Relationships Between the Efficiency of Crushing and the Handling Condition of Several Wood Crushers

This paper is concerned with the the efficiency of four types of hummer crushers and the size of the crushed wood particles. The relationships between the power requirement of the crusher of screenless and screened hammer mills were also examined.Three types of screened hammer mills and one type of screenless hammer mill, were examined.The main variables of the crushers were the scale of the mill, the screen opening, and the rotational speed.The relationships betweeen the efficiency and the handling condition of the crushers were as follows:Hu/τ0=r1(Dv/dv-1)-1(Rω2)2/3where r1 was experimental coefficiant. It was 7.8×10-5 for wood, and 7.0×10-4 for the bark of spruce.The size of the crushed particle, dv, was expressed as follows:dv=r2(Sd)1/2(Rω2)nwhere r2 and n were experimental coefficients. They were 2.6, -1/2 for wood, and 0.46, -1/3 for the bark of spruce.The power requirement for crushing wood was found to follow Kick's law for the four types of hammer mills examined.