Cyclone Dust Collector

 The cyclone is a widely used type of particulate collection device in which

dust-laden gas enters tangentially into a cylindrical or conical chamber and leaves

through a central opening. The resulting vortex motion or spiraling gas flow pattern

creates a strong centrifugal force field in which dust particles, by virtue of their inertia,

separate from the carrier gas stream. They then migrate along the cyclone walls by gas

flow and gravity and fall into a storage receiver. In a boiler or incinerator installation this

particulate is composed of fly-ash and unburned combustibles such as wood char.

CYCLONES ARE GENERALLY classified according to their gas inlet design and dust

discharge design, their gas handling capacity and collection efficiency, and their

arrangement. Figure 6-2 illustrates the various types of gas flow and dust discharge

configurations employed in cyclone units.

CONVENTIONAL CYCLONE. The most commonly used cyclone is the medium

efficiency, high gas throughput (conventional) cyclone. Typical dimensions are illustrated

in figure 6-3. Cyclones of this type are used primarily to collect coarse particles when

collection efficiency and space requirements are not a major consideration. Collection

efficiency for conventional cyclones on 10 micron particles is generally 50 to 80 percent.

HIGH EFFICIENCY CYCLONE. When high collection efficiency (80-95 percent) is a

primary consideration in cyclone selection, the high efficiency single cyclone is commonly

used A unit of this type is usually smaller in diameter than the

conventional cyclone, providing a greater separating force for the same inlet velocity and

a shorter distance for the particle to migrate before reaching the cyclone walls. These

units may be used singly or arranged in parallel or series as shown in figure 6-5. When

arranged in parallel they have the advantage of handling larger gas volumes at increased

efficiency for the same power consumption of a conventional unit. In parallel they also

have the ability to reduce headroom space requirements below that of a single cyclone

handling the same gas volumes by varying the number of units in operation.