Apparatus for cultivation of microorganisms on granular nutrient medium

An apparatus for cultivating microorganisms on a granular nutrient medium, comprising:

• a fluid tight vessel which houses:
• a vertical arrangement of perforated partitions dividing said vessel height-wise into a plurality of sections, said partitions being a first kind and a second kind alternatingly arranged height-wise of the vessel;
• the first kind including discs mounted to define an annular gap with the housing of said vessel, and the second kind including flat rings with a central opening, sealingly secured on the housing of said vessel, the annular gaps between the housing of said vessel and the central openings of the flat rings defining ducts for the passage of the nutrient medium into the underlying sections;
• cylindrical shells overlying each of said perforated partitions and defining in each respective section intermediate accumulators of the nutrient medium, wherein each said shell is mounted for vertical displacement, to define selectively a passage between said respective perforated partition and said shell for advancing the nutrient medium toward said ducts;
• and means for selective vertical reciprocation of said cylindrical shells;
• a drive shaft extending along the axis of said vessel;
• blade-type agitators accommodated in each said section of the drive shaft above said perforated partitions, that is, above said discs and flat rings;
• the blades of said agitators overlying said discs having a positive angle of curvature, to advance the nutrient medium from said intermediate accumulators toward said annular gaps;
• the blades of said agitators overlying said flat rings having a negative angle of curvature, to advance the nutrient medium from said intermediate accumulators toward the central opening of said flat rings;
• a loading port at the top of said vessel;
• a discharge port at the bottom of said vessel;
• connections for inlet and outlet gas flow communicating with said sections of said vessel.