MPX5010DP 'losing' pressure

[felipedias]

Hello guys. I'm using a MPX5010DP sensor to measure the water tank level. I've tried to seal the tube on the sensor of many ways, but it still losing the pressure. Over the time, Vout don't stops decreasing. The connections are ok, the measurement starts ok. Can anyone help me? Tnx!!

[TomasVaverka]

Hello Felipe,

For measuring standing water heights, the sensor leaks slightly over time, but if you are using the MPX5010DP CASE 867C-05, this is the package that leaks the least. Or case 867B-04. Those are the cases to utilize to minimize leakage over time instead of the SOP vertical port or SOP side port packages.

Further, the Tygon tubing should help. Several customers are using what amounts to similar product as a zip tie to secure the tubing. What we suggest is pick an ID (Inner diameter) slightly smaller than 4.775 (mm) for the port barb. Heat up the tubing slightly and slide this tubing on. Afterwards as it cools, it should be a strong seal. To secure it more, wire could be used, or very small zip ties. Note that some tubing also leaks slowly over time as air and water vapor can go through porous tubing material. 

Hope it helps.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.

[felipedias]

Thank you for answering.

Well, i am using the 867C-05 case, and tried to seal with silicon, and hot glue (each one at time, or one over the other). Zip ties was my firs try: unsuccessfully. And, using Tygon tubing too. The sensor is on the water tank, but completaly sealed (just the wire and the tubing leaves the sealed case). The inner pressure can make this difference?

I've seen the "Freescale pressure sensor directly exposed to car coolant during a month." Joshevelle post, and I didn't understand this: "In this kind of applications, we would recommend to use Parker O-lube silicone grease or DMS-T46 or T51. This type of grease is used by most of our customer without problems". How could I use some oil on that? This oil is the media or something to held the measurement?

I don't know what to do anymore :X
I was just about to produce in large scale to sell haha

Thank you again!