Design for Feeding From Bin

Thinking about building a bin and getting away from bagged coal. Trying to figure out a good way to feed the boiler right from the bin. Where the boiler is I'd have the auger go into the bin around the end of the bin. If I built the bin flat, how much coal would the worm pick up?

A 40-45 degree funnel cone up from where end of auger picks up.
Taller is better than wider... Big footprint bin does not help w/o sloped bottom.

The issue you have to deal with is referred to as "Mass Flow Of Materials.

NOW if you build a flat bin and simply stuff an auger in it it will pull all the
coal that the auger can transfer until the piles on both sides if the auger
can no longer move with mass flow to feed it and the auger will starve.for lack of
material to convey to the boiler.

There is huge amount of material on the home page about
bins and augers that you should also look at herein.

The EFM home page has an excellent description of a properly made bin and auger set up
using the Dog House method where the bin is sloped down to the auger end and feeds the
auger by gravity and the coal continues to feed it as the "Mass Flow" of coal is sliding down
and feeding the open auger end which is exposed.

The thing you have to remember is an open auger will pull everything forward until it
is gone or a shear pin breaks. The coal will flow forward until it can no longer flow from
conveying of the coal out of the bin because the bin does not have sloped sides that
would create the mass flow of coal.

The same issue occurs with an auger tube with an exposed and guarded end that you
would simply put on the floor of the bin it can only remove so much until you shovel more on it.

Ninety nine percent of the issue is where is it that your going to have the bin and you need to plan
around where it will be located in designing it as you want to make it as simple as possible to
reduce the labor involved.

The use of a dog house lets you bolt the auger tube tihe underside to take advantage
of the 21 degree angle for flow and flooding of the auger end.

Where I can put the bin would have the auger going into the right end of the bin. Perhaps I could make the dog house there and slope the bin to one side? Although a 45 degree angle would mean that half my bin is dead space.

Honestly unless you have a really high ceiling like 10 or 12 foot and want to spend a lot of extra money on materials it's not worth it. Anything below a 45 from the center of the auger end is dead space. We have a plastic 55 gallon drum inside the bin the auger goes into.

plumber wrote: Although a 45 degree angle would mean that half my bin is dead space.

That's why you need the high ceiling, you can build up. I had customer a customer with a 12 foot ceiling and something like a 8*8*12 bin with angled walls at the bottom. Might have been 10* 10. You could dump 10 ton into and it would just disappear....

I have a 4w x 8l x 4h bin with the walls angled from the 8' length toward the middle. There is a space of about 1' between the sloped boards at the floor It holds just under 2 ton of rice. The sloped board does not go to the top of the bin wall, there is about 1' of straight wall above it.

Since I had extra on a roll here already, I put tyvek on the sloped board so the coal slides better. My first year with it so I can't tell you how it held up yet, check back later this spring if it ever gets here and I'll let you know!

Head room is a wish. I've got 6 1/2 feet. I was thinking of 9x9x6. If I put the floor on a 45, I've only got a 5 ton capacity. I need 7. If I build it flat, will it fall at a 45? Perhaps I might be better off building a small bin and sticking with bagged coal.

i believe with a flat floor the slope of the coal left in the bin will be steeper than 45*. So if you put your auger in the middle of the 9x9 footprint you would have coal sloped ~ 5' up the walls of your bin as the auger empties out what it can reach in the middle. You have to rake the sloped coal toward the middle when you need to fill around the auger again.

Have you thought about using a 1 ton bag system on a pallet like someone else here has done? They move the pallet over their auger with a pallet jack and open a slide gate to allow the coal to flow to the auger. It is a very slick system.

If you look at the pictures of the bin at efm, and simplify it for home use, we never had a bit of trouble with it.

That skid system vermontday came up with is real slick. Perhaps I could make one on a smaller scale. Or a wooden skid about 5 feet tall. I was also looking at possibly getting a 275 gallon plastic tote. I'd like it to be hands off, but it may be more work than its worth. The layout of my basement really sucks! I have one window that's no where near the chimney, and I have the Mrs needs storage issue. If all else fails I can always use the barrel and keep pallets of bagged coal outside.
More reading to do.

The skid system requires a large uncluttered basement with a level, smooth concrete floor.

If you do not have that, you are out of luck.

If you do have that, you can tell the misses that you will have more time for her as you won't be shlepping coal!

Plumber,

Here's some quick drawings of my AA 260 bin. I realize the pics are out of order but I wasn't going to re do the drawings.

1 - shows a cross section of the bin showing how I stack 2x4's or 2x6's to rise the height inside the bin to stack the coal towards the dog house. This was done by using 2x4's on the side wall leaving space to slide the others into the groove.

2. Shows 1 possibility where you would just have the sloped section near the auger only so it would self feed.I added the 45* sloped floor if you really want to go that route. I don't have that in mine.

3. Shows an overhead view of my bin. Forgot to add the double access door located near the number 3 to allow me into the bin. Those doors are closed when the bin gets filled and leave a 4' tall open space to the bottom of the floor joist so one can climb out of the bin after packing it full.

When the bin gets filled, I leave about 18" of vertical height in the removable 2x4 's shown in fig 1. The bin self feeds the auger for quite a long time. As the level goes down, I start shoving coal from in front of the access doors towards the dog house stacking it up high above it. And continue to shovel as the level goes down. The 2x4-s allow me to empty the bin down to about 1/2 to 1 ton before requiring a refill.

4. Shows hot to put a barrel over the auger. Set it up on cement blocks so the coal can feed from the sides when the bin is full. 1 thing I noticed with this setup is that as the bin goes down, you constantly have to be shoveling coal into the barrel.

The shoveling that I do takes all of about 5 minutes 1 times per week.

Rick

Another requirement for using skids is having a low angle auger that the skids will not hit when set on the auger box.

Also, the pallet jack has to come in from the opposite end of the skid that the auger goes under and it has to have enough room to pull the pallet jack out from under the skid. The result is you need a fairly long amount of room in one direction.

Plumber, have you thought of putting the bin outside the basement? Than have a chute that allows you fill a smaller bin in the basement that you can fill when you need to.
Dan.