Radius tap

Radius taps. Static holes located one pipe diameter upstream and one-half pipe diameter downstream from the plate. 

Measurements by Harris and MagnaU [Trans. Jn.st. Chem. Eng. (London), 50, 61-68 (1972)] with a venturi (p = 0.62) and orifices wiSi radius taps (P = 0.60-0.75) indicate that the discharge coefficient for nonnewtonian fluids, in the range Nr (generalized Reynolds number) 3500 to 100,000, is approximately the same as for newtonian fluids at the same Reynolds number. 

Gasoline is pumped through a 2 in. sch 40 pipeline upward into an elevated storage tank at 60°F. An orifice meter is mounted in a vertical section of the line, which uses a DP cell with a maximum range of 10in.H2O to measure the pressure drop across the orifice at radius taps. If the maximum flow rate expected in the line is 10 gpm, what size orifice should you use If a water manometer with a maximum reading of 10 in. is used instead of the DP cell, what would the required orifice diameter be ... 

Can be used with comer taps, flange taps, or radius taps. 

Figure 5.20 shows the orifice (discharge) coefficient as a function of the orifice Reynolds number ( Rerf) and p = d D. There are a variety of standard orifice plate and pressure tap designs (e.g., Miller, 1983). The ASME specifications for the most common concentric square-edged orifices are shown in Figure 5.21. The various pressure tap locations are illustrated in Figure 5.22. Radius taps, for which the location is scaled to the pipe diameter, are the most reliable. Comer taps and flange taps are the most convenient, as they can be installed in the orifice flange and so do not require...

FIGURE 5.20 Orifice discharge coefficient for square-edged orifice and flange, corner, or radius tap. (From Miller, R. W., Flow Measurement Engineering Handbook, McGraw-Hill, New York (1983).)... 

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