Innovations from Venti Oelde Centrifugal fans in cement works – Avoidance and elimination of deposits

Centrifugal fans in cement works – Avoidance and elimination of deposits 1. Introduction In many industrial processes it is necessary to convey dust-laden gases. Caking in the fans and in the ducts used for handling dust-laden gases is always a problem when manufacturing cement and lime and in numerous other industrial processes. Deposits in the ducts cause a reduction in the duct cross-section, leading to an increase in the flow velocity and therefore to a higher flow resistance. The flow volume of the fan is reduced, i.e. throttled. The throttle effect is considerable because the flow resistance...

2.5 Moisture content The tendency to caking increases where there is a high moisture content in the air and material. This always occurs when the temperature falls below the dew point during starting up and running down. 2.6 Angle of repose of the solids Not only the opening angle of the impeller blades but also the natural angle of repose of the dust are important factors in the formation of deposits on the impeller blades. Practice has shown that deposits can be avoided if the dust has a low natural angle of repose and at the same time the opening angle of the impeller blades is more than 42°...

are therefore avoided. The size, position and angle of the blades are determined by the particle size composition, the density of the particles, the fan size and the tip speed of the impeller. 4. Cleaning methods In practice it is often found that deposits can only be reduced or displaced, but not completely prevented, so cleaning becomes essential. Cleaning should be possible during operation, and the cleaning intervals should be predictable and scheduled. However, if it is only possible to clean the fan when it is stopped and opened, then it is absolutely essential that interruptions in production,...

hopper with a volume of about 2 m3 which is connected to the fan inlet through a spigot with The use of coarse sand or a rotary valve at the discharge gravel is an extremely efficient side. A vibration monitor method of cleaning off firmly (Vibrocontrol 1000) is installed fixed clay components on the on the impeller-side fan leading impeller blade edges. bearing. The rotary valve is The material is fed into the actuated when the vibration gas stream on the inlet side velocity of the fan exceeds a of the fan. The sand or gravel pre-selected figure; the gravel particles strike against the is then...

4.4 Cleaning with fan opened and stationary Sandblasting is a widely used method, aimed specifically at removing firmly fixed and loose deposits (Fig. 8). When the impeller has been fixed in the required position, it is cleaned with a compressed air lance and blasting media (foundry sand or coarse sand). An experienced team of two will, for example, take about two hours to clean the system fan after a cyclone preheater. Figure 8: Cleaning the trailing edges of the impeller blades with compressed air lance and blasting media while stationary Industrial fans Dust collection and process air cleaning...