Nozzle

There are many nozzles on the market and definitely not limited to the information below nor the manufacturers. However as a general guide and for what most people need the information is a great starting point and probably will give you the desired result. If you are looking for something a little bit more niche we do have other products which will help ensure you get the correct application - just give us a call. 

NOZZLE CLASSIFICATION
For conventional hydraulic nozzles, spray quality varies according to nozzle size (defined by nozzle flow in l/min) and with pressure, larger sizes and lower pressures produce larger droplets.

Spray quality is defined by Volume Median Diameter (VMD) which is the mid droplet size where half of the volume of spray is in larger and half in smaller droplets. The BCPC International Spray Classification System, groups nozzles into five
categories: VERY FINE, FINE, MEDIUM, COARSE AND VERY COARSE, each category covering a range of VMDs.

It is important to note that drift potential varies according to spraying pressure, boom height and wind speed.

Hypro Nozzle Chart 

 Teejet Nozzle Chart

Have a look below or go straight to the HYPRO spraying guide : http://www.hypro-eu.com/fileattachments/Hypro-eu/en-gb/2016-English-Pocket-Guide-web.pdf

 OR

If you have a mobile - this Teejet app comes in pretty hand - http://www.teejet.com/tools/spray-nozzle_selection.shtml

Nozzle Chart

 Nozzle Code Understanding: At the end of a lot of nozzles you will see two letters - these mean:

VP - Variable Plastic

VS - Variable Stainless

VK - Variable Ceramic

VB - Variable Brass

SS - Stainless Steel

Nozzle choice

Choosing and maintaining the correct nozzles has an enormous impact on the accuracy and efficiency of agrochemical application. To select the correct nozzle for the job, follow the steps below:

(a) Follow the advice given on the product label (check whether there are any local environmental restrictions or requirements, such as LERAP in the UK).

(b) Check which type of spraying technique you will be using.

(c) Select your application rate – Lower rates will increase work rates in arable crops.

(d) Check your forward speed – high speeds over 12Km/h will increase your work rate and slower speeds of 8-12km/h are better for penetrating dense canopies.

(e) Check your pressure – Finer droplets are produced at higher pressures - individual nozzle charts show this relationship. Always read the pesticide label to determine which spray quality is required.

(f) Select the spray quality that you require. See below.

(g) Select the nozzle style for the required spray pattern.

(h) Make sure that you have fulfilled all criteria before you reduce buffer zone widths with LERAP rated equipment.

(i) Check that all constraints have been accounted for e.g. output of your sprayer pump.

Spray Quality

The most important performance characteristic of an agricultural spray nozzle is the size and the variation of droplets or spray quality that it produces. Conventional nozzles are classified by the droplet size that they produce at a given pressure according to the BCPC International Spray Classification System (e.g. coarse, medium, fine). Different air-inclusion nozzles also produce different spray quality but this cannot be determined by nozzle size. For example GuardianAIR nozzles produce smaller droplets than any other AI nozzle. For comparison of different AI nozzles see the 2010 HGCA Nozzle Chart. For Hypro nozzles, droplet-size is measured using a Phase Doppler droplet analyser and expressed as the Volume Median Diameter (VMD) in microns (μm). The VMD is droplet size where half of the volume of spray is larger and half is smaller than the stated droplet size.

Spray Pattern

Flat fan pattern:-  Available as a tapered spray for boom applications or an even spray for single nozzle applications, e.g. knapsacks, they have an elliptical orifice, which produces a narrow oval pattern. Tapered nozzles produce a triangular spray pattern where most of the spray is deposited immediately under the nozzle. By overlapping tapered sprays across a boom an even distribution across a boom can be obtained.

Deflect pattern:- Also known as anvil or flood nozzles, deflect nozzles produce wide angled flat pattern when operated at low pressures (around 1-2 bar). The nozzles generally produce a coarse even spray and are ideal for use with knapsack sprayers or applications of liquid fertiliser.

Cone pattern:- Nozzles produce either a solid circular even footprint (full cone nozzles) or a hollow circular footprint (hollow cone nozzles). Full cones are ideal for use with knapsacks for spot spraying where as hollow cones are used on air assisted sprayers and traditional boom sprayers when good coverage in dense canopies is required.

Nozzle filters

Sprayers provide filtration at all stages of the spraying system starting with a coarse basket, foot or suction filter at tank filling, medium filtration in front of the pump and finer pressure line filters between the pump and the pressure regulator or between boom sections. It is also possible to fit fine filters behind the nozzle, perhaps where no pressure line filters are fitted or for very low volume applications.

However, in practice it may be easier to replace a blocked nozzle rather than replace the filter and it is always advisable to carry replacement nozzles. Mesh size is important for nozzle filters and recommendations vary with nozzle size; 100 mesh (green) for nozzle sizes 01 and 03, 50 mesh (blue) for 04 to 08 and 30 mesh (red) for 10 to 20. Filter mesh recommendations are available on all Hypro nozzle charts. Nozzle filters may be cylindrical which provide the largest screening area, cup filters are an alternative where nozzle holder design dictates and ball check filters provide some anti drip control where there is no DCV or airstop on the holder.

Care of nozzles

NOZZLE WEAR

The rate at which nozzles wear depends on the abrasiveness of the liquid, the pressure used and the material that the nozzle is made of. A worn nozzle means that spray quality and spray pattern will both be compromised. Even with the most sophisticated flow rate governed sprayer this means that the operator loses control of these two most important spraying parameters.

MATERIALS

Polyacetal:- Provides good resistance to most chemicals and superior resistance to wear with most agricultural chemistry. Susceptible to strong mineral acids and a few organic solvents. Resistance to most alkalis is excellent. Organic solvents usually cause slight swelling without any other harmful effect.

Ceramic:-Highly resistant to abrasive and corrosive chemistry and provides superior wear resistance in abrasive applications and high pressures. Polyvinylidene fluoride (PVDF) Should be used with acid-based agricultural defoliation chemistry. Good resistance to wear. Resists many reagents and temperatures up to 300ºF. Susceptible to high temperatures above water boiling (210ºF) in combination with concentrated sulphuric and nitric acids. Preferred in industrial spraying applications.

Stainless steel : - Good resistance to chemicals and provides average wear resistance.

Brass:- Average resistance to most chemistry and poor wear resistance. Susceptible to corrosion especially with fertilisers.

CARE OF NOZZLES

Spraying nozzles are precision-engineered components. Always keep a new nozzle from a set and compare used nozzles with it to assess their condition over time. Nozzles should be replaced when their output (flow in litres per minute) has increased by 10% or more and at least every year. This can be assessed by reference to nozzle selection charts. To clear blocked nozzles, soak in water and clean with a brush and airline. For stubborn deposits soak in warm water and detergent, agitating occasionally. Never blow through a nozzle or poke with wires or pins – even the slightest damage to the orifice will alter flow rate angle and spray distribution.

Care of filters

Check filters regularly, cleaning out any debris under running water. Replace filters which are damaged to prevent blocked nozzles.

If you want more information - give us a call or fill in the box below. Sometimes depending on the conditions and what you want to do there may be a better solution then what is mentioned here ans as specialists we have the knowledge to point you in the right direction.