We are planning to install a new radar type LT in a vessel having an agitator. I will be obliged if someone can give be information about the minimum distance that should exist between the agitator and the flange of the radar type LT. I was informed that the performance of radar type LT is will be affected if the line of tranmission is affected by agitator movement. Which is the best type of guided wave radar which can be used for Ticl4 and TEAL service?

 

Mihir,

First you have to be specific that are you going to use non contact type or GWR type level transmitter. If you use non contact type, the cone angle of the radar should be such that the agitator does not coincide with the path of the wave. In case you use GWR type transmitter, it will not be dependent on the angle etc coz the wave will be guided thru the probe of GWR.

Paras Parmar
Field Design Cell
Control Systems & Instrumentation
[email protected]

 

Most transmitters have some sort of agitator blanking algorithm. These work sometimes. Using radar or ultrasonics in a vessel with an agitator is a problem. Here's why. In an agitated vessel, there is usually a vortex created by the agitator. What you want to know is "what the level would be if the agitator was turned off"... which is not a measured variable. What you will get is the apparent level with the agitator turned on. Besides that, every time the agitator intersects the beam of the radar level gauge, it will cause a false signal. If the agitator is turned off, and it stops in the beam it will give a false signal. The reason we use radar in these types of tanks is nothing else works well, except gamma nuclear, and nobody wants to use that anymore. You will
have to experiment. The agitator needs to be below the blanking distance of the radar gauge, and you will need to experiment with your agitator blanking software.

I would not recommend guided wave radar for agitated vessels, or for the applications you ask about.

Walt Boyes
Editor in Chief
CONTROL magazine
www.controlglobal.com

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It depends on the type of cable probe selected for your application as well as the dynamics of your process. Try www.flexar.info for basic information. There will be links for further more detailed information.

 

Dear paras,
first thing you cant use GWR for agitated vessel
second there is basic rules to install radar like your flange should be at the distance of 1/3rd of height of your vessel from wall to aoivd multiple reflection.

 

Dear Sir,
I had read your reply.To measure level in reactor with agitator,please go for krohne,germany make RADAR LEVEL TX MODEL BM70A,this model is specially made for agitator vessel,Intially rotate agitator in empty condition,radar will store that reading,you dont to do any thing just give installation command and height of tank to radar,radar will automatically store reading.Once this will finish,put radar in measuring mode.I had supply lots of radar in agitated vessel and it work fine.

One more thing,while you install radar at top of vessel,it should be installed at the distance of 1/3 of height from vessel wall to avoid multiple reflection problem.

In such a case you cant use guided type radar level transmitter,it can use when your di electric constant of material is less or when you are using bi phase media.

Just send me your company details,i will send you all the details.

Regards
Kalpesh Sheladiya
Krohne Marshall
India.

 

Dear Mihir

What is agitator speed ?
Is there any boiling liquid ?
Diameter of vessle ?
Di-electric constant of fliud ?
Tank MOC ?

I would appreciate your feedback on this

Jari
[email protected]