumferential direction and arranged at least one of outside the pressure box and the roll shell and adjoins or is arranged in the vicinity of a side wall of the pressure box on an outer side of the roll shell, and    wherein the cover is one of in contact with the roll shell and having a spacing of less than 100 mm from the outer side of the roll shell.    
   
   
       21 . The roll of  claim 20 , wherein the roll is one of a suction roll and a blow roll.  
   
   
       22 . The roll of  claim 20 , wherein the distance between the cover and the outer side of the roll shell is one of less than 20 mm and less than 10 mm.  
   
   
       23 . The roll of  claim 20 , wherein the distance between the cover and the outer side of the roll shell is substantially the same about the roll.  
   
   
       24 . The roll of  claim 20 , wherein the distance between the outer side of the roll shell and the at least one cover one of increases and decreases away from the pressure box.  
   
   
       25 . The roll of  claim 20 , wherein the distance between the outer side of the roll shell and the at least one cover fluctuates in at least one of a longitudinal and transverse direction of the machine.  
   
   
       26 . The roll of  claim 20 , wherein the at least one cover adjoins the at least one sealing element running approximately transversely with respect to a web running direction.  
   
   
       27 . The roll of  claim 20 , wherein the at least one cover adjoins an end of the pressure box located in the direction of rotation.  
   
   
       28 . The roll of  claim 20 , wherein the at least one cover adjoins an end of the pressure box located counter to the direction of rotation.  
   
   
       29 . The roll of  claim 20 , wherein the at least one cover extends over a circumferential region of one of at least 10 mm, at least 100 mm and more than 200 mm.  
   
   
       30 . The roll of  claim 20  wherein the cover extends in the circumferential direction over an entire region located outside the pressure box.  
   
   
       31 . The roll of  claim 20 , wherein the at least one cover extends axially at least over the entire perforated region of the roll shell.  
   
   
       32 . The roll of  claim 20 , wherein the at least one cover extends axially over a first portion the perforated region of the roll shell.  
   
   
       33 . The roll of  claim 20 , further comprising an adjusting device, whereby the at least one cover can be varied axially over a first width with respect to one of its distance and angle of attack in relation to the roll shell.  
   
   
       34 . The roll of  claim 33 , wherein the adjusting device is adjusted by one of hydraulically, pneumatically and mechanically.  
   
   
       35 . The roll of  claim 33 , further comprising a measuring device that measures a control variable and outputs the control variable to a controller, wherein, based on the control variable, the controller outputs a signal variable to the adjusting device, whereby the adjusting device which changes the position of the at least one cover in accordance with the signal variable.  
   
   
       36 . The roll of  claim 20 , wherein the at least one cover has one of a straight, curved, undulating, zigzag and irregularly broken terminating edge.  
   
   
       37 . The roll of  claim 20 , wherein the at least one cover has openings.  
   
   
       38 . The roll of  claim 20 , further comprising spacers, the spacers arranged between the roll shell and the at least one cover, wherein the spacers are in the form of at least one of rods, wedges or strips.  
   
   
       39 . The roll of  claim 38 , wherein the spacers are adjustable by an adjusting device.  
   
   
       40 . The roll of  claim 20 , wherein the at least one cover comprises at least one of a single material and a plurality of materials.  
   
   
       41 . The roll of  claim 40 , wherein the at least one of a single material and a plurality of materials is at least one of a metal, a plastic and a composite material.  
   
   
       42 . The machine of  claim 20 , wherein the machine at least one of produces and finishes at least one of a paper, a board, a tissue and a fibrous web.