摘要:
An unported vacuum drum (12) has a system of closely spaced small grooves (30) in the outer surface and holes (36) drilled in the drum (12) provide communication between the grooves (30) on the outer surface and a space on the interior (16) of the drum (12). The interior drum (16) can be connected to a source (28) of vacuum for applying the vacuum through the holes (36) to the grooves (30). In order to avoid defects that may occur in a web brought into contact with a drum (12), the outer surface of the drum (12) is covered with a porous sleeve (40). The pores (42) in the sleeve (40) enable the vacuum to be applied from the grooves (30) to the outer surface of the sleeve (40) for holding the web onto the sleeve (40).
摘要:
An unported vacuum drum (12) has a system of closely spaced small grooves (30) in the outer surface and holes (36) drilled in the drum (12) provide communication between the grooves (30) on the outer surface and a space on the interior (16) of the drum (12). The interior drum (16) can be connected to a source (28) of vacuum for applying the vacuum through the holes (36) to the grooves (30). In order to avoid defects that may occur in a web brought into contact with a drum (12), the outer surface of the drum (12) is covered with a porous sleeve (40). The pores (42) in the sleeve (40) enable the vacuum to be applied from the grooves (30) to the outer surface of the sleeve (40) for holding the web onto the sleeve (40).