Patent ID: 6446813
Filing Date: 2002-09-10
Classification: B03B,B07B,Y02W,Y10S

Abstract:
A method of classifying waste materials comprising arranging two sieve screens, each having an inlet end and an outlet end, one above the other to define a space therebetween, arranging the upper screen to be of coarser mesh size than the lower screen, supplying waste material to be classified to the inlet end of the upper screen, vibrating the screens, and blowing air between the screens from the inlet end and towards the outlet end whereby the waste material is separated into a plurality of fractions with fine material passing downwards through the lower screen under gravity, light material being blown away from the outlet ends of the screens, and large heavy material falling under gravity from the outlet end of the upper screen, and separately collecting the separated waste materials fractions, characterized by agitating a portion of the upper screen adjacent the inlet relatively vigorously as compared to the remainder of the upper screen, said portion being relatively coarse as compared to the remainder of the upper screen.