| 摘要 |
A molding sand mixer comprises an elongated tub with a pug mill type agitator therein. The agitator comprises a series of paddles mounted an an oblique angle on a shaft. Blade portions of the paddles which sweep the wall of the tub have a greater circumferential extent than shank portions of the paddles. The aggregate circumferential extent of the paddle blade portions almost fills the space around the periphery of the tub, when viewed in end elevation. There are, however, substantial circumferential gaps between the shank portions of the paddles when viewed in end elevation. The blade portions will substantially completely sweep the tub wall but sand in the vicinity of the shanks will be partially bypassed through said gaps. The paddle agitator is rotated at relatively high speed so that the sand is slapped and batted to cause it to fly and bounce in the tub. This aerates and ventilates the sand and removes heat therefrom, and breaks up clumps of agglomerated return sand for through mixing of the sand with water and blending of the sand with additives.
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