Tumbler screening machine

Operating behavior & mechanical features

The screenings are fed centrally, above the center axis, and travel either radially or spirally deflected to the edge of the drum according to the set vibration characteristics – the spiral shape is adjustable.

The deflection can result in the oversize grain not reaching the edge of the drum and therefore not being discharged. This would be important, for example, for control screening with a very low proportion of oversize particles. The size of the spiral deflection significantly determines the dwell time of the screenings on the screen bottom and therefore the screening result. It depends on the properties of the material to be screened, such as grain shape/structure, surface moisture and the desired screening result.

The screen structure consists of one to three screen drums and is connected to the base frame via spiral springs. The vibrating drive motor is mounted under the screen box, in the direction of the center axis.

The vibration exciter consists of two round disks with unbalances that can be changed at standstill. The disks are arranged at the shaft ends above and below the motor. The distance between the disks, the size of the unbalance weights on the upper and lower disk and the angle at which they are offset from each other determine the intensity and shape of the three-dimensional vibration characteristics together with the motor speed.
The vibration shapes can be optimally adjusted to the material to be screened and the required screening result
by simply moving the unbalance weights of the lower vibrating cell.