Scraped wall agitator

Claim 1

In a tubular vessel, an agitator to mix the contents of the vessel and to clean the wall of the vessel, which agitator comprises (a) a shaft axially and centrally positioned in the vessel, which shaft is connectable to an outside rotational drive source, (b) at least one spiral blade positioned helically around the shaft and supported away from the shaft by rigid supporting arms attached to the blade and the shaft, such blade proportioned in length and diameter to impel the contents in predetermined motion, (c) a series of straight plate segments spaced at predetermined uniform intervals along the blade and attached to the blade such that the segments extend from the blade toward the interior wall of the tubular vessel, the plane of each plate relative to axis of rotation being approximately the same angle as the helix angle of the periphery of the blade, but the plane of the plate relative to the helical blade being positioned to slant either away from or toward the direction of rotation of the shaft, said plate being constructed to flex with predetermined controlled pressure at the interior wall, (d) a flexible tip attached to the end of each segment and positioned and contoured such that by overlap of each tip with respect to the adjacent tip ends, all portions of the interior wall of the tubular vessel are contacted during a single revolution of the shaft.