October 1947 STATE PU^ T BOAW> ET-2W 
 
 United States Department of Agriculture 
 
 Agricultural Research Administration 
 
 Bureau of Entomology and Plant Quarantine 
 
 A GLASS CONTAINED FOE USE IN STUDYING AEROSOL SOLUTIONS 
 
 R. A. Fulton and F. D. Bern^ 
 Division of Insecticide Investigations 
 
 The preparation of liquefied-gas aerosols for experimental purposes 
 requires special equipment for the handling of liquids under a gage 
 pressure of 15 to 85 pounds per square inch. It is highly desirable to 
 be able to observe the solution for the presence of insoluble material 
 and for the study of physical and chemical changes in the solution. A 
 number of devices have been described for this purpose, but all have the 
 disadvantage of excessive weight (300-350 grams) of the container in 
 proportion to the weight of the liquid contents (10 grams). A glass 
 container has been developed which weighs approximately 400 grams and 
 has a capacity of 350 grams of the aerosol solution. 
 
 The container (fig. 1) was constructed from a strong glass bottle, 
 of the kind commonly used in the drug-store trade for citrate of magnesia, 
 and a refrigeration Y valve (B) with 3/8-inch male and l/8-inch female 
 outlets. The male connection of the Y valve was machined on a turning 
 lathe to the same shape as the glass stopper furnished with the bottle. 
 The end of the valve, H, was then drilled so that a l/4-inch (o.d.) 
 stainless steel tube (F) could be soldered into it. It was necessary to 
 notch the Y valve at D to hold the wire loop directly in position over 
 the center of the bottle and to produce an even pressure on the gasket (C). 
 The gaskets were made from l/8-inch sheets of neoprene or a polyvinyl 
 alcohol resinous material. The neoprene material is suitable for use with 
 the solvents in most of the aerosol formulas, but with the chlorinated 
 solvents it is necessary to use polyvinyl alcohol sheet stock. 
 
 For filling the containers with the aerosol solution, two methods are 
 used in the laboratory. The first method is similar to the procedure 
 commonly used in filling the steel containers. The bottle is washed and 
 dried, and the valve assembly is placed in the neck* where it is fastened 
 by a lever (E). A brass flared fitting (1/8-inch IPT to lA-inch SAE) 
 is attached to the valve at G. The bottle is then connected to a vacuum 
 pump to permit filling by vacuum. The insecticidal materials are dissolved 
 in the solvents to be used in the aerosol, and the solution is drawn into 
 the bottle through a l/4-inch copper tube with a 200-mesh screen on the 
 end. The bottle is then connected by means of a refrigeration hose to a 
 supply of Freon-12 (dichlorodifluoromethane) or a mixture of this gas with 
 Freon-11 ( trichlorofluorome thane) . The tank valve is opened to fill the 
 hose with the liquefied gas. The bottle is weighed, and additional weights 
 equivalent to the amount of the propellent gas to be added are then placed 
 on the balance pan. The Y valve is opened to allow the propellent gas to 
 flow from the reservoir, and closed when the calculated amount has been 
 
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 added. The tank is disconnected and the flared union is replaced with 
 a nozzle tip (1). The use of electric solenoid valves for filling 
 aerosol containers has been described elsewhere (1) . 
 
 The second method is used for filling the containers where the 
 final pressure of the liquid is under 50 pounds per square inch. The 
 weighed ingredients are placed in the dried bottle, which is then 
 weighed. The propellent gas is then cooled in a coil of copper tubing 
 packed in dry ice. The cooled liquid is slowly aided to the bottle until 
 the desired weight has been reached. The valve assembly is placed in the 
 bottle and fastened with the lever. The filled bottle is then allowed to 
 come to room temperature. It may be necessary to warm the bottle to 
 dissolve the insecticide. 
 
 The type of bottle used will withstand safely pressure up to 85 
 pounds per square inch. The bottles have been tested to 200 pounds per 
 square inch with no failures. At higher pressures the valve-locking device 
 will bend slightly, releasing the pressure within the bottle. As a 
 precautionary measure, a safety glass screen should be used when the 
 filled bottles are being handled on stone-top desks. 
 
 Literature Cited 
 
 (1) Fulton, R. A., Berlin, F. D., and Bochert, R. S. , Jr. 
 
 1947. A laboratory method for filling aerosol containers. 
 U. S. Bur. Ent. and Plant Quar. ET-245. ?-4 pp. 
 
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 Figure 1.— Diagram of glass aerosol container (left) including 
 detail of Y valve (right). 
 
UNIVERSITY OF FLORID/ 
 
 Nil" II LI 
 
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