B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
B01F27/00—Mixers with rotary stirring devices in fixed receptacles; Kneaders
B01F27/80—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis
B01F27/92—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis with helices or screws
B01F27/921—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis with helices or screws with helices centrally mounted in the receptacle
B01F27/9211—Mixers with rotary stirring devices in fixed receptacles; Kneaders with stirrers rotating about a substantially vertical axis with helices or screws with helices centrally mounted in the receptacle the helices being surrounded by a guiding tube