This system is now updated with a bigger version!

We started with a traditional flow sensor with an impeller but it was not accurate enough and was kind of invasive, especially when there was grains stuck in the impeller 🙂

Being physicists at trade we remembered something about differential pressure over a narrowing of a pipe and this venturi pipe for flow measurements was made.

The theory behind venturi pipes can be found at Wikipedia.

We used a published design example for our pipe:

And ended up with this:

The theory harmonizes well with reality during calibration, the only uncertainty is that the calculated flow depends on the density of the liquid, which is anything from pure water (SG 1.000) to quite a lot more (SG approximately 1.100). At least a lot for a physicist. But we can live with that.

The pressure resolution of the differential pressure sensor is about 0,0000610 PSI which corresponds to about 0.1 LPM resolution.

BOM

Differential pressure sensor: Honeywell ABPDRRV001PDSA3

For code contact us on Instagram.