Air Agitation Flow Control vs Tank Level


Thread Starter

Steve van Reenen

I am currently investigating the amount of Mine Slurry spillage at our Backfill Plant. I found the slurry tanks are agitated with compressed
air at full blast. The slurry tanks are filled every morning with the slurry product (and air agitated). In the evening the agitated slurry
product is slowly drained for underground use - thus the air is still fully openened. The lower the tank level drops, the more the product
is blown from the tanks - resulting in spillage. Can I control the amount of air flow (necessary for the agitation of the slurry product)with the tank level (Ultrasonic level transmitter/transducer)? Any better idea, please?

Two techniques you might consider:

1) Maintain a constant differential pressure between the air and slurry by reducing the air flow as the level falls. A dP measure between the base of the tank and the air could work, provided you can keep the impulse line on the tank clear. (Diaphragm isolation with a small air purge into the tank or use a Pneumacotor type device).

2) Measure the level and as it falls reset an air flow controller.

In either case the presence of solids in the liquor complicates the measurement issue, the control bit is quite easy.

Chris Hall
you will have to keep the amount of air constant however the pressure will be going down

So just put a rotameter in to see how much air is going in. This should be put on the high pressure side.

If you could use a pneumatic controller it would be easiest.
Just put a airoperated control valve in the line.
and a small flapper nozzle system in.
Yes i am PLC crazy but always looking at old methods as they simply work a lot better as all these electronics.
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