Dust 

Fans for solids: granulate, dust, fibres.

Fans for dust-containing gases must be designed in such a way that as little build-up as possible can form on the impellers and in the casing. Build-up on the impeller quickly leads to imbalance and bearing damage.

Impeller types
For dust applications, the impeller blades (Q-types) are designed in such a way that higher surface speeds prevent the formation of deposits on the back of the blade, which would compromise efficiency.

The casing must offer a way for easy cleaning. This is often achieved by a cleaning door on the casing. The area of the inflow and outflow (flexible transitions) must also be easy to clean and should contain as little dead space as possible. Depending on the application, spray nozzles for impeller and casing cleaning are integrated already.

Dust can be highly abrasive and granulate even more so. The exposed surfaces must be able to withstand this stress. Armouring at the inlet or exchangeable wearing plates in the casing may be necessary depending on the medium.

Dust generates a stronger static charge than pure gases. Any static electricity that builds up must be safely discharged. Dust can pose a high, often underestimated ignition risk, both as a cloud and through layers of build-up.

Special materials and special coatings such as ceramics, overlay welding etc. are used after precise clarification of the operating conditions. Special seals, e.g. SP seals with sealing air, prevent dust from penetrating the drive shafts.

Monitoring the fan vibrations is recommended for media containing dust, as this makes it easier to detect any build-up inside.