GrainAir Tubes Keep Grain Cool, Dry – for Jul. 23, 2010

As the size of on-farm storage bins continues to grow, keeping the grain inside them safe from spoilage becomes increasingly challenging. Aeration bins that allow for ambient air to be blown through the grain pile can help manage the problem, but they require a significant investment and can generate high energy bills when operating. And they may not always get the job done, either.

A Saskatchewan farmer, Gary Schreiner, experienced grain storage trouble first hand. “I lost four bins of canola for no reason at all. They only had 8.5 per cent moisture (content),” he says. “Two of them were aeration bins. I was so frustrated.”

During his search to find a solution, Schreiner heard of farmers putting cedar posts in the centre of grain piles to wick out moisture. “I figured why don’t I try to put something in the centre of a grain pile? I just started playing around with it (the idea),” he says.

That experimentation led to the invention of GrainAir Tubes five years ago which, Schreiner says, solved the storage problems on his farm. For the last four years, he has been marketing his invention to other Prairie farmers. The feedback so far has been positive.


GrainAir Tubes employ a simple design. They consist of corrugated tubing that runs up from near the bin floor, topped off with a dispersing cap that vents air and moisture at the hatch.

The GrainAir Tube system takes advantage of the natural convection air currents that develop inside a bin during cool fall and winter weather. Cold temperatures cool the bin walls and grain close to them. The resulting cool air flows down inside the bin walls and forces warmer air to rise through the centre of the pile. The warmer air carries moisture with it, which often causes crusts of spoiled grain to form at the top of a pile when the rising current hits cooler air and the moisture condenses.

But the GrainAir Tubes not only make it easier for the warm, moist air to rise through the centre of the pile, but they also allow it to vent out the top of the bin, preventing the typical spoilage pattern from developing. That increased air flow helps bring down the temperature at the centre of the grain pile.

Just how effective are GrainAir Tubes in reducing bin moisture levels? “It does vary a little bit,” says Schreiner. “The average I’m hearing is between 1- and two per cent (moisture content).” That reduction can happen in as little as 45 days. “I had reports back from last summer (where) people were taking canola out of their bins equipped with these pipes and the canola was still at -4 or -5 C Celsius at the end of July.”

“I’ve had guys say they were putting hot canola in 10,000-bushel bins (equipped with GrainAir Tubes) at the end of August and not turning it,” he adds.

In an interesting comparison, one other farmer informed Schreiner he had removed stored peas in December from two identical bins, except one was equipped with a GrainAir Tube and the other wasn’t. The temperature of the peas coming out of the granary with the tube was -12 C; the other had an internal temperature of 22.


Because GrainAir Tubes are freestanding, they can also be used in grain piles and Quonsets. “They seem to draw heat from 20 feet around,” says Schreiner. “Even with a bigger diameter (in a grain pile) the main problem is always the core. In Quonsets we’re finding about one every 25 feet down the centre is more than plenty.”

Schreiner also points out the GrainAir Tubes are easy to remove as farmers take grain out of Quonsets. “They can just tip them down and move them away,” he says. “Guys like them much better than having aeration screens running all over the floor.”

And unlike aeration systems, the GrainAir Tubes continue to work even on damp days. “It’s really unique in that it works when the weather is bad,” says Schreiner. He is currently evaluating their performance when inserted into aeration bins. Although the final verdict isn’t in yet, he says preliminary results suggest the tubes improve drying performance in that situation as well.

Equipping a granary with a GrainAir Tube starts at about $600 for flat-bottom bins and $1,300 for hoppers. They can be installed in most commercially available sizes.

For more informat ion on GrainAir Tubes, visit or contact the company at 306-933-1134.


About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.



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