Flange taps

Fig. 7. Orifice plate pressure tap locations. A, corner taps B, flange taps C, D taps D, 1/2 D taps and E, pena contracta taps. See text.

For a centered circular orifice in a pipe, the pressure differential is customarily measured between one of the following pressure-tap pail s. Except in the case of flange taps, all measurements of distance from the orifice are made from the upstream face of the plate. 

Flange taps. Static holes located 25.4 mm (1 in) upstream and 25.4 mm (1 in) downstream from the plate. 

A 1"—Schedule 40 pipe is flowing methane at 40 psig and 50°F. The flange taps across the orifice (0.750 inch diameter) show a 3 psi pressure differential. Determine the flow rate through the orifice. 

A 2 in. sch 40 pipe carries a 35° API distillate at 50°F (SG = 0.85). The flow rate is measured by an orifice meter which has a diameter of 1.5 in. The pressure drop across the orifice plate is measured by a water manometer connected to flange taps. 

Ambrosius, E. E., and Spink, L. K., Coefficients of Discharge of Sharp-Edged Concentric Orifices in Commercial 2 in, 3 in, and 4 in Pipes for Low Reynolds Numbers Using Flange Taps, Trans. ASME 69 805, 1947. 

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

Tap the four holes just drilled in the blind flanges for 34" NPT thread. Do not tap the thread all the way through the flanges. Tap each flange from the flat side, which will be the outside when electrolyzer is constructed. The flange faces that will be inside have a raised surface for gasket placement. 

Flange Taps. Static holes are located 1 inch upstream and 1 inch downstream of the plate. 

Calculate the size of an orifice for the bore of a flange-tapped orifice required to measure 12.84 ftVmin of gasoline in a 2-inch schedule 80 pipe. 

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...

Equation (8.37) is useful for design because Co is almost constant and independent of p provided JV o.o is greater than about 30,000. Under these conditions C may be taken as 0.61 for both flange taps and vena-contracta taps. 

Natural gas having a specific gravity relative to air of 0.60 and a viscosity of 0.011 cP is flowing through a 6-in. Schedule 40 pipe in which is installed a standard sharp-edged orifice equipped with flange taps. The gas is at 100°F and 20 lbj-/in. abs at the upstream tap. The manometer reading is 46.3 in. of water at 60 F. The ratio of specific heats for natural gas is 1.30. The diameter of the orifice is 2.(M) in. Calculate... 

The differential pressure depends on the location of the pressure taps. Pressure taps are located in four general arrangements as illustrated in Figure 4.14 flange taps, D and D/2 taps, comer taps, and pipe taps. Flange taps are typically placed on the pipe flange and are located 1 inch upstream and 1 inch downstream from the face of the plate to centerline of the tap. The D and D/2 taps are located one pipe irmer diameter upstream and one-half downstream from the face to the flange. Corner taps are located at the face of the orifice plate. Pipe taps are located 2.5 pipe irmer diameters upstream... 

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