Cyclone separators particle acceleration

A widely used type of dust-collection equipment is the cyclone separator. A cyclone is essentially a settling chamber in which gravitational acceleration is replaced by centrifugal acceleration. Dust-laden air or gas enters a cylindrical or conical chamber tangentially at one or more points and leaves through a central opening. The dust particles, by virtue of their inertia, tend to move toward the outside separator wall from where they are... 

Impactors accelerate the particles in a jet toward a surface (classical impactors) or toward a nozzle (virtual impactors). Both approaches can be used to remove large particles from the sample airstream and typically have steeper sigmoidal cutoff curves than cyclone separators. The remaining particles can then be collected using a filter, cyclone, or impaction onto a surface or into a liquid. Classical impactors are compact but need to be cleaned frequently. Virtual impactors reduce the cleaning problem but are more expensive to build than classical impactors. Impactors have been configured to collect particles of 0.1 to greater than 10 pm with reasonable efficiency. 

The cyclone separator (Figure 14-18) is a device that uses centrifugal forces to accelerate the settling of solid particles. Basically, a particulate-laden gas stream is introduced tangentially in the unit. Particles move to the cyclone separator walls and then to the bottom of the device. The gas first moves downward, then up to the top,... 

Cyclone collectors are popularly used both for particle removal and for particle sampling (Fig. 13.1). The separation process of a cyclone relies on the centrifugal accelerations that are produced when particle-laden fluid experi-... 

The cyclone, or inertial separation method, is a common industrial approach for segregating a dispersed phase from a continuous medium based upon the difference in density between the phases. The concept takes advantage of the velocity lag which occurs for dense particles with respect to a lower density medium when both phases are subject to an accelerating flow field, such as within a rotating vortex. The larger the acceleration, the smaller the particle which fails to follow the continuous phase streamlines and will migrate to the outer wall of the cyclone for collection. 

Venturi scrubbers Water is sprayed into the gases as they pass through a venturi. The acceleration of the gas flow in the venturi throat causes an intensive mixing of both media. The dust particles are damped, making them heavier, so that they can be separated in a cyclone or other system placed downstream. If the gas flow drops, the venturi throat is adjusted to maintain the collection efficiency... 

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