Patent attributes
The invention is a rotatable cylindrical roll for heat sealing heat sealable materials that includes a heating zone for sealing the material and a cooling zone for supporting the newly formed seal. The device comprises a conductive zone and a resistive zone that are in electrical communication. The resistive zone comprises a cylindrical member having a circumferential band of resistive material disposed on its surface. The conductive zone comprises a cylindrical member having a plurality of conductive strips extending laterally across its surface that are in electrical communication with the resistive band. Current is applied via a brush to the conductive strips. Current flows from the conductive strips into the resistive band and exits through a conductive strip that is in contact with a ground. Current path through the resistive band defines the heating zone, and the cooling zone is defined by area of the resistant band outside the heating zone.
