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The pneumatic knocker is used for bulk goods with material flow problems for instance bridging, funnel flow and residue formations, when high speed shakers and vibrators with soft sine-shaped oscillations are no longer effective.

The effect of the knocker is comparable to that of the famous “silo hammer”, but without distorted silo spouts additionally impeding the material flow.

The knocker is normally controlled by an electrical control system with a solenoid valve.
Within the area where the knocking takes place there should be enough space for the impact to expand in all directions.

Reinforcements of the silo walls and additional ribs should be avoided, as this increases the weight and the strength of the silo walls and thus reduces the effect of the knocker.

The Pneumatic Knocker produces an ideal elastic shock that is specified as the impact energy E = m/2 × v2 [kgm/s2 = Nm] and as impulse
J = m × v [kgm/s = Ns]. There is no impact force or out-of-balance such as vibrators generate.

The effectiveness of the knocker is evaluated according to the following rule: If the product can be knocked off or made to flow with a hand hammer, the Pneumatic Knocker is also effective.