Liquid aluminium is transferred from a casting furnace or transport crucible into a buffer channel. A conical regulator plug fitted with a float regulates the level in the casting channel that follows the buffer channel, ensuring a constant fill level in the casting die. If the level in the casting channel rises, the cross-section of the outlet is narrowed and the inflow of aluminium reduced.
The aluminium is transferred onto the rotating casting plate through fine boreholes in the die. At the same time, the rubber-mounted die is subjected to continuous vertical oscillation by a vibrating motor in order to encourage the aluminium flowing through the holes to separate into drops. The drops solidify immediately on hitting the rotating plate, which is cooled from below using water sprayed out of nozzles. The temperature of the cooling water is regulated and maintained at a constant level with the help of a second sealed cooling circuit with a built-in heat exchanger.
A high-pressure fan mounted above the rotating plate blows the drop-shaped granules away from their landing position into a collection chute, from where they can be conveyed to a packing station or transported to a container. Immediately after the removal point, felt rollers are used to apply a release agent to the rotating plate in order to prevent the granules from adhering to it. The size of the granules can be altered by adjusting the diameter of the boreholes on the casting dies and the frequency of the vibration generator. Granules are primarily used in the steel industry for deoxidisation purposes.
Essentially, the system is made up of the following components:
- A water-cooled casting plate sitting atop a large ball-bearing slewing ring
- A helical-geared motor
- A casting unit consisting of ceramic dies and a vibration generator
- A casting channel with a level-regulation mechanism
- A buffer channel
- Two cooling water circuits