| 摘要 |
Improved methods of operating batch or continuous blenders 10 having tub (11) and two agitators (17 and 18) extending parallel to each other, each agitator having horizontal shaft (19) and agitator ribbon (21) wound helically around the shaft. For batch-blending, the two agitator ribbons are wound in the same direction around the shafts, and the shafts are rotated in opposite directions for folding the product into the middle of the tub for mixing. The agitators are periodically reversed in direction of operation to prevent the build-up of product at end corners (36 and 37) of the tub and the consequent mechanical breakdown of ingredients which has occurred with previous blenders. For continuous blending to be carried out in a tub with twin agitators, the agitator ribbons are wound in opposite directions on their shafts. The agitators are rotated in opposite directions to fold the product into the center of the tub for mixing, with both agitators moving the product in the same direction lengthwise in the tub. The agitators' rotation direction is periodically reversed, with the time of reversed operation in each cycle being less than the time of forward operation, so that the product as a whole progressively moves toward discharge end (14) of the blender as the product is being mixed. When needed, scrapers (37 or 48) are attached to the agitator ribbons to scrape the wall of the tub upon rotation of the agitators in either direction.
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