Title page for ETD etd-06082009-142240
|Type of Document
||Leary, Pamela S.
||Factors affecting sawmill residue chip quality
||Master of Science
|No Advisors Found
|Date of Defense
A study was conducted to determine the effects of knife
angle, wood temperature, disk speed, anvil condition, and
residue type, on loblolly pine sawmill residue chip quality.
A 152-cm, six-knife, horizontal infeed, top-discharge
chipper restored to factory specifications was used as the
test machine. Chips were recovered after being blown 4m
vertically through a cyclone settler onto a screen pack with
the top screen blinded. OVersize chips were not re-chipped.
Material types included cants as controls, slabs, edgings,
and trim blocks. Chipper rim speeds included the
manufacturerJs recommended 3,385 meters per minute along
with 2,370 meters per minute and 1,693 meters per minute
achieved by the drift-down method. Knife angles included
30, 31, 32, and 33 degree straight grinds. Wood
temperatures ranged from arrbient temperatures of over 21
degrees C. through chilled (approximately +2 degrees C.) and
frozen (-4 degrees C.). The chip distributions from chipping
slabs and edgings were not significantly different from
those of the cants. Less than 50 percent of the weight of
the trim blocks was returned as acceptable chips in most
trials. Reducing disk speed resulted in a major reduction
in pin chips and fines. Knife angles had less effect on chip
size distributions than any of the other variables tested.
The percentage of pin chips and fines was greater for
chilled and frozen wood than for wood at ambient summer
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