Synchronising asphalt batch mixing

The synchronising drives are used in hot asphalt and bitumen batch mixing process. The batch mixing machine has two contra-rotating horizontally paddles, driven by a pair of Synchronised identical ratio Rossi bevel helical geared motors.

In this application it is vital to have both paddles synchronised to prevent one paddle driving into the other or for one paddle to take more load than the other, to ensure a proper mix of product and prevent failure of the expensive mixing paddles.

In previous designs synchronisation was achieved with the addition of large open gears on the opposite side from the gearboxes. These gears ensured the paddle shafts were mechanically synchronised, but needed lubrication and external guarding. Some machine designs also make use of a 1:1 right angle drive on the motor non drive end shaft with couplings and spacer shafts, but this also adds additional maintenance, weight and cost.

The Rossi solution removes the need for the external open gears or special motor designs and couples the two bevel helical gearboxes directly using standard catalogue product. This is achieved by the gearboxes being supplied with a standard option external shaft, known as Rossi U02H or UO2Hsin option. The geared units are supplied as a pair, and mounted with synchronizing shaft shafts end to end, allowing easy coupling of these shafts. The coupling only needs guarding and avoids the cost of gears and additional lubrication system.