全树木片的气流分选

本文简要论述瑞典Bacho工业公司研制的新型JGB重力气流分选机的工作原理,以及对该机进行生产性试验检测的结果。 该机能把全树木片混合物分选成工业木片和燃料木片两部分,能有效地把树皮、细小碎粒和砂质分离出来。但对枝丫木片的分选能力欠佳。同时,在分选期间有部分木材损失。

AIR SEPARATION OF WHOLE TREE CHIPS

Owing to the shortage of wood logs, the utilization of whole trees has become important. For example, chips from clearing logs and logging waste are used as raw material for paper and board manufacturing to an increasing extent.But one of the problems to be solved is how to separate bark, foliage and sand from the chips mixture before pulping. This paper presents a new type of gravity air classifier developed by Bahco Industry AB in Sweden. The classifier can separate a mixture of whole tree chips into two usable fractions-energy chips for fuelling and industrial chips as raw material for the pulp and board industries. An examination for the classifer had been done in ASSI fibe'rboard mill in Sweden. The classifier has been proved to be effective. This examination shows that the air - separation of whole tree chips from thinning or cleaning can provide an useful material for fiberboard manu-facturing. Separation of bark and needles improves board quality and reduces the water pollution. However, the branch and twig chips can cause feeding problem in defibrating. It is therefore more suitable to mix with conventional material. This examination also shows that air separation will cause some wood loss, which will affect the economic result. It is, however, closely related to the economic value of chips used as fuel.