RF Capacitance or Admittance Level Transmitter. 1

[PW2006]

I have the following questions.
(1) Can RF level transmitter be used for interface measurement? If it can, does it require that one phase of liquid is conductive and the other phase of liquid is non-conductive so that one phase is kind of invisible to this transmitter? How accurate will it be for interface level measurement? Is there any other concern of using RF level transmitter for interface measurement?
(2) It seems that RF Admittance level transmitter is less sensitive to the coating built-up on the probe than the RF capacitance level transmitter. They are very similar in measuring principles. Does this mean that I can always replace RF capacitance level transmitter with RF admittance transmitter? Is there any situation that the RF capacitance level transmitter actually is better and should be used instead of RF admittance transmitter?

Thank you in advance for your help.

 

[roydm]

RF probe should work well for interface provided the dielectric constants are different enough. I presume you are asking about insulated probes.
What two liquids are you trying to measure?
Roy

 

[PW2006]

We have several types of applications. At one application, we have caustic at bottom and hydrocarbon on the top. Guided wave radar sounds like another valid option. How does the RF lelel transmitter comparing to guided wave type level transmitter?

Regards,

 

[roydm]

I haven't used guided wave radar yet although we are specifying it for a new plant. According to all I have read GWR needs a significant difference in dielectric constant to get a good echo. One thing that might be a problem is an emulsified interface layer so make sure its located where the mixture has had time to settle.
Differential bubble tubes also work quite well even if the two liquids are quite close in SG.
Roy

 

[roydm]

I should have mentioned GWR will not work if you have the high dielectric constant on top low on bottom.
We have this in one of our processes water on top of oil (aprox 1.1 SG)
Roy