Ulva+ training notes for water based spraying (PDF 2786 Kb)

Ulva+ training notes for water based spraying (PDF 2786 Kb)
Always wear the best
protective clothing available
Always hold the sprayer
Always start at the downwind
edge of the field
Only spray if there is a cross
Never spray if there is no wind
Walk every three lines
Apply 10 litres (2 backpacks) of
spray per hectare
Always clean the sprayer and
remove the batteries after use
Only 10 litres water needed per
Only 1 hour to treat 1 hectare
Light to carry - only 5 Kg on
No pumping needed
To check contacts and connections
Check that the switch, switch end piece and centre connector are
clean and free of corrosion. Clean with a wire brush or knife if
necessary. If the brass screw on the switch is worn rotate it slightly
to expose an unworn part of the thread.
Check that the large spring which connects to the battery case is free
from corrosion. Clean if necessary.
Check the connections between the wires and the connecting screws
at the base of the motor. Clean if necessary.
When replacing the spray head ensure that the small nylon air vent
tube is correctly replaced within the extension tube.
1. Introduction and advantages of ULVA+
The ULVA+ is a new type of sprayer which is robust and easy to use.
Compared with a knapsack pump type sprayer the ULVA+ has several
important advantages.
Only 10 litres of water are needed to treat one hectare of a crop
such as cotton. This compares with between 200 and 300 litres
generally needed if using a knapsack sprayer.
Using the ULVA+ a single person working alone can treat one
hectare in around only one hour. This compares with around 8
hours needed if using a knapsack pump type sprayer.
The ULVA+ is very light to carry and easy to use as you carry
only 5 litres on your back (compared with 15 using a knapsack
sprayer) and no pumping is needed.
16. Basic Repairs
To replace the motor
Remove the atomiser disc and the nozzle.
Remove the motor front plate by undoing the four screws in the
motor housing and detach the front part of the motor housing.
Grip the motor by the shaft and pull to remove from the motor
Check the motor for signs of corrosion. The motor can be checked
using a battery.
If necessary replace the motor and, the two o-rings which seal the
motor and the two terminal connecting springs. When refitting the
motor make sure that the positive terminal (indicated by a small
mark) connects to the red wire and the terminals are correctly
aligned with the terminal connecting springs in the motor housing.
Replace the motor front plate, nozzle and atomiser disc.
To prevent corrosion of the motor during storage, after the spraying
season has finished, remove the motor and dry it by leaving in the sun
for a few hours. Put one small drop of oil on the bearing of the shaft
and reassemble, making sure that the motor housing is dry and the orings and terminal connecting springs are in good condition.
2. Background to droplet size and importance
The object of any chemical application is normally to spread evenly a
relatively small quantity of chemical over a relatively large area of
crop. To do this two things are generally used water and a sprayer.
The job of the water is to allow a small amount of chemical to be
spread. We must remember that water in itself does not kill insects
or weeds. The job of the sprayer is to break up the spray mix (water
plus chemical) into droplets so that it can be spread around the field
more easily. The smaller the size of droplet used the more droplets
can be obtained from the spray used.
However, the size of droplet also determines how far it is carried in
the wind with smaller droplets being carried further than larger
droplets. Smaller droplets, however are also more prone to
evaporation if a water based spray mix is being used and hence we
must select a droplet which is small enough to give us good coverage
of the crop and be carried by the wind to the crop but not so small
that it will evaporate before reaching the plant canopy.
Atomiser disc spins but does not spray or sprays
Feed nozzle blocked
Remove feed nozzle and check and
clean if necessary. Use a piece of
grass or soft wire - Do not blow
through nozzle
Atomiser disc is caked with dried
Remove and clean as necessary
The spray bottle is incorrectly fitted
or over-tightened
Remove and refit correctly
The threads in the spray bottle
Check and replace if necessary
holder and spray bottle are damaged
Liquid leaks from the spray head
Spray bottle not fitted properly
Remove and refit correctly
Flow valve from backpack is open (if
refilling system used)
Close flow valve
Feed nozzle or nozzle seal damaged Remove, check and refit or replace as
or incorrectly fitted
Filling cap (on twin neck bottle) is
incorrectly fitted or cap seal
Refit bottle or replace cap seal as
3. CDA - Principle and Advantages
Atomiser disc fails to spin or spins intermittently or slowly
Batteries incorrectly inserted
Check all batteries are fitted negative
(i.e. flat) end first
Batteries low or dead
Replace batteries
Worn switch screw
Check switch screw for wear and rotate
using to expose new thread if
Worn switch end piece
Check switch end piece for corrosion
and clean if necessary
Corroded or loose terminal
Check and clean terminal connections
Corrosion on battery case spring
Check battery case spring and clean if
Atomiser disc rubbing on motor
base plate - either atomiser disc or
motor damaged
Check disc and motor and replace if
Motor damaged or corroded
Remove motor - check and replace if
Motor terminal springs corroded
Check and replace if necessary
Wiring loose or corroded
Check and replace wiring if necessary
A knapsack type of sprayer breaks up the spray liquid into droplets (a
process known as atomisation) using what is known as a hydraulic
nozzle. With this type of nozzle it is difficult to control the size of the
droplet produced. A large number of big droplets are produced and
hence in order to get enough droplets to give good coverage all over
the field a high volume of water is needed - generally 200-300 litres
per hectare.
The ULVA+ uses a different method to break up the spray liquid into
droplets. It uses a rotary atomiser or spinning disc and the principle is
the same as a car tyres on a wet road which produce a fine mist of
spray. This method of producing droplets means that they are all
around the same size. The faster the speed that the disc rotates, the
smaller the size of droplet is produced. By spinning the disc at a fast
speed we can produce only small droplets which give better coverage
of the crop and field than large droplets. Because the coverage from
smaller droplets is better this means that the amount of water needed
to spread the chemical around the field is less and instead of 200-300
litres of water being needed to spray a hectare, we normally only
need 10 -25 litres of water. The amount of chemical needed,
however, remains the same - only the amount of water used is
Atomisation appears poor or intermittent with irregular or
overlarge droplets being produced
Motor turning slowly
Check batteries and connections as
Atomiser dirty or caked with dried
Remove and clean as necessary
Teeth on atomiser disc worn or
Replace atomiser disc
1 Litre Spray Bottle
Head Locking
14. Cleaning storage and maintenance
Metal Handle /
Battery Case
First spray out any remaining chemical into the crop or dispose of it as
you have been instructed by your extension staff.
To clean the sprayer half fill the backpack with water and shake it to
clean. Then half fill the spray bottle from the backpack to clean the
refilling tubes and, holding the head of the sprayer close to the
ground, spray out for a minute or two to clean the nozzle and disc.
Empty out the backpack and repeat using clean water.
Nozzle Holder
Extension Tube
After spraying it is important to clean the ULVA+ properly. If the
ULVA+ is looked after properly it will last for many years.
On / Off
From time to time remove the nozzle and disc in clean using water.
The grooves in the disc should be cleaned using an old brush
particularly if powders have been used through the sprayer.
You should never try to clean the head of the sprayer by
putting it in water as this will destroy the electric motor.
Wipe down the sprayer completely using a damp cloth and make sure
that the bottle and backpack are completely empty.
After spraying the batteries should be removed otherwise they could
leak and damage the sprayer. After removing the batteries collapse
the sprayer and replace the protective cover on the atomiser disc.
The sprayer should then be stored in a dry place, out of direct
1 Litre Spray
Head Adjuster /
Locking Sleeve
Bottle Holder
Feed Nozzle
Fixing Nut
Feed Nozzle
Motor In
Disc fixing
4. Main features of the ULVA+
The accompanying diagram shows the main features of the ULVA+
The spray head
An aluminium handle which carries the batteries and
The extension tube which joins the spray head to the handle
The most important part of the ULVA+ is the spray head where the
spinning disc is located. This disc breaks up the spray liquid into small
droplets a process known as atomisation and hence it is called the
atomiser disc. Spray liquid flows from a one litre spray bottle by
gravity through the feed nozzle onto the atomiser disc. The disc is
rotated by an electric motor, and the spray liquid is thrown off the
edge of the disc in the form of fine spray droplets.
The atomiser disc has small teeth around its edge in order to help
droplet production and it is important that these are not damaged.
For this reason you should always fit the protective cover when the
sprayer is not being used and the batteries are removed. The
atomiser disc can be removed by unscrewing the plastic screw which
fixes it in place with one hand while stopping the disc from turning
with the other.
The feed nozzle can be removed by unscrewing the fixing nut. If doing
this take care to ensure that the nozzle seal stays in position.
The angle of the spray head can be adjusted depending on the height
of the crop and locked into place by using the head locking sleeve.
The spray head is attached to the handle by an extension tube, which
allows the ULVA+ to be collapsed for transport.
The handle is an aluminium tube which contains the batteries and at
the end of which is the on/off switch for the sprayer. Spare nozzles
are kept in a holder on the handle.
13. Spraying - Very Low Volume
Go to the downwind edge of the field and count three rows from the
If using a backpack, fill the one litre spray bottle from the backpack.
Switch the sprayer on and check that the disc is spinning. It should be
possible to hear this.
Hold the sprayer downwind with the spray head between 75 cm and
one metre above the top of the crop. It is important to hold the
sprayer well above the top of the crop as this ensures that several
rows are covered with each pass. If the spray head is not held high
enough above the top of the crop then some rows will not receive
enough spray and others will receive too much. Remember, although
generally we spray every three lines, ideally the wind will take the
spray four or five lines so that good overlap occurs and all the cotton
rows are sprayed.
Turn the sprayer over so that the bottle is above the disc. Spray mix
will then flow through the feed nozzle and onto the disc. It should be
possible to see a spray cloud form which is carried by the wind into
the crop. Start walking. From time to time check that the spray is
being carried away from you into the crop by the wind. If the wind
stops or changes direction then stop spraying immediately.
At the end of the row stop spraying by first turning over the sprayer
so that the spray bottle is underneath the disc and the spray liquid
stops flowing and then turn off the sprayer at the switch.
Move three rows upwind and turn to pass back down the field.
Change the direction of the sprayer to make sure that the spray head
is again pointing downwind. This is done by swapping over the
position of your hands so that it points downwind and resume
spraying. Continue in this way until the whole field is covered.
5.The refilling system
If the ULVA+ is being used for very low volume treatments spraying a
water-based spray mix it is normally supplied with a quick refilling
system. This consists of a five litre backpack and a refilling tube with
tap which connects to the refillable 1 litre bottle on the spray head.
The backpack has a wide neck to make it easier to fill without spilling
and a filter. The cap is fitted with an air bleed which allows air to
enter the tank without liquid escaping and a cork seal to prevent
When the backpack is supplied the refilling tubes and the straps are
inside the tank and these must be fitted before use.
Fit the wider tube (with the tap at one end) to the outlet at the
bottom of the backpack and secure it using the metal clip provided.
Then connect to the narrow tube to the other end of the tap and the
refilling point on the bottle and clamping it to the bottle using the
small plastic clip provided.
The straps do not need buckles but are fitted through the attachment
loops on the backpack as shown. It is generally more comfortable to
cross the straps as shown.
To fill the 1 litre spray bottle from the backpack, hold the sprayer so
that the bottle is on the ground and open the tap. Liquid will flow by
gravity from the backpack into the bottle. Close the tap before the
spray bottle is completely full.
In general if spraying with 5 batteries and applying at a volume of 10
litres per hectare it will be possible to cover 2 to 3 metres with each
spray pass. If spraying cotton planted in rows of 75-90 cm spacing this
will mean that it should be possible to spray three rows with each
pass. Ideally although we only walk every three rows the spray will be
spread over four or five rows. This ensures that we get good
overlapping coverage and that every part of the field is sprayed.
You should always start spraying at the downwind edge of the field
and work progressively upwind with each spray pass. This means that
you are always walking in cotton which has not yet been sprayed and
you do not contaminate yourself from chemical already sprayed on
the cotton.
Remember although you walk and spray down every third
line the aim is to cover more than three lines to ensure an
overlap of successive sprays and no gaps in coverage over the
6. Chemical handling and safety
Chemicals used to control pests and diseases of crops are poisons and
care must therefore be taken when handling them. This includes
transport, storage, mixing and spraying.
Chemicals can poison the user in various ways, including:
Taking up through the skin
Breathing of spray through the mouth and nose
Taking in through the mouth
When using chemicals it is very important that you do everything
possible to prevent taking in chemical through any of these routes.
To protect the skin make sure that any part of your skin which might
become contaminated by chemical is covered. Ideally this means that
you should wear gloves, overalls, boots or shoes and a hat. If it is not
possible to obtain this clothing then it is important to protect yourself
as best as possible. Wear long trousers and a long-sleeved shirt for
spraying. If no gloves are available make sure that you wash your
hands thoroughly with soap and water both after mixing and after
spraying, especially if they have become contaminated. Make sure that
all clothing is thoroughly washed after spraying.
To protect against breathing in spray a mask should be worn. If this is
not available then a piece of cotton cloth wrapped around the nose
and mouth should be worn instead. This should be washed regularly.
To prevent chemicals entering through the mouth make sure that you
wash your hands thoroughly before eating or eating or smoking.
Remember - any chemical on your hands will be transferred to the
11. Spraying Technique - Very Low Volume
Remember, the droplets produced by the ULVA+ are small
and the spray mix is concentrated so care must be taken to
avoid contamination. It is important with the ULVA+ that the
correct spraying technique is used otherwise contamination will
Because the ULVA+ produces small droplets the wind can be used to
take the spray into the crop and rows do not have to be sprayed
individually. This does mean, however, that spraying must only be
carried out when there is a wind blowing.
Never spray if there is no wind.
For reasons of both safety and in order to get best coverage of the
crop spraying should only be carried out when there is a cross wind.
This ensures that the spray is taken away from the operator and best
coverage of the crop is obtained.
The ULVA+ should always be held downwind when spraying
other wise you will contaminate yourself.
Spraying is best carried out either in the morning or the evening as at
these times the temperature is cooler and the humidity higher. At
these times, also, the wind will probably be steady in both strength
and direction.
food or cigarette that you touch and go directly into your stomach.
As a general precaution make sure that chemicals are stored correctly
and keep them out of the way of children - in a locked place if
possible. Do not put chemical into bottles or containers used for
food or drink or use kitchen equipment for mixing or measuring
During spraying you must be aware of where the spray is going and
who or what it might be contaminating. Make sure that you are not
spraying other people or animals by mistake. If the wind changes in
direction and you start to get sprayed yourself, stop spraying
Remember - chemicals are safe if used properly but it is up
to you to make sure that you protect yourself
10. Chemical mixing - Very Low Volume
The process of mixing up the spray to use is a potentially dangerous
job as concentrated chemical is involved.
You should always wear gloves if available, when measuring out and
mixing chemical. If gloves are not available then make sure that you
wash your hands thoroughly with soap and water afterwards. Torn
gloves should not be used as these can allow chemical to come into
contact with the skin and then trap it close to the skin causing greater
contamination than if no gloves at all are worn.
To prepare chemicals for use with the ULVA+, using the 5 litre
backpack, either use the amount indicated on the label of the chemical
bottle for a five litre mix (half a hectare) or else calculate this as
First make sure that the tap in the tube between the backpack and the
spray bottle is in the closed position. Half fill the backpack with clean
water, making sure that the filter is in the neck of the tank. The filter
is important to trap any large particles in the water which might
otherwise block the nozzle.
Measure out and add the correct amount of chemical as calculated
and fill the backpack up to the 5 litre mark with water and replace the
cap making sure that it is well tightened.
Shake the backpack to make sure that the chemical is well mixed,
wipe down the outside and check for leaks.
If you are using powder formulations or chemicals which do not
dissolve easily these should first be mixed in a bucket before
transferring the solution to the backpack and filling with water. It is a
good idea to filter the mixture into the backpack through a fine cloth
to remove any undissolved powder.
After mixing clean all equipment.
6. Calculating the spray mix
Clear instructions may be available either through the extension
service or else on the label of the chemical bottle regarding the
amount of chemical needed and the correct nozzle to use. (e.g. put
50 ml of compound X into the 5 litre backpack, fill up with water and
fit the black nozzle to spray every 3 rows.)
If not, then you may need to calculate the amount of chemical needed.
In general the ULVA+ is used to spray insecticides using 10 litres of
spray mix per hectare. This means that a five litre backpack is enough
to spray half a hectare.
Remember with the ULVA+ we use the same amount of
chemical per hectare but reduce the amount of water.
For example; if the chemical label states that we use 500
ml of chemical per hectare , for half a hectare mix 250 ml of
chemical with 4 750 ml of water in the 5 litre backpack.
Walking speed
Flow rate
Total Spray volume
Spray pass interval
WS (m/s)
FR =
= WS
= FR
9. Preparing for spraying - VLV
Remove the protective cover from the disc and extend the sprayer.
Fit the bottle to the bottle holder taking care not to overtighten. The
filling point should line up with the extension tube.
To insert the batteries, first remove the switch end piece. This is
done by removing the switch as as shown and then removing switch
end piece.
FR (ml/min)
6 x SPI (m) x TSV (l/ha)
Fit five torch batteries into the handle of the sprayer, making sure that
they are inserted flat end, that is negative end, first.
6 x WS (m/s) x SPI (m)x TSV (l/ha)
Replace the switch end piece and switch. As there is a spring in the
battery case, it will be necessary to hold the switch end piece in place
as the switch is reinserted.
Check that the batteries are fitted correctly by turning the switch to
the on position. You should be able to see and hear the disc spinning.
Adjust the angle of the head to suit the height of the crop. This is
done by partially unscrewing the wing nut which holds the head fixing
mechanism in place and moving the head to a suitable angle before
locking it in place and re-tightening the wing nut.
The head should be angled back if the crop is short (i.e. on the top
notch of the adjuster) and forwards if the crop is tall (i.e. on the
bottom notch of the adjuster) as shown. For best results the nozzle
should be kept as close to vertical as possible when the head is in the
spraying position.
Assemble the tank and mix up the spray mixture as described.
The ULVA+ is now ready to start spraying.
Flow rate with
water (ml/min)
Red Black
8. Calibration
If clear instructions are not given either on the label or from your
extension worker, it may be necessary to calibrate the sprayer.
The amount of spray applied depends on three things:
The flow rate of the sprayer - i.e. how much comes out of the sprayer
each minute
The speed at which you walk
The distance between successive spray passes
These are related by the following equation:
Walking speed (m/s) =
flow rate (ml/min)
6 x distance between spray passes (m) x total spray
volume (l/ha)
These can all be measured and changed if necessary
Flow rate
The flow rate depends on the colour of the nozzle fitted and the
viscosity or thickness of the mixture being sprayed. As chemical
mixtures are often thicker than plain water flow rates should be
measured using the actual spray mix rather than just water.
To check the flow rate, remove the atomiser disc and measure the
amount which flows through the nozzle in one minute.
This table shows the flow rate of the range of nozzles using water
Walking speed
A normal walking speed through a crop can be reckoned to be 1
metre per second.
Example 1
Distance between spray passes
Row spacing = 80 cm
In general this is controlled by the distance between the rows of the
crop. For example if the space between the rows is 80 cm, then the
distance between spray passes can be 80 cm, 1.6 m, (2 x 80), 2.4m (3
x 80) or 3.2m (4 x 80). In general with 5 batteries fitted, the spray
will cover 2-3 m, so we spray 3 rows at a time.
Volume application rate = 10 l/ha
Walking speed = 1m/s
If we spray 3 rows at a time the distance between spray passes will be
Flow rate needed = 6 x 1 x 2.4 x 10 = 144 ml/min
Select the BLACK nozzle (nominally 150 ml/min with water) and
confirm that the flow rate with the spray mix to be used is suitable.
Example 2
Row spacing = 95 cm
Although the distance between the spray passes and the flow rate can
be changed they cannot be controlled absolutely. You must select the
most appropriate nozzle and then walk at a speed which gives the
correct application rate.
With experience you will learn the correct walking speed for the
particular product used, nozzle fitted and row spacing of the crop.
For example if after spraying an area known to be ½ a hectare there
is still spray mix left in the 5 litre backpack then your walking speed
was too fast. Alternatively, if the spray mix runs out before the area
is sprayed then the walking speed was too slow.
Volume application rate = 10l/ha
Walking speed = 1m/s
3 rows sprayed at a time - distance between spray passes = 3 x .95 =
Flow rate needed = 6 x 1 x 2.85 x 10 = 171 ml/min
Select the GREY nozzle (nominally 175 ml/min with water) and
confirm that the flow rate is suitable
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