On the mechanism of steam forming during impulse pressing of wet paper webs

摘要

Steam forming processes in wet paper webs under- going impulse pressing are characterized here in two different, yet complementary studies. In the first study, we measured the transient temperature profiles of wet paper webs undergoing compression at a constant rate in a heated platen press. Eight micro-thermocouples were embedded into 500 g/m~2 SBK wet paper webs at different elevations. The experimental conditions were such that the length of the pressure pulse was varied from 100 ms to 15s, the initial temperature of the platen press was set from 150 deg. C to 300 deg. C, and the initial dryness of the paper webs were held constant at approximately 30/100; approximately 600 experiments were conducted.