Effectively these are huge rectangular boxes, or troughs, usually fabricated from steel plate, containing two steel shafts with paddles attached along their length. They are commonly used for washing and sizing cemented aggregates, gravel, various ores and limestone etc.
Known as log shafts, from which the log washers take their name, the steel shafts are aligned parallel to each other within the box, and as they turn the paddles intermesh. The turning and intermeshing paddles facilitate material-on-material cleaning, with water jets, and they also crush and convey the material along the box to the exit point at the far end.
The custom gearbox designed by Renold Gears has a single input shaft with counter rotating double output shafts to drive the two logs.
The internal gearing was designed to ensure the logs are aligned perfectly and do not come into contact with each other during operation. As well as providing the torque to drive the machine the gearbox also acts as a bearing support to support the two logs. They will be supplied in two sizes to match the centres of the logs and the power of the machine.
Renold Gears has supplied gear units to this industry sector for over 20 years and the experience it has gained was a primary reason the company was chosen to provide this solution. The gearboxes were amongst the first to be produced on Renold's new £1.8 million, state-of-the art, Burkhardt + Weber machining centre at its factory in Rochdale.