| 摘要 |
A process for making a composite wood panel, fiberboard or the like comprises putting a mat to be pressed between the press platens of a press, compressing the mat with heated press platens in a first compression step without feeding in steam until a density of at least 50% of that of the product panel is reached, preferably 70 to 85%, in a second compression step feeding steam with a pressure of between 1 to 3 bar through both press platens and compressing further until from 10 to 40% of the compression occuring in the first compression step (this is taken as 100%) is attained, in a third compression step interrupting the steam feed, the density attained in the second step being maintained, and subsequently compressing with a pressure of steam which is greater than the steam pressure used in the second compression step. Advantageously the steam pressing step is characterized by a flushing event in which the steam issues from the steam pressing orifices of one of the press platens and flows through the mat and also into the steam orifices of the other one of the press platens which temporarily are cut off from the source of the steam. Furthermore during a final compression time interval the mat is exposed to the action of a vacuum source connected to at least one of the press platens to dry the mat.
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