PLC Density Control loop

[MayadaAhmed]

Hello,
I want to do a control loop, to control the density of slurry, what is the best practices in density control, and what good sensors to use, and is it better to measure it in tank or in pipe?
Please help

 

[5618]

We mix a slurry of lime in water. We circulate continuously from the bottom of the tank, through a Micro Motion coriolis flow meter which reads flow rate and density, and back to the mixing tank. When the process calls for lime, valves switch the flow to the process, then back to recirculate when the batch is done. We vary pump speed to recirculate slower than feeding the process.

Micro Motion have been excellent for us and we use them to monitor flow elsewhere. This is the only one where density is monitored. I don't think we've had one fail. This one is about 20 years old.

 

[cardosocea]

In tank is tricky if you don't have an agitator. Measuring in a tank is likely to become a bit crappy as the sensors can get clogged. It is cheaper-ish to do in a tank as all you need are two pressure transmitters and a fixed height between them.

 

[dvcochran]

Measuring Density of Slurry

Hello,
I want to do a control loop, to control the density of slurry, what is the best practices in density control, and what good sensors to use, and is it better to measure it in tank or in pipe?
Please help

Check out Vega.com. They have a good non-contact product. https://www.vega.com/en-us/products/product-catalog/density/radiation-based/minitrac-31

I agree with agitation to promote consistency. This can be difficult when moving slurry from one location to the next so the origination needs to be agitated so that the slurry is suspended as much as possible before reading density.

Can you tell us more about the application?