| 摘要 |
A vacuum-assisted hot plate is used to precondition webs (13), such as paper webs used in the manufacture of corrugated paperboard (12). The vacuum-assisted preheater(10) has a web supporting and heating surface separated into four sections, namely: an input section, a central upstream section, a central downstream section, and an output section. The sections are separated by three vacuum channels that are sized wide enough to prevent clogging from paper dust. The central upstream section and the central downstream section have convex surfaces. Vacuums applied to the vacuum channels provide a normal force to pull the traveling web against the heated surface, whereas the convex configuration of both the central upstream section and the central downstream section provide a normal force pushing on the paper web in the opposite direction. The result is effective positive contact of the traveling web against the heated source, thereby promoting effective heat transfer.
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