Want to put some inexpensive non-invasive sensors to measure pressurized water flow rate in 1/2" pipes. I don't want to have to install the device inline (invasive), rather it just clamp on or around the pipe.

I did some reading, and if I understand correctly I cannot use electromagnetic meters as they need electrodes in contact with the water inside the pipe (hence, invasive).

Is ultrasound the only way forward now? Are there any cheap sensors? If so, for potable water do i want to use doppler or transit time (i.e. does potable water contain many sonically reflective particles?).

Thanks
Billy

 

You are correct mag meters need to be in the pipe.

Clamp-on transit time ultrasonic technology is used to read potable water flow (without particulate or bubbles; those are the domain of doppler technology).

I doubt you will find 'cheap' sensors. Ultrasonic technology requires exciting the transducer (pinging) and an interpretation of the resulting signal so the electronics and the transducers have been sold as packages; not as components for a make-your-own system.

The market has a recent spate of transit time clamp-ons at about 1/2 the cost of the venerable mainstay players (suitable for water in clean pipe), but I would not characterize any as 'cheap' or inexpensive.

I have heard of ultrasonic clamp-on rentals for projects that do not require permanent, continuous reporting.