Measuring pressure increase due to fluid flow

[giovannioffeddu]

Hi all,

I am having problems performing reliable measurements using MPX2050DP.

I am trying to measure the pressure increase when flowing a fluid through a porous material. I have attached a schematic drawing of my set up: fluid is flown from the top using a pump; The sensor is connected through a small opening and a tube to measure the pressure, while the other inlet is left open to atmospheric pressure.

However, when I try to do this with dense materials the fluid prefers to take the easier path of flowing through the tube connected to the pressure sensor.

I was wondering if you could suggest a better way to use the sensor to solve this problem, or another product that might be better suited for the application.

Any help would be greatly appreciated!

[david_diaz · Accepted solution]

Hello Giovanni,

Please be aware that the NXP’s standard pressure sensor products are qualified to be used at dry air, only.

For the use of pressure sensors in any other environments than dry air will require additional precautions and protection of the sensing element inside the pressure sensor.

The complete die is protected with a silicone gel. The gel coating on the die should not come in contact with moisture as when wet, the gel can swell and cause unreliable readings. The gel must remain intact as it protects the active surface of the die and wire bonds from oxidation.

In this case I would like to suggest the methods mentioned on the following application notes:

1. AN3728 - Media Compatibility for IPS PRT Pressure Sensors

http://www.nxp.com/files/sensors/doc/app_note/AN3728.pdf

2. AN1516 - Liquid Level Control Using a Pressure Sensor

http://www.nxp.com/files/sensors/doc/app_note/AN1516.pdf

I hope this information will be useful for you.

If I misunderstood your question, feel free to let me know. I will be glad to help.

Have a great day.

David Diaz.

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