The term "pre-shredder" has taken off with the advent of "slow shredders" which are characterized by a slow movement of the order of 40-50 rpm maximum of the rotor (or rotors), as opposed to fast shredders which work in kinetic energy with high rotation speeds of 1000 rpm and more.
These pre-shredders are able to develop considerable values of torque on the rotor(s), which allows the grinding substrates to be crushed and broken during work. On the other hand, the outgoing particle size is relatively coarse due to this mode of operation, hence the term pre-crusher. Moreover, these machines are often used mainly for the reduction of volumes of waste to be treated, these shredded products often then being directed to subsequent recovery.
However, in recent times, these pre-shredders have undergone a significant technological development which has made it possible to obtain much finer and better calibrated shredded material than in the past, which is reflected in parallel by greater flexibility of use: crushing of used wood , forest waste, stumps, logs, deconstruction residues, HID, tires, household waste, green waste, bark, pallets and carpentry scrap, etc.
This development of pre-shredders also makes it possible to significantly reduce energy consumption (fuel) because it is no longer necessary to place a pre-shredder in cascade followed by a refiner (or a fast shredder) but a single machine which is capable of producing the required particle sizes in a single pass.
This is the case, for example, with the new TEUTON single-rotor pre-shredder from the manufacturer EGGERSMANN, or the FORUS twin-rotor pre-shredder.
Of course, these developments also contribute significantly to the current decarbonization objectives (reduction of CO2 emissions), as well as to the reduction of operating and maintenance costs. Another advantage of these machines is their relative insensitivity to the presence of foreign bodies such as large ferrous materials, or rubble in the substrates to be treated.
