Abstract: A compound disc is used to eliminate a secondary slot normally formed between adjacent shafts of a material separation screen. The compound disc comprises a primary disc joined to an associated secondary disc. The primary disc and the secondary disc each have the same shape but the secondary disc has a smaller outside perimeter and is wider. The primary disc and associated secondary disc are formed from a unitary piece of rubber. The compound discs are interleaved with oppositely aligned compound discs on adjacent shafts. In other words, the large disc is positioned on a shaft to align with a smaller disc on an adjacent shaft. The oppositely aligned and alternating arrangement between the large discs and small discs reduces problems that exist in screens that use in-line multi-sided discs.

Abstract: A method is disclosed for preparing mixtures of moldable plastic and a suitable amount (generally a minor amount) of additive material to be dispersed throughout the moldable plastic, which mixtures are intended for subsequent use in a plastic molding process, by a method which permits separation or re-classification of the mixture into its moldable plastic and additive material components in the event that the mixture turns out to be incorrect or obsolete. The method includes the steps of obtaining small pellets of a moldable plastic having a first shape, these pellets being substantially free of the additive material. These small pellets of moldable plastic are then mixed with small pellets of moldable plastic into which has been incorporated one or more additives, these pellets having a second shape which is classifiably different from the shape of the other plastic pellets.

Abstract: A method is disclosed for preparing mixtures of moldable plastic and a suitable amount (generally a minor amount) of additive material to be dispersed throughout the moldable plastic, which mixtures are intended for subsequent use in a plastic molding process, by a method which permits separation or re-classification of the mixture into its moldable plastic and additive material components in the event that the mixture turns out to be incorrect or obsolete. The method includes the steps of obtaining small pellets of a moldable plastic having a first shape, these pellets being substantially free of the additive material. These small pellets of moldable plastic are then mixed with small pellets of moldable plastic into which has been incorporated one or more additives, these pellets having a second shape which is classifiably different from the shape of the other plastic pellets.