Date03 September 2009

SUSTAINABLE working practices are expected to become the norm in the wider quarrying industry and the use of recycled and secondary materials will help many companies improve their environmental performance.

Bernardi Impianti International have recently launched their new RAP ecological dryer (RED), which is said to accept up to 50% recycled asphalt pavement (RAP).

The counter-flow-type dryer drum – which includes a special high-temperature combustor and a new internal blade system – accepts RAP fed directly from the existing cold feed system blended with the primary aggregate, thereby removing the need for any secondary RAP equipment, such as elevators, feeders and drying equipment.

The RAP and primary aggregate blend is retained in the blade system to ensure there is no direct contact between the flame and recycled material. This removes any thermic shock to the bitumen and allows the release of its moisture inside the drum.

The combustor inside the dryer drum is manufactured incorporating a special steel support system fitted with refractory bricks for high-temperature resistance. These bricks are arranged to protect the blended materials being dried from direct flame irradiation.

The system also eliminates harmful bituminous steam and dust through post-combustion, while optimizing combustion and reducing fuel consumption. The radiated heat generated by the combustor is used to heat the blend and, thanks to the softening of the bitumen and the release of humidity, a mixture of virgin aggregate covered with bitumen is produced.

According to Bernardi Impianti, the RAP and primary aggregate blend is sufficiently dry, so there is no problematic obstruction or adherence to the plant's elevators and screens. This allows the user to screen and size the blend, offering greater flexibility when determining the asphalt mix.

Bernardi Impianti have appointed Berkshire Engineering Supplies (BES) as their sole UK and Ireland distributors. As part of the dealership, BES offer a 24h technical backup service to customers, with spare parts available from their Aldermaston base in Berkshire.

RAP Ecological dryer

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