SPRAYERS FIELD I* 1482
1482
PUBLICATION 1482
FIELD
530.4
212
P1482
1974
(1981
print)
c.3
I*
Agriculture
Canada
SPRAYERS
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Canada
FIELD
SPRAYERS
D. T. Anderson,
Research Station, Lethbridge, Alta.
D. E.Clark,
Nova Scotia Agricultural
J. J.
College, Truro, N.S.
Sexsmith
Research Station, Lethbridge, Alta.
PUBLICATION 1482
CANADA DEPARTMENT OF AGRICULTURE
'
VJ
>
PUBLICATION
1482, available from
Information Services, Agriculture Canada, Ottawa K1
© Minister of Supply and Services Canada
Cat. No.
A53-1482
Revised 1974
1974
ISBN: 0-662-001 52-4
Reprinted 1981
5M-9:81
A 0C7
TIPS FOR SUCCESSFUL
SPRAYING
Follow directions. Read the
on container labels.
instructions
and take the
precautions
printed
Protect your eyes. Avoid inhaling chemicals and exposing
your skin
them for long periods. Wear the protective clothing and masks
are recommended on the pesticide labels.
to
that
Post the telephone number of the closest Poison Control Center and
the name of the pesticide being used beside your telephone.
Avoid spray
drift.
2,4-D and related herbicides may seriously damage
sensitive crops such as grapes, tomatoes, turnips, sugar beets,
beans,
and ornamental plants. Use at least 10
gallons of spray solution per acre (110 litres/ha) and apply it at the
lowest pressure at which the nozzles operate properly. Use the amine
or low-volatile ester formulations to reduce vapor drift. Spray only when
the velocity of the wind is less than 10 miles per hour (1 6 km/h).
carrots, tobacco,
fruit
trees,
Do
not apply mixtures of different herbicides, or mixtures of herbicides
foliar fertilizers, insecticides, or fungicides in a single application
unless this procedure is recommended on the label or by a competent
and
authority.
Use equipment designed
for the job.
Calibrate sprayers at least
once
a
wettable powders. Always operate
are using
if you
speed and pressure.
year and oftener
at the calibrated
Replace worn nozzles, defective hose, and
a
broken
pressure gauge
promptly.
Clean sprayers thoroughly after each use to prevent corrosion.
Preferably use one sprayer for herbicides and another for other pesti-
decontaminate the herbicide sprayer if you must use
an insecticide or fungicide on or near a herbicide-
cides. Otherwise,
it
for spraying
susceptible crop.
Use
different
handgun hoses
Store herbicides
partly
Keep
away from
empty containers
all
for herbicides
containers
for other pesticides.
other pesticides, seed, and fertilizer. Label
and dispose of empty ones safely.
from children and animals.
as dangerous,
away
and
CONTENTS
TYPES OF SPRAYERS
6
SPRAYER COMPONENTS
TANKS
PUMPS
NOZZLES
SCREENS
CONTROL VALVES
REGULATORS
PRESSURE GAUGE
HOSES
7
8
12
14
_ 16
_ 16
_17
BOOM-TYPE SPRAYERS
ROW-CROP SPRAYERS
UTILITY SPRAYERS
SPRAYER MOUNTS
SPECIAL SPRAYING TECHNIQUES
17
19
22
24
26
AGITATION
SPRAY DRIFT
27
SPRAYER OPERATION
29
29
33
36
37
38
39
CONTROL OF SPRAYER OUTPUT
CALIBRATION
CALCULATION OF SPRAY MIXTURES
CARE OF THE SPRAYER
DECONTAMINATION
RECORDS
ACKNOWLEDGMENTS
GLOSSARY
27
_
39
40
FIELD
SPRAYERS
Chemicals are widely used on the farm to control
weeds, insects, and diseases. The effectiveness of the
pesticide (herbicide, insecticide, or fungicide) depends on:
Use of the proper chemical
Application of the chemical at the
and at the proper time
recommended
rate
Proper use of the right type of application equipment.
This publication contains information on hydraulic field
their component parts, and how to use them
efficiently. There are sections on three adaptations commonly
used on Canadian farms, sprayer mounts, and operation of
the sprayer.
Consult your local agricultural authorities or obtain
publications from government or other sources on what
chemicals to use for the control of weeds, insects, or diseases.
sprayers,
NOTE
:
Metric measurements given in this publication do not correspond
with examples in the common (British) system,
because tank sizes, nozzle spacings, and so forth are not
equivalent. Examples in the two systems should therefore be
considered as different, although they are very similar.
exactly
vj
»
.
TYPES OF SPRAYERS
FOG GENERATORS,
aerosol
generators,
disperse chemicals in a fine airborne fog. These machines
are used to control mosquitoes and flies in large buildings,
parks, or similar areas. Fog generators are not usually used
on a farm.
AIR-BLAST SPRAYERS dispense pesticides into a
high-velocity air stream. They are generally used for spraying
orchards, large numbers of shade trees, and some vine and
vegetable crops. Sprayers of this type have been used in some
areas for spraying row crops such as potatoes, and to a limited
extent for field spraying of chemicals other than herbicides.
COMPRESSED-AIR SPRAYERS use air under pressure
to force a liquid through a nozzle. An example is the small
hand sprayer used around the farmstead and for spot spraying
in the field. Large compressed-air sprayers are not common.
also
HYDRAULIC SPRAYERS
called
dispense
chemicals
in
a
wettable-powder suspensions.
Water is the most common carrier for the chemical, and a
pump delivers the liquid under pressure to one or more
solution, in emulsions, or as
nozzles. Hydraulic sprayers are available with various types
of tanks, pumps, nozzles, screens, controls, and other
components. The type of equipment on the sprayer will
determine the usefulness for applying the various pesticide
formulations that are available.
The essential components of a hydraulic sprayer are
arrangement of sprayer
components.
Mechanical agitation
is an alternative to
illustrated in Figure
hydraulic agitation.
FIGURE
1
1.
The
correct
FILLER SCREEN
GATE VALVE
SUCTION TYPE STRAINER
AGITATOR LINE
PUMP
GATE VALVE
BY-PASS LIN E
FILTER OR LINE
STRAINER
PRESSURE REGULATOR
PRESSU RE GAUGE
SELECTOR
VALVE
&
SHUT-OFF
SPRAY BOOM
(3
SECTIONS)
NOZZLES WITH SCREENS
BIVERT SPRAYERS
are used to apply
multiphase invert emulsion.
herbicides
in
The
positivethe form of a
displacement-type pump draws a metered quantity of water
and herbicide from one tank and a metered quantity of oil
and emulsifier from a second tank. The metered quantities of
water, herbicide, oil, and emulsifier are mixed in a mixing
chamber on the suction side of the pump. The thick
mayonnaiselike emulsion of water and herbicide suspended
in oil is then pumped through the boom to special nozzles.
Bivert emulsion sprays, which are claimed to reduce spray
drift, are currently used for spraying roadsides and publicutility and railway rights-of-way. Bivert sprayers are not in
common use on Canadian farms.
SPRAYER COMPONENTS
The
parts mentioned in this section are
hydraulic sprayers.
common
to
all
TANKS
A
tank must
chemical corrosion. Steel tanks rust
care. Galvanizedsteel tanks give reasonably satisfactory service if they are
properly cared for but may eventually corrode. Aluminum or
aluminum-alloy tanks weigh less than steel tanks and resist
corrosion by most agricultural chemicals. Lightweight fiberglass tanks resist corrosion by many chemicals, including
and corrode
resist
readily
and need considerable
herbicides, insecticides, fungicides, most acids, and solutions
of the salts of most acids. Stainless-steel tanks and steel
tanks with
a special
by practically
all
baked-on factory
finish resist corrosion
agricultural chemicals.
A
45-gallon (205-
drum is the least expensive sprayer tank. When the drum
mounted in a vertical position, the return line from the
litre)
is
pressure regulator (see Figure 1) should deliver the liquid
bottom of the drum. Ordinary steel drums rust and
corrode rapidly, their openings normally are too small to
permit a wettable powder to be added conveniently, and
their design makes proper agitation of a wettable-powder
suspension almost impossible.
The choice of the sprayer tank depends on the chemicals
that are to be handled and the initial cost; a low-cost tank is
seldom a good investment. Corrosion and rust cause plugging
of strainers, screens, and nozzles; excessive pump wear; and
the eventual ruin of the tank.
Construction of the tank affects sprayer operation and
care. The opening should be at least 1 2 inches (30 cm) across,
splash proof, and equipped with a coarse screen. The cover
should be vented and sealed against dust. A large opening
facilitates filling and cleaning. The drain plug should be
located so that the tank can be completely drained for frost
to the
7
protection and for flushing out sediment. The return-flow
pipe normally discharges into the lower portion of the tank.
This helps to prevent excessive foaming of the solution. The
suction-pipe intake should be near the bottom of the tank
but not too close to the return-flow pipe. It is easier to
provide satisfactory agitation of spray material in a tank
with a round bottom than
square corners.
in
one with
a
flat
bottom and
PUMPS
Pumps vary considerably in capacity, operating speed
and pressure, and resistance to corrosion and wear. It is best
to consider the manufacturer's recommendations when you
select a pump for a sprayer. Pump capacity is affected by
speed and, for most pumps, by the operating pressure. The
capacity must be great enough to handle jobs requiring an
unusually high application rate. The pump must supply
liquid under pressure for hydraulic agitation if the sprayer is
not equipped with a mechanical agitator. When selecting a
pump, consult the manufacturer's performance tables or
charts and allow for about 25 percent reduction in capacity
because of wear.
The pump may be driven by a tractor PTO or by an
auxiliary engine. An auxiliary engine should have enough
reserve capacity to operate the
pump
at
maximum
pressure
and also a mechanical agitator when needed. Late-model
tractors have a choice of PTO speeds.
CAUTION: Most
positive-displacement-type
pumps
(gear,
diaphragm, and piston) are not designed to operate at
the 1,000-rpm PTO speed used on some tractors. Follow
the pump manufacturer's recommendations.
roller,
GEAR PUMP
(Figure 2) is useful for some types
of low-pressure spraying. It is inexpensive, but it wears
rapidly if operated continuously near maximum pressure.
Do not use brass gear pumps with abrasive materials such
as wettable powders. Some gear pumps are made of suffihandle wettable-powder
ciently
durable
materials
to
suspensions. Check manufacturers' recommendations before
using gear pumps for abrasive materials.
The ROLLER
(Figure 2) handles a wide range
of agricultural chemicals if properly equipped. The type
equipped with nylon rollers mounted in a special rustresistant, cast-iron case works well with most sediment-free
agricultural chemicals.
Rubber rollers are intended for
pumping water and are considered suitable for pumping
(most wettable
wettable powders. Abrasive materials
powders, derris, and sulfur mixtures) shorten the service life
of a roller pump. The pump housing, the roller slots in the
rotor, and the rollers are all worn by abrasive materials.
Replacing the rollers may not restore the pump to a serviceable
condition.
The
PUMP
8
DIAPHRAGM PUMP
(Figure 3) has been adapted
recent years. The pump is driven by the
PTO of a tractor and develops pressures of up to 130 psi
(900 kPa*). It gives excellent service with abrasive materials
and is well adapted for general sprayer use where pressure and
volume are not limiting factors.
The
for sprayer
use
in
The PISTON
PUMP
is
commonly used on high-pressure
sprayers but may also be used at low pressures. A radial
4-cylinder piston pump, usable at any pressure up to 500 psi
(3,450 kPa), has been developed for direct PTO drive as well
as for auxiliary-engine drive (Figure 15). Small single- and
twin- cylinder piston or plunger pumps (Figure 4), which
develop pressures of up to 500 psi (3,450 kPa), have also
been adapted for use with a tractor PTO. Some multicylinder
pumps are limited to speeds of 200 rpm or less (Figure 16).
Piston pumps should not be driven at a speed faster than the
manufacturer recommends.
Piston pumps designed for use on sprayers are usually
equipped with abrasion-resistant cylinder liners, valves, and
seats and with nylon fabric or leather piston cups. These
pumps will handle a very wide range of agricultural chemicals,
including abrasive wettable powders.
Piston pumps are equipped with either an internal or an
external air chamber. A chamber is necessary to dampen
pulsations in the liquid flow. A piston or plunger pump,
although more expensive than other types, is a sound
investment if the sprayer must be used for a variety of
FIGURE 2. Left,
pump; right,
spraying operations.
a roller
a gear
pump.
*
See "Glossary."
9
SUCTION
CUSHION
CHAMBER
DISCHARGE
CUSHION
CHAMBER
SUCTION
VALVE
DISCHARGE
VALVE
_ OIL LEVEL
BEARINGS
OIL
RESERVOIR
FIGURE
A
3.
diaphragm pump.
FIGURE
IN: All pumps of the positive-displacement type
must be operated with a bypass pressure regulator. Do not
use a hand valve or tap to control pressure.
PUMP
(Figure 5) is the only pump
of the types commonly used for sprayers that does not
displace liquid positively. The single-impeller centrifugal
pump must be operated at a high speed (3,000 to 6,000 rpm)
to obtain the capacity needed for spraying. Gears built into
the housing allow the pump to be operated from the PTO of
The CENTRIFUGAL
a tractor.
The centrifugal pump is not self-priming, therefore it
must be mounted below water level or a priming system must
be used. Most centrifugal pumps resist abrasion and are
claimed to handle wettable powders satisfactorily for years.
Never allow a sprayer pump to run dry. Rollers,
bearings, or all of them, may be severely damaged.
:
seals,
10
4.
A
piston
or plunger pump.
A
FIGURE 5
pump
centrifugal
mounted
on
directly
a tractor
PTO
11
NOZZLES
Nozzles (Figure 6) are manufactured for a wide range
of application rates and crop conditions. Performance tables
are available from most dealers; consult these tables when
selecting nozzles (see "Control of Sprayer Output").
Nozzle bodies are available with either male or female
thread
connections;
others
have clamp-on
connections,
are frequently used with aluminum or brass booms and
are readily removed for cleaning and inspection. Nozzle tips
or discs of various sizes are interchangeable in most bodies.
Nozzle tips are manufactured from several materials.
Generally, plastic tips resist wear better than brass or
aluminum tips. Ceramic, stainless-steel, hardened stainless-
which
and tungsten-carbide tips resist wear longer than the
other types.
CONE NOZZLES (Figure 6) are used mainly on row-crop
sprayers for applying insecticides and fungicides. The
nozzles operate best at a pressure of about 80 psi (550 kPa),
but higher pressures can be used if needed. Some nozzles
produce a hollow-cone pattern and are used for low-volume
applications where a fine spray is needed for thorough plant
coverage. Others produce a solid-cone spray pattern and are
used for high-volume applications where dense foliage
requires a penetrating spray. Cone nozzles can be used to
steel,
apply wettable powders.
FAN NOZZLES
commonly used on field sprayers
row-crop sprayers (see "Row-crop
produce tapered-edge spray patterns,
uniform coverage if properly overangles are 65, 73, and 80 degrees.
are
and may be used on
Sprayers"). Fan nozzles
which give reasonably
lapped. The usual fan
FIGURE
6.
Nozzle
components: 1,
double and singleswivel bodies
equipped with offcenter tips; 2, flat-fan
hollow-cone
and core;
4, full-cone tip and
threaded core 5,
clamp-on nozzle
tip; 3,
orifice disc
;
(screen, gasket,
flat-fan tip,
and body).
Nozzle bodies (male
or female 1 /4- or
1 /8-inch pipe thread),
screens (coarse
mesh, slotted, and
mesh), and caps
fine
in
assemblies
and 4 are
changeable.
i
12
1, 2, 3,
inter-
Nozzles with angles greater than 80 degrees are manufactured
some sprayer uses. The angle of delivery varies slightly
with pressure and governs the spacing of the nozzles on the
boom. Most fan nozzles used for full-coverage field spraying
function best at pressures of about 30 psi (205 kPa). The
proper alignment of fan nozzles on a field boom is shown in
Figure 10. When nozzles made from various materials were
used on a 13-nozzle boom to apply a wettable powder at
90 psi (620 kPa), the output from brass nozzles increased by
25 percent after spraying 100 acres (40 ha). The relative
wear resistance of 80-degree fan nozzles made of various
materials compared with brass nozzles was as follows:
for
brass
1
plastic
3
19
stainless steel
hardened stainless
77
steel
steel nozzle tips usually cost three to four times as much
as brass. Obviously, when abrasive materials are to be
sprayed, the wear-resistant nozzle tips are a good investment.
The
FLOODING FAN NOZZLES
provide a wide-angle (up
useful for low-pressure
spraying. Application volumes are higher than those used for
some pesticide spraying. These nozzles are normally used
for applying liquid fertilizers or herbicides, or both, that may
have to be immediately incorporated into the soil. Recent
experimental work indicates that a drift-resistant herbicide
spray may be produced when flooding fan nozzles are angled
about 10 to 15 degrees in the direction of travel.
EVEN-SPRAY FAN NOZZLES are designed to provide
uniform distribution within the spray pattern from each
nozzle. They usually provide a spray with a fan angle of 80
degrees and are designed only for the band application of
chemicals to row crops.
JET NOZZLES project a curtain of spray in a wide arc
for a considerable distance. One type, the off-center boom
extension nozzle, is sometimes used on the ends of a field
boom to extend coverage by 5 feet (1 .5 m) or more at each
end. They should be chosen to provide the same spray rate as
the other nozzles on the boom.
to
135 degrees)
flat
spray that
is
MULTIPLE-ORIFICE NOZZLES, or clusters of nozzles,
are used in place of a boom and spray a swath about 30
feet (9 m) wide. The rate of application depends on the width
of the swath (as determined by the spray angle and the height
of the nozzle), the liquid pressure, the orifice size, and the
travel. These nozzles are best used for spraying
roadsides, ditch banks, rights-of-way, and other places where
the use of a field or row-crop boom sprayer is unsatisfactory.
AGITATOR NOZZLES (Figure 7) may be used in the
spray tank to keep wettable-powder pesticides in suspension.
Hydraulic agitation is effective only if nozzles are placed in
the bottom of the tank and are supplied directly from the
pump. Jet agitator nozzles that use orifice plates to project a
stream of liquid are suitable for small spray tanks. Largevolume jet agitator nozzles with siphon caps should be used
speed of
13
in tanks of greater capacity than 100 gallons (455 litres).
With nozzles of this type the liquid is projected in a solid
stream through the center of the siphon cap. The siphoning
action draws in liquid and creates strong swirling currents to
the tank. The total volume of liquid
projected through the siphon cap is about three times the
amount supplied to the nozzle.
Agitator nozzles are available in brass, stainless steel,
aluminum with stainless-steel caps, and nylon. Wear
resistance is a major consideration when purchasing these
nozzles. Nozzles must be solidly mounted in the tank to
prevent whipping. The pump must be able to supply liquid
for the boom, the agitator line, and the bypass return line
(see "Agitation" and "Control of Sprayer Output").
agitate the liquid
in
SCREENS
Screens remove foreign material that might clog nozzles,
wear pumps, and interfere with the operation of valves and
controls. They must be accessible for cleaning.
The
the
used
(Figure 8) is usually in the line between
the tank. Filter elements are frequently
place of screens where water supplies contain fine
line strainer
pump and
in
suspended silt.
The screen
at the nozzle
than the nozzle aperture.
14
must have openings smaller
Interchangeable nozzle screens
FIGURE
nozzles.
7.
Agitator
come
mesh sizes from 20 to 200, which refers to the
of holes per lineal inch of screen (8 to 80 holes per
centimetre). The nozzle screen has a small surface area and
plugs quickly if the line strainer is not functioning properly.
slotted strainer (Figure 6) often is used at the nozzle
to prevent the buildup of suspended solids when wettable
powders are applied by nozzles with a high delivery rate.
When nozzle dribble may cause crop damage, use a
nozzle screen with a check valve in it. Nozzle dribble occurs
when the boom is shut off. The check valve prevents dribble
but does not interfere with the operation of the sprayer.
Extra care must be taken, when cleaning a nozzle screen
having a check valve, to remove any formation of gum or
accumulation of powder that would prevent the proper
operation of the check valve.
in
number
A
FIGURE
8. Strainers.
screen types;
center, large-capacity
Monel Metal screen or
Left,
replacement filter
element for use in the
line
between the
pump and
right,
the
boom
two types
;
of
suction strainers.
w
15
CONTROL VALVES
Sprayer controls (Figure 9) should be within easy reach
A selector shutoff valve that controls output
to one or all sections of the spray boom is useful.
of the operator.
REGULATORS
The pressure regulator provides a means of adjusting
pressure, within the limits of the pump. The relief-valve
regulator, which bypasses excess fluid to the tank, is
commonly used on low-pressure sprayers. When the boom
is shut off, the bypass pressure regulator allows the total
output of the pump to return to the tank. This usually increases
the pressure in the bypass line, especially if the bypass hose
is too small
V2 inch (1 3 mm) is the minimum recommended
;
hose
size.
The unloader type of regulator is used on high-pressure
sprayers. This valve bypasses excess liquid during operation
and, when the boom or handgun is shut off, returns all liquid
to the tank at a very low pressure. The unloader regulator is
a definite asset on sprayers powered by an auxiliary engine
and on sprayers equipped with a piston or plunger pump.
FIGURE
9.
controls.
Upper
Sprayer
left
to right, gate valve,
spring-loaded
ball-check pressure
regulator,
diaphragm-
type pressure regulator,
PRESSURE GAUGE
The gauge is mounted on the output side of the pump
provide
the operator with a visual guide in controlling
to
pressure. Accurate pressure control is essential for the proper
application of pesticides. A damaged or broken gauge should
be replaced with a good-quality unit calibrated over the
pressure range of the pump.
and selector shutoff
valve; lower left to
right, rope-controlled
boom
shutoff valve,
pressure gauge with
diaphragm-type surge
dampener, and
unloader-type
pressure control valve.
I
16
HOSES
Sprayer hoses convey liquid under high pressure.
Surging in the line, caused by shutting off the boom, can
increase the hose pressure considerably above the operating
pressure. Always use hoses rated for higher than the maximum
pressure the sprayer pump will supply. The size of hose is
important. If the suction hose is too small, the pump will be
starved. If the pressure hose is too small, the system must
work under extra pressure, and nozzles at the boom ends
may be starved. Always replace any hose with a size at
least equal to that supplied with the sprayer and never a
smaller size.
BOOM-TYPE SPRAYERS
GURE
10.
A
section
of a field
boom
showing proper
le
adjustment of
fan-type nozzles to
provide overlap of
spray.
The boom-type sprayers are usually equipped for lowpressure work, but some are designed for high-pressure
spraying. The low-pressure sprayer is best suited for applying
sediment-free chemicals to a field crop.
The sprayer is normally equipped with a tank, a pump,
controls for pressure regulation with bypass agitation of
material in the tank, screens, hose lines, and a boom. A
handgun is a useful accessory.
A boom-type sprayer should meter the correct amount
of the spray material and distribute the spray in a suitable
pattern (Figure 10) across the swath. The application rate is
determined by ground speed, nozzle spacing, nozzle size,
and operating pressure (see "Control of Sprayer Output").
A good spray pattern consists of a large number of small
droplets of uniform size, closely spaced and evenly distributed
across the swath. The spray pattern is influenced by the type
of nozzle, operating pressure, boom height, and operating
conditions.
The SPRAY
carries the solution to nozzles
spaced along the boom. It is usually hinged to fold upward
or rearward for transport. Most booms swing back under
heavy impact to protect the boom from damage.
BOOM
17
Most spray booms are made of aluminum or copper,
both of which resist corrosion. Others have a special baked-on
factory finish that resists corrosion.
The field boom is usually equipped with fan nozzles,
spaced 20 inches (50 cm) apart, that deliver 5 to 30 gpa
when the sprayer is operated at a speed of 4 to 5 mph and a
pressure of 30 to 40 psi (55-330 litres/ha at a speed of 6-8
km/h and a pressure of 205-275 kPa). Some pesticides are
applied with more than 30 gpa (330 litres/ha) of water and
require different nozzles (see "Control of Sprayer Output").
The boom must have enough support; the longer it is
the more support it needs. A boom longer than 30 feet (9 m)
should be supported by outrigger wheels and tie rods
(Figure 11). These help to keep the boom at a uniform
height, particularly on rough or rolling land.
WHIP is a problem with long booms. Vertical
and horizontal boom whip occurs on uneven ground,
particularly when the boom is not well supported. The spray
pattern becomes distorted, and some parts of the swath
receive a heavy application while others receive a light one.
Excessive boom whip is almost certain to cause poor control
of the application rate. Excessive vertical whip can cause
boom ends to hit the ground, thereby damaging the boom
and producing misses in the spray pattern.
To prevent boom whip, add extra braces. On long booms
use castor wheels with good tie rods. Always pin the tractor
drawbar, because this helps to eliminate horizontal whip.
When you buy a sprayer, make certain that the boom is
BOOM
adequately braced and supported.
BOOMLESS SPRAYER should not be used for
spraying (see "Nozzles"). This type of sprayer has a
single nozzle or cluster of nozzles instead of a field boom.
The
field
18
FIGURE
11.
low-pressure
A
trailer-
mounted boom-type
sprayer with outrigger
wheels and tie rods to
support the boom.
one type of
Inset,
field
marker.
closely knit pattern of fine
of the spray have an open
pattern of large drops. This variation can result in poor spray
distribution. Wind upsets the spray distribution from the
boomless sprayer more than from the boom sprayer.
The spray near the nozzle has a
drops, whereas the outer edges
CAUTION Never use a boomless sprayer when there
danger of spray drifting on to susceptible crops.
:
The FIELD
MARKER
The marker
is
is
any
(Figure 11) makes a guideline
overlaps and skips between
avoid
that helps the operator to
rounds. The marker is attached to the field sprayer with a
rope or cable. The length of the rope is adjusted to control
the position of the marker.
essential for
good
field
spraying. Use
it
open-field spray^work.
on
Another type of marker using a foam has proved useful
on golf courses and other areas where the soil surface should
not be disturbed. The tractor exhaust supplies the power to
generate the foam and deliver it to the special nozzles
mounted on both ends of the boom.
al!
FIGURE
12.
A
trailer-mounted row
crop sprayer. The
trailer provides high
frame clearance and
read.
adjustable wheel
The drop pipes
have
flexible
:onnectors to protect
the nozzles from
damage.
ROW-CROP SPRAYERS
Row-crop sprayers (Figure 12) are either tractormounted or trailer-mounted (see "Sprayer Mounts"). The
component parts are similar to those used on the boom
sprayer, but the
placement
for
boom
row
is
designed to provide proper spray
crops.
ST
y^
19
>0
*
t
Most ROW-CROP BOOMS are for four, six, or eight
rows. The length of the boom depends on row spacing and
is usually not more than 28 feet (8.5 m).The boom has nozzles
centered over each row and drop pipes between the rows.
The lower end of each drop pipe has swivel connectors
(Figure 6) and nozzles. Drop pipes used for tall crops also
have one or more nozzles mounted along the pipe. This
type is often called a corn-drop pipe. A flexible mounting
protects nozzles and pipes from damage if they hit the ground.
Skid-supported drop pipes are used where one or
more nozzles must be positioned close to the soil surface for
accurate placement of the spray. The skid is hinged to the
boom or sprayer frame and is held to the soil surface by
gravity or by a coil spring or similar device. Accurate
positioning of nozzles to place the spray under the leaves of
crops in rows or on a band of soil between rows is called
directed spraying. If directed spraying is to be done properly,
the crop plants should be of uniform height and the soil
surface should be smooth.
Some row-crop booms are of the universal type. They
are equipped with short lengths of spray hose leading to
each nozzle and drop pipe. A system of clamps is used to
position the nozzles on the boom accurately for various row
spacings and for different heights of crop.
The choice of nozzle depends on the type of spraying
to be done (see "Nozzles"). Use cone tips on row-crop
sprayers to obtain complete coverage of the growing plant.
Use at least five nozzles per row (Figure 13) when
spraying tall crops such as corn. Always use enough nozzles
to cover the entire plant with a penetrating spray from the
BAND SPRAYER
(Figure 14)
is
essentially a
soil. Use press wheels on the planter to pack the
loosened soil around the seed.
Rotary tillers of the row-crop type are used to mix
chemicals into the soil. Power-driven units mounted on a
tractor give good results. Commercially available units use
a hood over each tiller unit to increase the mixing action.
20
13. Sections
row-crop booms
showing nozzle
adjustments when
three nozzles and five
nozzles are used for
each row.
14.
A
band
sprayer.
row-
crop sprayer adapted to apply chemicals in a band. A nozzle
is placed to treat a 6- to 1 2-inch (1 5-30 cm) band along or
over each row. Even-spray nozzles are preferred for band
spraying, but flat-fan nozzles can be used. Cone nozzles
should not be used for band spraying. If wettable powders
plug the nozzles, increase the application volume by using
nozzles with larger orifices and coarser screens.
To apply chemicals in a band to the soil surface without
incorporating them, mount an even-spray nozzle behind
the planter press wheels, and adjust the nozzle height to
spray a band of the desired width. Commercial band-spraying
attachments are available from some planter manufacturers.
Some preplant chemicals need to be worked into the
soil for best results. To incorporate the chemical into the soil
mount a tiller unit on the tractor (Figure 14) and pull a
row-crop planter behind the tractor to plant seed in the treated
band of
of
FIGURE
top and sides.
The
FIGURE
One
even-spray fan nozzle,
mounted
in front of
each of the
hooded power-driven
rotary
treats a
tiller units,-
band
for
Press wheels
of
of soil
each row.
in front
and behind each
planter unit provide
good seedbed
conditions.
Rotary-hoe (rotary-weeder) attachments are made for
many row-crop
cultivators.
Mount two
units in
tandem
for
each row, and offset the spider wheels on the rear unit to
give an overall spacing of about 1 V2 inches (3.8 cm) between
wheels. Reverse the spiders to provide a treading rather than
a picking action. The soil and chemical may not mix properly
Adjust for
complete plant
coverage
21
siifeHsJrv'lF
if the soil is very hard, too moist, or stony. Commercial band
applicators that use the rotary-weeder principle are available.
Various methods of soil incorporation for band spraying
have been studied intensively. Where a pesticide requires
thorough preplanting incorporation in the band, the hooded
power-driven rotary tiller has given better results than the
rotary-weeder or drag-harrow-type attachments.
Special HIGH-CLEARANCE
SPRAYERS
are available in self-propelled models. The sprayer is equipped
ROW-CROP
with
boom
a
high-pressure
pump and
a
row-crop boom.
A
field
also available. These sprayers have a clearance of
over 5 feet (1.5 m) and are especially adapted for use in
tall crops.
is
UTILITY
SPRAYERS
Utility sprayers (Figures 1 5 and 1 6) are mostly used for
high-pressure applications but can be used for low-pressure
spraying if a low-pressure regulator is added. They are
available in flat-bed, trailer-mounted, and tractor-mounted
models (see "Sprayer Mounts"). The utility sprayer may be
used to apply insecticides to livestock and to barns and other
buildings. Trailer-mounted and tractor-mounted models, if
equipped with a suitable boom, can be used for insect or
weed control in field and row crops. The utility sprayer can
also be used for spraying fence lines, ditch banks, and other
out-of-the-way places. If you must use the herbicide sprayer
for applying insecticides or fungicides, be very careful that
crops are not damaged by herbicide residue left in the tank
(see "Decontamination").
A
FIGURE
15.
sprayer:
1, radial
utility
4-cylinder piston
pump;
2, large-
capacity line strainer;
3, surge chamber and
gauge; 4, unloadertype pressure
regulator. The tank
is equipped with a
mechanical agitator
and with a large
hatch-type opening
for
easy servicing.
22
4
3
FIGURE
16.
A
utility
sprayer.
The
twin-cylinder
vertical
piston
pump,
the surge chamber,
the pressure regulator,
the line strainer, and
the
handgun
outlet
are easily identified.
A
sprayer should have a pump that will handle
of chemicals, including abrasive materials. A
positive-displacement pump of the piston or plunger type
is best; it should be capable of operating at any pressure up
to 400 to 500 psi (2,750-3,450 kPa). An un!oader-type
pressure-control valve is needed to protect the pump. A
large-capacity screen that will stand up under high suction
pressure is essential because the solid material in a wettablepowder suspension will build up in screen openings. A partly
plugged screen can starve the pump.
The tank should be equipped with a mechanical
agitator. Wettable- powder spray mixtures must be vigorously
agitated to maintain a uniform suspension.
If you
use a hydraulic agitator, make certain that the
pump has adequate capacity to supply liquid for the boom
or handgun, agitator nozzles, and
bypass liquid (see
"Agitation").
A
(Figure 17) is useful for spraying barns
and cattle and for spot applications around the farmstead
or in the field. Buy a good-quality handgun and an adequate
length of high-pressure, chemical-resistant hose. Afast-acting
shutoff handle helps save expensive chemicals. The gun
should be sturdy to withstand hard wear and high pressure.
a
utility
wide range
HANDGUN
The single-nozzle gun
useful for spraying cattle held
a wide selection
of orifice discs or tips. Select the right size of tip for the
spraying to be done. Too large a tip wastes expensive spray
material; too small a one makes the job take too long. One
type of single-nozzle gun is adjustable for any pattern from
in
crowding pens.
It
is
can be equipped with
23
FIGURE
17.
Handguns.
Left,
multinozzle spray
gun
;
center, single-
nozzle
utility
guns
shown with and
without a trigger
handle; right,
single-nozzle gun
with trigger handle.
The nozzle body is a
swivel type, and
the slide handle
and control rod
direct the spray when
treating cattle.
Interchangeable discs
or tips are available
for
all
guns shown.
stream to a fine cone spray. Sometimes called a
or pencil gun, it is useful for washdown work, handling
water-base paint, and general spraying.
The multinozzle gun is useful for spraying barns to
control flies, farmsteads to control mosquitoes, and brush
a
solid
utility
along
roadsides,
ditch
banks,
FIGURE
18.
A
trailer-mounted
sprayer.
and other out-of-the-way
Tandem
wheels are use
places.
The handgun nozzle should have an abrasion-resistant
Stainless steel resists abrasion better than brass or
aluminum. Stainless-steel discs with tungsten-carbide inserts
are more expensive than other types, but are economical
where large quantities of abrasive materials are to be sprayed
at high pressures.
tip.
support a
large-capacity tank;
outrigger wheels
provide boom support.
The pur
PTO-mounted
the spray
valve
is
s>
controlled by a
rope (see Figure
SPRAYER MOUNTS
FIGURE
9).
19.
A
swather-mounted
The
TRAILER-MOUNTED SPRAYER
generally used
to apply herbicides or insecticides to field and row crops.
This sprayer is usually equipped with a tank of 100-200
gallons (455-910 litres) capacity; larger tanks should be
carried on oversized tires or on tandem wheels (Figure 18).
Generally, the liquid sloshes less in a tank mounted crosswise
than in one mounted lengthwise. A trailer-mounted sprayer
should be stable and have a sturdy frame. For row crops, the
sprayer needs an axle clearance of 30 inches (75 cm) or
more and wheel-tread adjustment for various row spacings.
The TRACTOR-MOUNTED SPRAYER costs less than
the trailer type and is readily adapted for use in row crops.
It is excellent for use on small acreages, for spraying row
24
is
sprayer.
crops, or as a second unit where one machine is used for
insecticides and fungicides and the other for herbicides. The
capacity of a rear-mounted tank or of two straddle-mounted
tanks should not exceed 100 gallons (455 litres). Excessive
weight on the tractor may damage the crop. The boom needs
adequate bracing because it is generally suspended from the
tractor. It should not be more than 30 feet (9 m) long or it will
sway and whip on rough fields and distribute the spray
unevenly.
The SWATHER-MOUNTED FIELD SPRAYER (Figure
19) is often preferred, because you can use the swather
during the off-season. The self-propelled swather frame
makes an excellent base for the sprayer, which may be
25
equipped with either a 100-gallon (455-litre) or a larger
tank. Consult the swather-equipment manufacturer before
using a larger tank or you may overload the swather framework
and wheels. Check your speed of travel carefully and maintain
constant speed for best results.
The FLAT-BED UTILITY SPRAYER is usually carried
in a truck, which provides capacity for large loads and easy
movement over long distances. A truck-mounted sprayer is
not generally used for field spraying because of the low and
uniform speed required for best results.
SPECIAL SPRAYING
TECHNIQUES
Hydraulic spraying, with the use of a water carrier
pesticide that dissolves in water or an emulsifiable
concentrate that forms an emulsion with water, has been
used on Canadian farms for many years. Such solutions or
emulsions have the same viscosity as water, and in a spray
the droplets drift and settle like water droplets. Special
spraying techniques have been developed in an attempt to
reduce the spray drift hazard.
INVERT EMULSIONS form in the sprayer tank when a
small amount of water is mixed into a solution of pesticide,
emulsifier, and oil
(often diesel fuel). A spray with a
consistency like cream is delivered by the nozzles.
BIVERT EMULSIONS are multiphase invert emulsions
that have been developed recently. Special emulsifiers must
and
a
be purchased for each pesticide. The emulsifier is added to a
tank containing diesel oil (ratio 1 :1 4). The pesticide is added
to the water tank. The water phase is mixed with the oil
phase (ratio 6:1) in a mixing chamber on the suction side of
a positive-displacement-type pump (see "Bivert Sprayers").
The pump forces the mixture to special nozzles that deliver a
thick mayonnaiselike spray. This spray is claimed to eliminate
drift.
The manufacturer's directions must be followed
exactly.
A THICKENING AGENT added to the spray mix in the
tank produces a gellike mass that must be pumped by a
positive-displacement pump.
A PARTICULATING AGENT injected into the spray in
the tank produces large particles (containing the pesticide)
at the nozzle. No special equipment, other than the injector,
is required to apply a particulated spray. Considerable care
and skill are required because the acidity and temperature
of the water, as well as other factors, affect the proper
formation of large particles at the nozzle. Drift control with
particulated sprays, as with thickened sprays, is reported to
be excellent.
DRIBBLE BARS have been developed to apply soluble
pesticides where spray application must be precisely
26
controlled. In row-crop spraying the use of a dribble bar and
shields provides a means of applying pesticides to the soil
between rows while protecting the crop in the rows. Dribble
bars operate at low pressure and use large volumes of water.
special DRIBBLE-TYPE NOZZLE, fitted to a vibrating
unit operated by a small direct-current electric motor, has
been used to spray where drift control is critical. The nozzle
at a high frequency to produce a fan-spray
is oscillated
A
pressures of 1 to 6 psi (7-41 kPa) produce
a spray free from droplet drift. The nozzle is fitted with an
adjustable and replaceable sleeve, which allows for various
spray widths up to 3 feet (1 m) from each nozzle. The nozzles,
called 'Vibrajet' nozzles, can be used for spraying between
crop rows or for full-coverage spraying depending on the
pattern.
Low
sleeve used.
AGITATION
pesticides in the form of solutions or emulsions
are being sprayed, the return flow from the bypass pressure
regulator usually is sufficient to mix the contents of the tank.
The return flow should not be less than 10 percent of the
boom output, or not less than /2 gpm (2.25 litres/min), when
the sprayer is operating. The flow should be directed to the
bottom of the tank (see Figure 1 ).
When
1
MECHANICAL AGITATION
has been used satisfactorily
for many years to keep wettable powders in suspension.
Where wettable powders are sprayed often, mechanical
agitation is preferred, and a tank with mechanical agitation
is a good investment.
HYDRAULIC AGITATION will, if properly used, keep
wettable powders in suspension. Do not depend on the
return flow from the bypass pressure regulator. Connect the
agitator line to the pressure side of the pump. Do not connect
the agitator line and agitator nozzles to the line from the
bypass pressure regulator. Make certain that the pump has
sufficient capacity to supply the boom, the agitator line, and
some bypass flow. When installing agitator nozzles (see
"Nozzles"),
follow
the
manufacturer's
recommendations.
The nozzles must be rigidly installed near the bottom of the
tank. As a rule the agitator line will require 3 to 6 gpm for
each 100 gallons of tank capacity (3-6 litres/min per 100
litres) (see "Control of Sprayer Output"). Use the gate valve
in the agitator line (see Figure 1) to restrict flow sufficiently
to prevent foaming in the tank.
SPRAY DRIFT
Herbicide, fungicide, and insecticide sprays may drift
for considerable distances in two ways as very fine droplets
carried by wind; and as vapor from a volatile chemical that.
:
27
when
diffused
in
fairly
calm
air,
may damage
susceptible
plants.
The drift of pesticide sprays is a serious problem. In one
study, drift deposits from droplet drift were measured on the
downwind side of afield sprayed ina10-mph (1 6-km/h) wind
with 8 ounces per acre (560 g/ha) of 2,4-D. The deposits
were 0.29 ounce per acre at 250 feet (20.3 g/ha at 76 m) and
0.15 ounce per acre at 1,200 feet (10.5 g/ha at 366 m).
Measurable deposits were detected 1 mile (1.6 km)
downwind.
The size
of the droplets in a spray varies from very fine
(fog-size and mist-size droplets, less than 100 microns in
diameter) to fairly large (light and moderate rain-size
droplets, 500 to 1,000 microns in diameter). Fog-size and
mist-size droplets drift readily. At low pressure (e.g., 20 psi
or 1 38 kPa), low-volume spray nozzles produce very few fine
droplets (about 1 5 percent by volume). The proportion of fine
droplets in the spray increases rapidly as pressure is increased
to 30 psi (205 kPa) and higher. At 40 psi (275 kPa) the spray
contains an appreciable quantity of fine droplets (about 50
percent by volume). At 60 psi (415 kPa) the spray consists
mostly of fine droplets (about 75 percent by volume). At
pressures of 40 psi (275 kPa) and higher, the drift hazard
is
great.
with herbicides such as 2,4-D has
demonstrated that, when the recommended
amount of chemical is applied in 10 gpa (110 litres/ha) of
Field
research
repeatedly
water,
weed
gpa (34-56
control
is
as
good
as that obtained
when
3 to 5
and crop tolerance is greater.
Do not allow herbicides to drift onto crops, ornamental
litres/ha) are used,
flowers, shrubs, or trees that are susceptible to the chemical.
Do not expose yourself continually to chemical vapors and
drift; operate in a cross breeze if possible. Do not let insecticides drift across garden areas or fields containing forage.
Remember, pesticides can be poisonous to man and animals
and must always be used with great care.
To reduce the
possibility of spray drift:
Apply pesticides in at
pressure of 30 psi (110
10 gpa of solution at a
litres/ha at 205 kPa), or lower
least
the spray pattern is maintained. The control of drift is
more important than the inconvenience of using more
if
water.
Use special spraying techniques where they
applicable (see "Special Spraying Techniques").
are
Do not spray when winds exceed 8 to 10 mph (1316 km/h).
Replace faulty nozzles and clean partly plugged nozzles,
which may cause fogging.
If obtainable, use a chemical that will reduce the vapor
drift.
28
:
.
SPRAYER OPERATION
CONTROL OF SPRAYER OUTPUT
Sprayer output
is
normally governed by four factors:
pressure, and
nozzle capacity, speed of travel, fluid
nozzle spacing (width covered by each nozzle).
Nozzle capacity is the volume of liquid delivered by
1
the nozzle in gallons per minute (or litres/min). Capacity is
determined by
The orifice size of the nozzle
The pressure of the spray solution
at
the nozzle.
gpm
(litres/min) at a specific
pressure. They are sometimes rated in gpa (litres/ha) for field
sprayer use, but such a rating is misleading because it is true
only if the nozzle is used at the specified pressure, spacing,
Nozzles are generally rated
in
and speed.
Fluid pressure affects nozzle output, spray pattern, and
droplet size. Very low pressures produce poor spray patterns,
psi or 275 kPa and higher) produce
will drift. Liquid pressure should be
that
sprays
foglike
fine,
within the recommended range for
but
possible
kept as low as
the work to be done. Do not adjust the pressure to change the
and high pressures (40
nozzle output.
2.
Orifice size
is
an important factor. The nozzle orifice
subject to wear. As the size of the hole increases the amount
of spray material delivered increases and the spray pattern
changes. In a recent survey of 1,171 farm sprayers being
used in Western Canada, 40 percent of the brass nozzles
tested were found to have an increased output of greater than
is
FIGURE
20.
A
low-speed farm
speedometer.
10 percent of
their original rating.
Any nozzle that delivers 10 percent more than it did
when it was new should be replaced because the pesticide
29
not be distributed uniformly on the crop. This lack of
uniformity may result in crop damage and in variations in
pest control.
3.
Speed of travel must be carefully regulated. Any
variation in forward speed changes the number of gallons of
spray material applied to an area. Halving the forward speed
doubles the application volume. Because tractor wheels slip
and truck speedometers cannot be read accurately at speeds
below 10 mph, speed should be calibrated (see "Calibration"). A low-speed farm speedometer (Figure 20) is
available at many automotive supply stores. This type of
speedometer is easily attached to a sprayer, is inexpensive,
and is useful for maintaining a constant forward speed.
4.
Nozzle spacing is usually fixed on field-boom
sprayers but is adjustable on most row-crop sprayers.
To adjust the spray output of a field sprayer, change
the nozzle size, or the speed of travel, or both.
will
The
relationship
between
determine sprayer output
is
shown
the various factors that
in the following formulas
:
For full-coverage field spraying, gallons per acre
5,940
X
gallons per minute (one nozzle)
miles per hour
X
nozzle spacing (inches)
=
or, litres/ha
X litres /min (one
km/h X nozzle spacing
60,000
nozzle)
(cm)
For row-crop spraying, gallons per acre
X gpm
5,940
(one nozzle)
miles per hour
X
litres
X
X row
=
no. of nozzles per
row
spacing (inches)
=
or, litres/ha
60,000
=
/min (one nozzle)
X
no. of nozzles per
row
km/h X row spacing (cm)
For band spraying, gallons per acre
5,940
X
(in
the band)
gallons per minute (one nozzle)
miles per hour
or, litres/ha (in
60,000
X
band width (inches)
the band)
X
litres
=
/min (one nozzle)
km/h X band width (cm)
For a change
in
miles per hour2
gallons per acrei
houn
gallons per acre2
miles per
30
speed only,
or
km/h2
=
km/hi
——
litres
/hai
litres
/ha2
=
:
The correct size of nozzle tip needed for a major
change in the output of a sprayer can be determined by
either of two methods. The first method is to obtain the
information from nozzle performance tables available for
inspection at most implement agencies. Note: These tables
usually list nozzle-tip output in U.S. gallons. To obtain the
output in Imperial gallons multiply the output in U.S. gallons
by 5/6 (or to obtain the output in litres multiply the output in
U.S. gallons by 3.785). The second method is to calculate the
required nozzle output by using the appropriate formula
Two
examples follow.
1.
A field sprayer is used to apply 2,4-D at 10 gpa
at a speed of 4 mph and a pressure of 30 psi (1 1 2 litres/ha at
6.4 km/h and 205 kPa). The nozzles are 20 inches (50 cm)
apart. Use the formula for full-coverage field spraying, which
can be rewritten as follows
mentioned previously.
:
=
Gallons per minute per nozzle
gallons per acrexnniles per hourxnozzle spacing (inches)
5,940
10x4x20
=
0.135
5,940
or,
litres/min per nozzle
x km/h x
litres/ha
=
nozzle spacing (cm)
60,000
112
x
6.4
x
50
=
0.597 litres/min, or 597 ml/min
60,000
A
row-crop sprayer is used to apply 1 50 gpa of
mph and a pressure of 40 psi (1,685
litres/ha at 4.8 km/h and 275 kPa), with five nozzles for each
40-inch-spaced (102-cm) row. Use the formula for row-crop
spraying, which can be rewritten as follows
2.
spray at a speed of 3
=
Gallons per minute per nozzle
gallons per acre
x
miles per hour
5
or,
X
X
3
X
X
40
=
X km/h X row
5
X
X
5,940
,
ftft
O.bl
=
no. of nozzles per
1,685
(inches)
5,940
litres/min per nozzle
litres/ha
row spacing
row
no. of nozzles per
150
x
4.8 X
ztt^tt^
102
row
=
spacing (cm)
X
60,000
..
c
2.75 litres/mm
_,
.
60,000
31
Order nozzle tips with an output as close as possible
the calculated value and within the desired pressure
range. Install the tips and calibrate the sprayer.
to
The capacity of the sprayer pump (gpm or litres/min)
sometimes limits the spray volume (gpa or litres/ha) that can
be applied. The capacity of the pump can be obtained either
from the manufacturer's tables or by measurement.
To measure the pump output:
Disconnect the bypass pressure return line from the
tank, shut off the boom, and connect a handgun to the
pump.
pressure side of the
Operate the sprayer at the desired pressure and at the
proper pump speed for 1 minute. Catch all the water
delivered by the handgun and the bypass pressure
return line. When no handgun is available, catch the
water delivered by all the nozzles on the boom.
Add
the
in
minute
1
number
of gallons (or litres) of water collected
from the bypass pressure return line and the
or all nozzles on the boom to determine the
actual capacity of the pump (gpm or litres/min).
handgun
This measurement will indicate whether the
pump
has
sufficient capacity to handle required spray jobs adequately.
new pump is needed, procure one that has the
If a
highest anticipated volume output. Calculate the required
pump output as follows
:
=
Spray output, gallons per minute
(a)
X
miles per hour
swath width
(feet)
X
gallons per acre
495
or,
litres/min
swath
= km/h X
width (m)
X
litres/ha
600
Allowance
(b)
pass
=
of
25 percent for
—— X
25
pump wear and
by-
spray output
Agitator line requirement (if wettable powders are
to be used) = gallons per minute from one agitator
nozzle X number of agitator nozzles (litres/min X no. of
nozzles)
(c)
Pump
capacity
emulsions
Pump
(a)
+
=
(a)
required
+
capacity required
(b)
+
32
mechanical
spraying
solutions
or
if
hydraulic agitation
is
used
=
(c),
Before you purchase a
of
for
(b).
agitation
for
new
sprayer, consider the use
spraying
wettable
powders.
Mechanical agitators are trouble-free and less expensive than
the larger pumps required to supply the agitator line.
CALIBRATION
There are many ways to calibrate a sprayer, that is, to
determine the volume applied in gpa (litres /ha) The following
method is straightforward, and the calculations are simple:
.
Operate the sprayer to ensure that
properly at the desired pressure.
Check the nozzle performance.
is
it
functioning
the tank about half
nozzle for 1
minute and measure this water in fluid ounces with a
measuring cup. Any nozzle tip that delivers more than
10 percent above its rating should be replaced. Replace
the whole set of tips when measurement indicates
appreciable wear. This will occur after about 100 hours
of use with some nozzles, or after a few hours if brass
tips are used for spraying wettable-powder suspensions.
full
Fill
of water. Catch the output of each
Set out two stakes
the field.
660
feet (40 rods or
200 m) apart
in
Pick a level spot and fill the sprayer tank with water.
Operate the sprayer to ensure that the supply lines and
boom are full before finally filling the tank. Record the
water level on a measuring stick.
between the stakes in both directions at a
speed and pressure; turn the boom on as you
pass the first stake and off as you pass the last stake in
each direction. If the sprayer is not equipped with a
low-speed speedometer (see Figure 20), record the
time required to travel 660 feet (200 m) while spraying
between the stakes. Note the tractor gear used and mark
Spray
definite
the throttle setting.
Carefully measure the amount of water required to
the tank to the original mark on the measuring
stick. This is the amount needed for spraying a distance
refill
of
1,320 feet (400 m).
Calculate the application volume
following formula
gpa by using the
in
:
gallons per acre
gallons of water added
=
boom
X
33
length (feet)
To calculate the application volume
following formula
in litres/ha,
use the
:
litres/ha
Note:
=
of water
litres
:
;
boom
—(m)
— X 25
added
length
Boom
length, as used in this formula, is not the
of the spray boom pipe but that of the spray
swath. For single-coverage spraying, the boom length is
equal to the number of nozzles times the nozzle spacing.
measured length
33
:
The speed
can be determined from the following
of travel
table
Time to travel
660 feet
(min)
(sec)
7
3
2
30
45
30
52
30
14
1
1
1
Forward
speed
(km/h)
Time to travel
200 m
Forward
speed
(mph)
(min)
(sec)
4
6
3
2
5
1
00
00
00
00
30
6
1
12
12
1
2
3
1
2
4
10
6
8
If it is not practical or convenient to use calibration
stakes 660 feet (200 m) apart and a shorter distance is
necessary, use the longest possible distance between stakes
to obtain an accurate calibration. Calculate the ground speed
by using the following formula
:
X
0.682
=
miles per hour
distance traveled (feet)
time (seconds)
or
X
3.6
km/h =
distance traveled (m)
time (seconds)
Calculate the application volume as follows
=
gallons per acre
X
gallons of water added
boom
length (feet)
or litres /ha
The following
=
boom
12
when
the application volume
X
33
40
a
40-foot (12.2-m)
"
54.5
X
(boom
6
=
25
X
length)
36
=
112
12 .2
six
litres/ha
rows and the row
total
width of the spray
is
iQ
18
x
+
6
feet, or
12
-
X
..
90
- =
5.4
100
m
and, if 16 gallons (72.7 litres) of water are required to
the tank, the application volume is
16
X
18
34
33
=
on
the
111.7 litres/ha or
'
row-crop sprayer covers
36 inches (90 cm), then the
is
pattern
boom
refill
is
a
If
width
9 pa or
"
for
the calibration stakes are
2 gallons (54.5 litres) of water are required to
1
tank,
length
boom-type sprayer has
a
If
X 25 X 400
(m) X distance (m)
added
sample calibration calculations
different types of sprayers,
660 feet (200 m) apart.
and
1,320
distance traveled (feet)
litres
-
are
X
x
33
29.3 gpa, or
72.7 X 25
^-7- 5.4
ooc
= 336.5
.
,.
+
refill
,
litres/ha
band sprayer has four nozzles and each nozzle
If a
covers a 14-inch (35-cm) band, the total width of the spray
pattern (boom length) is
4X14
=
._
12
and,
if
,
4
.
4.7 feet, or
"
—=
X
35
,
1
m
„
.4
100
'
2 gallons (9 litres) of water are required to
tank, the application
=
volume
4.7
the
is
9
1
refill
25
*
4.0 gpa,
or
"r
=
60
1
litres/ha
1.4
In band spraying, the area actually sprayed is not the
as the field area. Recommendations in publications on
pest control are based on acres (hectares) actually sprayed.
The field area covered by each tankful of spray material can
be calculated as follows
Note:
same
:
X row
no. of gallons in tank
application
volume (gpa)
no. of
litres in
X
tank
or
application
volume
width (inches)
band spray width (inches)
X
row width (cm)
X
(litres/ha)
band spray width (cm)
If the band sprayer previously mentioned had 82 gallons
(373 litres) of spray mix in the tank and was used on 36-inch
(90-cm) rows, the field area that could be sprayed with
the 82 gallons (373 litres) would be:
82
X
36
14X14
=
X
X
373
ic
1 5 acres, or
160
'
—90
=
-
6 ha
35
the calibration discloses that the sprayer output
requires adjustment, change the speed of travel.
If a
row-crop sprayer traveling at 5 mph (8 km/h)
applies 29.3 gpa (330 litres/ha) and a more desirable
application volume is 40 gpa (450 litres/ha), calculate a
new speed by using the following formula
If
:
Required speed (mph)
=
present speed (mph)
X
present output (gpa)
desired output (gpa)
.,_
,
present speed (km/h)
X present output
(litres/ha)
desired output (litres/ha)
The new speed
5
will
X —29. 3 =
40
be:
_
Q
3.66
mph, or
,
8
—
X——330 =
450
_ Qft
5.86
.
.,
km/h
Pull the sprayer past the calibration stakes to check
the speed setting and the sprayer output. Maintain the
same pressure and the same forward speed in the field
as were used during the final calibration run.
35
If
adjustments in speed fail to provide the desired
spray volume, then you need different nozzle tips (see
"Control of Sprayer Output").
CALCULATION OF SPRAY MIXTURES
Agricultural extension workers usually express the
quantity of chemical needed to control a weed, insect, or
disease as the amount of the active ingredient or acid
equivalent; but directions on the can or package may be
given in amounts of the product. The label on the can or
package also indicates the amount of actual chemical in a
gallon or pound of the product. Two simple formulas allow
the conversion of active ingredient (or acid equivalent)
recommendations to ounces or pounds of commercial
product. If the active ingredient content of a liquid product is
given on the label in ounces or pounds, use this formula
:
Ounces
(fluid) of
commercial product per acre
ounces active ingredient recommended per acre
X
ounces active ingredient per gallon
or in metric units
Litres of
=
160
:
=
commercial product per hectare
active ingredient
recommended (g/ha)
active ingredient in product (g /litre)
If the active ingredient content of a dry powder product
given on the label in percent, use this formula
is
:
Pounds
pounds
of
commercial product per acre
active ingredient
recommended
=
per acre
X
percent active ingredient
or: Kilograms of
commercial product per hectare
active ingredient
recommended
(kg /ha)
100
=
100
percent active ingredient
Mixing instructions are usually given on the label, but the
mixing proportions can be calculated as in the following
examples.
A
ounces acid equivalent
of 2,4-D per acre (420 g/ha). The commercial product
contains 64 ounces (i.e., 4 pounds) acid equivalent per
gallon (2 kg in a 5-litre can, or 400 g /litre). The application is
to be made at TO gpa (112 litres/ha) and the sprayer tank
holds 200 gallons (1,000 litres). The amount of commercial
2,4-D required is 6/64 X 1 60 = 15 fluid ounces for each
acre (420/400= 1.05 litres/ha). Each 200-gallon tankful
will spray 200/10 = 20 acres (a 1,000-litre tankful will spray
1,000/112 = 8.9 ha). Therefore each tankful requires
20 X 15 = 300 fluid ounces or 300/160 =17/8 Imperial
36
cereal crop
is
to be sprayed with 6
gallons of commercial product (1.05
An 80
percent wettable powder
X
is
8.9 = 9.345 litres).
to be applied at the
pounds active ingredient per acre (2.25 kg /ha) in a
band. The row-crop sprayer applies the wettable-powder
rate of 2
at the rate of 15 gallons per sprayed acre (170
and the tank holds 90 gallons (400 litres). The
bands are 10 inches wide on 24-inch row centers (22 cm
wide, 60-cm centers). The amount of commercial product
required is 2/80 X 100= 2.5 pounds per acre (2.25/80
X 100 =2.81 kg /ha), the number of sprayed acres per
suspension
litres/ha),
90-gallon
90/15=6
(per 400-litre tankful,
tankful requires 6
25 =
2.81 = 6.6 kg). The field
area that can be treated with the 90 gallons of spray
is
90/15X24/10=14.4 acres (with 400 litres it is
400/170
60/25 = 5.65 ha).
tankful
is
400/170 = 2.35 ha), and each
15 pounds of product (2.35 X
X
X
CARE OF THE SPRAYER
Before using the sprayer, clean
all dirt,
sludge, and scale
from the tank, pump, hose lines, boom screens, nozzles, and
handgun. Plugged nozzles do a poor spraying job. Check the
sprayer thoroughly for worn parts. Examine the pump and
recondition it if necessary. Follow the manufacturer's
instructions on pump lubrication. Check the pressure gauge,
and if its accuracy is doubtful replace it. Be sure that all boom
supports and braces are in good condition and are adequate
to give proper support in the field. Examine all hoses and
connections for leaks, especially the suction hose. An air
leak in the suction line seriously interferes with the operation
pump.
Mix chemicals thoroughly with clean water. Dirt plugs
nozzles and screens and causes rapid pump wear. Use a
strainer on the suction line when you fill the tank from a
of the
stream, or storage reservoir. Make certain that the
on the end of the suction line is suspended in the
water so that it will not be in contact with sand and debris.
The use of a check valve in combination with the suction
strainer will prevent siphoning of the chemical mixture out of
the tank back into the ditch, stream, or storage reservoir.
Adjust the height of the field boom and align fan nozzles
to overlap spray patterns about 2 inches (10 cm) above the
crop (Figure 10). On a row-crop sprayer adjust the boom
height to cover the tops of the plants with spray from the
overhead nozzles. Adjust the height of the drop pipes and
the angle of the swivel nozzles to cover the plants with
spray from the sides (Figure 1 3).
Calibrate the sprayer at least once a year and always
operate it at the calibrated speed and pressure (see "Calibraditch,
strainer
A variation of 1 mph or of 10 psi (1.5 km/h or of
69 kPa) can seriously change the rate of most applications. Do
not travel faster than about 5 mph (8 km/h) because highspeed operation greatly increases boom sway and whip.
tion").
37
Clean the sprayer daily after each use by flushing the
pump, and hoses thoroughly with clean water. Clean
the filter, screens, and nozzles. Drain the tank and allow it to
dry. The tank may be slowly corroded by some chemicals.
Regular cleaning is a worthwhile safeguard.
Use a toothbrush or other soft material to clean a
nozzle tip. Never use a piece of wire, a nail, or other metal
object because these will damage the orifice, distort the
spray pattern, and greatly increase the nozzle's output.
At the end of the season, store the sprayer properly.
After decontaminating it, drain the tank, hose lines, pump,
and boom; then clean and reassemble the filter and screens.
Protect a steel tank with an oil or kerosene coating. Follow
the manufacturer's recommendations for storing the pump.
tank,
DECONTAMINATION
A sprayer used for herbicides should not be used to
apply an insecticide or fungicide to a crop that is sensitive
to herbicides. Minute traces of a herbicide that remain in
the tank and hoses after ordinary cleaning can cause damage.
If, in an emergency, the herbicide sprayer must be used for
applying insecticides or fungicides, decontamination of the
equipment will provide some assurance against crop damage.
Furthermore, because some fungicides and insecticides are
highly
poisonous, decontamination is a wise safety
precaution.
If a pesticide in emulsion form has been used, flush
out the tank and system with clean water. Fill the tank and
system with a mixture of household ammonia and hot water
(1 gallon to 100 gallons or 1 :100). Recirculate the solution
through the pump for several minutes. Leave the solution in
the machine overnight. Again recirculate the cleaning
solution, completely drain the tank and system, rinse
thoroughly with clean water, and dry out the tank and other
parts of the sprayer.
Alternative cleaning solutions are:
washing soda per 100 gallons of water
kg per 500 litres). Clean the sprayer in the same
(1
manner as described for ammonia.
2
pounds
of
percent solution of commercial activated charcoal.
Wash the sprayer for about 2 minutes and rinse thoroughly. This method is fast but expensive.
1
water-soluble herbicide or a wettable-powder
pesticide has been used in the sprayer, flush out the tank and
system with clean water. Scrub the tank thoroughly with a
detergent solution and run it through the system. Rinse out
this solution and use the ammonia or soda treatment
previously mentioned.
Hoses can become so saturated with chemicals that
they cannot be decontaminated. Use separate handgun
hoses for herbicides and for other chemicals and never use
these hoses for conveying drinking water.
If
38
a
: :
Consult provincial publications for advice on the disposal of spray mixtures drained from sprayers, rinse solutions,
chemical containers, unused chemicals, and contaminated
hoses.
RECORDS
Records of calibrations and spraying operations are
very useful for any sprayer operator and are essential for a
custom operator.
The record of calibrations will indicate, by comparison,
when sprayer nozzles are worn enough to need replacing.
The following type of record has proved useful
RECORD OF CAUBRATII
FORWARD
DATE
SPEED
(MPH)
(km
GAL. TO
REFILL
APPLIC.
PRESSURE
(PSI)
TANK
(GPA)
(kPa)
(litres)
(litres/ha)
REMARKS
RATE
v
A
record
of
spraying
operations
is
V
becoming more
essential, especially for the sprayer operator covering a large
area of his own or customers' land. Such a record is
useful if spraying operations later result in some legal action.
A type of record that has proved useful follows
DATE
AND TIME
RECORD OF SPRAYING OPERATIONS
AREA
SPRAYER
PESTICIDE USED
SPRAYED
MPH PSI GPA
PRODUCT
AMOUNT
(ACRES)
(km/h) (kPa)
(litres/
(ha)
hai
TEMP.
F
(°
C
)
MPH
(km/h;
<t
ACKNOWLEDGMENTS
The authors thank the following
illustrations in this publication
for
permission
to
use
:
McGraw-Hill Book Co. (Pump Selection and
Application, by T. G. Hicks, 1957)
Figures 4 and 7. John Brooks & Co. Ltd.
Figure 5. Niagara Brand Chemicals
Figure 12. National Sprayer and Duster Association
Figure
3.
39
The Ontario Department
of Agriculture and Food supplied
the prints of these figures.
We are grateful to Mr. H. J. Mather for his contribution
to Canada Department of Agriculture Publication 1157
(1963), and members of the Ontario Herbicide Committee for their contributions to the Ontario Department
of Agriculture and Food
Publication 256 (1966).
Material from both these bulletins has been used in
this publication.
GLOSSARY
FLUID
MEASURE
Imperial Fluid
20
fluid
Measure
ounces =
2 pints
=
1
1
pint
quart
1 gallon
4 quarts =
Measure
16 fluid ounces
= 160 ounces
U.S. Fluid
= 1
quarts =
2 pints
4
=
1
pint
quart
1 gallon
= 128 ounces
Metric Fluid Measure
1
litre = 1,000
Conversion Factors
millilitres
(ml)
= 1.2 U.S. gallons = 4.546 litres
= 0.833 Imperial gallon = 3.785 litres
1
Imperial gallon
1
U.S. gallon
MEASURES OF AREA AND DISTANCE
rod = 16 /2 feet = bY2 yards = 5.029 metres
1
acre = 160
square rods = 4,840 square yards = 43,560
square feet = 0.405 hectare
1 mile = 320 rods = 1,760 yards = 5,280 feet = 1 .609 kilometres
1
metre (m) = 100 centimetres (cm) = 1,000 millimetres (mm)
1
kilometre (km) = 1,000 metres
1
hectare (ha) = 10,000 square metres (m 2 )
1
1
MEASURES OF SPEED
mph — miles per hour;
km/h — kilometres per
rpm
—
1
mph = 88 feet per minute = 1.609 km/h
hour; 1 km/h = 16.7 metres per minute
revolutions per minute
power takeoff; standard PTO speed is 540 rpm, but some
tractors are equipped with 1,000-rpm PTO shafts.
PTO —
SPRAYER TERMS
— gallons per acre
per minute
pounds
square
per
—
—
—
gpa
litres/ha
gpm — gallons
litres/min
inch pressure
6.89 kPa
kPa— kilopascal (1,000 pascals) 1 Pa = 1
psi
pressure)
;
1
psi
litres
=
;
40
per hectare
per minute
(often called
litres
N/m
2
pounds
CONVERSION FACTORS FOR METRIC SYSTEM
Approximate
Results
conversion facto r
Imperial units
in:
LINEAR
25
30
inch
x
foot
x
yard
mile
xO
x
(mm)
(cm)
metre (m)
9
6
1
millimetre
centimetre
kilometre
(km)
square centimetre
square metre
hectare
(cm 2
(m 2)
cubic centimetre
cubic decimetre
cubic metre
(cm 3
(dm 3
(m 3
(mi)
U)
AREA
square inch
square foot
x
6 5
x0 09
xO 40
acre
)
(ha)
VOLUME
cubic inch
cubic foot
cubic yard
x
16
x
28
xO
8
x
28
pint
x
0.57
quart
gallon
x
1
.1
litre
x
litre
bushel
x
4 5
36
hectolitre
28
45
kilogram
fluid
ounce
millilitre
litre
)
)
)
iO
(O
(h*)
WEIGHT
ounce
pound
x
x
short ton
(2000
xO
lb)
gram
tonne
9
(g)
(kg)
(t)
TEMPERATURE
°F-32 xO 56
°F-32 x 5/9)
degree fahrenheit
(or
degree Celsius <°C)
PRESSURE
pounds per square nch
x
6 9
x
746
kilopascal
(kPa)
watt
(W)
(kW)
POWER
horsepower
75
kilowatt
xO 30
metres per second
kilometres per hour
x
SPEED
feet per
second
miles per hour
1.6
x
(m/s)
(km/h)
AGRICULTURE
bushels per acre
gallons per acre
quarts per acre
pints per acre
fluid ounces per acre
tons per acre
pounds per acre
ounces per acre
plants per acre
Examples: 2 miles
x
1
6
==
xO 90
23
x
1
x
2.8
1.4
x
x
1
70
24
x 2
112
x
x
x
70
2 47
32 km,
1
5 bu/ac
hectolitres per hectare
litres
litres
litres
millilitres
tonnes
kilograms
grams
plants
per
per
per
per
per
per
per
per
xO 90=13 5h//ha
hectare
hectare
hectare
hectare
hectare
hectare
hectare
hectare
(h«
ha)
U'/ha)
U
1
ha)
(£/ha)
(m£/ha)
(t/ha)
(kg /ha)
/ha)
(plants/ ha)
(g
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