United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
RPFRIG IATOR-CAR DUSTERS
By R. D. Chisholm, Division of Insecticide Investigations,
V. A. Johnson, Division of Japanese Beetle Control,
and P. S. Mock and C. V. Marshall, Pennsylvania Railroad-/
The treating procedures/ authorized for use as a basis for certifi-
cation of products regulated by the Japanese beetle quarantine provide
for the treatment of sacked white potatoes in refrigerator cars and
trucks with DDT. This treatment involves the distribution of 1 ounce
of 10-percent DDT dust per 2500 cubic feet before loading and an addi-
tional ounce after loading. Distribution of the insecticide is accom-
plished by means of an approved duster!/ (patent applied for) which uses
carbon dioxide as the propellant. The operation of this duster involves
a number of steps which were considered to be impractical in connection
with the rapid treatment of large numbers of refrigerator cars. This
paper describes two practical modifications of the approved duster,
single-unit (plate 1) and double-unit (plate 2), whichwere used for
the treatment of over 10,000 refrigerator cars and trucks during the
sumer of 1947.
The modified dusters were designed jointly by the Bureau of Ento-
mology and Plant Quarantine and the Pennsylvania Railroad and were
constructed at the Wilmungton, Del., shops of the railroad. The final
designs and blueprints& were completed on February 19, 1947, and con-
struction was accomplished soon thereafter. Later, information regard-
ing the modified dusters was made available to other railroads, State
representatives, shippers, and others associated with the Japanese
beetle quarantine. Large-scale use was begun late in June 1947.
I/The authors are indebted to G. J. Baetzhold, Division of Japanese
Beetle Control, for the drawings presented in this paper.
2/U. 3. Bureau of Entomology and Plant Quarantine. Treating pro-
cedures authorized for use as a basis for certification of products
regulated by the Japanese beetle quarantine. Unnumbered publicatic-.
49 pp. 1947. _Frocessed*7
_/R. D. Chisholm, L. Koblitsky, W. C. Fast, and E. D. Burgess.
Insecticide duster. U. S. Bur. Ent. and Plant Quar. ET-237. 5 pp.
4/Bluerint prepared from vandykes furnished by the Pennsylvania
Railon.d be obtained from the Bureau of Entomology and Plant Quarantine.
Description of the Dusters
The construction o- the single-unit duster can best be described
with reference to the numbered parts in plate 1.
The assembled duster is shown in figure 1. It consists of an
insecticide container (1) attached to pipe (2), a measuring device (3)
screwed onto the top of insecticide container (1), and a storage hopper
(4) bolted onto the top of measuring device (3), equipped with an
agitator (5), and supported by pipe (2) and brace (6).
The construction of insecticide container (1) is shown in figure 2.
It consists of a pipe caL (7) into which is screwed a pipe nipple (8).
A gas-inlet tube (9) extends from the upper end of nipple (8) through
the bottom of pipe cap (7) into pipe (2). A longitudinal section is
removed from the lower end of gas-inlet" tube (9) to form scoop (10).
An insecticide-outlet hole (11) is drilled through the bottom of pipe
cap (7) into pipe (2).
The construction of measuring device (3) is shown in figures 2 and
3 (partly cut away). In figure 2 the measuring device (3) is shown in
the same plane as in figure 1, whereas in figure 3 the plane is at right
angles to that in figure 1. The bottom of housing (12) is threaded to
accommodate the upper end of nipple (8), and the top is shaped for
bolting to storage hopper (4). A tapered core (13) is fitted into
housing (12) and is held in place by means of washer (14) and nut (15)
screwed onto threaded end (16). A dished spring washer (14a) is used
between the principal washer (14) and the nut (15) to keep the tapered
core (13) constantly seated. A lug (17) is attached near the other end
of core (13), which is shaped to provide a square head (16a). This end
of core (13) and the end of housing (12) are shown in figure 4. A side
view of this end of housing (12) is shown in figure 5. The upper half
of the end of housing (12) is shaped to provide a notch having a
vertical surface (18) and two horizontal surfaces (18a). The horizontal
surfaces (18a) are opposite each other to engage lu-T17), and thus
permit rotation of core (13) through 1800 and insure proper positioning
of measuring cavity (20). Measuring cavity (20) and opening (21) are
of the same inside diameter as nipple (8). Two views of rotating
handle (19) are shown in figure 6.
The construction of storage hopper (4) is shown in figure 1. It
is attached to measuring device (3) by several, preferably eight, machine
screws equally spaced (22) and to pipe (2) and brace (6) by clamps (23).
It is equipped with a hinged cover (24). A gasket (22a) is located
between measuring device (3) and the hopper (4). The points (22b,
figure 3) indicate threade screw holes to receive the screws (22).
The construction of agitator (5) is shown in figure 1. It consists
of a shaft (25) extending from above brace (6) almost to the top of
measuring device (3). Vertical and horizontal views of agitator
vanes (26) which are attached to shaft (25) are shown in figure 7.
Shaft (1) is aligned by means of sleeve-T27) attached to pipe (6), as
shown in figure 8, and by a hole in cover T24). Knob (28)is fitted onto
the end of shaft (25) and held in place by set screw (29) and groove (30),
as shown in figure 9. A coil compression spring (1) is secured on the
shaft (25) by means of washer (32) and cotter pin 33), insuring a
positive return of the agitator when forced downward in the dusting
The duster is connected to a carbon dioxide fire extinguisher by
means of a flexible hose attached by pipe union (34). It is essential
that the tank or supply line be equipped with a trigger release to in-
sure economical use of propellent gas and best distribution of the
The double-unit duster shown in plate 2 consists substantially of
two single-unit dusters mounted on a plate so that the discharge ends
of the pipes (2) are pointed in opposite directions. Forty-five-degree
elbows are screwed onto the ends of the pipes. The vertical sections
of the pipes (2) are eliminated, and the horizontal sections are joined
by means of a tee which is connected to the gas source as described
Operation of the Dusters
To operate the duster, storage hopper (4) is filled with the
insecticide; measuring device (3) is rotated to the charging position,
as shown in figure 3, by means of rotating handle (19); knob (28) on
agitator (5) is struck sharply several times causing the insecticide
to fill measuring cavity (20); measuring device (3) is rotated through
180 degrees by means of handle (19), so that cavity (20) is in the
discharging position as shown in figure 2; and high-velocity carbon
dioxide is released into pipe (2). Part of the gas is diverted from
pipe (2) into nipple (8) and cavity (20) by means of scoop (10) and
gas-inlet tube (9), thereby causing the insecticide to enter pipe (2)
through outlet hole (U1). The insecticide is dispersed by the remainder
of the gas and is discharged from pipe (2). After the storage hopper
has been loaded the remainder of the operation requires less than
To use the single-unit duster in refrigerator cars, the duster is
lowered through a hatchway into an ice bunker, the end of pipe (2) is
inserted through the screen, and the insecticide discharged as described
above. These operations are repeated at the diagonally opposite end
of the car.
To use the double-unit duster, the duster is placed on the floor
of the car close to a doorway, so that the discharge pipes are parallel
to the long axis of the car and the 45-degree elbows are directed upward
at 45 degrees with reference to the car floor. Both units are dis-
charged simultaneously so that an empty car may be dusted with one
operationwhich requires less than-2 seconds.
Each unit measures a charge of 1/2 ounce of a mixture consisting of
10 percent of DDT and 90 percent of pyrophylite. This mixture is pre-
pared by blending 20 parts by weight of a micronized mixture containing
equal weights of DDT and pyrophyllite with 80 parts of pyrophyllite.
zz: ZI 2zb
-0 12 18
17 18 -is
Plate l.-Views of single-unit duster.
Plate 2.--View of double-unit duster.
UNIVERSITY OF FLORIDA
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