Abstract: A rotating claw drum for shredding discarded material (such as used carpet) is created from flat circular plates that are stacked tightly together on a driveshaft or drum, to create an impermeable drum face that prevents particulates from entering and fouling the internal mechanisms. Each flat plate is provided with at least one claw-holding slot in its outer rim; 6 to 12 slots preferably should be provided in each plate. Locking means (such as a locking bar that will pass through aligned locking notches in the slots and claws) will lock the claws in place while the drum is in use. After the drum has been stopped, a locking bar can be removed, to release a damaged claw from its slot so it can be replaced, without having to disturb any other claws.

Abstract: A method and machine are disclosed for using a cold dry abrasion step for separating segments of discarded carpet into pile material (usually nylon) and backing layers (usually polypropylene) for recycling. A preferred method of abrasion uses dry ice pellets (made of frozen carbon dioxide) which are ejected at high speed from a set of nozzles that shoot the pellets directly into an abrasion zone, as a segment of discarded carpet on a conveyor system is being stripped apart and disassembled. The dry ice pellets "freeze" the binder material (usually latex) by lowering it to a temperature that makes the binder brittle and easy to break apart. The pellets also serve as abrasive agents, in a manner comparable to sand-blasting; however, unlike sandblasting or liquid (steam or chemical) systems, the dry ice pellets evaporate (sublimate) directly into gas without going through a liquid phase, and without leaving any liquid or gritty residue.