Читать книгу Agitator Design for Gas-Liquid Fermenters and Bioreactors - Gregory T. Benz - Страница 36

The power and torque from the reducer are transmitted to the tank contents by means of a shaft with diameter d, extending a distance L from the mounting flange. On the shaft are mounted one or more impellers of diameter D and actual blade width or height, W, located off bottom at a distance C. For this book, we measure C from the bottom edge of the impeller. Some other sources use the centerline of the impeller. We also define D as the flat‐to‐flat dimension of the blades in plan view, rather than the swept circle, called D_S. This makes a difference of about 1% in the calculated diameter for a pitched blade turbine of standard design, for example. This is illustrated in Figure 3.3, along with a few other relevant dimensions, such as the blade thickness, t_b.

For multiple impellers, we would use subscripts such as D₁, D₂, C₁, and C₂.

Figure 3.3 Swept diameter.