Grain bin capacity?

Ok, trying to figure out what these 2 bins SHOULD hold. corn or soybeans, standard test weights. One is 14' diameter with 10' tall sides. Not concerned about the roof capacity. The other is 20.8' diameter and 18.5' height. I try 3 different online calculators and get 3 different answers. Small bin we put 4 full Brent 440 gravity wagons of beans in, I figured 1600bu, wagons were heaped. Ins adjuster laptop ins program came up with only 1386 bu, all 3 calculators came up with more. I think that ins program is wrong, I have no claim, but I dont want to have my APH drop if that not accurate.

Diameter x height will give the cubic feet, but I don't know how many cubic feet are needed for one bushel of beans, or corn for that matter.

14 foot diameter holds 123.1 bushels per foot. 20.8 foot diameter holds 271.9 bushels per foot. USDA form CCC-637. Ask for a copy at the office- charts for 9.5-35.8 foot dia bins.

Volume times point eight equals bushels.

Dave get on sites that sell bins. Bet they can tell you. It isn't going to be real accurate. Bushel is determined by weight. So lite corn or beans will take more volume than perfect stuff.

Rick

I used the Pocket Reference Guide by Thomas Glover and I'll probably prove that math is not one of my strengths. The formula for cylinder volume is Pi R squared For Pi use 3.1428571, the radius of the first bin is 7 (1/2 the diameter) so the formula becomes 3.1428571 (7x7)10=1539.9999 call it 1540 the same reference guide says to convert from cubic feet to Bushels (US) multiply by .8036 so 1540 x .8036=1237.5 (bushels) The other bin I'm not sure if you measurements are feet and fractions of or feet and inches but it should be close, I get 5054 bushels. Now let the debate start!!

http://www.extension.umn.edu/specializations/cropsystems/M1080-FS.pdf


This pdf is from University of Minnesota Extension and has a lot of useful info. Basically it is a little bit of geometry, you figure the volume of a cylinder (bin) which is pi (3.14)x radius squared x height. Then multiply the answer by 0.8 to convert cubic feet to bushels. This will get you close but moisture, density,and test weight will all influence the total. Remember you are selling by weight not by volume. For record keeping purposes for crop insurance we only use the actual bushels sold when we haul the grain out if at all possible. A volume measurement can only get you so close.

Dave the way to figure the volume of a bin is as follows: The radius of the bin squared, times 3.14, times the depth. Then divided by 1.25 or multiply by .8 that is the volume of a bushel.

So the 14 foot bin would be as follows:
7 x 7 x 3.14 = 153.86 cubic feet per foot
153.86 x 10 = 1538.6 total cubic feet
1538.6/1.25 = 1230.88 level full.

So if you have a cone up in the middle that would add a little. Then the adjuster at 1386 is real close.

The larger bin:
20.8/2 = 10.4 radius
10.4 x 10.4 = 108.16
108.16 x 3.14 = 339.6224
339.6224 x 18.5 = 6283.0144
6283.0144/1.25 = 5026.41152 so basically 5000 bushels


You have to remember that Brent rates those wagons with dry corn. From Brent's web site(Capacities measured with #2 corn 15% moisture (56 pound test weight) Also this is a calculated volume on Brents parts. So you would have had to fill the corners and then shake the load down and then refill it. So rarely do you get the rated capacity in them. Also they will not hold as many bushels of soybeans. Usually about 4-6% less. The test weight of soybeans is usually less than corn. Plus the volumetric measure will not match the weight exactly.

Just hauled three wagons of soybeans for a neighbor. All Parker 2500 wagons. They hold 320 bushels of dry corn. They only held 295 bushels of soybeans. This is across the scales.

Here is the way my USDA hand book describes a bushel.
( A bushel is a volume measurement. Specifically, a volume bushel is the equivalent of 1.244 cubic feet (normally, a figure of 1.25 cubic feet is used). Looking at it another way, there are 4 pecks or 32 quarts in a bushel. Test weight is a measure of the weight of grain (usually expressed in pounds) per volume bushel. Each different type of grain has a standard bushel weight at a specific moisture content. These are: corn (shelled) – 56 lbs. at 15.5% moisture, soybean – 60 lbs. at 13% moisture, oats – 32 lbs. at 14% moisture, wheat – 60 lbs. at 13.5% moisture, and barley – 48 lbs. at 14.5% moisture. Given these relationships, volume calculations can be used to get a reasonable estimate of the number of bushels. Similarly, grain weight can be used to estimate bushels and is probably the most accurate method if adjusted for moisture.)

What I have found over the years is this: That corn will have more bushels when figured by volume and soybeans a little less.

That 1400bu would sound about right for that size bin.

Typically you will get less that bu of beans in that bin - here in MN beans tend to test lightweight.

This year esp, you cold have gotten more corn than that in the bin, as corn was testing 61-62.5 testweight for me. _However_ the volume calculation of the bin won't account for heavier corn, so unless the took a test weight & accounted for that, it won't show up.

I got 375 bu of corn on my truck this fall, had it piled higher & got 333bu of beans on the truck. Couple years ago when corn test weight was barely 50, I couldn't hardly get 300bu on the truck..

We live in an odd world where a bu is a volume measurement, but any time you sell grain the take the weight & moisture of it and convert to an 'ideal' bu.... So we never really know what we have.

If you are familiar with your wagons then you can guess what they hold. If you are new at this, typically you can't get on a wagon what the manufacturer rates it at based on volume - they get them heaping full to the corners in their rating.

Oneyear I filled my bin - about the size of yours - with beans, the govt guy measured it and said so & so many bu. I hauled it to the elevator in spring, and the coop guy was nice to me, the beans were weighing light enough to dock but they wanted beans that summer so he gave me the accepted weight on the ticket.

Well, when you did the math, it got all messed up, I came up with less bu that the govt guy estimated - because of the weight difference of what my beans really were vs what the coop wrote down. FSA wasn't worried about it, they said happens all the time, but had me a little anxious there for a bit.

--->Paul

Another way to do it is as follows. Bin diameter x bin diameter x .7854 x height x .8. This will figure the bin on a level basis. For a normal peak figure the same formula and divide by 3 for the peak capacity and add to the level total. This also works for a partially unloaded bin. Just figure the depth of the cone and divide by three, subtracting from the outside height. This is the way my crop insurance adjuster does it as well. Mike