Abstract: According to the present invention, there is provided a stirred tank for storing yeast slurry to be supplied to fermentation tanks where fermented foods such as beer are fermented, is characterized in that a stirring impeller is provided within the stirred tank and so constructed that a maximum diameter of a rotation body defined by the rotation of the stirring impeller is 60-90% of the inner diameter of the stirred tank, and the height of the rotation body is 70% or more of a standard depth of the yeast slurry normally stored in the stirred tank.

Abstract: According to the present invention, there is provided a stirred tank for storing yeast slurry to be supplied to fermentation tanks where fermented foods such as beer are fermented, is characterized in that a stirring impeller is provided within the stirred tank and so constructed that a maximum diameter of a rotation body defined by the rotation of the stirring impeller is 60-90% of the inner diameter of the stirred tank, and the height of the rotation body is 70% or more of a standard depth of the yeast slurry normally stored in the stirred tank.

Abstract: An axial-flow impeller having a maximum blade width less than 20% of the impeller diameter, the pitch angle at the radial position 0.6 is 12.degree.-22.degree., the width at the tip end portion of the blade is 12-75% of the width at the radial position 0.6, the pitch angle at the tip end portion of the blade is 5.degree.-10.degree. smaller than the pitch angle at the radial position 0.6, the width at the root of the blade is 40% or more of the width at the radial position 0.6, and the pitch angle at the root of the blade is 25.degree.-50.degree.. An axial-flow impeller having a maximum width of the blade 20% or more of the impeller diameter, the radial position of the maximum width portion is 0.4-0.8, the pitch angle of the maximum width portion is 12.degree.-22.degree., the width at the tip end portion of the blade is 12-75% of the maximum width, and the pitch angle at the tip end portion of the blade is 5.degree.-10.degree.

Abstract: A mixing apparatus includes a bottom ribbon blade adapted for viscous fluid contents. The mixing apparatus includes a vertically positioned mixing vessel including a cylindrical wall and a bottom wall disposed on a lower portion of the cylindrical wall wherein the bottom wall is of a semi-ellipsoid shape, dished shape, or circular cone shape with an obtuse apex angle and each of the convex surfaces of which is oriented downwardly. An impeller shaft is vertically and coaxially aligned within the mixing vessel and a helical ribbon blade is disposed within the mixing vessel in such a manner as to be rotated by a driving mechanism via the impeller shaft.