Field Notes

A Tank Pressure Plan That Knows When To Relax

A new air cart patent's real content is a surrender clause: when the fan cannot feed every tank, the software rations what is left.

Clay-diorama editorial illustration of a utility tank with a pressure dial and valve.

What changes in this design

Without the record's stated process, a reader might assume someone simply looks at the readings and decides whether to change a valve.

Here, the system repeatedly compares the meter-and-tank pressure differences with a target range and then adjusts valves.

It gives a reader a quick way to recognize the focus: repeated checking of readings and valve changes within planting equipment.

Pulsing and blow-by, written down in 1997

An air seeder cart is a row of pressurized tanks on wheels. Seed or fertilizer drops from a tank into a metering wheel, and the wheel hands it to air moving down a hose. For that handoff to work, the tank has to sit at close to the right pressure relative to the air passing the meter. Too little and the product will not enter the airstream correctly and pulsing will occur, which means product delivered in disjointed batches rather than a continuous flow. Too much and you get blow-by of unmetered product past the top or bottom of the meter.

Those phrases are not mine. They come from a patent Deere & Company filed on 18 August 1997 and had granted in September 1999, with David Walter Gregor named as inventor. Gregor also wrote down the cause. Carts drew their pressurizing air from a plenum downstream of the fan, and the air pressure at the plenum may differ from the air pressure in the primary distribution manifold. Measure in the wrong place, hold the wrong pressure. Twenty-eight years later, the failure modes are unchanged.

Under a dollar a bushel of margin

Here is why a fraction of a kilopascal is worth an engineer's year. Canola seed runs $85 to $90 an acre, something like $800 to $900 for a 22.7 kg bag that covers ten acres. Industry budgeting built on the Saskatchewan crop planner puts total cost of production at $563.88 an acre at 40 bushels. Alberta cash bids in April 2026 sat between $14.84 and $15.67 a bushel. At $15, that leaves under a dollar a bushel. Saskatchewan farmers intended to seed 12.2 million acres of canola in 2025, over half the national crop. A meter that pulses across ground like that is not a nuisance, and neither is one that lets unmetered seed blow by.

The 2018 loop and the 2026 fallback

The obvious answer is a feedback loop, and one already exists. CNH Industrial Canada filed for it in April 2018 and had it granted in November 2019: sense static pressure in the storage tank and in the meter housing, compare the difference against a threshold set somewhere between 0.125 and 1.246 kPa, open a valve to admit air from the primary line. Sense, compare, actuate. Seven years old, same company.

So what is left to patent? The application filed on 4 February 2025 by Matthew James Stefaniuk and Anthony Albert Loeffen, published 6 August 2026 and still pending, keeps the loop and adds one rule. When a tank's pressure differential falls below the minimum while that tank's valve is already fully open, the controller lowers the maximum pressure threshold. Not for that tank. For the others.

That is a rationing rule. It's the machine conceding that the fan cannot supply every tank at once, and choosing to lower everyone's ceiling rather than let one tank starve. I don't think that's a small thing to write into a claim. It is a hardware limit being managed in software, and the claim says so plainly.

Twenty-five days later, a Saskatchewan alliance

The dates are worth laying side by side. Five weeks after the application was filed, the company cut 373 jobs, 198 at a North Dakota plant and 175 in Minnesota, citing current and anticipated market conditions. Its 2025 industrial net sales came in at $15.35 billion, down 10 percent year over year. Then on 31 August 2026, twenty-five days after this application published, it announced an alliance under which Bourgault Industries will build co-branded air drills, air carts and digital control systems for its dealer network, while its Saskatoon plant stays on planters and combine headers. I read the filing differently after that. It looks like a closing artifact.

Since January 2024, a Colorado law has required agricultural equipment makers to give owners and independent repair shops the embedded software, firmware, tools and documentation needed to diagnose and repair a machine, and failing to is a deceptive trade practice there. A patent whose entire substance is a rule about when to lower a threshold lives inside that.

The open question

I keep coming back to twelve site-years of Alberta trials, 2016 to 2019. Under irrigation, narrow-row precision planting beat the air drill by about 10 percent, 8.2 bushels an acre. Under dryland it was a tie: 34.9 against 34.8. The same group's general manager, Ken Coles, found no correlation between final plant density and yield, and expected emergence of only 40 to 60 percent. So the honest question is not whether the rationing rule works. It's whether a machine that meters better puts anything more in the bin, and I did not find evidence that it does.

Sources

Reporting for this piece drew on the published filing and the references below.

The record, briefly. US20260223766A1, “System and Method for Automated Tank Pressure Adjustment” The abstract describes iteratively comparing meter and tank pressure differences with a target range and adjusting valves in an agricultural seeding implement.

More angles on this

The Seed Method's Extremely Serious Fresh StartAnother reading from the same A01C classification family, planting; sowing; fertilising.
Seeds Are Being Asked to Land With IntentionAnother reading from the same A01C classification family, planting; sowing; fertilising.
CPC A01C: Planting; sowing; fertilisingThe official classification family this record was filed into, published in the USPTO Cooperative Patent Classification scheme.
The Leveling Bar Has a Very Firm Opinion About LevelAnother reading from the neighbouring A01B classification family, soil working in agriculture or forestry.
Confectionery, Seen Through the Eyes of a Tiny MuseumAnother reading from the wider A23G classification family, cocoa.

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