Pneumatic knockers resolve disruptions in material flow by causing the silo outlet to vibrate. They are very gentle on the silo wall and avoid dents that would lead to further problems with the material flow.
The pneumatic knocker achieves its high rate of impact power through spontaneously released energy stored in the form of compressed air. The percussion piston, designed as a permanent magnet, adheres to the anchor plate in the resting position. When the supplied compressed air overcomes the magnetic force, the percussion piston detaches from the anchor plate and is greatly accelerated at a speed of 6 to 7m/s. The percussion piston hits the striker; the striker transfers the impact to the silo wall. After the compressed air has escaped, the spring pushes the piston back into its original position.
The big advantage over vibrators is that there is no imbalance; the pneumatic knocker creates an elastic shock.
singold gerätetechnik offers pneumatic knockers in six sizes. The right size depends on the thickness of the silo wall. The company’s range covers wall thicknesses from 1 to 25mm. The number of knockers and at which points of the silo that they are to be ideally installed should be assessed individually depending on the discharge situation. It is recommended, for example, that rectangular containers have at least two knockers. They are attached to the two flatter sides and operate interchangeably.
The pneumatic knocker can be effective in a multitude of application situations and is therefore available in different materials and designs with a temperature resistance of up to 140°C. For slowly rotating drums, hot walls and filling or emptying stations with changing containers, there is a variant of the pneumatic knocker, the QJ distance knocker.