Continuous compartmented mixer

A continuous mixer comprising:

• an elongated tub having at least two end-to-end compartments, each compartment having first and second opposed ends and two side-by-side arcuate troughs ending between said ends,
• a pair of rotatable horizontal shafts extending through said compartments,
• an elongated agitator mounted on each shaft in each compartment for rotation in said arcuate troughs upon rotation of said shafts, one agitator in a compartment having means thereon for urging a product in contact therewith to move towards the second end of the compartment when the shaft on which it is mounted is rotated in a forward direction and to move towards the first end of the compartment when the shaft is rotated in a reverse direction, the other agitator in the compartment having means thereon for urging a product in contact therewith to move towards the first end of the compartment when the shaft on which it is mounted is rotated in a forward direction and to move towards the second end of the compartment when its shaft is rotated in a reverse direction,
• means for cyclically rotating said shafts in unison first in their forward directions and then in their reverse directions and for setting the ratio of forward and reverse rotation times in a cycle of operation,
• means for continuously transferring a portion product in the first of two adjacent compartments from that compartment into the next of said compartments at a controlled rate of transfer,
• means for continuously discharging a portion of a product in the last of said compartments from that compartment at a controlled rate substantially the same as said rate of transfer.

A method of mixing a product in a mixer tub having first and second end-to-end compartments, said compartments each having first and second opposed ends, said compartments having a generally vertical partition therebetween which is the second end of said first compartment and the first end of said second compartment, a pair elongated agitators disposed in each compartment for rotation about parallel horizontal axes extending between the ends of the compartment, one of each pair of agitators having means thereon for urging a product in contact therewith to move towards said second end or the first end of its compartment in response to forward or reverse rotation, respectively, thereof, and the other agitator of the pair having means thereon for urging a product in contact therewith to move towards said first end or said second end of the compartment in response to forward or reverse rotation, respectively, thereof, said partition having two openings therethrough, a solid screw rotatable in unison with each of said agitators, said screws extending through said openings, said screws each having surfaces thereon for urging a product in contact therewith to move from said first compartment to said second compartment, or vice versa, in response to forward or reverse rotation, respectively, of the agitator with which the screw rotates, said method comprising:

• repeatedly reversing the rotation of the pair of agitators in each compartment so that for each repeated cycle of operation both agitators rotate in unison in their forward direction for a predetermined length of time and then rotate in unison in their reverse directions for a predetermined length of time,
• setting the speed of rotation of said agitators to produce optimal mixing of the particular product in said mixer,
• setting the ratio of the length of times of forward and reverse rotations of said agitators so that said screws transfer product from the first to the second compartment at a desired rate.