Method and device for preheating a pressed material mat

The invention relates to a method for preheating a pressed material mat (2) before it enters a press (4)， in particular during the production of wood-based panels， the pressed material mat (2) permitting a double-belt preheating device (3) with an upper， endless， gas-permeable Conveyor belt (5a) and a lower， endlessly circulating gas-permeable conveyor belt (5b) runs through， wherein the pressed material mat (2) with a heated fluid that contains steam， is applied and thereby heated. The method is characterized in that the pressed material mat (2) in the double-belt preheating device (3) is initially acted upon in a first stage with a first heating unit (7) with a steam-air mixture with a set dew point， which the mat from One surface flows through to the opposite surface and thus over the entire mat thickness to a temperature (T 1) is heated and that the press mat (2) in the double belt preheating device (3) is then acted upon in a second stage with a second heating unit (9) on both sides with steam or with a steam-air mixture and thus only the surface layers on a second Temperature (T2) that are higher than the first temperature (T.1) is.