Mixing process

Claim 1

In an improved process for agitating a liquid and adapted to achieve and maintain substantial homogeneity and uniformity therein, the step which comprises subjecting a liquid which, from about 10 to 90 per cent by volume, fills a generally enclosed, horizontally elongated treating zone simultaneously to a combination of: A. cyclical vertical displacement in said zone such that at a cycle rate in the range from about one-half to 60 times per minute, 1. first, said liquid is subjected to a vertical lifting force greater than that exerted downwardly thereon by gravity, and at least sufficient to move vertically at least about 10 per cent of the total volume of said liquid from a gravitationally lower region to a gravitationally higher region in said zone, and 2. secondly, such so displaced liquid is subjected to a gravitational falling force by effective removal of said lifting force therefrom, the total gravitational falling force applied thereon being at least sufficient to return substantially all of such so displaced liquid to said gravitationally lower region before said cycle is repeated on such so displaced liquid, B. rolling action in a generally peripherally located and generally horizontally extending region in said zone, said region extending circumferentially about the entire internal periphery of said zone, said region being continuously moving in a direction which is generally normal to the horizontal, said rolling action being produced by a similarly so moving band of pressure located adjacent to but following behind said region, said band of pressure exerting a force on said liquid in said region at least sufficient to cause movement of a portion of said liquid in said region along a roughly crosssectionally circular path normally away from the adjacent internal periphery of said zone adjacent to said band of pressure towards the interior of said zone a distance which is generally less than the maximum distance across said zone at a given peripheral position and then back towards said internal periphery forwardly of said band of pressure before moving towards said band of pressure, there being a shear rate between said internal periphery and said zone of pressure of at least about 5sec. 1, C. horizontal displacement in said zone in a longitudinal circulatory manner at a cycle rate such that the actual volume of said liquid moved from one end region of said treating zone to the opposite end region thereof and back within one minute is equivalent to from about one-tenth to 30 times the total volume of said liquid in said zone, such equivalent volume and the horizontal circulation rate for such liquid so moved, respectively, being approximately proportional to said cyclical vertical displacement cycle rate in any given instance, while continuously maintaining substantially the total volume of said liquid in said zone under laminar flow conditions.