Separating the Chaff from the Nuts
By Don Comis
January 24, 2008
The Agricultural Research Service
(ARS) has signed a cooperative research
and development agreement with Flory
Industries of Salida, Calif., to develop an add-on device to control dust
emissions from nut harvesters.
Southwestern Cotton Ginning Research Laboratory in Mesilla Park, N.M., and
Buser in ARS
Production and Processing Research Unit at Lubbock, Texasworking with
Flory Industries engineers Seth Richmond and Mike Floraare testing a
prototype device that uses centrifugal force to trap soil and bits of leaves
and sticks so the harvester emits cleaner air.
Mechanical shakers grab trees and shake out nutsmainly walnuts,
almonds and pecans. The nuts, plus unwanted leaves and twigs, fall to the
ground and are swept into windrows. Pick-up machines then scoop up the
windrows. Air flowing through the harvester separates the nuts from debris that
also includes soil particles. The debris blows out into the air through a side
exhaust as the nuts are conveyed into a cart pulled behind the harvester.
The prototype is trapping the debris and some dust, but it needs more work,
primarily because of the difficulty presented by the 12,000-cubic-foot-a-minute
airflow through the harvester and out the exhaust. Whitelock modeled the device
after the large cyclone dust collectors attached to cotton gin exhausts.
But a tree nut harvester can't afford to have the huge cyclone that would
normally handle that much airflow in cotton gin exhaust. Unlike a stationary
cyclone attached to the outside exhaust of a cotton gin, the tree nut harvester
has to be driven under the low tree canopies of many orchards.
The same harvester, with modifications, is used throughout the country to
harvest various tree nuts, mainly almonds and walnuts in California and pecans
in Georgia, Texas, New Mexico and Oklahoma.
This research is part of ARS' national program to develop agricultural
technologies that minimize contamination of the air by dust particles from food
and fiber production.
ARS is the U.S. Department of
Agricultures chief scientific research agency.