Re: Wet Fly Ash Feeder
Hello,
You are handling wet mixed fly ash and bottom ash (10% to 20% moisture). You have mentioned the possible use of belt feeder, apron feeder and vibrating feeder.
You have not mentioned screw feeder, appropriate to muddy material. Also think about this. If found suitable, it will result into very clean condition as hopper and screw feeder will create enclosed condition, and surroundings will be free from muddy dirtiness.
The hopper outlet shape would be cylindrical trough matching to the inside screw. The screw feeder will have positive action to pull out material from hopper bottom and likely to be less prone to choking.
Ishwar G. Mulani
Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis is ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world). New print Nov., 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
Visit website: www.conveyor.ishwarmulani.com ■
Wet Ash Feeder
Further to Mr Mulani's comments, another advantage of a screw feeder is that it will employ a wider, parallel outlet, as I consider 1ft width dubious for this duty. flight tip clearance and screw arrangement can be such as to clear lumps and small tramp metal. The flights should constructed to resist 'logging'. The conveying length is do-able, but slightly long for a screw feeder. An 'Expanded flow' regime may be employed for the hopper construction to save headroom as the height of the feed hopper is unlikely to be such that the depth of material above the stressed arch at the transition would have the strength to support the span. An screw feeder manufacturer with experience in this field, such as Ajax Equipment, should be able to quote for your requirements, and carry out tests on the product to verify the optimum hopper wall angle. ■
Wet Fly Ash Feeder
We are exploring the feasibility of processing wet, mixed fly and bottom ash (10-20% moisture) through a dryer and classifier. The feed rate will range between 50-100 wet stph, depending on the moisture content). The wet ash will be loaded via a front end loader from a stockpile into a feed hopper, equipped with a top-mounted grizzly screen. We are having difficulty selecting a feeder. The mixed ash is generally no larger than an inch in diameter and is probably 60% passing 325 mesh. It forms somewhat durable agglomerations that can be broken down by hand or with a bucket of a loader without too much difficulty. We are somewhat concerned about the potential for tramp metal in the feeder system as the nearest magnetic separator will be downstream prior to the dryer. The biggest concern we have is avoiding bridging in the feed hopper, which has been design with 70 degree walls, a tapered opening (1 ft on tail end to 3' on the discharge end) and inward sloped walls on the discharge side of the hopper. We have been considering belt, apron, and vibratory pan feeders. Feed conveying distance will be 20-25 ft. Top consideration is high reliability and low maintenance demands. Secondary consideration, but certainly not unimportant, is equipment cost. Any suggestions? Any feedback is much appreciated ■