... machine: infinite speed variation; rpm in the fermenter: 70~600rpm±1%,The height of the stirring oar can be adjusted, too ... by circulating pump(Grundfos, Denmark), autocontrol (cooling water+5°C)~65°C±0.1°C,temperature probe(US) pH detection and control 2.00 ... DO detection and control 0-150±3% displaying precision 0.1%, sensor (Mettler, Switzerland) and shielding lead(Mettler, Switzerland) Feed ...