Wedge flow meters from EMCOWEDGE are used as primary elements in ISO standardised flow measurement of liquid, gas and steam. The EMCOWEDGE type EWF is especially suitable for viscous and slurry liquids. The wedge design makes it less sensitive to solid particles, mitigating the risk of clogging. Bi-directional flow is possible.
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Design and calculation standards |
ISO 5167-6, EN, PED 97/23 EC, ANSI/ASME and RW Miller |
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Sizes |
DN 50 600 2” – 24”, larger sizes upon request. |
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Pressure rating |
PN 10 400, 150 2500 lbs |
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Material |
Carbon steel P235GH, P250GH, P265GH, A105N, A106 Gr. B, A350 Gr. LF2, A335 Gr. P5 and P9, AISI 316, Duplex, Super Duplex, 6Mo, heat resisting steels, other materials on request including internal hard facing by cladding. |
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Material wedge |
As pipe material above including optional cladding of hard alloy materials. Solid wedge according to ISO 5167-6. |
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Mounting style |
Flanges connection according to ISO, DIN or ANSI |
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Pressure taps |
DN 25, DN 50 and DN 80, 1”, 2” and 3” or small size tappings : 4 – 10 mm, Standard is 1 set of tappings. Optional 2 or 3 sets of tappings available. Close coupled tappings (studed olet) with reduced tapping volume. Special flanges for chemical seals. |
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Flange facing |
Flat or raised face according to DIN 2526 or flat, raised face or ring type joint according to ANSI B16.5 |
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Element ratio (h/D) |
0,2, 0,3, 0,4, 0,5 and 0,6 (β between 0,377 and 0,791) according to ISO 5167-6 |
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Discharge coefficient C |
0,77 – 0,09 x β. In accordance with ISO 5167-6 applicable for sizes 50mm ≤ D ≤ 600mm |
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β-range |
0,377 ≤ β ≤ 0,791 (0,2 ≤ h/D ≤ 0,6) |
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Accuracy |
+/- 4 % un-calibrated, +/- 0,5 % calibrated. (of discharge coefficient) |
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Repeatability |
+/- 0,2 % |
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Pressure loss |
(1,09 – 0,79 x β) x DP |
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Limits for Reynolds No |
10.000 – 9.000.000 |
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Installation requirements |
7 x D up-stream and 6 x D down-stream taken from the end of the disturbance to the centre line of the up-stream tapping and from the centre line of the down-stream tapping to the start of the disturbance according to ISO 5167-6. |
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Shut-off valves |
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Condensing chambers for steam flow measurement |
Pipelines carrying highly viscous liquids are often heated by steam tracing. EMCOWEDGE can be delivered with steam tracing for lowering the viscosity for better measuring accuracy. The steam tracing can be delivered in 2 designs: Semi-steam jacket and full steam jacket. The latter is supplied with process flange connection typical 2 pipe sizes larger than the process pipe. The steam jacket is supplied with 2 steam connections and 1 drain connection.
The fluid must be in one phase, and the pipe should run full without pulsations. Before installation, ensure the primary element is clean and protected from corrosion and physical damage. Proper pipe run involves fitting the wedge flow meter between straight cylindrical sections of constant cross-sectional area without obstructions. The required minimum straight lengths depend on the h/D ratio and the nature of obstructions like bends or reducers. Inner pipe diameter variation should not exceed 1% of D used in the differential pressure calculation.
The preferred orientation is a horizontal pipe run with tappings pointing to the side. Tap locations require two pressure tappings equally spaced from the wedge, with the “+” tapping on the upstream side. Safety measures include equipping the pipe system with a safety device. Insulation is recommended for elevated temperatures.
Download the installation guide above for more detailed information.
Element ratio (h/D), h = wedge gab, D = inner pipe diameter
