How Does a Side Discharge System Work on a Grain Bin?
Side discharge systems are a smart solution for moving grain out of storage bins when speed, accessibility, and layout flexibility matter. Commonly used on farms, feed operations, and small commercial grain setups, side discharge systems allow grain to exit a bin from the sidewall instead of straight down through a center sump.
So how do they work, and when does it make sense to use one? Let’s break it down.
What Is a Side Discharge System?
A side discharge system is a grain unloading setup that removes grain from a bin through an outlet in the sidewall of the bin rather than through a traditional center floor sump. The system typically feeds grain directly into a truck or sometimes a conveyor or auger positioned outside the bin. Sidedraws work strictly with gravity, so there are no motors or pieces of equipment to turn on.
What you need to know about side discharge systems.
Make sure your bin is designed for a side discharge system and it is used correctly!
Important point before we go any further. Grain bins must be designed to support the use of a side discharge system. Side Discharges can only be used on stiffened grain bins. Often these grain bins might need to have heavier gauge body sheets or added wind rings to allow the safe use of a side draw. Another important thing to know about side draws is you must follow the bin manufacturers guidelines for use. Generally speaking, they are meant to be used until the grain is done coming out of the side draw, then the bin needs to be finished unloading from the center sump. Once the pressures are completely equalized, then the bin could potentially be filled back up again. Constant improper use of a side draw, such as transferring grain from other bins to a side discharge bin and side drawing, then filling and side drawing again can make the grain bin egg shaped and eventually cause structural damage or failure of the bin. Again, consult with your grain bin manual, manufacturer or dealer.
Other than potential additional wind rings or heavier bin gauges, Side Draw systems should consist of interior baffles along the side wall of the bin that go all the way down to the discharge port, or where the grain leaves the bin. These baffles are designed to only allow the grain from the very top of the grain mass to flow down the baffles and out the bins. Grain naturally flows toward the lowest open point. When the side discharge gate is opened, grain moves laterally toward the outlet as unloading begins. At the outlet duct or port, there will be a gate that is opened. This is most often a manual rack and pinion gate, but could also be electric. After this gate, there is typically spouting and possibly hinges to lift the spout up when not being used.
Side discharges will never completely empty a bin. The grain left in the bin will start at the height of the bottom of the discharge gate and build up at the angle of repose across the bin. SO there will allows be another means of completely emptying the bin from the center, with traditional screw augers, conveyors, and or sweep augers.
Why Use Side Discharge Systems
✔ No Motors or Running Equipment- less electricity use, less costs and simple use.
✔ Low Maintenance- with no motors or moving parts, there is very little wear and tear or maintenance on side draws!
✔ Faster Load-Out- simplicity of pulling up to a truck load out side discharge and opening a gate you can typically get 9,000BPH + unloading speed.
✔ Less chance of plugging center sumps- plugging a center sump on conventional bin unloads is a terrible situation. Although side draws do not eliminate this, they often will remove the clumps of rotten or unconditioned grain from the top of the bin and pull them out the side draw, before they get a chance to cause a problem in your sumps.
✔ Still get some grain out if you plug center- if your center sump unfortunately becomes unplugged, at least you can still get a significant amount of bushels unloaded out of your bin!
✔ Multiple Side Draws to Common Equipment = Blending- some setups may have multiple bins with side discharges that go into the same conveyor, allowing blending of multiple tanks.
When a Side Discharge System Makes Sense
A side discharge system is a good choice if:
- You bin is big enough to get enough bushels out of it to justify the cost of installation
- Generally speaking, tall skinny bins provide the best usability as proportionally you can get more bushels to free flow
- You want to take precautionary measures against center sumps unplugging or other unload equipment not working properly.
- You want low maintenance
Final Thoughts
Side discharge systems offer a practical, flexible way to unload grain from bins without complex below-ground infrastructure. For many farm and ag operations, they strike the right balance between efficiency, cost, and long-term serviceability.
If you’re planning a new grain bin installation or upgrading an existing system, understanding how side discharges works can help you design a setup that fits your operation today — and grows with you tomorrow. Call Agri-Systems to learn more today!
