| 摘要 |
In order to provide web handling which mitigates marking of the web, externally-pressurized porous media gas bearings are used for vacuum rollers, which provide differential tension, and also for air turns, which provide non-contact turning of webs. The porous media gas bearings mitigate three of the biggest issues with the current technology, including cost, high flow rates and low pressure, and web marking. By introducing positive pressure or both, various configurations are presented which allow for improved differential tension, or non-contact conveyance. By also employing externally-pressurized radial bearings, more alternatives are provided, including conveyance and lateral motion of webs without the use of motors. Lastly, employing novel lightweight materials allows for yet other configurations which also employ some of the same aforementioned benefits. |
