LIBRARY 
 TE PLANT BOARD 
 January 1950 
 
 ET-280 
 
 United States Department of Agriculture 
 
 Agricultural Research Administration 
 
 Bureau of Entomology and Plant Quarantine 
 
 A SPRAYER FOR DISPENSING 
 SMALL MEASURED QUANTITIES OF LIQUID 
 
 By Orin A. Hills and Edgar A. Taylor, 
 Division of Truck Crop and Garden Insect Investigations 
 
 A sprayer for applying small measured quantities of liquid insecti- 
 cide to individual plants has been devised and used successfully in plant* 
 tolerance tests on cantaloups. With the technique used it is possible to 
 spray single plants without affecting adjoining plants. 
 
 The sprayer is made from 
 1/4- inch pipe and various fittings, 
 as shown in figure 1. The liquid 
 to be dispensed is measured out 
 and poured into the spray gun 
 through stopcock A, which is 
 fitted with a small funnel. A 
 priming cock such as is used 
 on some stationary engines or 
 tractors is excellent for this 
 purpose. During this operation 
 the air vent, stopcock B, is open 
 and stopcock C, which is for the 
 release of the spray material, is 
 closed. When the spray gun has 
 been filled, stopcocks A and B 
 are closed and pressure is 
 applied from a compressed-air 
 tank through the hose line D. 
 Stopcock C is then opened and 
 the spray released through the 
 nozzle E. If desired, a cylinder 
 of liquid carbon dioxide equipped 
 with a suitable regulator may be 
 substituted for the compressed- 
 air tank for applying the pressure. 
 
 Figure 1. --Close-up of sprayer. 
 
Digitized by the Internet Archive 
 in 2013 
 
 http://archive.org/details/sprayerfordispenOOunit 
 
2- 
 
 An open cylinder 13.6 inches in diameter and 18 to 20 inches tall is 
 used to confine the spray material and thus protect adjoining plants. 
 Since this cylinder encloses 1 square foot, dosages can easily be con- 
 verted to an acre basis. 
 
 Figure 2 shows the sprayer in operation on a cantaloup plot being 
 grown under lath shade. One operator is releasing the spray material 
 while the other is measuring out the dosage for the next application. A 
 carbon dioxide cylinder equipped with regulator valve and trip release 
 is being used. For this spraying the regulator valve was set for a 
 pressure of 60 pounds per square inch. After the spray material has 
 been poured into the gun and all stopcocks closed, the trip release is 
 opened momentarily before the spray is released. There is then sufficient 
 pressure in the hose line to dispense the liquid in the spray gun. 
 
 Figure 2. --Sprayer in operation. Carbon dioxide tank 
 equipped with regulator valve and trip release (circled) 
 being used. 
 
JNIVERSITY OF FLORIDA 
 
 3 1262 09242 9108