P2 for grain storage

["Richard Yoder, P.E." <nbdc-nics@navix.net>]

Pat & P2tech,

>From page 10 of the February, 1997 "Mechanical Engineering" journal article,
"Freezing Bugs Out", by Michael 
Valenti:

	"The same cooling technology used to preserve fresh-picked fruits and
vegetables is now protecting 
stored grain from insects.  In a recent demonstration project - sponsored by
the Electric Power Research 
Institute's Agriculture Technology Alliance in Walnut Creek, Calif.; Western
Resources Inc. in Topeka, Kan.; 
and Cinergy Corp. in Plainfield, Ind. - chilled aeration would replace the
chemical protectants and fumigants 
that control insect infestation of grain bins.
	Insects devour about $500 million of stored grain in the United States
annually, according to an 
Oklahoma State University estimate.  To counteract that, methyl bromide and
phosphine are used to control 
insect infestation of stored grain.  By 2001, however, methyl bromide will
be banned by the federal government 
to protect the stratospheric ozone layer.  Scientists want to limit the use
of phosphine in light of reports 
that some insects are building an immunity to the chemical.
	Researchers from Purdue University in West Lafayette, Ind., adapted the
chilled-aeration technology, 
which has been used for some time in Europe to control the temperature and
moisture of stored grain, thereby 
inhibiting insect populations.  The Purdue system consists of a mobile
chilling unit built by AAG Manufacturing 
in Milwaukee.  This unit contains a vapor-compressor refrigeration system
whose air ducts are connected to the 
fan units on grain bins.  The blower is equipped with
variable-frequency-speed drives to reduce energy 
consumption by as much as 20 percent, according to Dirk Maier, assistant
professor of agricultural engineering 
at Purdue.
	The chiller rduces temperatures down to less than 60 degrees F.  Wheat
chilling trials conducted at 
Kokomo Grain Co. in Amboy, Ind. and Mennel Milling Co., in Mexico, Ind.,
demonstrated the chiller was capable 
of cooling grains to a protective level in an average of 220 hours and would
keep the grain cool for four to 
six weeks.
	The chilled-aeration technology is mature enough to be used commercially,
noted Maier.  'We are working 
on the economics to reduce the costs a bit.  Mass production of the chilling
units would help.'"

Living in the middle of grain country, I've seen the liberal use of an
earlier fumigant - carbon tetrachloride 
- lead to more than one clean-up project.  I hope this information helps.
 
ry
-- 


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