A
shaker movement permits an arbitrary path of motion in a
shaker's shaking action. The
shaker movement comprises independent control over the "X" and "Y" directions of the shaking actions by a pair of track assemblies, each track
assembly comprising a pair of fixed rods and a pair of sliding rods that are interconnected with each other in a rectangular, grid-like pattern. Motion in both directions can be driven by a single motor utilizing independent
pulley-and-belt systems or by two synchronized motors which are connected to a sliding rod of each track
assembly. By altering the
relative amplitude,
phase angle, and frequency between the "X" and "Y" directions, the shaking action can follow a desired path. The shaker path can be varied from the traditional circular orbital motion or
linear motion, to a new group of shaking patterns in which the direction of the shaking movement can reverse. The new patterns of shaker movement cause the liquid being shaken to be more thoroughly mixed, with less power input, and at a lower
angular frequency than is practical with traditional paths of motion. This results in higher rates of
gas transfer to and from the liquid, resulting in greater growth of a bacterial culture, and for higher rates of
mass transfer at equivalent levels of energy input.