Pullman herald. [volume] (Pullman, W.T. [Wash.]) 1888-1989, 1917-08-24
STATIC ELECTRICITY
CAUSES EXPLOSIONS
state College Officials Make Import
ant Findings Concerning Sep
arator Fires
tBy Prof. o. L. waller)

(By Prof. o. L. Waller)
After studying smut explosions
and fires in Washington wheat fields
for four years the state experiment
station has reached the following
conclusions:
/. There is static electricity about
an operating separator. This static
electricity will set fire 10, and con-
sequently explode, smut and dust
made by finely pulverized straw or
other organic combustible material
that may be floating in dense clouds
In and about the separator An ex-
plosion of this character is merely a
matter OF getting the combustible
dust and the air mixed in the right
proportions.
2. Threshing machine operators
who have wired their separators so
as to carry off and ground" the sta
tic electricity have had no explosions.
Draw Off Dust With Fan
..
smut and air can be greatly diluted
and therefore rendered less explo-
sive-by using an exhaust fan to
draw off the smut dust from the cyl
inders.
4. When dust and smut have been
drawn off, over the cylinder, the sep
arators have gone through the season
without an explosion.
8. The fire that usually destroys
wheat, straw and shocked grain, is
on the outside of the machine. If
the litter is kept from accommodating
under and near a thresher, the de-
structive outside fires are more like
ly nct 10 "oI>T.
SprinKIers Control Fires
G. Separator operators who have
installed a properly designed sprink-
Ter system in their threshing ma
chimes have been able in most cases
to control the fires starting with a
smut explosion with small damage
These conclusions represent the
finding of 10 men of the State Col
lege and experiment station staff,
among whom were engineers, chem
lists, farm crop specialists, farm me-
chanics, separator operators, and
practical wheat growers.
Static electricity Is generated in
an operating threshing machine by
the action of straw, smut, and other
material whipping against the NOV
ing parts of the separator 1t is con-
densed on metallic parts of the
thresher, which are more or less in
sulated from the ground by the
grease and oil OF the journals, and
by the wooden parts of the separator.
Sparks Jump Across Gap
This electricity, when accumulated
in sufficient quantity, jumps over or
breaks down the insulation, forming
a spark very much like lightning in
the sky or electricity jumping the
spark gap in spark plug. This con-
dition is always present when grain
is threshed in very dry weather. Sep
arator men have seen these electric
displays in the cylinders when run
ming at night, and often receive
shocks by coming in contact with
some part of the machine.
Smut is highly inflammable. When
dry and mixed with air in the right
proportion it is fired by the electric
sparks; in fact, a mixture of air and
smut ignites very much as does the
mixture of air and gasoline ignite in
an automobile engine.
Other Causes for Fires
Even when separators are wired TO
remove the static electricity. or
equipped with exhaust fans to re-
move the smut cloud from the cylin-
ders, there still may be fires due to
the apparatus being out of order. OF
matches. or sparks from the engine
For such fires sprinkler system
should be installed on every sopar.
ator. The pipes for this system
should run around the entire ma
chine, should be Of sod size anG
should be provided with consider
able number of spray uozzles. boil
inside and outside Of the machine
The nozzles should be so set as Il
give an abundant and reasonably fin,
spray. The separators most success
fully combating fires have had THEN
sprinkler system connected directl,
with the steam boiler, which afford,
high pressure and some live steam
and water inside the separator.
Must Regulate SprinIxIers
Failure of sprinklers have oc
CURED where there was improper dis
tribution of the water and sprinkle,
holes so large that the pressure wa,
reduced before tho fire ,,,o,, - NJ