| 摘要 |
STEAM SEAL OF BAG PLY A steam seal machine and process is disclosed to seal together the two contiguous edges of an inner heat sealable ply in a multi-ply tubular bag form. The bag forms are conveyed transversely to their length by a first continuous conveyor and then by an intermittently operating conveyor into an openable steam chest. The second conveyor stops, and the steam chest closes so that it envelops the open mouth of the bag form. Steam is admitted to the steam chest through a valve and this steam penetrates the open end of the multi-ply bag form to seal together the contiguous edges of the heat sealable ply. In this way the steam need not penetrate through several layers of kraft paper or other reinforcing plies. The steam valve is closed, the steam chest opens and the second conveyor restarts to convey the bag form beyond the steam chest so that a part of a successive bag form may enter the steam chest. This part may be the top, bottom or side of the bag form whereat the heat sealable ply is being sealed. |
