Level indicators

Regarding the jacketed vessels, best for you to contact one of the radiometric manufacturers. Depending on what part of the world you are in, these are some of the manufacturers:

http://www.bertholdtech.com
http://www.ohmartvega.com
http://www.thermo.com
http://www.endress+hauser.com

As for the water pits, sonic level would probably be the best choice if you want continuous level. Capacitance point level for on/off. Probes come in
various lengths so you can have them be at various lengths for multiple points. Many manufacturers exist for these devices. The following are just a few.

http://www.ohmartvega.com
http://www.endress+hauser.com
http://www.drexelbrook.com
https://pia.khe.siemens.com/index.aspx?nr=4916

Best Regards,

Larry K.

Thanks every one for invaluable suggestions. I will contact E+H.

Thank you.

Hi Mahesh-

This thread is now three weeks old. I was curious if you have selected or picked a new level controls system yet? Let the thread know when you do. I would be curious which system you picked and how it worked.

Thanks-
-Steve

Hello, I manufacture products that control and eliminate foam. If the foam is not present, you can get a true reading from the sensors.

Ask the moderators for my e-mail address if you have any questions. JP

Hi, We tried all sorts of defoamers, most of them are either pollutants (High COD/BOD), or they are degraded by the bacteria in the process, or they are supplied by companies with dubious enviromental records. Anyway, why spend even more on chemistry, when any float switch will work. I went to see the system last week, the main tank ultrasonic is struggling to be +/- 15% accurate, the two radar sensors had lost their EEPROM settings (again), one of the Dissolved Oxygen probes has stopped working but despite 50cm of thick foam, the float switches were working perfectly.

Marc Sinclair

Based on my experience with rubber/latex emulsions, the only suggestions I could make would be either flush-mounted diaphram hydrostatic transmitter(s), or weigh cells, with a point detector (ultrasonic) as a rough overfill indicator. Contact type sensors will get gunked up with the material, while most non-contact types can't deal effectively with the foaming over a measurement range. Using an ultrasonic solely for overfill is acceptable, especially if you wash it down periodically.

Check out a guided wave radar device. Magnetrol makes a good one that I have experience with. I'm sure there are other brands.

The "wave guide" is just a metal rod so it has no moving parts and it is easy to clean. Also, the wave guide does not need to be straight, so it can be bent around agitators, or into the bottom of a cone bottom tank.

I use them in fermenters to see through the foam on top. Changes in impedance generate reflections which are measured to calculate where along the guide the reflection was generated.

Call magnetrol and I'm sure they can send a rep out to test their instrument for your particular application before you buy...

good luck
-Zack Zwitter

Currently, I am working with a service engineer on radiometric level transmitters. I hope proper sizing to zero off foam and the rubber that sticks to the tank wall should provide better results. I can't use any contact type level transmitters as rubber will stick to the rods (at least 3" thick). Appreciate your comments/suggestions.

Thank you.

You will likely have to re-zero the detectors every few weeks, as the signal drifts caused by foam and rubber buildup on the vessel inner walls
increases. If the rubber buildup goes to a maximum, and then doesn't increase, you'll only have to re-zero the detector once or so a year, or
after every cleaning.

Walt Boyes
Editor in Chief
Control magazine
www.controlglobal.com
blog:Sound OFF!! http://www.controlglobal.com/soundoff
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