Russian magazine (2014 eng.)
With more than 90 years experience in the size reduction sytems and 50 years in rubber technology, PREVIERO is among the leading companies in the manufacturing and installation of grinding and blending lines for natural and synthetic rubber including, within the others, SIS,SBR,BR,NR,NBR and EPDM. PREVIERO size reduction lines are used in the majority of rubber processes including polymerization, tire production, glue production, rubber compounding and mixing lines, extrusion, devulcanization and recycling.
The state of art technology of the rubber grinding and blending systems is for sure reserved to the field of the tire production where, together with the quality of the process, it is also necessary to grant a very high efficiency. In the Tire industry Previero can provide a series of grinders able to directly grind rubber bales of 25 – 35 – 100 kg, down to the dimensions required to store, stabilize and dose the rubber to the mixers.
The most evident advantage of our solution is the possibility to have a fully automatic control of the rubber feeding system, including the possibility to automatically weight the material in front of the mixers , to obtain a better and more stable master batch. The compounds obtained with Previero systems are more homogenous within the single batch and also within different batches.
The Tire production feeding system is composed of the following machines :
- Feeding area: composed of feeding conveyors to allow the dosing of the rubber bales into the grinder.
- Grinding area: composed of a grinder with production 5- 20 tons/h to allow the size reduction of the rubber to the required dimension (customer specification), minimizing the Anti-Sticking consumption.
- Storage and blending area: composed of blenders with capacity of 2 – 5 or 10 tons, to allow the rubber homogenization and the storage of the chopped pieces for the necessary time. The high speed discharging up to 23-30 tons/h increases the line efficiency and the immediate availability of the rubber upon mixer request.
- Weighing system: composed of scale conveyors to allow the control of the quantity of the rubber fed into the mixers.
The advantages of such a process are the followings:
QUALITY: All rubbers qualities are weighed when still in bales before grinding and the ground material can be blended before the internal mixer. Results achieved with Previero technology are:
- Feeding of the internal mixer with correct quality and quantity of rubber
- Reduction of the risk of off spec masters
- Reduction of off spec tires
- Guarantee of a much better tolerance on the tires quality
ECONOMY: Off spec rubber bales can be checked before grinding to define the correct mix of rubbers and to blend them to obtain the required homogenized product. Results achieved with Previero technology are:
- Reduction of input material cost
- Increase of tires quality (less off spec)
AUTOMATION: The line can automatically feed the bales into the grinder, dose the antisticking agent, convey the material to the rubber blenders and discharge the material into the internal mixers. Results achieved with Previero technology are :
- NO operator influence on the final material quality
- Constant and regular process with minimum stops
INTERNAL MIXER OPERATION: The ground and blended rubber is weighed and dosed to the internal mixer . Results achieved with Previero technology are:
- Less absorption peeks
- No need for pre-heating
- Optimal charges tolerance
- Less mechanical job, that means less wearing
- Shorter internal mixer time thanks to a better and immediate dispersion into the mixer chamber
All our grinding systems are completed with a suitable liquid and powder anti-sticking dosing unit that can be minimized and dosed according to the type of rubber and operational conditions from 500 to 10.000 kg each. Our system can be integrated with a supervision software easy to be integrated with the line production control.