It consists of double cone on rotating shaft.
It is usually used for small amount of powders.
It is efficient for mixing powders of different densities.
Material is loaded and emptying is done through the same port.
The rate of rotation should be optimum depending upon the size, shape of the tumbler and nature of the material to be mixed.
The rate of rotation commonly ranges from 30-100rpm.
Mixing occurs due to tumbling motion