Flow Meter Selection

Ask the professionals who make thousands of these per year.

While studdying for my degree, I was employed manufacturing "flowmeters" with 4mm tube diameter that were medically implantable to measure flow in the corronary artery of the heart. These were "doppler" style by choice since we already had an elecromagnetic flowmeter on the aorta feeding blood to the whole body. We were also measuring "impedance" of the chest cavity to monitor total instantaneous blood volume in that space.

Needed to use different monitoring signals to eliminate potential cross-talk between signals.

Spare time in the lab was spent building pacemakers etc. Fun times!

Yes, I can. You need to be on the phone to various instrumentation equipment suppliers from here onwards, to get quotes. I could do it for you, but that might make you lazy, and we don't want that, do we?

In my job, I work with flow meters regularly, and was with you until I hit that "no power" requirement. Unless you mean no power except 4-20ma loop power, you have a tough requirement, especially with a pulse output. I agree with all the other posts - talk to a flow meter company, or their representative.