| 摘要 |
<p>A tunnel for freezing scrap is adapted to reduce consumption of volatile liquid cryogens. The tunnel is rotated in an inclined oriientation to move scrap from a scrap inlet to a scrap outlet. A liquid cryogen is injected into the tunnel. The scrap inlet may incorporate a screw drive or other mechanism to reduce loss of gaseous cryogenic material. An exhaust conduit permits discharge of spent gaseous cryogen. The temperature of the spent gas is sensed and indicated, and the rate at which spent cryogen is exhausted and fresh cryogen is introduced is varied with the temperature. A discharge end of the tunnel contains an annular plate which prevents free discharge of liquid cryogen. A longitudinal rib attached to the interior surface of the tunnel adjacent the plate lifts scrap from liquid cryogen accumulating at the plate and drops the scrap through the central opening. The plate is inclined relative to the rotational axis of the tunnel so that the opening in the plate is angled to properly receive the scrap. The rate of processing is controlled by varying both the rotational speed and inclination of the tunnel so that different degrees of tumbling action can be provided at a desired processing speed.</p> |
