Refiner - Contd...

Rubbing actions are considered as the main separating actions in the disk refiner process. When the materials, such as wood, pass through the gap between the disks, the reverse rotating disks give the wood the opposite dragging force, which tend to tear wood fibers apart. Compare the typical threshing actions in the cylinder-concave, the refiner gives more tender threshing separating actions without breaking the fibers.

Applications:

Paper industry

Reference:

ORNL drawing 93M-5104, adapted from H. E. Boyer and T. L. Gall, Metals Handbook, ed. H. E. Boyer, T. L. Gall, American Society for Metals, Metals Park, Ohio, 1984.

Gravity Table

Gravity table is used to separate (sort) materials by physical properties including density and particle size.

The basic actions involve vibration and air pressure.

There is a series of fans blow air which create pressure under a porous cover. This upward force gradually lifts the lighter material and produces a reduced amount of friction force between the material and gravity table surface. With the action of vibration, heavier materials which touching the surface of gravity table slowly move up, while the lighter materials which are not touching the table surface slowly move down.

Factors effect the separation: airflow, material quality (e.g. poor quality kernels that have low test weight)