What you need to know about spray nozzles or tips

The nozzle of the spray equipment is the key to:

Types of nozzles

According to the “distribution pattern” of the product/drops coming out of the sprayer, the nozzles are classified into 3 groups and can be:

The flat fan nozzle presents a greater number of different nozzles and a greater range of variation in the size of the drops produced according to its manufacturing technology.

Currently, nozzles are made of plastic polymers - longer lasting than the brass used in the past - and more economical. They can also have a polymer body (like a case) and an insert center of stainless steel or ceramic, which provides greater durability and resilience.

According to ISO Standard Nº 10625, the flow rate of the nozzles is identified by a color code.

The pressure in the circuit has an effect on the product sprayed by the nozzles.

Furthermore, there are effects on flow and distribution. To double the flow rate, the pressure must be multiplied by 4, which in practice is not possible because the nozzles exceed the proper working range and the pressure would be excessive for the components of the hydraulic circuit.

Fan nozzles

It forms a narrow inverted ‘V’ shaped pattern, with a “normal” distribution. The product is concentrated in the center and dissipates evenly towards the ends.

• Product distribution: uniform, but wider with greater angle of the nozzles.
• Drop size: Generally medium
• Use: suitable for the application of selective herbicides - defoliants and foliar fertilizers

As the fans of neighboring nozzles partially overlap, the flow must be homogeneous along the boom and they must be located on the boom in such a way that, depending on the working height, there is an overlap of at least 30% between nozzle and nozzle to even the distribution of the sprayed liquid

The nozzles must have an angle close to 15% in relation to the boom axis in order to prevent the neighboring flat fans from “colliding” with each other, producing failures in the distribution.

1. Regular or “standard” flat fan nozzles:

   1. Material: polymer or with stainless steel or ceramic inserts, the oldest and most economical
   2. Working range: 2 to 4 bars
   3. Spray angles: 80 and 110 º
   4. Drop size: very fine to medium drops (depending on flow rate and working pressure).

2. XR extended range flat fan nozzles

Used to reduce drift (lowering pressure), or to increase coverage without increasing volume.

For application of herbicides in fallow land, when weeds are hidden by stubble, because it allows increased penetration while maintaining good application uniformity.
Working range: from 1 to 4 bars (some of them can reach 5 bars and double the flow rate by increasing the pressure and maintaining the spray angle of 1 bar).

1. Drop size: Medium and small drops (can be used as a “multifunction” depending on < or > pressures) It can produce large drops when the pressure is lowered without closing the fan or produce small drops when increasing it.

Double or “Twin” fan nozzles
Greater penetration is sought in dense crops, since, by having a double fan, one at the front and one at the back, the liquid penetrates better through the spaces between the leaves.

1. Spray angles defined by the 2 fans 60º (each fan 80º, 110º etc.)
2. Total flow 3 gal/min (each fan 0.15 gal/min)
3. Drop size: < than the equivalent nozzles of a simple fan because the flow is divided into two fans. In the direction of advance, the first fan sprays the plant from the bottom up, and the second from the top down, on two different levels.
   The same effect can be achieved with the so-called Twin Jet, or double tips and with inverted Y-shaped inserts.

Anti-drift nozzles (first generation DG)
Designed to reduce drift by wind.
Benefit: minimizes product waste; treatment efficiency and economic savings are achieved.
Recommendations: post-emergent and preventive treatments. It has a small prechamber in front of the exit orifice in which the smaller drops join together and the amount of drift prone drops decreases.

1. Drop size: somewhat larger than the previous ones. The cover is removable to clean the nozzle if necessary.

Mirror or deflector nozzles:

1. Distribution of the product: It comes out in a uniform, wide jet through a small hole that hits an inclined surface, breaking into countless drops.
2. Drop size: medium/coarse to very coarse; degree of coverage is low because they are projected at a wide angle towards the ground and low drift
3. Spray angles: As the pressure increases, they rise to >130º approx.
   An important aspect is that you have to stop using them when they wear out, since they can produce an irregular distribution.

Air induction Nozzles (AI)

These are nozzles designed as highly effective “Anti-drift”. They have a narrow section in the tube through which the liquid flows. Connected to this sector are two orifices that connect to the outside air: 1 measures the liquid flow and 2 forms the spray pattern. Between the two there is an air aspirator that takes it to the inside of the nozzle to mix it with water.

This system, due to the so-called “Venturi effect”, draws air from the outside - more noticeable when the liquid speed is > - a factor that depends on the working pressure.

1. Work range: from 2 to 8 bars. (works best from 4 bars at high pressures)
2. Drop size: coarse to very coarse; larger size because they contain small air bubbles inside that break when they hit the leaves, providing greater coverage.
3. Advantage: when they reach the target, by releasing the air contained inside, the drops “pop”, producing several drops of smaller size, which increases the coverage. The distribution of the product reduces the risks of drift to the maximum.
4. Use: pre-emergence and post-emergence herbicides and fungicides and insecticides.

TeeJet Turbo Nozzles

1. The design is a combination of the “low drift” and “deflector” nozzles.
2. Working range: from 1 to 6 bars - great versatility to change the flow rates.
3. Disadvantage: It is difficult to unclog in case of obstructions, be careful with wettable powders. It is also possible to find them with air induction. 

Dual fan air induction nozzles

1. Produce a double fan, to improve penetration
2. Drop size: coarse, but < than those of the simple flat fan air-induced nozzles. Intermediate size.

Eccentric flat fan, “Off Center” or impact nozzles

1. It has the characteristic that the flat fan extends only to one side.
2. They are not very widespread and their main uses are for under the canopy type applications or to be placed at the end of the boom covering the lateral areas.

Other types of flat fan nozzles.

There are other types of nozzles that, in some cases, can originate from a combination of different models.

1. Air-induced Turbo TeeJet (TTI). They produce very coarse droplets, > than those from single-air-induced and single Turbo TeeJet nozzles.
2. Air-induced double-flat fan nozzles.
3. Air-induced double-fan anti-drift nozzles (DGTJ).
4. Double-fan Turbo TeeJet (TTJ)
5. Another type that is gradually gaining market share is nozzles that form a single piece with the cap. This is the case of a type of Turbo included in the cap or the AIC from TeeJet that are air-induced.
6. TeeJet AIUB. They are air-induced and have an eccentric flat fan.

5. Conical or turbulence nozzles 

Due to the turbulence generated in the circular path of the liquid in the nozzle chamber, it takes the form of a cone upon exiting. This results in fine droplets, which allows for good coverage of the crop; allowing the droplets to also penetrate the underside of the leaves.

They are mainly used in insecticide and fungicide applications where it is required that the drops penetrate correctly into the crop canopy, moistening the entire area. Pressure between 3 and 5 kg/cm2 is required. They are ideal for strong penetration and expanded coverage of treatments with insecticides and fungicides.

They can be either hollow or full cone. 

Hollow cone nozzles

In these nozzles, the liquid enters through the central and upper part of a piece shaped like an inverted cylinder, and exits through small lateral ducts, which creates the rotary movement. There are versions with air assistance.

This nozzle has two parts, following the order of the liquid path, turbulence core (NT) that regulates droplet size and diffuser disc (DD) that regulates flow rate.

The NT is a flat disk that has holes that divide the liquid mass, this allows the liquid a spiral rotation movement while being contained by the housing of the nozzle.

The greater the number of holes, the smaller the drop size. The DD regulates the flow rate, the greater the diameter, the greater the flow rate.

After passing through the NT, the liquid crosses the DD and comes out in the form of a conical and hollow spiral, which when projected on a flat surface looks like a ring.

In general, they are recommended for the application of insecticides, fungicides and defoliants.

1. Drop size: this is the type of nozzle that produces fine and medium-fine drops.
2. Coverage: excellent for the application of fungicides, but with a high risk of wind drag (under adverse environmental conditions, it is recommended to work during the night or the first hours of the morning, in particular, with <temperature and relative humidity).
3. Working range: 5 to 20 bars (the limit is the maximum pressure that can tolerate the other components of the sprayer equipment - filters, valves, bodies, etc.)
4. They provide a jet that wets in the form of a circular crown. The most common angle is 80º
5. This type of distribution pattern can also be achieved through the combined use of dosing discs and turbulence cores whose lateral grooves (1 to 4) cause the liquid to take on a rotating movement and the disc doses the flow that arises from the interaction of each disc with each turbulence core.
6. Advantage: using disk and core, different combinations between disk, core and pressure allow you to manage a greater number of alternative flows.
7. Disadvantage: its installation in spray bodies is cumbersome. 

Full cone nozzles

Deliver a uniform, circular and full pattern

1. Drop size: coarse to very coarse drops.
2. Working range: at low pressures of 1 to 3 bars.

The design is similar to the hollow cone nozzle, but the disc that has helicoidal ramps has a central hole by which the liquid fills the center of the cone. Its wide spray angle makes it possible to place it at a greater distance on the boom (up to 100 or 110 cm), placing the boom at a greater height.

In general, they are recommended for the application of fungicides. It is also used in the generation of spray in conveyed jet (turbine) machines for orchards. In addition, if certain turbulence nuclei are combined with the dosing disc, small droplets can be produced.

Nozzles for fertilizers applied to the ground

 They have one or more holes to output the product in “jets”

1. Use: distribution of liquid fertilizers.
2. Size: large drops, with flow rates similar to the rest of the nozzles.
3. In general, there is an interchangeable plate with a calibrated orifice that regulates the flow rate 

The ground application of phytosanitary products can be done as:

Sources:

• Manual for agricultural applicators Responsible and efficient use of phytosanitary products Cid, Ramiro and Masiá, Gerardo Editorial Coordination: Bogliani, Mario 1st Edition National Institute of Agricultural Technology - Agroindustry Research Center
• Agricultural spray tablets, their correct selection and use for optimal application quality INTA Pedro Daniel Leiva
• Inta - Good Practices for the application of phytosanitary products / Brambilla V. Gómez Hermida M. Bogliani
• Sprayer Calibration How to perform a safe and efficient application, taking care of costs and the environment? Eng. Mag . Fernando R. López Rodríguez*
• Backpack sprayer: what to take into account to achieve efficient use? AgroSpray 28 May, 2020 AGROSMART, AGROSPRAY, PRODUCTS, AGRICULTURAL SERVICES 2 Knowledge for the Integrated Management of Phytosanitary Products PTI057 and the Structural Project Sustainable Management of Phytosanitary Products PEI054
• Field Bugs INTA Drifts in Application of Pesticides in Critical Areas
• Argentina Gob.ar Application of pesticides in critical areas. Eng . Rubén A. Massaro. INTA EEA Oliveros.
• FAO Manual for the Preparation of Pesticides CASAFE Manual for the Responsible Use of Phytosanitary Products 2020
• Bulletin of Disclosure N°41 ISSN 0328-3380 Guide for the proper use of pesticides and the correct disposal of their containers Agr. Eng. Fanny Martens INTA - Rural Extension Agency Tandil May 31, 2018
• INTA EEA Oliveros. Popular Article Keys to minimize the drift Eng Agr. Ruben A. Massaro
• Evaluation of plant barriers to mitigate spray drift Lic. Copes Walter EEA Alto Valle. INTA National University of Comahue Faculty of Engineering Master's Degree in Environmental Intervention. Environmental Engineering Orientation
• CASAFE Preventing drifts in the application of phytosanitary products
• INTA Reports Precise Applications: How to Control Drift