Design of the Inlet

The cross section of a tangential inlet tube to a cyclone is often rectangular. Inlets with circular cross sections ( pipe-type inlets) are mostly used only in small sampling cyclones and in some applications where a simple circular inlet can achieve the desired separation and/or simplicity of construction and low cost are prime considerations. Certain shop and grain-processing cyclones fall into this category. 

Aside from generating turbulence, a poorly designed inlet transition section, namely one that is too short, can lead to particle fouling and to rapid erosion of the cyclone s inlet target zone (see Chap. 12). This is particularly true if the transition piece was installed, in part, to decelerate the incoming flow ahead of its entrance into the cyclone. 

As we mentioned in Chap. 1, the simplest inlet configuration for a cyclone is the so-called slot inlet, where the inlet simply joins the cyclone body flush with the outer wall. However, if the inlet is relatively large (as it is in the high capacity cyclones, see the previous section) or the solids loading is high, it is better to offset its position radially. In this way, it joins the cyclone outside the body (see, for example, Fig. 15.1.4) and is gradually restricted so that its outside radius matches that of the cyclone. This is the scroll or wrap-around type of inlet. 

Equipping a cyclone with an inlet scroll, as depicted in Fig. 15.1.4, produces an effect upon cyclone performance that is similar to that produced by increasing the body diameter, while keeping the vortex finder diameter constant. This is so because the scroll increases the inlet radius relative to a 

One type of scroll inlet is the circular scroll. Figs. 15.1.4 b and c illustrate simple 90° and 180° circular scrolls. These, along with 270° and 360° scrolls (not illustrated here), are the four most commonly encountered in practice. We note that, unlike logarithmic scrolls (see below), the radius of curvature 

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Chapter 3 focuses on all aspects related to the chromatographic column. A major part explains and specifies the kinds of stationary phases as well as their chemical structure and properties. This part may be used as reference for special questions and will help those looking for an overview of attributes of different stationary phases. Packing procedures, as well as the design of the inlet and outlet heads, are very important for column efficiency. When deciding on the dimensions of a column the pressure drop also has to be taken into account. 

The flammability limits depend on the temperature and pressure. At elevated temperatures and pressures, a given mixture may be flammable, even if this is not the case at ambient conditions. It is a key objective of the design of the inlet zone of a CPO reactor to prevent ignition and thermal combustion. 

Flow instabilities result when a good portion of the total pressure drop occurs in the outlet head of the calandria. Flow instabilities can be reduced in such a system by throttling the liquid as it enters the calandria. This reduces the fraction of the total pressure drop occurring in the outlet head and stabilizes the system. Throttling the liquid inlet affects the performance in much the same way as lowering the liquid level in the body. The total fluid circulation is reduced. However, the whole problem can be eliminated with proper design of the inlet and outlet heads of the calandria. 

Reviewing the tasks of the contemporary coastal engineer of our example in more detail, she must first be able to do the functional design of the inlet stabilization. This involves the application of knowledge about, for example ... 

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