Pipeline flow meter
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A new steam pipeline with a pressure of 1.0 MPa was added; the diameter of this pipeline is DN350. The flow meter manufacturer stated that it is not possible to manufacture a flow meter for DN350, and that ones with a diameter of DN300 meet the requirements for measurement. The matter was referred back to the design institute for confirmation. But the flow meter is connected via flanges, and the flanges are DN350 – does this constitute a change in diameter? What are the requirements for installing straight pipe sections? I asked the design institute, and they said to consider it based on the connection flange DN350, with no change in the diameter of the pipeline. Could you help me figure out if this is the case?
If the flow meter tip is 350, it is not considered by the design institute
Should the distance of that straight pipe section be calculated based on the flow meter’s DN300 size or DN350 size?
According to the data sheet, the flow meter has a flange size of DN300, but the pipeline is DN350; therefore, a diameter change is necessary in order to install it. The length of the straight pipe section is calculated starting from the position of the reduced-diameter ends. The exact length required for this straight pipe section depends on the choice of flow meter; different flow meters and different manufacturers have varying requirements. For typical orifice plate flow meters, a length of 20D in front of the ends and 10D behind them is sufficient, though longer lengths are generally preferable. Finally, did you choose PN50 for your flange? Is it a bit big?
Hello, the flow meter comes with a flange of DN350, so it can be connected to pipelines of DN350.
It seems that a vortex flow meter has been chosen; it already features a changing diameter, with the interior of the flow meter having such a design
For the retracted type, when installing, consider a straight pipe section of 350 as well
Flange 350, diameter 300 – this is not feasible; it’s a vortex flow meter that requires a straight pipe section. Why aren’t orifice plates or nozzles chosen for this operating condition?
According to this data sheet, the connection flange is of type 300, which does not match your description; a size change is required
The density of saturated steam at 1.0 Mpa is 5.64 kg/m3; your data sheet shows 4.7, which refers to superheated steam. The flow meter requires temperature and pressure compensation, so a multivariable flow meter should be used. First, the normal steam flow rate must be determined. The selected range is 12,000 to 120,000. As for what the normal value is, with a pipe diameter of 350, it’s not necessary to use a flow meter with a 350 mm diameter; a 300 mm diameter flow meter will suffice, and it’s possible that a flow meter with a 200 mm or 250 mm diameter will also meet the requirements. We chose a too large diameter for the steam flow meter in our plant.
The flow meter can be used to determine whether, after the meter’s diameter is reduced, the flow rate will still meet the requirements specified for DN350 Doesn’t the DN350 pipe mentioned earlier become useless then?