PROCEDURE AND APPARATUS FOR THE SORTING OF WOODS SHIPS

摘要

A two-stage procedure is disclosed for sorting wood chips. The chips are directed to a gyratory screen in the first stage and to a disc screen in the second stage. The chip flow is divided in the first stage into four fractions of which the first fraction contains mainly oversized chips and is directed to a pin chipper, from which it emerges as suitable-sized chips and is directed back to the gyratory screen of the first stage. The second fraction contains acceptable sized chips and most of the overthick chips and is directed to the second or thickness screening stage. The third fraction consists mainly of acceptable chips and is directed to a pulping process, while the fourth fraction consists mainly of fine particles and is directed to a burning station. In the second or thickness screening stage the chip flow is divided into two fractions of which the rougher fraction comprises overthick chips and is directed via a rock and metal separating device into a slicing machine and then back to the first stage gyratory screen, while the finer fraction comprises acceptable chips and is passed directly to the pulping process.