Method for the manufacture of particle board

Abstract

Methods and apparatus are described for the manufacture of particle board in which a fleece of particle material with admixed binder is formed on an endless belt 1 at a forming station and is subsequently passed through a series of presses and heating devices where it is consolidated into particle board. The lower, and preferably also the upper, covering layers of the fleece are selectively warmed at the forming station to activate the cold binding capability of the admixed binder and endow the fleece with sufficient stability to withstand the handling stresses as it is passed from one endless band conveyor to another. pa The selective warming is conveniently achieved by means of respective heating devices each of which incorporates a number of pairs of oppositely poled capacitor plates arranged alternately side by side along the length of the fleece and extending over the full width thereof. In this way longitudinally extending field lines pass between the capacitor plates and penetrate to a required depth in the associated covering layer. In an alternative embodiment, in which the fleece is conveniently deposited in sequential layers on the endless band fleece carrier, the first layer, which forms the lower covering layer is warmed by passing it between a pair of capacitor plates.