摘要 |
<p>Material is fed into a revolving drum which has an interior configuration, preferably in the form of a helical blade, to convey the material at a controlled rate through the drum. A low temperature gas, such as nitrogen, is introduced into the drum downstream when viewed in the direction of travel of the material, in a liquid state at a controlled rate through a spray nozzle system, thereby continuously exposing the material to the cooling effect of the gas. A portion of the gas is recirculated from the upstream end to the downstream end of the drum. The material is pre-cooled in the upstream portion of the drum. After exiting from the drum, the material may be crushed or impacted and separated.</p> |