Center sealing device for a plastic film in a packaging apparatus
US4288967A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 30, 1979 |
| Grant date | Sep 15, 1981 |
| Priority date | — |
| Expiry date | Nov 30, 1999 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C66/8181
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A heat sealing device in a packaging apparatus utilizing a plastic film for continuously seal an overlapped axial portion of the plastic film. The device comprises a pair of heating rollers which are rotatably and oppositely placed to hold the overlapped portion of the film between them. Each of the heating rollers has a heating surface in its outer periphery which is pressed against the film and a coaxial and annular sealed chamber which is formed inside the heating surface and contains working liquid as a heat medium. A heat source is provided to be opposite at least to a portion of the sealed chamber to heat the working liquid. The working liquid generates vaporized gas upon heating by the heat source, and the pressure and the temperature in the sealed chamber are maintained at a predetermined degree so that the vaporized gas is condensed substantially at the temperature for fusing the film.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.