Patent ID: 6955461

Claim:
An apparatus comprising: a container, the container having a bottom and a bottom drain; a tickler impeller in the container above the bottom of the container, the tickler impeller having at least two curved blades mounted on a vertical shaft for rotation in a container, the curved blades extending upwardly at an angle from the horizontal of from 15° to less than 90°, each of the blades having a concave face which faces downwardly towards the bottom of the container and a convex face opposite the concave face which convex face faces upwardly, the concave face leading and convex face trailing when the tickler impeller is rotated in the direction of rotation of the tickler impeller, the concave face curvingly facing downward from the end toward the shaft to the end of the blade opposite the shaft, the angle from the horizontal and the downward angle of the face being effective for creating an inward swirl towards the a bottom of the container when the tickler impeller is rotated in the direction such that the concave face leads and the convex face trails.