STATE PLANT BOARD
Maroh 1944 ET-216
United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
DISPENSER FOR AEROSOLS AND HIGHLY VOLATILE FUMIGANTS
By Floyd F. Smith, Division of Truck Crop and Garden Insect
Investigations, and L. D. Goodhue and W. R. Ballinger,
Division of Insecticide Investigations
a The development of the liquefied gas method of producing insecticid-
al aerOs6ls j/ has introduced a new technique to the entomological testing
laboratory. It is not possible to handle these highly volatile solutions
in the ordinary way, and some method must be devised to measure and disperse
mall quantities of liquid under pressure. The following is a description
of a combination container and measuring device which, without waste of ma-
terials, can be used to handle aerosols, highly volatile fumigants, or less
volatile liquids propelled by some liquefied gas.
Description of Apparatus
The dispenser can best be described by referring to the lettered
parts in the drawing (fig. 1). The tank (A) is made of sheet iron approxi-
mately 0.05 inch in thickness, which is suTflolent to withstand 1,000 Ibs.
per sq. in. pressure. A tank sold coimercially as an aerosQl container was
found suitable. It was 2-1/2 inches in diameter and 7 inches high. It is
provided with a screw plug'(B) and lead washer (C) in the upper end and a
low-melting safety plug (D) Tn the lower end. TMe valve (E) is attached
to the lower end of the tiik (A) by soldering or brazing. It Is a standard
1/2-inch-pipe angle valve with-a special wrench (P). The space around the
stem of this type of valve is se large that small quantities of liquid can-
not be measured because they do not rise into the glass cylinder (I). This
space was greatly reduced by filling it with hot lead and drilling one small
hole at (G). The valve stem had an enlargement which was removed before the
lead was poured. Part of the valve was ground away so that it would fit in-
side the frame (H), and the top of the lead at (G) was smoothed to form a
good seal with the leather washer (F). The frame (H) is made from a piece
of 1/2-inoh brass pipe 7 inches long. Windows 1/2 Tnoh wide beginning very
close to the bottom are out to within 1 inch of the top on each side. The
top is threaded inside with 5/8-inch pipe threads to accommodate the Y-valve
(.) with the nut (K) to hold the valve rigid.
SGoodhue, L. D. Insecticidal Aerosol Production. Indus. and Enrin.
Chem., Indue. Ed. 54 (12)s 1456-1459. Dec. 1942.
The frame (H) is soldered to the valve (E) and up the side of the
tank (A). The heavy glass measuring tube (I) wTth smoothly ground ends
to seat in the washers (F) is of 1/2 inch outside diameter and is xradu-
ated to 1/2 ml. It is held in place between the leather washers (F, F)
by screwinr down the valve (J)).
The valve (J) is a standard Y-valve for use on small drums contain-
ing liquefied gas refrigerants. It has a 3/8-inch male pipe oonneotion
for the drum and a 1/8-inch female pipe thread at the outlet. This valve
is also filled with a small amount of solder or lead so that the upper wash-
er (F) has a smooth bearing surface. This valve does not come equipped with
the "hand wheel (L), so one was added later.
The needle (M) is for soil treatment; it consists of a nipple with
a hexagon nut, to which has been soldered an 8-inch piece of heavy-walled
1/4-inch metal tubing. The tip is closed and pointed. Holes 1/64 inch in
diameter are drilled from opposite sides at (N) near the tip, and some of
the metal is filed away to recess the openings and prevent logging by
soil. Any other desired connection can be made in place of the needle
(N). For use with aerosols a 0.017-inch-diameter capillary (0) 4 inches
lone, soldered in a nipple, is used as a nozzle. Permanent connections
can also be made to a small fuirration chamber at this point.
To fill this dispenser with methyl bromide, it is only necessary to
pour the chilled liquid in through the opening which is closed by the plug
(B). When carbon disulfide and dichlorodifluoromethane are used, the carbon
disulfide is poured in, and the liquefied gas is added through the measur-
ing device by connecting the valve (J) to the source of supply. Aerosol
solutions are also loaded through the valve (J) by the same technique used
to transfer any liquefied gas from one container to another.
To measure out and release a desired quantity of aerosol solution
or fumigant, close the upper valve (J) and slowly open the lower valve (E),
which allows liquid to flow, withGo-t boiling, into the glass tube (I) up-to
the desired mark. The lower valve is then closed, the whole apparatus is
inverted, and the charge flows out as the upper valve (J) is opened.
Uses for the Apparatus
The apparatus is obviously well adapted to dispense small quantities
of an aerosol solution. '/here many different solutions are being tested,
a complete apparatus should be available for storing and dispensing each
d/here a number of tests are to be made with a volatile fumigant
such as methyl bromide, the dispenser is also well suited. The fumigant
can be measured and dispensed quantitatively without loss and without the
trouble of cooling the liquid below its boiling point. The fumigant can
be released into a fumigation chamber by !nserting the soil-injecting
needle through a hole in a stopper in the side of the chamber.
Fumigants such as carbon disulfide that do not have pressure enough
for self propulsion can be mixed in suitable proportions with some liquefied
gas. One example is three parts of carbon disulfide and one part of dichloro-
difluorokethane by weight. The mixture containing ethylene dichloride and
methyl chloride is another example.
The device has proved suitable for measuring out methyl bromide for
small-chamber fumigations. With the needle for soil fumigation in place,
practical tests on the treatment of ant hills with methyl bromide also have
been made. In 76 tests against several species of ants (including Formica
fusca var. subserica Say, F. pallidefulva schaufussi var. incerta Emery,
F. pallidefulva Latr. var., Lasius niger var. neoniger Emery, and Tetramorium
_aespitum (L) as identified by M. R. S-ith), single treatments with 2 c.c. of
methyl bromide injected about 4 inches below the surface have killed out colo-
nies in hills up to 14 inches in diameter. The material is injected and the
openings to the colony are closed by stepping on the loose surface soil. Treat-
ments have been made in lawns, vegetable gardens, flower borders, and among
plants growing in flagstone wal",s, without evidence of plant injury on blue-
grass, red top, Dutch clover, zinnias, marigold, pachysandra, mugho pine,
Torenia, and strawberry. However, severe injury and even death has, occurred
to endive plants growing in pots or in the field, to carrots in the field,
and to bluegrass in lawns containing no ant colonies. The bluegrass was
killed out in patches about 4 inches in diameter. Apparently injury did
not occur on plants growing in the vicinity of treated ant hills because
the subterranean galleries permitted greater dispersion of the fumes than
occurred in undisturbed soil.
Preliminary tests on ants with the carbon disulfide-dichlorodifluoro-
methane mixture up to dosages of 3 c.c. of CS per square foot gave less re-
liable results than those obtained with methyl bromide.
11SR PI 'n
CROSS SECTION OF DISPENSER
UNIVERSITY OF FLORIDA
3 1262 09240 8664