Radar Level Transmitter 4

[tomnewf65]

We are having an issue in with Radar level transmitters on a slurry tank at our plant in fort mcmurray Alberta. The temperature has dipped to -35 C the last few nights and 2 normally reliable radar level transmitters have begun dropping out. When steam heating is applied to the electronic modules they begin tracking again. Obviously this is a temperature issue (even though these units are rated for - 40 C). I was just wondering if anyone had experience something similar and had any thoughts on whst part of the electnics is causing the signal lose. The transmitters are rosemount 5400 series.

 

[IRstuff]

While air might be at one temperature, anything that's exposed to the night sky can experience a totally different temperature, due to the radiative losses been larger than convective gains. Going another 20°C below the air temperture might not be surprising:

http://www.astroshow.com/dewtell/dewtell.htm

http://www.baihp.org/pubs/nightcool/index.htm

TTFN

FAQ731-376

 

[danw2]

I've found that if the antenna gets wet that level radar doesn't work. Water seems to suck up the RF.

Is it possible that the temperature inside the tank/silo/vessel dropped below the dewpoint and that the resulting condensation on the antenna is eating up your RF signal?

If the electronics are rated to -40, I suspect that a reputable design would work to that temperature, but the electronics' operation is predicated on a dry antenna.

 

[tomnewf65]

Thanks guys, I checked for condensate last night, and there was significant build up. It was a balmy -52 C at our plant last night. Life in northern Alberta.

 

[powerjunx]

Handful of Crude oil tankers ship uses rosemount radar level transmitter having parabolic antenna..problem existed such inert gas trapped or dirt build up on antenna surface, prolong extreme negative temperature where mist from tanks frozen in antenna surface that makes the transmitter dull or non-responsive leading to false ship's instability as appeared in monitor.

With this, retrofitting a inspection hole and hooking up steam tube to periodically clean, blow through the surface and eventually heats up the transmitter when sailing at cooled climate regions.


"..the more, the merrier" Genghis Khan