Calibration of Hand Held Sprayer Equipment

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Calibration of Hand Held Sprayer Equipment
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Calibration of hand held spraying equipment -
summary

• Always follow high hygiene standards when working
  with crop protection products
• Spraying equipment must be calibrated at least
  once in every season of use
• Keep calibration records
• Product labels often contain recommendations on
  optimum application volumes, timing and the
  choice of nozzles

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Calibration of hand held spraying equipment

• There are many different ways to calibrate
  spraying equipment
• This module contains several examples of
  calibration procedures for the following spraying
  equipment-
• Single nozzle knapsack and lance sprayers
• Multi nozzle boom sprayers
• Hand held mist blowers
• Compression sprayers

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Calibration of hand held spraying equipment

• Factors affecting application volume -
• Forward speed
• Nozzle size, type and condition
• Sprayer pressure
• Operator accuracy

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Calibration of hand held spraying equipment

• Forward speed
• Forward speed will vary between spray operators
• Always calibrate in the actual spraying situation
• Crop density and growing conditions will have an
  effect on walking speed (flood/irrigated crops)
• It is very difficult to maintain an even forward
  speed when trying to walk at an unnatural forced
  pace
• Do not use adjusted forward speed to vary the
  output of hand held equipment unless there are no
  other alternatives to achieve the desired
  application volume

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Calibration of hand held spraying equipment

• Pressure
• Built in control systems
• Pressure regulators
• External control sytems
• Control flow valves
• Several manufacturers make control flow valves
  that can be fitted behind the spray nozzle to
  keep constant pressure. Valves are available with
  a working pressure of 1 (yellow), 1.5 (red), 2
  (blue) and 3 bar (green).

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Calibration of hand held spraying equipment

• Nozzles - fans, hollow cones
• Changing nozzles gives the greatest flexibility
  in spray liquid sprayer output
• Many different types of nozzles are available
  which can generate contrasting application
  volumes and spray qualities. Nozzles are colour
  coded according to emission rates

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Calibration of hand held spraying equipment

• Operator accuracy
• Even with a full, calibrated and checked sprayer
  operator accuracy can have a major impact on the
  final results achieved.
• It is important to -
• Maintain a constant forward speed
• Keep the nozzle at a uniform height above/from
  the target
• If using a lever operated knapsack maintain a
  uniform pumping action
• If spraying in a Zig Zig pattern ensure forward
  speed is suited to the width of the spray area to
  ensure even cover
• Ensure accuracy in mixing the correct dose of
  product to the spray tank

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Calibration of hand held spraying equipment

• Before carrying out any calibration
• Fill the sprayer with water and test that the
  sprayer is working well and has no leaks.
• Check that the nozzle is functioning correctly.
  Change the nozzle if needed.
• Why calibrate?
• Enables the accurate calculation of how much
  product to add per tank and that products
  optimal safe use. Under-dosing can lead to
  product failure, over dosing can lead to
  un-acceptable crop residues and other risks.
• Both under-dosing and over-dosing lead to wasted
  product and wasted money.

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Easy calibration method

• This method allows the calibration of single and
  multi nozzle sprayers without the use of
  calculations.
• Items required -
• A clean non-leaking knapsack with appropriate
  working nozzle
• A means of measuring swath width and area to
  spray
• Graduated measuring jug
• Clean water
• Stopwatch or watch with a second hand
• Calibration disc/chart
• Calibration record sheet

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Easy calibration method

• Calibration process
• Fill the knapsacks spray tank to maximum rated
  capacity with clean water.
• Set the correct operating pressure.
• Spray holding the nozzle at the required height
  and measure the swath width.
• Using the calibration chart find out how far you
  must walk to cover 100m2
• Continued over.

Most nozzles have an optimum height of 50cms
above the first intercepting surface
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Easy calibration method cont.

1. Measure out the required distance to enable you
   to spray 100m2 (this should preferably be done in
   the intended spray area to provide a reliable
   walking speed).
2. Prime the sprayer and fill the tank to the
   maximum rated graduation line or if there is no
   line fill to the top.
3. Walking at an even speed spray the 100m2,
   recording the amount of time taken to complete
   the task (if you spray more than one row do not
   record the time taken turning at the end of each
   row).
4. Refill the sprayer to the same level as in step 6
   recording the amount of water required.
5. Using the calibration chart find out the
   application volume per ha.
6. Record all the results on the calibration form.
7. Repeat steps 7 to 10 three times to ensure
   accuracy.

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Calibration chart
Volume per ha
200l
50l
175l
250l
225l
150l
125l
100l
75l
Step 9
1000ml
1750ml
1500ml
2500ml
500ml
1250ml
2000ml
2250ml
750ml
Volume sprayed (for 100m2)
Step 4
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Sprayer calibration wheel
Litres per ha
Millilitres per 100m2
Time to spray 100m
Wheels such as these are useful to calculate
different application volumes at different
walking speeds
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Calibration records - easy calibration

• The following items should be recorded during a
  calibration -

Date Name or Sprayer number Name or Sprayer number Nozzle type and number
Name of sprayer operator Sprayer pressure
Time taken to cover 100m2 (secs) Nozzle height (cm) Nozzle height (cm) Swath width (m)
Sprayer output per 100m2 (mls) Sprayer output per 100m2 (mls) Calculated volume (Litres) per hectare Calculated volume (Litres) per hectare
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Kalibottle calibration method

• This method allows the calibration of sprayers
  using the Kalibottle.
• Items required -
• A clean non-leaking knapsack with working nozzle
• A means of measuring swath width and area to
  spray
• Kalibottle
• Clean water
• Stopwatch or watch with a second hand
• Calibration disc/chart
• Calibration record sheet

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Calibration using the Kalibottle
Kalibottles are designed to fit over the sprayer
nozzle to collect its emitted spray during a
calibration. The Kalibottle has a graduated scale
which allows the user to determine the
application volume per hectare. Follow the steps
to achieve an accurate calibration -
Caution When full the Kalibottle is heavy and
could damage the sprayer lance and trigger
assembly.
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Calibration records using Kalibottle

• The following items should be recorded during a
  calibration -

Date Name or Sprayer number Name or Sprayer number Nozzle type
Name of sprayer operator Sprayer pressure
Time taken to cover 25m2 (secs) Nozzle height (cm) Nozzle height (cm) Swath width (m)
Sprayer output per 25m2 (mls) Sprayer output per 25m2 (mls) Calculated volume (Litres) per hectare Calculated volume (Litres) per hectare
Repeat the calibration three times to ensure
accuracy
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Static calibration

• This calibration process works best with
  multi-nozzle sprayers because it not only gives
  an overal measurement of sprayer output but also
  allows the indentification in variation of flow
  from each nozzle to be measured.
• Items required -

Sprayer Clean water
Watch with second hand Means to measure 100m
Measuring jugs Calculator
Calibration sheet Spare nozzles
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Static calibration cont.

• Calibration process
• Measure out 100m in intended spray area.
• Record the amount of time taken to walk the 100m,
  this should be done with the sprayer as it would
  be used by operator.
• On a level surface place a jug under each nozzle.
• Prime the sprayer with clean water.
• Place the nozzles over the jugs and spray for 1
  minute.
• Record the output of each nozzle
• If any nozzles are more than 10 from the mean
  output then they should be changed.
• Repeat steps 5 to 6 three times to ensure
  accuracy.
• Use the collected measurements to obtain the
  output per hectare.

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Static calibration calculation

• Static calibration calculation -

Information required Example
Nozzle spacing (m) Nozzle output per minute Number of nozzles Forward speed (m/sec) 0.50m 650mls 4 0.9m/sec
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Static calibration records
Sprayer name Date Operator Nozzle type Number of Nozzles
Sprayer pressure Time to walk 100m
Nozzle output Nozzle output Run 1 Run 2 Run 3
Nozzle 1 Nozzle 1
Nozzle 2 Nozzle 2
Nozzle 3 Nozzle 3
Nozzle 4 Nozzle 4
Nozzle 5 Nozzle 5
Total output per minute Total output per minute
Mean output (divide total by no. nozzles) Mean output (divide total by no. nozzles)
variance (difference between nozzles) variance (difference between nozzles)
Output/nozzle/sec (mean / by 60) Output/nozzle/sec (mean / by 60)
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Calibrating mist blowers

• A mist blower can be calibrated using the easy
  calibration method.
• When calibrating a mist blower it is important to
  hold the nozzle at the same angle as will be used
  when spraying.
• Water to the nozzle is often gravity fed so
  altering the nozzle height will increase or
  decrease the flow rate.
• You do not need to have the fan running when
  calibrating mist blowers.

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Calibrating compression sprayers

• To enable accurate calibration of controlled
  outputs of spray liquid from a compression
  sprayer the sprayer must be fitted with a
  constant flow value to enable constant pressure
  to be achieved.
• A compression sprayer can be calibrated using any
  of the calibration methods mentioned in this
  Power Point.

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Calibrating for inter-row applications

• Sometimes not the whole area within a treatment
  zone needs to be sprayed
• Inter-row weed control
• Crops grown in rows or in beds

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Calibration for band application
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Efficient knapsack use

• If the calibrated output is too high or too
  low changes can be made to ensure the application
  is made to suit the label recommendations and the
  crop geography.
• Increasing or decreasing walking speed will
  reduce or increase application volume per ha.
• Difficult to maintain an un-natural walking
  speed.
• Increasing or decreasing sprayer pressure (if
  possible) will increase or decrease spray volume.
• Will alter spray coverage and may increase spray
  drift.
• Changing the nozzle to one that has the correct
  output.
• This is the best solution.
• More information available in the nozzle
  selection training module.

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Calculating product rate using dosage wheel for
knapsacks
If available use the calibration disc to work out
how much product to add to each knapsack.

• Select product rate (B)
• Select calibrated application volume (A)
• Identify knapsack volume (C)
• Result is the amount of product required for each
  knapsack (D)

If you do not have a dosage wheel then use the
following formula to calculate doses per knapsack
-
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Trainer notes

1. Ensure that there is sufficient space to enable
   participants to calibrate sprayers.
2. Have sufficient spraying equipment to ensure that
   there are no more than 3 people per sprayer.
3. Calibration equipment and sheets.
4. If using the Kalibottle have sufficient bottles
   and calibration discs.

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