Today, many companies offer storage bins, such as Brock, Sukup, GSI, Chief, AGI, and agricultural or commercial grade. These companies, each as competitive as the next, offer quality products to meet your needs. A few technical variations may make one product a little more suitable for your needs, but on the whole, they're all equivalent.
One of the keys to storage is, of course, the quality of your grain bin assembly. Unfortunately, this is usually where the problem lies.
In this article, discover the key points to watch out for when installing your bin. These points will make all the difference to your storage success year after year.
As they say, a job well done makes all the difference!
The right fan for your bin
There are 4 types of fan, including:
Axial
Inline centrifugal
Low-speed centrifugal
High-speed centrifugal
Each of these fans is good and suited to a particular purpose. But THE question is: which one do you need?
If you're storing cereals or small grains like buckwheat, you'll need a high-pressure fan. The less space there is between the grains, the harder it will be to circulate air from the floor to the roof.
On the other hand, if you're storing large grains such as soybeans or corn, you'll be better off with a high-flow fan. Why would you do this? Because you'll be able to cool your bins more quickly and prevent them from heating up. The other advantage of high-flow fans is that they can dry your grain.
These fans can be divided into two groups: high-flow fans and high-pressure fans.
As can be seen from the graph above, the fans on the right offer very high flow rates, but are not very tolerant of pressure. If there are too many restrictions, the fan won't be able to push the air through the grain mass. In this sense, if you have an axial fan on a 30-foot bin with wheat in storage, your grain may heat up before the fan even manages to cool it down.
If you look to the left of the graph, you'll see the two fans that are able to push air through a very dense mass of grain. These fans are mainly used for cereal and small grain bins such as canola and quinoa. On the other hand, if you have corn grain silos of 1,000 tons or more, these fans will take much longer to cool them down, potentially leading to overheating and higher electricity costs.
Comparaison
36-foot-diameter, 30-foot-high, 600-ton corn bin
10 HP in-line centrifugal fan
Cooling time: 60 hours
36-foot-diameter, 30-foot-high, 600-ton corn bin
10 HP low-speed centrifugal fan (1,750 RPM)
Cooling time: 30 hours
To see if you have the right fan, use the University of Minnesota's online calculator.
Cooling time for a bin = 15 / unit flow rate [CFM/BU].
Our recommendations:
For bins under 160 tons, cereals and other small grains, opt for in-line centrifugal fans and high-speed centrifugal fans (3,400 RPM).
For soybean and corn silos and dryers (air or propane silo-dryers), choose axial fans and low-speed centrifugals (1,750 RPM).
Where to install your fans on your bin?
Have you opened the installation guide for your bin? Have you noticed that the manufacturer recommends positioning the fan in line with the discharge screw?
The reason is simple: this way, air travels UNIFORMELY under the bin, ensuring proper ventilation of your grain. Otherwise, problems are bound to arise!
Unfortunately, the unloading screw takes up a lot of space under the floor. If the fan is placed perpendicular to the screw (at 90°), the screw forms a wall and impedes ventilation. What's more, if you have “U”-shaped floor supports (see image below), these again interfere with ventilation.
Number of air outlets
If you have a 10 HP fan, you need 10 air outlets.
BUT NO! As we saw earlier, each fan has a different airflow!
One square foot of opening in the roof of your bin lets in 1,000 CFM of air. If your fan pushes 10,000 CFM, depending on the size of your air intakes, that takes:
Outlets type | Dimension | CFM | Number of outlets | Price | Total price |
Round | 10 int. | 550 | 18 | 65 | $1,170 |
Round | 13 int. | 1050 | 10 | 144 | $1,440 |
Square | 15 x 15 in. | 1500 | 7 | 222 | $1,554 |
Square | 18 x 18 in. | 2250 | 5 | 284 | $1,420 |
Think about it! Would you rather compromise the integrity of your bin by making more holes in the roof, or invest a few extra dollars to reduce the risk of water infiltration?
Embossed or cut roof sheeting
Once you've decided on the number of roof vents, it's time to select the number of embossed roof sheets. Yes, there are 2 types of roof sheet: one is solid and the other is pre-cut and embossed during manufacture.
Why do you think bin manufacturers go to the trouble of making 2 types of roof sheets instead of one? Pre-cut factory sheets are specially designed to prevent water infiltration thanks to their raised edges, and to facilitate on-site installation. Of course, these roof sheets are slightly more expensive because they take a little longer to manufacture, but they're also safer for your storage.
The other option is to cut the roof sheets on site. This practice, though widespread, is hardly to your advantage. It may be simpler for your local sales representative, since he'll have less inventory in his warehouse, but if you order your bin in advance, it won't be any more complicated for you or him! So planning ahead is always a winner.
Waterproofing your bin
Did you know? You can lose up to 30% efficiency if your bin isn't sealed to the concrete slab.
When ventilation is activated, the water under the floor is blown to the outside.
When ventilation is active, the air seeks its way out, and the easiest path is the one it will take! So, if the concrete base isn't even and there are gaps between it and the bin wall, it won't get through there before it gets through the 20 to 40 feet of grain in storage.
The more grain you have in your bin, the denser the grain, and the less efficient you'll be. Think about it: 30% is the ⅓ of the air your fan pushes. If you have a bin dryer, that means your drying will cost you nearly 50% more, simply because you'll have to dry longer to get the same job done.
Shape of concrete base for bin
Is your concrete slab dome-shaped or bowl-shaped?
While the question may seem far-fetched, if your concrete slab is slightly bowl-shaped, and the seal with the bin is inadequate, there's a risk of water seeping under the floor, thus meeting all the conditions required to have a storage problem. Basically, if water seeps into your subfloor and you ventilate your grain, the air will absorb the water and dampen the
grain, which is something you don't want!
Is your concrete slab aging, cracked and bowl-shaped? If you're planning to keep this bin for many years to come, resurfacing it could be a very wise choice.
Conclusion
Let's face it: for every point in the assembly of your bin that isn't done properly, you're exposing yourself to storage problems and financial losses. What's the point of investing thousands of dollars if you're only going to put your business at risk? Taking the time to do things right always pays off!
On the other hand, if you have old bins, but they're in good condition, it might be a good idea to give them a facelift. You could clean the subfloor, reseal the concrete slab, change your fan to the right model and a more powerful one, reorient it and add plugs to the roof, among other things. Growers who have done this type of upgrading report a considerable improvement in their packing capacity and the quality of the grain they market. It's no accident! If you triple your ventilation and eliminate losses, you practically multiply your ventilation by five.
