Water meters and air flow

[Derlyn]

Does anyone know of water meters that can distinguish the difference between airflow and water flow through them.

All the meters that I have checked so far, cannot.

[Blurock]

Does anyone know of water meters that can distinguish the difference between airflow and water flow through them.

All the meters that I have checked so far, cannot.

Yes, that is a problem. Mechanical meters are designed to measure the volume of fluid passing through them, whether its water or air.
The flow of water or air will move the mechanical parts of the meter which are attached to a dial or an odometer type counter that registers the consumption.
To prevent these registers to record air flow, one will require an air valve to be installed before the meter. Municipalities are supposed to install air valves in their reticulation system to prevent air being measured.
The problem is lazy workers who do not flush pipes properly after an installation, resulting in sand and mud particles in the reticulation. They should also bleed the system of air and open valves slowly to avoid a sudden gush of water causing damage downstream.

[AndyD]

Auto air bleed valves are cheap but I doubt they'd let you install one before the meter, only after it.
https://za.rs-online.com/web/p/air-e...ce=1&gclsrc=ds

In process control we use electromag meters which measure electronically, they can diferentiate between air and water flow but they're expensive.

Ultrasonic flow meters are widely used for domestic water billing but I'm not sure how immune to measuring air flow they are. According to some of their manufacturers they don't measure air but this may not be true for all of them. Also they're readily available in SA so might be worth a try.

[Derlyn]

Thanks for that, Andy. It seems as if for the domestic consumer, the air bleeding valve is the answer, however, you are correct about the municipality not allowing one to install anything on their side of the meter.

Seems as if one is snookered.