“We're very confident that we'll get the results we expect.”
Conrad Fingerson is referring to this spring's planned field testing of a prototype machine for drying windrowed hay. If the invention performs as expected, alfalfa can be baled the same day it's cut — perhaps by a baler that's part of the dryer.
Fingerson, of Chatfield, MN, and co-inventor Donald Eickhoff of nearby Wykoff, expect that the field tests will reveal the need for a few minor modifications. But they hope dryers of the same basic design will be manufactured and available to growers as soon as next year.
The machine dries hay economically, they say, because it utilizes the same principle as corn drying, with an added wrinkle for greater efficiency.
Like corn dryers, it burns propane to heat air for drying.
“We're burning fuel directly,” Fingerson explains. “We're taking every available btu out of the fuel. That's why corn drying works and that's why this works.”
But unlike most corn dryers, the heated air isn't discharged after it's forced through hay. It's reheated, this time to a higher temperature; then it passes through hay again. It's heated and used five times before it's finally discharged.
With proper temperature control within the machine, exiting air will be at or near 100% relative humidity, indicating nearly 100% drying efficiency. That is, almost all of the energy produced will have been used for drying, say Fingerson and Eickhoff.
Air is heated and reheated by five stationary burners situated at strategic locations on both sides of a long cylinder. The air is pulled through the dryer by a 25,000-cu ft/minute fan, entering at the rear and exiting at the front.
Hay's packed into compartments that make up the cylinder. Wet hay is packed into the turning cylinder at the bottom, and dry hay discharges near the bottom after making the full circle. Hay stays stationary within the compartments, so leaf loss is minimal, say Fingerson and Eickhoff.
As the air moves through the dryer, it dries progressively wetter hay. This allows the air to be heated to higher and higher temperatures without damaging the crop.
Air is heated as it enters, then its temperature drops as it passes through almost-dry hay. Then it's reheated to a higher temperature before passing through wetter hay, etc. The final burner heats the air even further for removing moisture from the wettest hay.
On-board motors run dryer components and the electronics. On the prototype, the drying fan is pto-driven, but Fingerson and Eickhoff figure commercial units may be self-propelled.
In most situations, say the two inventors, hay will be field-dried to about 45% moisture, which usually happens within a few hours after cutting. Then the dryer will take it down to 18% moisture or less for baling. They figure taking a ton of hay from 45% to 18% moisture will require 9.5 gallons of propane, at a cost of about $10/ton at today's fuel prices.
If the hay was at 35% moisture (which may take a full day), fuel costs would be less than half that.
They expect the machine to sell for about the same price as a big combine.
“It would take a reasonably large grower to justify it, or two or three growers could buy one together, or one could buy the machine and do custom drying,” says Fingerson.
“We're taking every available btu out of the fuel. That's why corn drying works and that's why this works.”
— Conrad Fingerson
They estimate that the dryer will move through fields at up to 5 mph, turning out about 10 tons of dry hay per hour. Drying could take place 24 hours a day.
Fingerson, who has an engineering degree, is half owner of another manufacturing company; Eickhoff is a retired farmer with a penchant for invention. His corn and hog farms are now operated by his family.
The two have spent 12 years and about $500,000 developing their dryer. Both a lab-scale dryer and a field dryer were previously constructed and tested.
This dryer was built by Ken Connaughty, owner of a local machine shop. Connaughty made many contributions during the 11½2 years of construction.
The drying concept and several of the prototype's components are patented, and additional patents are pending. When field testing is completed, the two inventors will look at ways to bring the dryer to market, including working with existing manufacturers.
The same concept could be used to dry corn, they say. Current corn dryers use 1,500-1,700 btus for each pound of water removed. This one uses significantly less than that, according to Fingerson and Eickhoff.
For more information, call Connaughty at 507-864-2955.