MP3V5004DP application for level measurement

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MP3V5004DP application for level measurement

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lorenzomarcanto
Contributor II

We are using the pressure sensor exactly for its intended application, water level measurement in a tank. The tank is about 15cm high and the sensor works fine, with about 1mm precision (even more than we need for the application). We used an arrangment like the 'washing machine' application note, with a dip tube in the tank from above. We are with the opening at about 1.5-2mm from the bottom (the exact level is software calibrated)

There is an issue however: if some liquid enters in the tube obviously the measurement is wrong. The 4-2.7mm PU flexible tubing from the sensor directly in the liquid almost immediately 'sucks' some water for capillarity or thermal expansion so we used some fittings and go to a 8-6mm PA tube for the final dip section. It works mostly fine but, occasionally, a big drop will still cling to the opening and mess up the measurement until shaked down (or until it evaporated).

Is there some trick to make it work correctly?

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JozefKozon
NXP TechSupport
NXP TechSupport

Dear Lorenzo,

perhaps a tube with inner surface from some hydrophobic material would be a solution. For example a same size tube as you use, with a Teflon (Polytetrafluoroethylene) inner surface could be good idea. 

This video could be interesting for you: https://www.youtube.com/watch?v=sPoTJ0GCkHU

I have found a company from Germany producing tubes with hydrophobic inner surface. Please see this link.

With Best Regards,

Jozef

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830 Views
JozefKozon
NXP TechSupport
NXP TechSupport

Dear Lorenzo,

perhaps a tube with inner surface from some hydrophobic material would be a solution. For example a same size tube as you use, with a Teflon (Polytetrafluoroethylene) inner surface could be good idea. 

This video could be interesting for you: https://www.youtube.com/watch?v=sPoTJ0GCkHU

I have found a company from Germany producing tubes with hydrophobic inner surface. Please see this link.

With Best Regards,

Jozef

804 Views
lorenzomarcanto
Contributor II

PTFE tubing is on its way but we tried with silicone (the stuff used in coffee makers) and it's already way better. Thanks for the suggestion