12 Farmers’ Bulletin 1185. 
TABLE I.—Capacity of cylinders of double-acting Spray pumps, in fractions of a 
gallon. 
Length of stroke, in inches. 
Diameter 
of Gyunder, = Li RIT a a ae ae 
| in inches 24 4 ; 
! = — = SR 
| | ‘ 
2 0.068 | 0. 082 0. 109 0. 136 
23 | . 086 | 103; =} . 139 ~ 172 
23 . 106 T1227 .170 ~ 212 
23 129 . 154 206 . 257 
3 . 153 . 184 245 . 306 
] 
The smallest barrel pumps will hardly supply a single nozzle, and 
can only be used for small patches of alfalfa, while some double- 
acting hand pumps with 3 by 5 inch cylinders deliver as high as 9 
gallons per minute, and therefore are capable of supporting 10 
nozzles. Such a pump will spray an acre in about 11 minutes, if 
labor is’ available to keep it going at 30 strokes per minute. The 
same pump driven by a 2-horsepower gasoline engine at 50 strokes 
per minute will deliver 15 gallons per minute and easily supply 10 
nozzles, each delivering 14 Pallone This is 25 per cent above the re- 
quirements of an Sane moving 200 feet per minute and makes it 
possible to drive 250 feet per minute and spray an acre in nine 
minutes. 
Modern orchard spray outfits are usually of the duplex or triplex 
type with small cylinders and short stroke, and are designed to give 
a comparatively small flow and high pressure. They are less suit- 
able for alfalfa spraying than the older pumps with larger cylinders 
and longer stroke, designed for larger flow and lower pressure. 
Seventy-five pounds pressure is enough for successful spraying for 
the alfalfa weevil, although it is possible that a better distribution of 
the poison is obtained at a pressure of 100 to 125 pounds. Higher 
pressures cause needless wear and strain upon the machinery. 
The necessary capacity of an outfit having been decided upon, it 
remains to select the parts to conform to it and to the conditions 
under which the work must be done. Capacity is not the only thing 
to be considered in selecting or assembling ‘an outfit. The truck, 
tank, pump, engine, boom, and nozzles can be chosen in such a way 
as to avoid later trouble and expense. 
THE VEHICLE. 
Almost any kind of wagon or truck can be used to haul the equip- 
ment. For a light outfit an express wagon or an ordinary farm 
wagon, preferably with no sides, is satisfactory. If planks are used 
for the bed, the engine, pump, antl jack can be bolted to one of them. 
If an ordinary wagon box is used, a plank to which the machinery 
is bolted can be slid into it lengthwise and nailed or bolted down. 
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