It should only be knocked when the silo outlet is open and the following equipment is in operation, otherwise the product may be compressed.
The Pneumatic Knocker is mounted according to Fig. 3. The AP welded plate is welded directly onto the silo cone. The rounding of the silo plate is balanced by flattening or by means of large welding seams. The welding plate Type APTxxx is used for smaller diameters. Insulated or rubberised walls or aluminium silos require special mounting plates.
The Pneumatic Knocker is to be mounted so that the deaeration borings are facing downward. Dust humidity and aggressive vapours, must not enter through the deaeration borings.
The compressed air is set to 4-4.5 bar, which corresponds to 0.5 bar above the release pressure of the knocker (depending on Type approx. 2.5 to 3.5 bar). The length of the operating time should be so adjusted to make sure that the impact will be released (approx. 3 to 5 seconds). The break time is selected according to material flow. It must not be to short, so that the Pneumatic Knocker has time for deaeration (deaeration time min. 4 sec) and should as far as possible be long enough to reduce the wear and tear and compressed air consumption. For shorter interval times can be reached with a larger valve or with, a quick-action exhaust valve (SE).
During operation, all screws and all nuts must be checked as to their tightness and, if necessary, be tightened by means of a torque wrench.
As to the maintenance unit, the condensate must be discharged from the filter, lubrication oil with approx. 46 cSt is to be refilled, the adjusted pressure and the oiler function is to be checked again.
Adjusting the Electrical Control Unit.
For product conveying out of a silo, cycle times of 5 to 20 seconds are recommended. Too frequent knocking should in any case be avoided, otherwise the product would be compressed. Continuous falling product should be knocked off in cycle times up to 30 minutes. If the layer of product becomes too thick, an avalanche-like break-off could block the outlet or overload the following machines. If several knockers are mounted on the periphery, it is preferable to activate them one after the other. The product flow and the air consumption is then constant. Residue in the container scales can be emptied with 2 to 4 impacts in a cycle time of 2 to 4 seconds. We can supply the necessary equipment for the electrical control of the knocker.
Regulations for Accident Prevention and Mounting
It is only allowed to install and use the Pneumatic Knocker as a knocking and evacuating device on silos, containers, cylinders and walls, after having paid special attention to the instructions and in accordance with the technical data given therein. Mounting, maintenance, pre-operational and operational as well as post-operational handling of the equipment and the accessories shall only be carried out by trained and qualified personal in compliance with the legal prescriptions and safety regulations. The knocker has to be installed, secured and controlled so that – in case of self loosened screws, cracked welded joints or other specific defects – there will be no danger for persons, animals, products or objects to be damaged or polluted.
The Pneumatic knocker shall be actuated only after having been tightly screwed on, otherwise its own bottom plate may be destroyed.