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HOSE & HANDGUN SPRAYING
A handgun (hand-nozzle or hand-lance) is used to control and direct the spray pattern to the ground, shrub or tree. They must be constructed of long lasting and noncorrosive materials such as brass, stainless or aluminum.
The handgun fits to a hose of any length from the sprayer allowing operator mobility. The hose should be as short as possible while still permitting operator mobility.
Liquid looses pressure due to friction as it travels through the hose, 1-3 psi (0.07-0.21 bar) for each foot (30 cm) of hose. For most operations
1
/
2
" (1.25 cm) inside diameter hose is adequate. Trees over 40 ft (12 m) high require
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4
" (2 cm) inside diameter hose and a sprayer pump capable of delivering a volume of at least 20 gpm
(75 lpm) and a pressure of at least 400 psi (28 bar).
NOZZLES
Always be alert to the possibility of a plugged or damaged nozzles. Serious misapplications may result. Check nozzle output periodically.
Modern nozzles use spring and diaphragm check valves to insure positive cutoff of chemicals without drip.
Snap-on caps make replacing and cleaning nozzles, quick, easy and fool proof with proper reinstallation.
An operator can see at a glance if all nozzles are the same size by the color code.
3 FUNCTIONS FOR A SPRAY BOOM NOZZLE
1. Regulating the flow is done through size of the orifice (opening) within the nozzle. All nozzles, regardless of type, have some point within them that regulates the flow of liquid. Obviously, the larger the opening the greater the rate of flow volume. Volume is expressed in Gallons Per Minute (gpm) or Liters Per Minute
(lpm). Do not confuse the term volume with application rate, which will be covered later.
As pressure increases, the flow volume in a given nozzle also increases. For example, an average size nozzle which discharges 0.52 gpm (1.4 lpm) at 30 psi (2 bar), will discharge 0.73 gpm (2 lpm) at 60 psi
(4 bar). In this example, an increase in pressure of 100% has caused an increase in discharge of 40%.
Some nozzles deliver a small volume (for example: 0.2 gpm (0.75 lpm)). Some nozzles deliver a relatively large volume (for example: 1.5 gpm (5.7 lpm)), or 7 1 /
2
times as much as the smaller nozzle in this example.
The amount of material (volume) to be applied is determined by the effect the chemical has on the turf.
2. The nozzle on a sprayer is to form the liquid into droplets. The size of the droplet is determined by two factors design and system pressure (psi/bar).
Particular applications are done best by big droplets such as systemic fungicides, insecticides and some herbicides in order to reduce drift. Other applications require small droplets like contact fungicides and some herbicides. Again, this is determined by whether the chemical is foliar applied or soil applied. Large droplets for soil applied material, small droplets for foliar applied materials that evenly cover the plant better.
Pressure also affects droplet size. More pressure at the same nozzle produces smaller droplets, more subject to drift. The general rule on pressure is to use the lowest pressure possible with just enough to form adequate spray nozzle patterns.
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NOZZLES
(CONTINUED)
3. Disperse the material in a specific pattern that will insure even distribution of chemical across the swath covered by the boom.
As shown (to the right) the pattern formed by flat fan (TeeJet) nozzles would show most liquid concentrated at the center, then tapering off where it begins to overlap with the next nozzle-approximately
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. The pattern of liquid dispersed by the hollow-cone is more even across its width. Each nozzle overlaps the adjoining nozzle by 100%.
That is to say the area covered by each nozzle extends to the center of the two nozzles on either side.
In order to properly develop their spray pattern, each nozzle must be the proper distance from the next nozzle (spacing) and the proper height above the ground.
NOZZLE SCREENS (STRAINERS)
Smaller nozzles require nozzle screens or strainers to prevent clogging.
• Teejet type nozzles size 8001 and 80015 require 100 mesh screens.
• Teejet type nozzles from size 8002 through 8008 require 50 mesh screens.
• Turbo TurfJet Nozzles Size 1/4 TTJ02-VS and larger do not require strainers.
• Turbo Floodjet Nozzles TF-VS2 through TF-VS3 require 50 mesh screens.
• Turbo Floodjet Nozzles TF-VS4 and larger do not require screens.
SPACING
Turf spray nozzles are normally 20" (51 cm) apart. Some cases 40" (101 cm), depending on the type of spray boom and type of area to be sprayed.
Very fine, level areas (golf greens and tees, bowling lawns, tennis courts, etc.) may be sprayed with nozzles spaced every 10" (25 cm).
BOOM HEIGHT
Height is very important in permitting spray nozzles to develop their proper spray pattern. If nozzles are too high, excessive overlap develops. If nozzles are too low, there is not enough overlapping of nozzle spray patterns.
NOZZLE
TYPE
80° Flat Fan
65° Flat Fan
Turbo TurfJet
Turbo TurfJet
Turbo Floodjet
Turbo Floodjet
NOZZLE
SPACING
20" (51 cm)
20" (51 cm)
20" (51 cm)
40" (101 cm)
20" (51 cm)
40" (100 cm)
HEIGHT ABOVE
THE GROUND
18" (45 cm)
12" (30 cm)
15" (38 cm)
19" (48 cm)
16" (41 cm)
18" (45 cm)
Improper nozzle height or spacing prevents proper application of chemical. Some areas are under treated and chemicals are ineffective. Some areas are overtreated with wasted chemical and possible turf damage.
Operating your sprayer at a desired speed and pressure on a hard, dry surface is a good method of checking spraying consistency. Observe nozzles in operation, observe if the area dries evenly. If there are alternating wet and dry streaks, raise or lower the spray boom. If the wet streaks are directly under the nozzle, the boom is too low. If the wet streaks are between the nozzles, the boom is too high.
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