Failure (Error # 3) in a EJA DP tansmitter (Yokogawa) used as a boiler¦s drum level sensor

[lcms]

Dear Sirs,

The company where I work (rubber production industry) as a Process Engineer has two Alfa Laval Boilers MP-6.5 (6.500 kg/h)for saturated steam 170# generation fully automated with Yokogawa instrumentation, including FF communication platform. This steam generation area has been working for more than six months and since then three boiler drum DP level sensors (Yokogawa model EJA-110 have already broken down (permanent failure code ERR AL.02 and AL.03, CPU burned) in both boilers (two in Boiler tag A and one in boiler tag B). Each boiler has two different approaches for level control, and the DP sensor is used on the most advanced one (3 points level control, including flow and pressure trim). Now we are using the old fashioned level control based upon three electrode switches (ON-OFF control), and this is impairing our boilers performance (efficiency and pressure variation).

I would really appreciate if one of you guys has any clue, or even better, a previous experience in what might be happening that could cause so many failures. Another important information: - the technology of this kind of sensor are the resonance silicon and the sensor that was first installed in the same column of blown down valves were relocated to a different location to avoid vibration that were causing another alarm (ERR AL.02) that changed his status to MANUAL OVERRIDE and obliged us to disconnect and reconnect it to return it to AUTOMATIC MODE.

Thanks in advance,

LCMS.

 

[xnuke]

Are the transmitters exposed to ambient and process temperatures within their specifications (less than 85 C ambient, less than 120 C process)? I've seen many transmitters burn out from various manufacturers due to high temperatures in steam systems because they weren't installed properly and exposed the transmitters to temperatures above the specifications.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[lcms]

Dear xnuke,

First, thank you for your fast reply. Concerning your question, the transmitter is well protect against temperature, and the impulses lines are far from the heat sorce and full with cold water (condensate). Our main concern, regarding enviroment conditions, are related to vibration since the main principle of measuring (resonance of silicon) could be affected by this vibration. Are you familiar with sealing these impulses lines? To my mind this could absorb these kind of undesired noises.

Best Regards,

LCMS

 

[danw2]

>working for more than six months

Any chance these units were manufactured in the aftermath of tsunami and Fukishima meltdown? It wouldn't surprise me if quality suffered in the aftermath of disasters of that magnitude.