木材渗透性可控制原理研究

A STUDY ON THE PRINCIPLE OF PERMEABILITY CONTROL OF WOOD

本文研究了木材渗透性可控制机制,探寻了渗透性可控制原理。结果表明,影响渗透性高低的最主要因素为纹孔膜微孔半径和数量,微孔大而多者,渗透性高;微孔愈小,微孔里气-液界面上毛细管张力愈高,对液体流动的影响愈大,浸注愈难,欲使浸注液深注入木材,必须施一与此微孔半径相应足以克服此张力的压力。若欲改善低渗透树种木材的难浸注性,似应从纹孔入手,用化学的、物理的和生物的等方法增大和增多有效纹孔膜微孔半径和数量,以减小毛细管张力,降低使用压力,增大流量率,提高渗透性。

The principle of permeability control of wood was studied. The results showed that the main factors affecting permeability of wood were the effective radius and the number of pit membrane openings. The permeability of wood which has large and many pit membrane openings is high. The smaller an opening is, the bigger the capillary tension at the gas-liquid interface in the opening is and the more difficult the impregnation of wood with liquid is. An impregnation pressure which is equal to the capillary tension at the gas-liquid interface in the pit membrane opening and enough to overcome the tension must be applied to the wood when the deep impregnation of wood with liquid is needed. One effective measure to improve the impregnation of wood seems to increase the radius of pit membrane openings and their number in order to reduce the capillary tension and the applied impregnation pressure, and subsequently to increase the flow rate and the permeability.