RF Admittance

[jeebusmn]

Hi,

We want to measure the level in a cooling water basin. The water is going to be pretty dirty and there might be some slime and foam. The people in process compared it to toilet bowl water. I talked with a vendor about using a RF Admittance Leveler and he said that it would work but it would just have to be cleaned every so often.

What is every so often and would a bubbler be a better choice? I was told by a guy in process that he has seen capacitance levelers that had to be cleaned every shift? How much does teflon coating help?

How mucky and dirty does your process have to be to mess up a rf admittance leveler?

I don't have any field experience so answering these kinds of questions is hard for me.

 

[Ashereng]

All these exotic level measurement solutions!!!

How about a simple magnetic level indicator (float) with transmitter? It's old school, and it works.

http://www.magnetrol.com/us/html/products.asp?family=21

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[controlnovice]

More expensive, but try non-contact Radar. No cleaning necessary. More expensive up-front, but with no cleaning- it'll pay for itself.

______________________________________________________________________________
This is normally the space where people post something insightful.

 

[Cat3347]

Exotic level measurement solutions? Huh? RF is not what I would call "exotic".
Modern RF Admittance electronics can ignore most coatings /slime. I've seen probes in more extreme applications only be cleaned once a year or so. Of course..every application is different. Just keep an eye on it. BTW..if you have to clean an RF probe every shift...then its time to try a different probe or a different technology.
If coatings worry you...then look for non-contacting solutions. Radar, Ultrasonics, etc. More expensive, and each have limitations. Mist, evaporation vapors, etc are something to worry about.

 

[jeebusmn]

Thanks for the suggestions. It is a little reinsuring Cat3347, that you thought RF Admittance was a possible application. The experienced process engineer, who told me how terrible using a capacitance leveler would be in this application, I think was basing his entire opinion on older non-rf models.

Ultimitely, I decided to go with a fishing weight pressure transmitter for a couple of reasons.

A: It is cheap, 1/2 to 2/3's as cheap as anything else.
B: I doubt it will have to ever have to be cleaned. As long as it is wet, pressure should be felt on its pizoelectric disc. And if it needs to be cleaned, pulling up a fishing weight is a lot easier than trying to clean rod.
C: Installation is painless. Mount a pvc pipe and drop the transmitter in the pipe.
D: It is not what the Process guy wanted, a bubbler (I was against this from the start. If they are so great, how come so many vendors are discontinuing them) so I don't have to worry about my Boss looking like he is take orders from another department.
E: It looks like a bomb-proof solution.