United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
PROPELLER-BLOWER APPLICATOR FOR FUMIGATION WITH HYDROCYANIC ACID ./
By Harold R. Yust
Division of Fruit Insect Investigations
A multivane blower applicator for applying hydrocyanic acid beneath
tent-covered trees (Fulton et al. 1) was described by Fulton and Nelson
(2) in 1946. Further experience showed the need for a machine that would
give better immediate distribution of the gas. Therefore, an applicator
with a propeller fan that gives good gas distribution without post-release
circulation was developed and built. A Dumber of other improvements were
incorporated in the new unit. This applicator was tested for hydrocyanic
acid fumigation of citrus and is now being used in the Hall scale fum-
igation at Chico, Calif*
Two views of the applicator are shown in figures 1 and 2. The
essential parts are a propeller fan, a gasoline engine, and a liquid hydro-
cyanic acid tank mounted on a wheelbarrow* A standard vaporizer wheelbarrow
frame was used with a 3.85- by 20-inch pneumatic tire. The overall length
of the unit is 8 feet.
The fan is powered by a Ay-cycle, 1-cylinder gasoline engine that gen-
erates 1.5 hp. at 2600 r.p.m. The engine is air-cooled and weighs 38
pounds. It is located directly behind the wheel on an adjustable mounting.
A flexible metal hose connects the engine with a muffler 3 inches in di-
ameter by 22 inches long. The muffler is next to the wheel and the exhaust
is directed toward the fan* The metal hose is insulated with plastic as-
bestos and wrapped with glass cloth* The engine is enclosed on three sides
and there is a hood on hinges over the top. A 4-inch-high guard on the hood
prevents the tent from slipping down on the engine. A strip of duck cloth
the width of the engine housing and 8 inches long extends to the ground
behind the wheel*
The propeller fan is in front of the wheel, is 16 inches in diameter,
and has a depth of 4 5/32 inches. It has 4 blades and is the pressure
type. The blades, hub, and spider are made of steel. The blades have
a 27-degree pitch and the fan is directed upward about 5 degrees. The
fan housing is 17 inches in diameter and 8 inches long. It has a ground
clearance of 15 inches when standing on the level and a clearance of
about 9 inches when pushed on the level. The fan is mounted on a
shaft 15/16 inch in diameter, which extends along the right side of the
1/ The American Cyanamid Company, Azusa, Calif., cooperated in con-
structing the applicator.
wheel to a point above the engine. The shaft is between the muffler and the
wheel and has two self-aligning ball bearings. The shaft pulley is 3 3/4
inches in diameter and the drive pulley is 3 1/2 inches. The unit operates
wit'i a 3.-inch V-belt. The pulleys and belt are enclosed by the engine
h _-i-. In operation the fan rotates counter clock,.ise at approximately
17 r.p.m. At th-s speed with a static pressuree of 0.1 inch of water the
fan :li"?r -7r C.f.m.
A -t iJ rd '-yjr.jocyanic acid 'uump -nd a tank with 45 pounds' cap-icity are
.oun.' ne- t to L'ie engine. The tank is connected by a 1/4-inch capper tube
to a 2- -lt nozlpi located in front -f the fan. The tibe is insulated with
_-.tric lo m. Tie nozzle is centered near the leading edge of the fan
h i-ig. The holes in the nozzle are 5/64 inch in diameter. The nozzle
L .-J a check ialve to -irevent leakage of the hydrocyanic acid in the tube.
In oerjtion the propeller-blower applicator is pushed under a tree
thro" a "dog Iln1" I. the tent with the fan directed toward the tree
cen&.ter. The tent ski't is draped over the engine housing. The required
do.Ce is ispanmed into the air stream of the fan. The fan creates a turbulence
of the iir under the tree and distributes the hydrocyanic acid as it is re-
leasId. Ine n"ttil panel, between the engine and the wheel, and the strip of
C-rLVJiS clo'h ext,,"ndig to the ground prevents the hydrocyanic acid vapor from
esc i:ping toward the operator while he is pumping the hydrocyanic acid under
the tent-covered tree. As the unit is pulled out the fan blows the opening
dovn. In the citrus fumigation tests the front opening of the fan was
covered with hardware cloth, 1/2-inch mesh, to protect the fan from the tree
1. rs and foliage. Gu:ris along the wheel, shaft, and fan keep the tent from
becoming entangled in the moving parts. The muffler reduces the engine noise
so the necessary conversation of the fumigation crew may be heard. The ex-
h-. t line is Iisulited and shielded to prevent burning the tent.
(1) r'itonp, R. A., 6isbey, R. L., and Yust, H. R.
1941. The behavior of hydrocyanic acid gus under a fumigation tent.
Jour. Econ. Ent. 34: 777-783.
(2) Fulton, R. A., and Nelson, H. D.
1946. Use of the blower applicator in fumigation. Calif. Citrog. 31:
TWA.- -.-I f V-I!Tru.
Figure l.--Side view of propeller-blower applicator, showing location
of essential parts.
Figure 2.--Front view of propeller-blower applicator,
showing fan and nozzle.
UNIVERSITY OF FLORIDA
3 1262 09242 9314