Slurry level measurement


Thread Starter


We have a slurry comprising 30% Bleaching Clay, 60% Hexane, 10% Vegoil. This is being agitated in a batch mixer vertical vessel which is almost 6 metres tall and 2 mts in diameter, and cooled by internal cooling coils.

The vessel has an agitator with blades at almost 1.5 mts spacing along its length. There are cooling water coils also located along the inner periphery of the vessel. There is approximately 3 inches gap between the inner wall of the vessel and the cooling coil.

Options I guess would be:
- Bubbler
- Non-contact type like UT/ Radar etc
- Capacitive?

The presence of the agitator & cooling coils is a major hindrance.

The question is what is the best way of measuring level?

Thanks in advance.


Remote Seal LT is an option provided you have suitable nozzles.

U can go for ultrasonic provided the LT is equipped to compensate for the pulses generated due to agitator blades.

If slurry is not sticky in nature, Guided wave radar is also a useful option.

U can consider nucleonic. though u will have to size it properly if u prefer non intrusion type.
Using dp transmitter with capillary and sealed diaphragm may have its limitations as this relies on the Specific Gravity of the liquid in the tank. considering the liquid is a composite of 3 components I would look at some other options unless you can guarantee the composition percentages.

You would definitely be better off exploring the option of a radar type level transmitter or even a magnetic follower type such as a Type 75/101 from Vaihinger. of course this will involve some modifications to your tank to add isolation valves and level chamber.

The use of nuclear level gauge is an option however cost amongst other things will be a problem.
If you go the DP or sealed route, make sure you create a PM to flush out that line. Cause crap WILL pile up in there and throw your readings off in time. But yea its hard to go wrong with ultra sonic LIT
Actually, it is really easy to go wrong with Ultrasonic level transmitters in agitated reactors. I recommend strongly against using them. Even with sophisticated agitator-blanking algorithms, the wave and vortexing action in an agitated vessel make ultrasonics and even pulse radar level systems problematic and sometimes worse than useless. FMCW Radar (that is the expensive kind) works USUALLY. I strongly recommend load cells and inlet flow measurement for agitated reactors.

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