Meanwhile the influences of a hopper structure on the flow patterns of wet materials are different from dry materials . usually the critical open diameter of a hopper for dry particles is more than 3 times of particle diameter , but not less than 4 times for wet particles . for dry particles , the hopper angle which causes transformation from funnel flow into mass flow is about 45 同時料倉結構參數(shù)對干濕顆粒流動特性的影響也存在一些明顯的差異:對于干顆粒,滿足不結拱的料倉開口度尺寸至少為顆粒直徑的三倍,而濕顆粒則要求料倉開口度至少為顆粒直徑的四倍;干顆粒由漏斗流向整體流轉換的角度在45度左右,而濕顆粒的轉換角度為40度左右。