vortex

In fluid dynamics, a vortex is a region within a fluid where the flow is mostly a spinning motion about an imaginary axis, straight or curved. That motion pattern is called a vertical flow.

A vortex mixer is a simple device used commonly in laboratories to mix small vials of liquid. It consists of an electric motor with the drive shaft oriented vertically and attached to a cupped rubber piece mounted slightly off-center. As the motor runs the rubber piece oscillates rapidly in a circular motion. When a test tube or other appropriate container is pressed into the rubber cup the motion is transmitted to the liquid inside and a vortex is created. Most vortex mixers have variable speed settings and can be set to run continuously, or to run only when downward pressure is applied to the rubber piece.

Applications:
Vortex mixers are quite commonplace in bio-science laboratories. In cell culture and microbiology laboratories they may be used to suspend cells. In a biochemical laboratory they may be used to mix the reagents of an assay or to mix an experimental sample and a dilutant.