Abstract: An oscillatory stirring apparatus for liquids in a container comprising a stirring assembly attachable to said container and means to supply at least two cyclically alternating flows of air under positive and negative pressures to said stirring assembly, said stirring assembly comprising a housing containing at least two pressure-activated chambers spacedly arranged within said housing, a stirring rod dependingly supported within said housing, means interconnecting a portion of said rod within said housing with each of said chambers, means on the exterior of said housing to connect said chambers to said air flow supply means and means to secure said housing to said container in sealing relationship with an opening in said container.

Abstract: A stirring rod is inserted through a resilient suspension diaphragm which is sealably secured to the underside of a closure for a flask or container. An L-shaped support bracket is attached to the outer, upper surface of the closure. The upstanding leg of the bracket carries an expansible pressurizable chamber which is connected, on its outerside, to a supply of single phase ACA and, on its innerside, to the upper portion of the stirring rod extending above the closure by a horizontal link which, at one end, is fitted over the stirring rod and at the opposite end is secured to the expansible chamber. The horizontal leg of the bracket which is secured to the closure carries, at its extremity opposite the upstanding leg, support means, to the upper end of which is attached a camming plate. The camming plate extends toward the upper portion of the stirring rod but stops short of this portion to allow controlled lateral movement of the stirring rod toward the camming plate.