1984 - Volume #8, Issue #2, Page #36[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story | Read this issue]
Huge Wood Harvester Turns Trash Into Energy
Built from the ground up and mounted on D-4 Caterpillar tracks, the new wood harvester was designed by the California inventor and manufacturer primarily for clearing up the millions of tons of wood trash trimmed from trees in orchards every year. But, when equipped with a heavy-duty cutting blade across its broad front, it also clears land of scrub trees and brush, turning everything it picks up into a shredded wood material that's used as a power source for electric power generating plants.
In orchards, where trash is usually raked into big piles and burned, the low-profile harvester moves up and down between rows of trees. Two big reciprocating claws that reach out 7 ft. in front of and 7 ft. out to the side of the harvester, pull material into the huge throat of the machine, breaking anything that's too big to fit. Three feeder chains with knife teeth attached pull the trash back into the machine where big rollers crunch it all up and feed it to a hammermill with 24 50-lb. hammers spinning at 130 mph.
Depending on the size of the screens fitted to the hammermill, the wood comes out the back with the diameter of a pencil and anywhere from 3 in. long up to 1 ft. Once processed, a rear auger carries the shredded wood out to trailing wagons.
The harvester has a 600 hp. engine and the capacity to handle up to 15 tons of material per hour. It'll handle trees up to 6 in. in dia., and occasionally chunks that are much larger, traveling at 5 mph. A 5-ft. dia. flywheel provides power to the hammermill, which is outfitted with knives on the hammers on the land clearing machine to handle the tougher material.
"As the price of electricity increases, interest is building for a way to use wood wastes. Because the materials are so bulky, we've had to automate all the equipment to keep labor at a minimum," DuBose told FARM SHOW. He says he gets about $22 a ton for the processed material and charges the growers $6 to $8 a ton for removing it. For land clearing, he charges $150 an acre cleared.
Because air pollution regulations are getting more restrictive, DuBose says growers are looking for alternatives. "They can't have anything on the ground in their orchards, yet they usually aren't allowed to burn the trash. Also, conventional ways of removing trash often compacts the soil around the roots of the trees. Our machine only applies 7 lbs. of pressure per square inch and only makes one pass through," says DuBose.
The company also makes a large "wood fuel shuttle" that is specially designed to run behind the harvester and dump into roadside trucks. Dubose suggests operating two shuttles for every harvester.
The harvester sells for $275,000 while the shuttles sell for $40,000 apiece. A special truck-filling conveyor sells for $22,000.
For more information, contact: FARM SHOW Followup, Tink, Inc., 2361 Durham-Dayton Hwy., Durham, Calif. 95938 (ph 916 895-1806 or 895-0897).
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