Leakage issue about the MPXV5050GP

[alanhe]

Hi, we are using the MPXV5050GP, and find that there is the leakage issue about the sensor. we did the test as following: we use the syringe and give the sensor a pressure of 20kpa, then we keep the pressure and find that from the output data of the sensor, the pressure keeps droping. So could you please tell me the leakage level of the senor, or whether there is other sensor that is better at sealing. Thank you for your answer in advance.

[david_diaz]

Hello Alan,

Thank you for writing.

Leakage is an unspecified and therefore not guaranteed performance characteristic of NXP devices. However, NXP does perform a 100% leakage test on all ported devices after assembly. The intent/extent of NXP's test capabilities is as a manufacturing quality tool/gauge to identify gross leakers (devices outside the leak test limits), NOT to quantify leakage as a cc/sec performance characteristic.

With the above in mind, the maximum allowable leakage rate (for these devices) at our test gate is 0.182kPa/sec (with 50kPa absolute applied). This maximum rate can be considered "worst case" (prior to any handling/processing by the customer which may induce package stresses which affect port-to-package sealing) and the typical production distribution for leakage rate is well within the test limits. That said however, the current process and equipment capabilities do not allow NXP to build and test to (or guarantee) a tighter requirement. NXP is striving to improve its ability to meet a no-leak requirement through continuous improvement programs (CIP's).

An additional recommendation when using ported pressure sensors, I would recommend to use hose clamps to helping prevent leakage and loosening, hose clamps provide a stronger connection to the sensor port. Clamps that are recommended for use in applications as described are the Oetiker Two-Ear Clamp, and the Oetiker One-Ear, and Special Clamp from Newage Industries.

AN1513: Mounting Techniques and Plumping Options of MPX Series Pressure Sensors

If you are having a high rate leakage, I would recommend you to contact your distributor to create a CQI quality report since it’s probably related to a quality issue.

Please find here below some additional information that might useful to aid your design.

For all NXP standard pressure sensor products (e.g. MPX5050GP), any environment other than dry air, will have some impact on the reliability and lifetime of the product. NXP’s silicon pressure sensors are NOT compatible with oil, gas, petrol and water or water vapors, or chemicals.

A determination must be made if this impact is acceptable for the application.

I hope this information helps.

Regards,

David

[thierry_saive]

Hello David.

I face the same need of evaluating the leak rate of the sensor (MPXV5004GC7U in my case)

In our application, a given amount of air is trapped at the base of a water tank but connected with a pipe to the sensor.
The air pressure gives an information about the level of water in tank.
In case of leak, the amount of air will reduce, water will finally go up in the pipe, distording the level measurement.

In your answer above, you stated: "the maximum allowable leakage rate (for these devices) at our test gate is 0.182kPa/sec (with 50kPa absolute applied)."
It would definitely help to know which amount (volume or mass) of air is trapped in between the pressure test équipement and the sensor.

Could you give some values or at least rough estimation ?

Many thanks

Thierry

[igadotti]

Dear David,

I am trying for some time already to solve the leaking issue on my system.

After reading this topic my conclusion is to stop the project immediately, because it will never work!

In my opinion, no-leak requirement is mandatory. Otherwise level measurement is impossible by using this kind of pressure sensor.

Sorry to say that, but it is really disappointing...

Thanks,

Iaran