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Flange orifice flow meterOrifice flange assembliesDescriptionOrifice flange assemblies are used in conjunction with orifice plates for flow measurement of smaller ormedium size pipes at lower or medium pressure ranges. The flange connection is of a RF type and thedifferential pressure tapping system is with flange taps.Specificationorifice flange types:slip-onRFwelding neckring-joint welding neck –large or small tongua facenominal diameters:25 mm (1”) to 500 mm (60”) – above on requestflange rating:ASME,300,600,900,1500,(ASME B16.36 – ASME B16.47A and BAPI 2000, 3000, 5000, 10000 15000 (API 6 )2500lbs(RF,RTJ)flange materialcarbon steel, Stailess Steel, exotic material, duplex material.materials of bolts and nuts:stud bolts: A193-B7, B8, etc.nuts: A194-2H, 8, etc.jack bolts and nuts: A193-B7, B8 etc. –gaskets:sheet gaskets 1.5 mm (ASME B16.21)spiral wounded gasket 4.5mm – (ASME B16.20)piping connection method:ANSI: butt welding type (ASME B16.25)valveIT srlvia Caduti di Reggio Emilia, 2740033 Casalecchio di Reno Bologna Italyph 39.051.9912714 email [email protected] IT03007691201share capital Eur 100.000,00

TypeSlip-on flangesThe slip-on flange has a low hub because the pipe slips into the flange prior to welding. It is welded bothinside and outside to provide sufficient strength and prevent leakage. Slip-on flanges are all bored slightlylarger than the O.D. of the matching pipe. They are preferred over welding neck flanges by many users dueto their lower initial cost, but final installation cost is probably not much less than that of the welding neckflange because of the additional welding involved.Socket welding flangesThe socket welding flange is similar to the slip-on flange except it has a bore and a counter boredimension. The counter bore is slightly larger than O.D. of the matching pipe, allowing the pipe to beinserted into the flange similar to a slip-on flange. The diameter of the smaller bore is the same as the I.D.of the matching pipe. A restriction is built into the bottom of the bore which sets as a shoulder for the pipeto the rest on. This eliminates any restriction in the flow when using a socket welding flange.Welding neck flangesThe welding neck-flange is normally referred to as the “high hub” flange. It is designed to transfer stressesto the pipe, thereby reducing high stress concentrations at the base of the flange. The welding neck flangeis the best designed butt-welded flange of those currently available because of its inherent structural value.It is expensive because of the design.valveIT srlvia Caduti di Reggio Emilia, 2740033 Casalecchio di Reno Bologna Italyph 39.051.9912714 email [email protected] IT03007691201share capital Eur 100.000,00

Pressure tap connectionsPressure connection holes in the pipe should be 1/2” for 4” and larger lines, 3/8” for 3” lines and 1/4” for2” lines. When flange taps are used, insert a drill of the proper size through the connection holes in theflanges and drill through the pipe. When connections in the pipe are used, weld half-couplings to the pipeat the proper locations, insert a drill through them, and drill through the pipe. Round off the edges of theholes slightly to be sure that no burrs remain in the pipe.Flange tapsPressure connection holes are located in the flanges 1” upstream and 1” downstream from thecorresponding orifice plate faces (see fig. 4 and fig. 5)Corner tapsOn lines smaller than 2”, the orifice flange union shown in fig. 6 is used. The effect is that the pressure tapsare right at the orifice plate.valveIT srlvia Caduti di Reggio Emilia, 2740033 Casalecchio di Reno Bologna Italyph 39.051.9912714 email [email protected] IT03007691201share capital Eur 100.000,00

2,5 D and 8 D taps, also called full-flow pipe tapsConnections are installed 2,5 pipe-diameters upstream from the upstream face of the orifice plate and 8pipe diameters downstream from the upstream face of the orifice plate.1 D and 0,5 D taps, also called radius tapsThis type of connection is modification of and has largely replaced the Vena Contracta taps. It yields equallyaccurate results and has the advantage that the downstream connection is easier to locate. The upstreamconnection should be at 1 D above the upstream face of the orifice plate, but location of the upstreamconnection anywhere between 0,5 and 2 D introduces only negligible error. The downstream connection islocated 0,5 C from the upstream face of the orifice plate.“Vena Contracta” tapsThe upstream connection (dimension M) may be located anywhere between 0,5 and 2 pipe diametersabove the upstream face of the orifice plate. The downstream connection (dimension N) is made at thepoint of maximum flow constriction and is given by the table below:valveIT srlvia Caduti di Reggio Emilia, 2740033 Casalecchio di Reno Bologna Italyph 39.051.9912714 email [email protected] IT03007691201share capital Eur 100.000,00

Orifice meter runsDescriptionOrifice meter runs are used for measuring the flow at higher accuracy. The orifice meter runs aretherefore, not the ones simply weld pipes to upstream and downstream sides or an orifice assembly, butthe ones welding smaller inside diameter pipes to smaller diameter of flanges, then, finish inside diameteror the pipe / flange assembly by boring or honing to the specified dimensions with the required tolerancesand surface roughness (see fig. 20 and fig. 21).Type and drawingOrifice meter run (both sides fanged):valveIT srlvia Caduti di Reggio Emilia, 2740033 Casalecchio di Reno Bologna Italyph 39.051.9912714 email [email protected] IT03007691201share capital Eur 100.000,00

i Orifice meter run (butt welding ends)valveIT srlvia Caduti di Reggio Emilia, 2740033 Casalecchio di Reno Bologna Italyph 39.051.9912714 email [email protected] IT03007691201share capital Eur 100.000,00

A restriction is built into the bottom of the bore which sets as a shoulder for the pipe to the rest on. This eliminates any restriction in the flow when using a socket welding flange. . On lines smaller than 2”, the orifice flange union shown in fig. 6 is used. The effect is that the pressure taps are