Transfer suction roll for transfer of a material web

A suction roll (21) for deflecting a moving web (17), comprising:

• a perforated cylindrical suction shell (22) having axially opposite end covers (27) mounted in roller bearings (25) for supporting rotation of the shell (22);
• a stationary suction box (24) mounted inside the shell (22) and defining a suction zone (37) spanning a first arcuate portion of the shell (22);
• a stationary suction hood (26) resting on the outside of the shell (22) within the span of said suction zone (37) and a defining a second arcuate portion (37a) of the shell, which second portion draws a vacuum in the suction box (24);
• wherein a third arcuate portion (37b) of the shell adjacent the second portion (37a) of the shell and within said first arcuate portion (37), defines an active area of web transfer of the rotating shell (22) whereby the drawn vacuum in the suction box (24) acts through the perforations in the active area of the shell to draw the web toward the shell as the moving web is deflected by the active area.

A suction roll (21) for deflecting a moving web (17), comprising:

• a perforated cylindrical suction shell (22) having axially opposite end covers (27) mounted in roller bearings (25) for supporting continuous rotation of the shell (22);
• a stationary suction box (24) mounted inside the shell (22), including a cylindrical central portion coaxial with the axis of the shell and sealing members (32) in contact with the inside of the shell, whereby said cylinder, sealing members and an arcuate portion of the shell define a suction zone (37) of the shell;
• a stationary suction hood (26) on the outside of the shell (22), drawing a vacuum in the suction zone;
• and
• an active area of web transfer (37b) on the rotating shell (22), subject to the suction of the suction zone, through the perforations in the rotating shell to draw the web toward the shell as the moving web is deflected by the active area.