Jason Finnie of Portage la Prairie, Man., uses a grain vac to put wheat and oats into a 90-foot Harvestore silo. His is a
Thor Conveyair model, which vacuums grain up then blows it out with air pressure. Finnie connects his vac to a six-inch air-sealed pipe permanently fixed to the side of the silo. At the top, the pipe makes a right-angle turn and runs 12 feet horizontally to the middle of the silo where the grain drops in. Without a vac to do the job, Finnie could not have made full use of this silo for grain storage.
They Finnies used to run a dairy and still have three Harvestore silos on their farm. The use one for high-moisture barley, which goes to the cattle in their 1,000-head feedlot. They added aeration and sweep augers to the other two — a 60-footer and the 90-footer mentioned at the top — in 2000 and converted them to giant grain bins. The question was how to fill them. The longest auger on the market could fill the 60-footer, but not the taller one. Some farmers have cut holes in the side of too-tall silos so they can fill them part full with an auger, but only a leg or a pneumatic system can reach to the top. The Finnies decided on the simple air system, which they could set up themself for lower cost.
“The cyclone at the top was a couple hundred bucks. The elbow was a couple hundred. Then you need couplers, which are more than the pipe itself. In the end, it was less than $2,000 per silo and we did the work ourselves,” he says.
Ray Guscette, owner of Grain Vacs Inc., in Clear Lake, Iowa, has set up “well over 100” old silos with air-fill systems. “Cattle have gone out of this area and we’ve got Harvestores sitting empty,” Guscette says. Working with Thor Conveyair and now Farm King, which bought Conveyair last year, Guscette converts silos into supersized grain storage bins just the way Finnie did.
Finnie says his grain vac can move oats at the same capacity as a 10-inch auger. Wheat, being heavier, is slower. According to Farm King, its grain vac moves wheat to the top of a 90-foot silo at a rate of 1,700 to 1,800 bushels per hour.
Farm King repainted Thor Conveyair vacs red and named them Model 6640. Otherwise they’re the same as Finnie’s. Suggested retail price is $28,390 with a hose kit. It requires a minimum 110 PTO horsepower tractor. The key feature remains the air lock, a low rpm rotary valve that transfers grain from the vacuum side of the system to the pressure side.
Some grain vacs suck grain into a central chamber and then discharge into the truck with a short length of auger. The air lock system with pneumatic discharge gives you more flexibility in how far you can move the grain. Discharge pipe can also go around corners, so you can fill bins in a more confined space than you could with an auger.
Walinga of Guelph, Ont., has been making pneumatic grain vacs for decades. I asked company sales manager Tom Linde if farm-
These photos from Farm King show a typical bin piping set up on the left and the better set up on the right. Not only is the better set up cheaper — it only has one angle-piece at the top — but it gives you higher filling speeds, says Ray Guscette, who has set up over a 100 used silos with pneumatic grain fill systems. There is always grain dropping out of the air stream and tumbling back against the flow, he says. With the sloped stretch along the side of the bin top, grain continues to tumble against the flow right up until it reaches the discharge point. But with the horizontal stretch, grain no longer tumbles against the flow for that final length of pipe. Instead it drops to rest at the bottom of the pipe until the air stream picks it up again. The supporting structure of that horizontal last leg is a major boost to the system’s grain-moving capacity. “Fifty per cent of the capacity of a pneumatic grain moving system depends on how you set up the piping,” Guscette says. A big part of that is whether the final length of pipe is horizontal or sloped, he says.
ers could replace an auger with a grain vac? “Yes,” he said. “In fact, in Ontario 90 per cent of the farmers with our Agri-Vac grain vacs use them to empty AND fill their bins. The number is about the same in Indiana.”
Linde says the percentage drops as you move west. In Western Canada, grain vacs — for those farmers who have them — are mostly used to empty flat-bottomed bins. “But if you’re going to spend $30,000 on a piece of equipment, why not use it for two things?” he asks.
The cost to put up a permanent fill pipe that runs up the side of a bin and discharges in the middle is $2,000 to $3,000 per bin, Linde says, echoing Finnie’s tally. Walinga is working on a system to link a number of bins, so you just need one vertical pipe to fill a whole row of bins. The next step up in pneumatics is a stationary unload pit. You dump into a central pit, which connects to all your bins through a series of air-lock pipes. Walinga makes these systems, too.
The biggest Walinga Agri-Vac is Model 8614, which can move 7,000 bushels of wheat per hour and requires a tractor with 200 PTO horsepower. “You’re also dealing with an eight-inch pipe. You almost need two guys on that hose,” Linde says. “This model is generally for guys with half a million bushels of corn on the ground who want to fill semis and clean up the pile quickly.”
Walinga’s next size down is Model 7614, with a seven-inch pipe, 4,200-bushel per hour capacity, and 140 PTO horsepower requirement. Suggest retail price for this model is around $30,000, Linde says.
OTHER USES FOR PNEUMATIC VACS
Pneumatic grain vacs can simplify other grain handling chores. You can move grain from one bin to another all at once without needing to fill trucks and move augers around. You can also unload from the bottom of a bin and put grain back into the top of the same bin all in one seamless cycle. Conditioning canola in storage is a lot easier. You set up the vac once, turn it on and let it go until the job is done.
Finnie has thought about taking the flighting out of an auger to create a portable airlock tube so he could fill any bin without needing a permanent tube fixture on each bin. He hasn’t tried this, yet.
The downside of vacs compared to augers is cost and capacity. Most of you already have augers. They’re simple, relatively cheap, and can move grain quickly. As you may have concluded already, capacity for any pneumatic grain vac drops as you add more pipe. “For every 20 feet of hose, you lose 4.5 per cent of capacity,” Linde says.
But if you’d like a simpler way to move grain from bin to bin, to condition a bin of canola, or to make use of an empty silo in the area, a pneumatic grain vac can do the job.
Jay Whetter is the editor of Grainews.