A new machine for producing chunkwood
o As fossil fuel resources are depleted and prices esca-specified length. The largest chunks or discs produced late, there are increasing pressures for alternate indus-by these machines are equal to the bolt diameter and trial fuels. Wood is one alternative, particularly for about 2 inches long, with much fracturing along the industries located in heavily forested areas. However, a grain. The chunks produced with either device can be way is needed to reduce small trees and forest residue
... rest residue readily used as energy wood or as a preferred intermeinto a convenient form for direct combustion as a pri-diate form for manufacturing structural flakeboard. mary or supplementary fuel or as a wood gasifier The first invention, a helical or spiral head chipper, has feedstock, been described ( Barwise et al. 1977. Erickson 1976). : The latter is an involuted disc chunker (Barwise et Chips produced with conventional whole-tree chip-_d. 1982). This chunker and the results of initial pets are small and not ideally suited for solid fuel prototype testing are described here ( fig. 1 ). combustors even though such chips are currently being Used. Wood and coal, both solid fuels, generally require large combustion chambers. When wood is used to supplement coal, the typical pulp-size chips burn faster than stoker-sized coal, so the wood is burned off first. To obtain nearly equal combustion time for wood and coal, a larger wood particle is needed. Also, when pulpsize Chips are burned in large industrial units, high stack gas velocities carry small particles and fly ash up + the stack as solid particulates. Larger wood chunks would eliminate this problem --chunks ranging in size from a cigarette package up to 2-to 4-inch long discs from-small diameter wood. Also, the flakeboard industry would benefit from the longer fibers that the larger particles would yield. The Forest Products Laboratory in Madison, Wisconsin (Erickson 1976), recommended the development of a "+fingerling" particle 2-1/2 to 3 inches long with a preferred cross sectional area of less than 1 square inch that could be ring flaked to yield the length properties desired for manufacturing exterior grade structural flakeboard. The chunks derived from this device can easily be further reduced in size to permit ring flaking. Responding to this need we have developed two prototype devices to produce chunky wood particles to Figure 1 . --Experimental involuted disc chunker.