Discarded tires contain non-rubber components such as fibers and metal, what’s more, the discarded tires’ volumes are quite large. The non-rubber components is not conducive to the grinding process, and also affects the quality of powder and recycled rubber. So before crushing, we often need to dispose the non-rubber components contained in the rubber by removing, separating, rubber cutting, etc.
1. Non-rubber components removal
We need to remove the bead of waste tires. One way is to transect waste tires and cut off bead, which can be only suitable for small tires (smaller than car tires). Another way is to remove bead by using rotary bead cutting machine. The operation method is rotary fixed tire plate, and cut off the bead, which is suitable for giant tires. Sometimes, it needs to separate the tread and fetus by the tread separation machine and remove cycle in the tire tube.
2. Rubber cutting
After classification and non-rubber components removal, the waste rubber has different lengths and thicknesses, so it can’t be crushed directly, or it will affect the safety of the crushing equipment. So, we must cut the rubber first, and we often use crankshaft cutters to cut the rubber.
The main structure of the whole tire cutting machine is composed of a pair of rotary shafts, and the two shafts are equipped with several carbide knives. The knives are crossing in the working process, and cut the whole tires into pieces. The whole tire cutting machine can cut the car tires, lorry tires and radial tires into 25mm*25mm pieces. The production capacity is 4-5t/h. The powder plant of annual output 10000t only needs one device to meet production requirement.
The process of cutting tires into pieces is to hang the tires in the conveyor with hooks and then feed into cutting room. The relatively rotary knives cut the tires into required sizes. The machine is equipped with steel rotary race. If the rubber piece is larger than 25mm-25mm, it will get back on the cutting machine to be cut again along with the screen bezel edge. The tire cutting machine has two types, stationary and mobile. Stationary cutting machine is powdered by a fixed powder supply while the mobile cutting machine is powdered by mobile diesel generators. In the United States waste tires stacked area, they often use stationary cutting machine to cut the tires into pieces on the spot and then transport out the pieces for further process, which is very convenient.
For frozen crushed waste tire, it often doesn’t need the above process. It needs to feed the whole tires into freezing equipment, or cut the tires into definite size by the cutting machine and then feed into freezing equipment to crush.