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Flow measurements

Flow measurements

Flow measurements

Hi, does anyone know the best flow measurement device for water without using turbine or ultrasonic ones. We need this device for 600 l/s, 1500 l/s, 750 l/s, 150 l/s. The water came from a river. The main problem is that we want to use one that allow us the minor distance required (for less measurement errors) between this flowmeter device and the nearest accessories (elbows, tees).  Thanks in advance

RE: Flow measurements

There is a flowmeter called V-Cone that may suit your requirements.
The company (McCrometer) claims that straight runs of pipe requirements are minimun.
I´ve seen these flowmeters installed in a gas conditioning plant and seems to work good, but you should ask for other references.

The link is:

Hope this help.

RE: Flow measurements

I looked up in Instrument Engineer's handbook.

Table II tabulates straight run pipe requirements upstream/downstream as multiple of pipe diameter.

The following types of flow meters have no straight run requirement at all according to the table (can have obstruction immediately upstram and downstream):  mag flowmeters, mass flowmeters, metering pumps, positive displacement gas meters, positive displacement meters, variable area flow meters.   (I am a little surprised about mag flowmeters... I though they had a 5D requirement.)

Some others with lower requirements (upstream/downstread diameters):
thermal meters 5/3
Turbine flowmeters 10/5
vortex flowmeters 15/5
The accuracy is also tabulated on same table along with several other application selection criteria.

RE: Flow measurements

also you are probably aware that flow straighteners in upstream and downstream pipe can reduce straight-run requirements for a given instrument.

RE: Flow measurements


electricpete has given a good idea of flow straighteners. You can use corriliolis mass flow meters for better accuracy and shorter straight lengths. (I have seen installations where they are put immediately after bends)

But they are expensive. By the way what accuracies you require and what are the pipeline sizes?


RE: Flow measurements

These are reasonable sized water lines he is talking about.  150 l/sec is about 2400 gpm, likely a 10" line.

RE: Flow measurements


As I need not tell you, you can use localised velocities of upto 8 m/s for water application for measuring applications. Any comment on it?


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