High level switch for hydrated lime silo

[itdepends]

We have an application where we overfilled a hydrated lime silo. The silo has a guided radar level probe but in this instance the level jumped rapidly from 80% to 100% and the silo overflowed before the operator could shut off the lime supply. The silo is relatively small (70m3) and holds less than a full truck of lime. The hydrated lime is pneumatically blown into the silo.

One of the possible mitigating actions is to install a high level switch in the silo. Does anyone have experience with high level switches (or other indications) in this type of application? The hydrated lime density is very low- only 350kg/m3 when settled and lower when just blown (it flows like water when fluidised).

Cheers,

ItDepends

 

[shahyar]

I generally put HLS on lime silos with horn. Also, I put three level switches as the shape of cone inside of silo can not be predicted during the off loading. At the end of off loading because of "dulite stream", lime powders goes at the other side of the cone and stacks up over there. This is the reason you see a "jump" from 80% to 100%.

Hope this help.

 

[itdepends]

Thanks Shahyar,
I've had some other feedback along similar lines- installing a high level switch (vibrating tuning fork) inside the silo

 

[leakyseal]

We just installed a new silo with LAH instrumentation. Vibrating fork style is good for this. I agree that a couple around the perimeter are good cheap insurance.