Classification of centrifugal separators

The first and simplest is the circular or pipe-type inlet. See Fig. 1.3.8 a. Such inlets are typically foimd in inexpensive cyclones constructed from sheet-metal wherein some sacrifice in separation performance is acceptable. Many woodshop and grain processing units are designed with this type of inlet. Unhke the slot-tjrpe inlet described below, pipe-type inlets eliminate the need to fabricate a round-to-rectangular inlet transition section. 

The fourth type of inlet we wish to describe is that of swirl vanes. As shown in Fig. 1.3.8 d, a swirl-vane assembly allows the gas to enter the cyclone parallel to the axis of the cyclone The swirl-vane assembly is positioned between the vortex finder (or, in case of a straight-through device, see below, a central solid body) and the outer (body) wall of the cyclone. This type of inlet is often inserted in cylindrical-bodied cyclones rather than in cylinder-on-cone or conical-bodied geometries. When it is, we refer to the separator as a swirl tube. Swirl tubes are often of small size (by commercial standards) and are most commonly arranged in a parallel array on a common tube-sheet within a pressure-retaining vessel. They are normally fed from, and discharge into, common, but separate overflow and underflow plenums. 

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