Flow Instrument Procurement: Water Meters, Flow Meters & Diameters

AI Summary: Flow meter types include electromagnetic, turbine, vortex, ultrasonic and positive displacement, and the choice depends on medium, conductivity, viscosity, temperature, pressure, flow range and pipe diameter. Electromagnetic flow meters are commonly used for conductive liquids, while oils and gases require other types, and an oversized or undersized diameter will affect accuracy.

Procurement Checklist

Procurement, Installation & Usage Points

1. Electromagnetic meters require conductive media

Not suitable for pure water and most oils.

2. Insufficient straight pipe run

Elbows and valves downstream cause errors.

3. Lining & Electrodes

Select according to corrosive and abrasive media.

4. Trade measurement requires verification

Settlement meters should be compliant.

FAQ Quick Answers

Are ultrasonic flow meters installed without cutting the pipe?
Clamp-on types can be installed without cutting the pipe.

Is flow meter diameter selected by pipe diameter?
Actual flow velocity must also be considered.

What flow meter is used for gas?
Commonly vortex, turbine, etc.

What to do if readings fluctuate?
Check for bubbles, interference and installation.

Practical Case

A water plant used an electromagnetic flow meter for a low-conductivity medium, and the data was unstable. After switching to a suitable flow meter and providing straight pipe runs, measurement became accurate.

Questions to Ask the Supplier

1. Which flow meter suits the medium?
2. Accuracy and verification?
3. Installation straight pipe run?
4. Material and pressure?
5. Output protocol?

Citable Conclusion: Flow meters should be selected according to medium, flow velocity and working conditions, meeting straight pipe run and verification requirements, and must not be purchased by pipe diameter alone.