#looking for a ElecMag flow sensor#

Hey guys I'm looking for suggestions on affordable Mag sensors (or substitute tech) that can replace regular turbine flow sensors!?

Need more info. What is the application and what is the problem with turbine flow sensors that you are trying to solve?

Mass Air Flow sensors as used in cars and industrial are reasonably accurate and not very expensive if you can adapt an existing product.

Auto engines used to use the Speed Density method, estimating flow based on engine speed, air temperature and air pressure along with an efficiency table.

Pitot tubes can measure velocity. Add temp, pressure and the size of the pipe and you get flow.

sdturner:
Need more info. What is the application and what is the problem with turbine flow sensors that you are trying to solve?

Mass Air Flow sensors as used in cars and industrial are reasonably accurate and not very expensive if you can adapt an existing product.

Auto engines used to use the Speed Density method, estimating flow based on engine speed, air temperature and air pressure along with an efficiency table.

Pitot tubes can measure velocity. Add temp, pressure and the size of the pipe and you get flow.

Thank you!
My purpose is to create a water management system that is IoT based, I have everything intact leaving a flow sensor! my end market doesn't like the turbine flow sensors that contact directly the water but want something non intrusive for measuring the flow!

I don't know of a way to measure water flow without some contact. The only idea I have (and I don't know if it's possible) is using the magnetohydrodynamic effect.

Other possibilities:

You can get food safe pressure sensors - The faster the flow the lower the pressure. Maybe measure regular pressure and have a reduction in diameter and measure the pressure at the higher flow rate and use the differential pressure to measure flow.

A pitot tube.

A heat flow sensor similar to many MAF sensors in cars. You can get food safe thermistors sealed in glass or stainless steel. You need 2 sensors. One measures the ambient water temperature and the other drives the sensor to a fixed temperature above ambient. The power needed to hold that temperature is used to determine the flow rate. The faster the flow, the more heat is carried away and the more power it takes to maintain the temperature.

sdturner:
I don't know of a way to measure water flow without some contact. The only idea I have (and I don't know if it's possible) is using the magnetohydrodynamic effect.

Other possibilities:

You can get food safe pressure sensors - The faster the flow the lower the pressure. Maybe measure regular pressure and have a reduction in diameter and measure the pressure at the higher flow rate and use the differential pressure to measure flow.

A pitot tube.

A heat flow sensor similar to many MAF sensors in cars. You can get food safe thermistors sealed in glass or stainless steel. You need 2 sensors. One measures the ambient water temperature and the other drives the sensor to a fixed temperature above ambient. The power needed to hold that temperature is used to determine the flow rate. The faster the flow, the more heat is carried away and the more power it takes to maintain the temperature.

really creative solutions but the problem is that the water is really polluted and thus its like a solvant or solution not water water! and for measuring solvants its better to use Ultrasonic transducers as turbines or any mechanical moving parts are clogged!

What about using maxbotix or similar type of ultrasonic transducers already available ? (the basic principle is to send a ultrasound wave and receive it on the other side on the other transducer! but I have talked personallly with maxbotix guys they don't have a solution)

I have been going through various chinese websites like this >> China Aluminum 90dB 14mm Waterproof Ultrasonic Sensor with Pin RoHS - China Ultrasonic Sensor, Ultrasonic

what your take on that ^ ?

Interesting problem. I have no idea if ultrasonics would work, but they are cheap enough it might be worth a try.

Maybe you would see a Doppler effect if you send the US through the pipe diagonally?

Maybe you would see a lateral shift if you send the US through the pipe perpendicularly? Put the ultrasonic emitter on one side and put several receivers on the opposite side. Would the moving water shift the signal laterally, so you'd see the the signal shift from one sensor to the next the faster the water flows?

How is it done in chemical and sewage plants? Do they just use glass & stainless steel and replace the parts regularly?

That is an interesting problem. At one time I was looking at measuring the difference between two thermistors to measure flow. One of the thermistors was heated and the other was just in the flow, the temperature difference was going to be used to tell what the flow was. I think I got the idea from looking at thermal mass flow meters.