Your biggest problem is the small diameter of the opening of the hopper

which is all of your problem.

At a minimum you need to increase the diameter of the bottom opening of the

hopper to allow it to flow more freely after increasing the size of the down stream

handling equipment.

Ideally you would want to install a second open hopper below the current hopper

three to four times the size of the "new diameter" of the draw down opening which

would allow the hopper to flow more freely with not restrictions. ■

Originally Posted by m.qaredaqi

hi everybody

i am working in a plant that beatific iron ore tails. the material that we fed to our plant is sticky fine (80 % under 100) and wet ( about 6 to 10 % moisture !). is there any solution to resolve choking of chute of bin. (the mentioned bin has gravity mechanism with a vibrating feeder to control rate of discharge.

Dear Mr.M.Qaredaqi,

You may fix ceramic tiles at the conical end of the bin. Sticking may be much reduced. But please ensure that there would be no direct impact on the tiles. Ceramic tiles are non-sticky, wear resistant. But brittle in nature.

Regards, ■

If your material is fine and wet, my first thought would not be a vibrating feeder. It may be acting as a vibrating compactor.

I would have thought a positive acting live bottom feeder like multiple screws would be better. This is commonly used on sewage sludge, clay and other high moisture cohesive materials.

If you dig out the pan of the feeder under the hopper opening, does more material flow down onto the pan. If it does you have a discharge problem not a hopper problem. ■

The first step should be to measure wall friction to verify whether the bin wall is steep enough for mass flow. It appears to be designed as an expanded flow bin and the transition is at a span where there would not be a prospect of arching, ratholing or self-clearance of the upper contents. Shear tests would extablish the size of effective outlet necessary to avoid arching, however, the real difficulty is expected to lay in the transition to flow sideways down the vibrating feeder, as this looks to be a simple, bolted on connecting chute that allows the vibration to act on the body of material under the outlet to compact the material and restricts the exit path.

The most positive solution would be to fit inclined ribbon screws with clog-resisting flight construction, progressive pitch and carefully designed transition hopper. A quotation can be sent by sales@ajax.co.uk if copies of drawings were provided. ■

Be thankful for the moisture. That's how you are getting material to stay on the steeply inclined belt.

Then again: It is quite surprising that you get much out of this bin in the first place.

If the hopper outlet is proportional to the conveyor skirt requirement then what extraction rate was it designed for?

Then ask why there is a vibrating pan feeder subjected to abrasive burden and possibly throwing rusty water all over the shop?

The job was on a hiding to nothing on the drawing board, regardless of the spec which nobody read or understood at the project phase.

Before you can extract you have to get material to the extraction point. If you fit additional flow promoting equipment you stand the very good chance of lessening the available wall angles.

As already mentioned, vibrating equipment will simply increase the constipation.

Ceramic tiles are correctly refused since they would simply increase the restriction: regardless of their durability during cleaning.

If you have to smack it with a hammer then the issue is clearly in the hopper. See JD's query.

About Big Blasters (air cannon): I was on the lookout for incorporating them as a retrofit option, blind flanges at the ready; sort of thing, a couple of years back. I would be still waiting for an answer from the sales guys if I was still interested. Knock them on the head, now.

By the way, it is normal and preferable to have very similar suspension chain lengths for pan feeders. Pendulum lengths from school days. I bet it even shows 'checked' and 'approved' in the Contractors drawing Title Block and 'Approved with Comment' on the Owner's copy. Some things never change. Just keep a few rubber mallets, sledgehammers; like the pavers use, at the ready and let them get on with it. Some disasters do not merit attempted remedy. Think about it. If you alter it and it still doesn't work (it won't) you will get blamed and the original tosser will walk away laughing. ■