LIBRARY STATE PLANT BOARD Marxjh 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. Balllnger« Division of Insecticide Investigations The development of the liquefied gas method of producing insectlcid- al aerd86l8 1/ 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 soutll 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 fumlgants, or less volatile liquids propelled by some liquefied gas* Desoription of Apparatus The dispenser can best be described by referring to the lettered parts in the drawing (fig. l). The tank (A) is made of shedt iron approxi- mately 0.05 inch in thickness, which is sufficient to withstand 1,000 lbs. per sq. in. pressure. A tank sold commercially 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 (jD) in the lower end. fhe valve (E^) is attached to the lower end of the tank; (a) by soldering or brazing. It is a standard l/2-inch-pipe angle valve with""a special wrench (P), The space around the stem of this type of valve is so large that small quantities of liquid can- not be measured because they do not rise into the glass cylinder (l_). This space was greatly reduced by filling it with hot lead and drilling one small hole at (^). The valve stem had aji enlargement which was removed before the lead was poured. Part of the valve was groTond away so that it would fit in- side the frame (E) , and the top of the lead at (G) was smoothed to form a good seal with the leather washer (£). The frame (H) is made from a piece of l/2-inoh brass pipe 7 inches long. Windows 1/2 inch 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 3/8-inch pipe threads to accommodate the Y-valve (J) with the nut (K) to hold the valve rigid, -J Goodhue, L. D. Insecticldal Aerosol Production. Indus, and Ene-ln. Chem., Indus, id. 34 (l2)» 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 (l_) with smoothly f!;round ends to seat in the washers (F_) is 07" l/2 inch outside diameter and is ?rradu- ated to 1/2 ml. It is held in place between the leather washers (_F, F) by screwing 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 connection for the drum and a l/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 sxirface. 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 hexag-on 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 l/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 clogging by soil. Any other desired connection can be made in place of the needle (N). For use with aerosols a 0.017-lnch-diameter capillary (O) 4 inches long, soldered in a nipple, is used as a nozzle. Permanent connections can also be made to a small fur.igation 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 dichlorodif luoromethane are used, the carbon disulfide is poured in, and the liquefied gas is added through the measur- ing device by connecting the valve (£) 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 measvire out and release a desired Quantity of aerosol solution or fxmiigant, close the upper valve (j) and slowly open the lower valve (E), which allows liquid to flow, withe .4t''boi ling, into the glass tube (_l) 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 atiparatus is obviously well adapted to dispense small quantities of an aerosol solution. V^ere many different solutions are being tested, a complete apparatus should be available for storing and dispensing each solution. Where a number of tests are to be made with a volatile fvmigant 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 oan be released into a fvjmigation chamber by inserting the soil-injecting needle through a hole in a stopper in the side of the chamber. -3- Fumigants suoh as carbon disulfide that do not have pressure enough for self propulsion can be mixed in suitable proportions vrith some liquefied gas. One example is three parts of carbon disulfide and one part of dichloro- difluor cine thane by weight. The mixture containing ethylene dichloride and methyl chloride is another example. Practical Testa 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 75 tests against several species of ants (including Formica fusca var. subserica Say, F. pallidefulva schaufussi var. incerta Emery, jF. pallidefulva Latr. var., Lasius niger var. neoniger Emery, and Tetramorium oaespitum (L) as identified by M. P.. Snith), 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 inquiry on blue- grass, red top, Dutch clover, linnias, marigold, pachysandra, mugho pine, Torenia, and strawberry. However, severe injury and even death has ooc\irred to endive plants growing in pots or in the field, to carrots in the field, and to bluegrass in lawns oontaining 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-dichlorodif luoro- methane mixture \xp to dosages of 3 c.c. of CS- per square foot gave less re- liable resxilts than those obtained with methyl bromide. Digitized by the Internet Archive in 2013 http://archive.org/details/dispenserforaeroOOunit N- w M ;;^tt^ i^ FIGURE I. CROSS SECTION OF DISPENSER SHOWING DETAILS OF CONSTRUCTION UNIVERSITY OP FLORIDA III: 1 niilliiliniiil 3 1262 09240 8664