Method of defibring incompletely defibred vegetable material

摘要

A method of defibring with selective separation of hard particles, vegetable material, e.g. cellulose, wood, plants, which has been soaked, steamed, pre-hydrolised, or incompletely broken up by any known methods, comprises subjecting the material to a beating action in a hammer mill in the presence of water or other liquid continuously flowing through the mill and discharging the defibred product and the hard particles separately from the mill. One or more rotatable hammers are preferably disposed in a p cylindrical housing the bottom of which is formed as a perforated plate. The material to be treated is introduced at one end of the housing and if the flow of liquid is not strong enough for feeding the material forward, it is moved forward by slightly inclining the housing or suitably shaping the hammers, and the detached fibres are flushed through the perforated plate while the hard particles are ejected at the other end of the housing. The ejection of hard particles from the mill may be assisted by water jets directed into the housing. The liquid in the mill is dammed back to such an extent that liquid is always present in the mill. The peripheral outer edges of the hammers may be roughened or toothed. The various steps of pre-treatment of the vegetable material may be combined in any desired manner.