An apparatus for securing a sheet of filter material about the
circumference of a dye tube. The apparatus includes a mandrel support
table having a tube loading station, a sheet wrapping station, a sealing
station, and a discharge station; hollow, air permeable mandrels supported
on the table; a table drive to sequentially index the mandrels to each of
the stations; a vacuum chamber extending from the tube wrapping station to
the sealing station to draw a vacuum inside each mandrel at and between
the wrapping and sealing stations; a tube feeder for feeding tubes onto
mandrels at the tube loading station; a sheet feeder for feeding sheets of
filter material into engagement with tubes at the wrapping station; a
mandrel drive for rotating each mandrel at the wrapping station to wrap
the sheet around the circumference of a tube supported on the mandrel; and
a sealer at the sealing station for sealing the sheet to itself to cover
the tube. In one embodiment the sealer is a heated roller which wraps and
seals the sheet around the tube simultaneously in a single operation.