In my tanker driving days, and nights, I was sometimes called on to couple up to a powder tub for delivering flour and similar powders. First impressions were that the tanks seemed extraordinarily voluminous for the tonnage carried. I was told that this was because flour, cement and the like were severely aerated by the gravity discharge filling and they maintained this aeration throughout a 3 hour journey, at least, vibration consolidation and all.

Maybe your product is similar. So give it a 3 m drop and see what happens: dust generation taken care of that is. ■

It can be difficult to de-aerate a fine powder quickly because the bulk becomes less porous as it settles. A hopper should be mass flow to secure the maximum residence time for the air to settle out. However, fluidised powder will not mass flow as the internal friction is invariably less than wall friction. This means that the material must settle to a stable flow condition before reaching the converging section of the hopper. Not only that, but the flow channel should be as large in cross section as possible and be as even as possible. The optimum construction is a 'V' shape hopper with a screw feeder the generates uniformly progressive extraction. Only when the powder loses fluidity can it be mechanically compacted bt the feeder screw as, if excess air is present, it will re-expand when the compacting forces are released.

essential the same applies to roller presses, pill manufacture and the like. More needs to be known about the specific system to assess the most promising approach. ■

I think it will be very difficult to de-aerate a fine powder as the bulk becomes less porous as it settles...,the material must get to a stable flow condition before touching the converging system.Hope more replies will be appear and will help you more. ■

Hello,

Possibly a short screw conveyor having cut and folded flight could be solution. It promotes agitation, aeration and mixing. Aeration implies reduction in bulk density. Cut flight with counter acting paddle produce still higher degree of agitation and aeration. Screw conveyor also does this function in totally enclosed condition, so there would not be dust emission. Refer experienced manufacturer of screw conveyor for specific information.

Regards,

Ishwar G. Mulani

Author of Book : Engineering Science And Application Design For Belt Conveyors (new print November, 2012)

Author of Book : Belt Feeder Design And Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916

Email: conveyor.ishwar.mulani@gmail.com

Website: www.conveyor.ishwarmulani.com ■

Yes we have everything that you need at Quadro Liquids. Our equipment is great quality for an even better price. Come check us out and see if we can help you out! ■