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Marker spray: nozzle output and quantity sprayed

How many litres per minute should each nozzle give, and does the sprayer hit the ordered dosage?

Answer: When you service or function test a field sprayer, the nozzles should deliver the quantity the farmer ordered in litres per hectare. Performance per nozzle depends on dosage, forward speed and distance between nozzles. The calculator works out the performance each nozzle should deliver, and the dosage you actually get from your collection measurement, so you can see the deviation.

Formula

Dyseydelse [l/min] = l/ha × km/t × dyseafstand [m] ÷ 600

Udbragt mængde [l/ha] = dyseydelse [l/min] × 600 ÷ (km/t × dyseafstand [m])

600 kommer af 10.000 m² pr. ha ÷ (1000 m pr. km ÷ 60 min pr. time)

Symbols and units in the formula
SymbolMeaningUnit
doseringDesired delivered quantityl/ha
hastighedApproach speedkm/t
dyseafstandDistance between nozzlesm
maaltMeasured performance per nozzle (collected in measuring glass)l/min
=Performance each nozzle should deliverl/min
=Quantity delivered with the measured performancel/ha
=Deviation from desired quantity%

Validity and source

Source
Kalibreringsformlen l/min = l/ha × km/t × dyseafstand ÷ 600 (dysekataloger og SEGES' vejledning om kalibrering)

Does not apply when

  • Measure multiple nozzles across the entire boom at the pressure used in the field, and compare with the nozzle catalogue. The limits for how much a nozzle may deviate are in the rules for the legally required function test of field sprayers.

Worked example

The calculator's own default values inserted. The figures are calculated with exactly the formula the tool uses.

Substituted

  • Desired delivered quantity150 l/ha
  • Approach speed7 km/t
  • Distance between nozzles0.50 m
  • Measured performance per nozzle (collected in measuring glass)0.90 l/min

Giver

  • Performance each nozzle should deliver0.875 l/min
  • Quantity delivered with the measured performance154 l/ha
  • Deviation from desired quantity2.9 %

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Sådan bruger du den

Ved service og ved den lovpligtige funktionstest af marksprøjter skal du kontrollere, at dyserne giver den mængde, landmanden har bestilt. Ydelsen pr. dyse afhænger af doseringen, hastigheden og dyseafstanden. Beregneren regner, hvad hver dyse skal give, og hvad sprøjten faktisk udbringer ud fra din opsamling.

Step by step

  1. Indtast den ønskede mængde i l/ha.
  2. Indtast hastighed og dyseafstand.
  3. Mål dyseydelsen med et måleglas i 1 minut.
  4. Aflæs afvigelsen.

Typical errors

  • At måle ved et andet tryk end i marken.
  • At glemme at hastigheden ændrer mængden.
  • At måle på én dyse.

Examples from everyday life

Kontrol af sprøjte før foråret

En landmand vil sprøjte 150 l/ha ved 7 km/t med dyser på 0,5 m afstand. Du opsamler i ét minut ved arbejdstrykket og måler 0,9 l/min pr. dyse.

Desired delivered quantity
150 l/ha
Approach speed
7 km/h
Distance between nozzles
0.5 m
Measured performance per nozzle (collected in measuring glass)
0.9 l/min

It means: Dyserne skal give 0.875 l/min. Med den målte ydelse udbringes 154 l/ha, altså 2.9 % afvigelse.

Slidte dyser

På en ældre sprøjte måler du 1,0 l/min på flere dyser ved samme tryk og samme ønskede dosering.

Desired delivered quantity
150 l/ha
Approach speed
7 km/h
Distance between nozzles
0.5 m
Measured performance per nozzle (collected in measuring glass)
1 l/min

It means: Sprøjten udbringer 171 l/ha, 14.3 % for meget. Så stor en afvigelse skyldes oftest slidte dyser, så de bør skiftes, før sprøjten bruges.

Rule of thumb

Ved 0,5 m dyseafstand og 6 km/t svarer 1 l/min til 200 l/ha.

How to check the answer

Dobbelt hastighed ved samme dyse giver halv mængde.