March 1%8 ET-251 United States SepartBent of i^rioulture A«rlc\2ltural Sesearch Adainiatratlon Bureau of Sntonology and Plant Qnarantine AS IMPfiDTXD AXB3S0L NOZZUB TOR USE OH XHGIKX SZHAnSTS' By A. H. Teomaae 2)iTieion of Control Inreetl^ations Aerosol no tiles for use on jeep and airplane engine exhaust • were dereloped during World War II under tlie Office of Scientific Hesearch and Derelopment. ^is work was carried on naialy at the Unirersity of Illinois under the direction of H, 7. Johnstone. Becently a nossle has heen devised in this Bureau which is more effieiont and more easily con- structed thaa the prerious noszles and can be used on snail trucks and tractors. This type of nossle utilises the heat of the exhaust to lower the riscosity of the oil in the aerosol solution, and the velocity of the exhaust gases to hreak up the oil. The speed of the engine, the rate of flow of the solution, and the anount of constriction at the noisle deter- mine the particle sise. The nossle is constructed of pipe fittings, and very little maehiming, or special equipment, is required (fig. l). ▲ 1/8- inch pipe cap (A) is first slotted on hoth sides with a thin hacksaw hlade so that there is 3/32 inch of metal at the center separating the slots. These slots are made 3/I6 inch from and parallel to the closed end of the cap. The outside of the cap is then machined down to 17/32 inch (o.d.) from the slot to the open end and 1/2 inch (o.d.) from the slot to the dosed end with a slight taper at each end. The slotted cap (^) is then attached to a l/g-inch pipe nipple (B) k inches long, and a 1/S-inch pipe elbow (C) is attached. Into a 1-1/2-inch jy pipe nipple (I) 6 inches long is drilled a hole 13/32 inch in diameter /I 2-5/8 inches from one end. A 1/8-inch pipe nipple (S) 3 inches long is put through this hole and attached to C. A - ^rl nch brass pipe nipple (£) /, 5/8 inch long is then attached to a pipe reducer (T) 3^i^^o 1-1/2 inches "'^ in diameter, and the reducer to the pipe nipple X. B is then brazed to I so that A is centered in £. figure 2 shows the nossle partly assembled. The aerosol solution can be si^plied from a tank by gravity feed, by air pressure, such as from an amy type of hand-pump sprayer, or bjr a small gear or rotary pump, V-belt driven. -2- The flezlbla hose fron the solution tank is attached to the pipe nipple 0, and the open end of nipple S Is attached to the engine exhaust. It aay he necessary to slot X about 1 Inch deep In four places and then expand It slightly so that It will slide easily orer the exhaust line. When the exhaust outlet Is a threaded pipe, the nozsle can he attached with a regtilar pipe fitting. This type of noizle Is particu- larly well STilted for tractor exhausts. It can he attached directly orer the engine hy renorlng the auffler and using an elbow to point the nosxle horizontally. Vfhen the nozsle Is attached dose to the engine, the back pressure may be excesslTe. The back pressure should not be greater than 10 pounds, and the arerage running pressure should be between ^ and 10 pounds per square Inch. A snail pressure gage can be Installed In the line and a 1/2- Inch gate ralre used to regulate the pressure. Tlgure 3 shows such a nozzle and relief ralve attached to the engine of a 30- horsepower sprayer-duster. The aerosol solution In this ca«e Is supplied by the gear puitp on the machine, ^Ich Is so arranged that either the air-blast sprayer or the aerosol nozzle can be used. figure k shows the nozzle attached to the exhaust of a pick-up truck. In an assembly of this type considerable heat Is dissipated before reaching the nozzle. For this reason the aerosol solution is more difficult to atomize and the output should be reduced. The entire exhaust line should be tight for this method of attachment. To release the aerosol solution the engine speed should be as high as can be maintained with safety. The nozzle should be allowed to heat up for a minute or tw(^ and the rate of flow should then be adjusted so that no blue smoke emerges, which Indicates too small a particle size. If the flow is too great, a heary spray is released and large particles fall Just in front of the nozzle. The rate of flow should be about 1/5 quart to 2 gallons a minute, depending on the particle size required. This type of aerosol dispenser should be used in the seme manner as other aerosol field machines. In the field the aerosol should be released about 1 hour after sunset on the windward side of the area to be treated. A suitable aerosol formula contains 3 pounds of technical BDT dissolred in 2 gallons of xylene and then in 3 gallons of lOW motor oil. A OIL ft BRAZE s\\\\\ \\N\\\\\\N\\^ D / wwvw \\^\\\\\VV\\\\ \V\V\\\\ EXHAUST h\\\NNN\\\\\\\NN\\\\\\\N\\\\\\\\S: Figure !• — Exhaust aerosol nozzle. Figure 2.— Exhaust aerosol nozzle partly assembled. Digitized by the Internet Archive in 2013 http://archive.org/details/improvedaerosolnOOunit Figure 3« — Aerosol nozzle attached to the esdianst of a 30-hor8epoirer sprayer duster. This photograph shows the method of attaching a preemire gage and relief valve. Figure U* — Close-up of aerosol nozzle attached to the exhaust of a pick-up truck. UNIVERSITY OF FLORIDA 3 1262 09240 9779