Pneumatic Knocker – Type K
Product properties
Maximum impact effect with lowest weight
.01application
The Pneumatic Knocker is used for bulk goods with material flow problems for instance bridge, siphon 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.
.02Construction & Functioning
The Pneumatic Knocker achieves a very high impact energy due to the spontaneously released stored compressed air energy.
The left picture shows the construction of the knocker:
The piston (1) designed as a permanent magnet, adheres in the end-position to the anchor plate (2) until the compressed air fed through the lid (3) overcomes the magnetic force.
The impact piston (1) loosens from the anchor plate (2), is very highly accelerated by the accumulated compressed air and hits onto the striker (4) with a speed of 6 to 7 m/sec., which transmits the impact to the silo wall.
After deaeration of the knocker, the impact piston (1) is pressed back into the starting position by means of the spring (5).
.03Sizes & Selection Chart
The Selection Chart below provides a rough reference for selecting the adequate size and number of Pneumatic Knockers for round silos of 60° cone. In case of rectangular containers, a minimum of two knockers are mounted on the flatter sides.
Move your cursor to the desired section (smartphone users have to click):
Important parameters for the selection of the right knocker:
- Thickness of the container
- Container material
- Container diameter
- Operating temperature
- If present, insulation thickness for the selection of the mounting
- Choice of version in aluminium, steel or stainless steel
- Protection type for operating environment
For the electrical components:
- Desired operating voltage
- Number of knockers
- Protection type for operating environment
For help in selecting the knocker, please send us the completed questionnaire. Any drawings, sketches or photos of existing plants are also helpful.
.05Mounting & Operation
For the assembly and operation of the pneumatic knocker the components shown in the picture are required:
- Attaching the Pneumatic Knocker Welding plate AP. With small pipes, small containers or containers with insulation welded plate in T-shaped APT
- Pneumatic 3/2 way solenoid valve in the desired control voltage.
- Electrical control for solenoid valve to desired control voltage. An existing PLC control can also be used.
- Pneumatic connectors and cables
- Maintenance unit for pressure reduction to 3.5 bar operating pressure, drainage and lubrication of the knocker is recommended.
Choose the right knocker for your application.
We have two types of knockers in our range: Our classic ‘singold’ Pneumatic Knocker Type K is suitable for many applications attaching the knocker on the silo wall. The special developed Pneumatic Distance-Knocker Type QJ is suitable for knocking from a distance against slow-moving drums and filling or emptying stations with moving containers.
Suitable accessories for
your Pneumatic Knocker.
Welding Plates
Pneumatic Valves
Electrical Controls
Sound Insulation
Maintenance Units
Do you have any questions?
Taking your individual situation into account, we are happy to assist you.
