Double fourdrinier papermaking machine - has controlled water content in suction boxes at the water extraction stage to keep the fourdriniers wet.

摘要

The double fourdrinier (1,2) papermaking machine has a number of water extraction bars (5, 15) within the fourdrinier loops, where each lie against the inner surfaces of their fourdriniers, in groups within suction boxes (4, 14). The suction boxes (4, 14) each connected to an underpressure, face each other with at least a partial overlap. The direct or indirect underpressure supplied to the suction boxes (4, 14) is set so that the fourdrinier is constantly wetted as it passes through from water within the suction box. Pref. the separate suction boxes (4, 14) are each connected to a stand pipe (8, 18) with an underpressure which is adjusted to keep the water level (8.2, 18.1) in each stand pipe (8, 18) above the top edge of the suction box (4, 14). USE/ADVANTAGE - The system is for the water extraction stage of a double fourdrinier papermaking machine. The operation keeps the fourdrinier wet so that the paper quality is not damaged or weakened by splashing from water in the suction boxes.