| 摘要 |
In the mfr. of a fat enriched powder the base powder and finely divided fat are fed into the tunnel where a cold air current rises through a perforated base plate to hold the powder and fat spray in turbulent, fluidized suspension, air being extracted via filters at the top of the tunnel. The powder, pref. sized at 200 to 700 mu, is fed in at one end of the tunnel and atomised fat, droplet size pref. 5-70 mu, is sprayed upwards into the tunnel treatment chamber through the base plate adjacent the feed end. The base plate slopes downward from the feed end to discharge end of the treatment chamber and cold air is supplied from a series of air chests beneath the base plate, each air chest being located directly below a filter suction chest in the top of the treatment chamber. The % wt. fat w.r.t. powder is pref. 14-33%. The air temp. is pref. 0 to 15 degrees C and the air extracted via the filters is recycled to the treatment chamber. Used in mfr. of fat-enriched powder, esp. skimmed milk powder enriched with an animal or vegetable fat such as lard, tallow, palm oil, coconut oil etc., partic. for feeding calves. High ratio of prod. output to air usage and energy requirement compared with spray-drying tower process. |
