Originally Posted by mancisidor

Does anyone can help me with information about wheel of used vehicles in pieces between 5 and 25mm? We have doubts about the Flow properties of the product. We are afraid that the product vill not go out throug a 500mm diameter spout of the silo.

Thank you.

We need more information from you Mancisidor,

with your stating the use of a spout it infers you

are blowing the scrap pieces into the silo.

Please clarify the storage and delvery ends of

the scrap processing system.

If any product is not uniform in size it most likely

will effect the outloading of scrap simply due to

gravity and weight of scrap pieces. ■

Are you talking about a wheel as in something made of steel and attached to a vehicles axle, or the rubber tyre that is mounted on the wheel and in contact with the road surface ??? ■

Shredded tyres might well expand when approaching the discharge, from the compressed state imposed by the weight of overhead rubber. Such expansion could indeed cause bridgeing across a smaller orifice. Half a metre sounds big enough..but. Fitting some sort of discharge promotion device will not overcome the situation if the orifice is too small. A vibrator would make things worse. What you might consider is fitting a cone baffle some distance above the outlet spout so that the weight is relieved. Just make sure that the subsequent compression, as the rubber flows through the new restriction, has time to relieve as it approaches the outlet.

Am I on the right track, Lyn? ■

Can you put it into a 4.2m dia. silo, yes

Will it flow out by gravity alone through a 500mm dia outlet, problematic.

You've tested the electromechanical vibrating feeders for conveying, but thy need to be tested in conjunction with a bin of sufficient size to give a good indication of full scale results. Seek out feeder suppliers who have such a test plant and enquire from them for your equipment stipulating you want to witness trial running.

And remember to give them representative materials that come from your shredder. ■

Originally Posted by mancisidor

Dear M. louispanjang

What do you mean with fitting a cone baffle some distance above the outlet spout? What is a cone baffle?

If you fix a hollow cone, apex uppermost, in the centre of the bin then the cone will support some of the material weight. This leaves the rubber below in a less compressed condition which will reduce the particle growth behaviour which we suspect might otherwise contribute to bridgeing.

You must ensure that the cone is high enough over the start of the hopper so that it doesn't impede the descent of material through the bin. Bin capacity will be reduced ...but its better than a binful of gummed up rubber. ■

You do not indicate the size of the pieces but, in any case, 500 mm is almost certainly inadequate for a 60 degree conical silo to relialy discharge. The wall friction will be high, so 60 degrees is little better than 45 degrees as the rubber will not slip on the walls. A plane flow transition of mass flow design may be suitable, but it would also be prudent to incorporate some overpressure relief.

You will also have to carefully design the belt extraction interface to secure progressive extraction. As this will have to accomodate the 500 mm width it would seem oppertune to look at a final outlet slot of extended length, even if the initial width is somewhat smaller than 500 mm. The task calls for some expertise on a 4.200 diameter silo. I would be expecting an expanded flow construction at 2,500 diameter to be needed, with minimum principle stress relaxation on the final slot. ■

Why the used tire seems more useful than the news ? I have seen many company buying that. ■

We have manufactured screw conveyors for rubber crumb. We are sure that a square bottomed silo with multiple screw set up on the bottom would work. If you need more information please email thomson@wameng.com and I will send further information. ■

I recall we had the same issue in the design of silos/ hoppers for the storage of grain. The key issue here is that there will be some form of bridging action accross the hopper, which can form up inside the silo as well, preventing discharge of the stored material. A vibrating poker solves this problem, by breaking up the bridge and allowing free-flow of the material out of the hopper. ■

Originally Posted by Richard TJ

I recall we had the same issue in the design of silos/ hoppers for the storage of grain. The key issue here is that there will be some form of bridging action accross the hopper, which can form up inside the silo as well, preventing discharge of the stored material. A vibrating poker solves this problem, by breaking up the bridge and allowing free-flow of the material out of the hopper.

Since when does grain (wheat, barley etc) hang up in silos and require mechanical assistance to discharge it

All those I've ever seen have either a simple conical bottom, or a flat bottom and sweep auger to finally discharge the repose material after gravity discharge has been completed. ■

Looks like you've plenty of buyers. All you have to do now is get it out of the bin.■

The picture shows you the sharp chines hut to relieve pressure from the out flow

in many cases the sweeping auger is useful ... for lower density bulk

■

Almost no one changes their own tires anymore and the recycling of old tires is done by professionals who generally do so in an environmentally safe way. When you take your car in to have the tires changed at the local garage or tire shop there is almost always provision for taking your old tires for recycling. Approximately 1 in 4 of those old tires is retreaded and used again on another automobile somewhere. In many parts of the world old tires are ground up and used to make rubberized asphalt for highways or shredded and used as a base for gravel roads or as a sand or gravel substitute in some other road construction application. Some old tires are chopped up and used as part of the surface for indoor tennis courts or other indoor sports playing fields. For many applications, recycling old tire rubber is cheaper than collecting and processing new rubber. ■