Chute Inserts
It depends on what you are trying to achieve:
1. Are you interested in mass flow -- if so, then one or more partions should be used to divide hopper into sub-regions depending on hopper opening, tonnage, final height of skirt flow, and rock size
2. Gate opening with belt should be more than 3 x largest rock diameter, and if possible about 5 x larges rock passing size, but, depends on frequency of large rock. However, the feeder shear plane may be many times the largest rock size.
3. The hopper size dimensions should be selected to fit all governing conditions including keeping the slot opening as small as possibe to minimize power and belt wear. What does Colin's book or Colin say about it? ■
Slump And Belt Feeder Exit Length Beyond Shear Gate
The belt feeder shear gate should be positioned and dimensioned to contain the product when drive power is turned off. The surcharge angle should have some allowance for low friction product behaviour calculated back from the head pulley. A free flowing product must have a cutoff gate to contain the product from fluidizing.
Realize the vertical flow also has inertia which must be arrested when power is cut. This will add to the distance allowance back from the head pulley to the shear gate. ■
Re: Witches Hats / Transverse Insets - Belt Feeder
Yes Larry, I am designing for mass flow.
I have had testwork done on the iron ore and its interface with the selected liners (duaplate). The material is very difficult to handle see the tunra graph attached.
I need a wide belt feeder to acomodate a hopper opening of (1300-1600mm) but my flow rate is only 300 tones an hour. Hopper half angle is 20 deg, and the blue and green lines are duoplate across and with the grain.
Max particle size is 32mm (50mm if crusher is out of normal settings) so i was planing on an opening of 150mm. @ 300 t/hr belt speed is 110mm/sec.
I have looked into a transverse insert to reduce feeder loads and help with hopper structure. However then my thininking is the bed height will increase to 300mm then the belt speed becomes 60mm/sec.
By slump i mean the material coming of the head pulley in surges because of the slow belt speed. There is plenty of room from the hopper to the head pulley so i am not too concerned about uncontrolled discharge.
I am not aware of colins book can you please provide the full title and authors full name.
Also can you please confirm the 3 to 1 length to width ratio between partitions is required to maintain the wedge flow pattern? or is this criteria relaxed as the inserts are not full height.
Attachments
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Re: Witches Hats / Transverse Insets - Belt Feeder
Originally Posted by nordell
1. Are you interested in mass flow -- if so, then one or more partions should be used to divide hopper into sub-regions depending on hopper opening, tonnage, final height of skirt flow, and rock size
2. Gate opening with belt should be more than 3 x largest rock diameter, and if possible about 5 x larges rock passing size, but, depends on frequency of large rock. However, the feeder shear plane may be many times the largest rock size.
3. The hopper size dimensions should be selected to fit all governing conditions including keeping the slot opening as small as possibe to minimize power and belt wear. What does Colin's book or Colin say about it?
Dear Mr. Nordell,
Currently, I am doing research on a stockpile tunnel apron feeder having a long opening slot and with a hopper above it divided with transverse vertical inserts. The purpose of the study is to provide for uniform draw of bulk solid (crushed ore) from the hopper along the length of the feeder and for reducing the initial load. Publications I have access to deal mostly with general issues. Could you, please, direct me to a relevant paper or web-source being more specific with regard to the combination of long opening feeder and partitioned hopper? Thank you ■
Re: Witches Hats / Transverse Insets - Belt Feeder
Hello,
Your query is not clear. Possibly it seems something like this:
There are cross plate (barrier) in skirt board where say first cross plate provides flow opening height of 150 mm above belt, second provide flow opening height of say 300 mm above belt, third provide opening height of say 450 mm above belt, etc. It is understood that above barrier plate will also extend above hopper - skirt board interface for some height ?
If it is so, this can help to draw down material from hopper outlet length, equally in 3 - steps. But such arrangement would be suitable for granular or very small size lumpy material; otherwise lump wedging between belt and such barrier edge would cause serious wear / damage to the belt and jamming (non-functional situation). I am not familiar to said arrangement and readers who have dealt with such arrangement, can provide more information. Continuous expanding cross section of skirt board (width as well as height) is superior and safe.
Ishwar G. Mulani
Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis 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
Website: www.conveyor.ishwarmulani.com ■
Witches Hats / Transverse Insets - Belt Feeder
Do transverse inserts inside a hopper have the same requirements as the outlet of the feeder interms of height from the belt?
IE if the minimum height for the opening below the insert is 3 times max particle size and i have one insert half way along the length of the hopper, then the outlet at the end of the hopper is going to be at least 6 times max particle size (neglecting the width of the insert), to acheive a constant release angle.
This only is an issue for me because my situation has large particle sizes and low thoughputs resulting in very slow belt speeds and i am concerned about slumping off the end of the head pulley.. ■