Change in Droplet Size from Plugged Air Induction Ports on

Venturi Nozzles

Introduction

Débora O. Latorre, Thomas R. Butts, Jesaelen G. Moraes, Greg R. Kruger

Department of Agronomy & Horticulture, University of Nebraska-Lincoln

Applicators use a wide variety of nozzle to make pesticide applications today. There are

many different types of venturi nozzles used and applicators are often concerned about the

spray pattern, droplet size distribution and overall effectiveness of venturi nozzle when

spraying in dusty conditions or other situations where the air induction ports could become

plugged. These type of nozzles produce larger droplets. Part of what is believed to cause

this effect is inducing air into the liquid inside of the nozzle body.

Objective

Evaluate the droplet size distribution of five venturi nozzles and the effect of plugged air

inclusion ports.

Material & Methods

Ultra Lo-drift nozzle

(ULD12004 and ULD12006)

http://w

ww.sprayerdep

ot.com/

Air Induction flat fan spray tip

(AI11004 and AI11006)

http://teejet.it/m

edia/461409/cat51a_m

etric.pdf

Air Induction XR flat fan spray tip

(AIXR11004 and AIXR11006)

http://teejet.it/m

edia/461409/cat51a_m

etric.pdf

Turbo Teejet Induction flat fan spray

tip (TTI11004 and TTI11006)

http://teejet.it/m

edia/461409/cat51a_m

etric.pdf

Turbo Drop XL tip

(TDXL11004 and TDXL11006)

http://w

ww.sprayerdep

ot.com/

o air inclusion ports open,

o one port plugged, or

o two ports plugged**TTI nozzles which were tested as either open or plugged due to

having only one port.

Results & Discussion

LaserWind

30-cm

Figure 1. Illustration of the low speed wind

tunnel and laser diffraction system used for

droplet spectrum analysis.(Courtesy from Thomas R. Butts)

Figure 2. Five venturi nozzles used to evaluate droplet size from plugged air induction ports.

Figure 5. Comparison of the percentage of droplets ≤ 150 µm for five venturi nozzles using the 04 (A) and 06 orifice (B) with no plugged ports, one

plugged port and two plugged ports.

Conclusion

Different nozzles will perform differently when the air induction ports plug. Because there is not clear trend as to

how nozzles will perform, it is recommended that applicators try to keep nozzles clean and air induction ports

unobstructed as much as possible.

A nozzle*plugged port*orifice size interaction was significant for the DV50 and RS (p<0.0001); however a similar

pattern emerged across orifice sizes.

TTI nozzle plugged the DV50 increased by 6.5%, and 4.3%, for the 04 and 06 orifice sizes, respectively.

AI and TDXL nozzles two ports were plugged the DV50 decreased by 15.0 and 13.9% for the 04 orifice sizes,

and 13.5 and 12.6% for the orifice 06, respectively.

TDXL and AI nozzles for the orifice 04 produced more percentage droplets ≤ 150 µm with two ports plugged,

AIXR produced more with air inclusion ports open plugged

Completely randomized factorial design

Conducted using a low-speed wind tunnel at the Pesticide Application Technology Lab

Droplet measurements: Sympatec HELOS-ARIO/KR laser diffraction system.

Water sprayed at 276 kPa with three replicates.

Five venture nozzles (Figure 2).

Each nozzle was tested

Data were subjected to ANOVA using the PROC GLIMIX procedure in SAS v 9.4 and

means were separated at P α=0.05 using Fisher’s protected LSD test and the Tukey

adjustment.

Volumetric droplet size spectra parameters used: Dv10, Dv50, Dv90, Relative Span (RS)*,

and Percentage of fine droplets ≤ 150 µm.

A

b b

a

bb

a

b b

a

b

c

a

0.9

0.95

1

1.05

1.1

1.15

Open 1 Port Plugged 2 Port Plugged

Re

lati

ve S

pan

Port

AI AIXR TDXL ULD TTI

Figure 3. Comparison of the Dv50 for five venturi nozzles using the 04 (A) and 06 orifice (B) with no plugged ports, one plugged port and two

plugged ports.

A

Figure 4. Comparison of the Relative Span (RS) for five venturi nozzles using the 04 (A) and 06 orifice (B) with no plugged ports, one plugged port

and two plugged ports.

Means comparison between nozzle*port by the same letter are not statically significant using Fisher’s Protected LSD at α=0.05

b b

a

a

b

a

b

c

a

a b

0

0.5

1

1.5

2

2.5

3

Open 1 Port Plugged 2 Port Plugged

Perc

en

tag

e d

rop

lets

≤ 1

50 µ

m

Port

AI AIXR TDXL ULD TTI

*Means comparison between nozzle*port by the same letter are not statically significant using Fisher’s Protected LSD at α=0.05

A

b b

a

b b

a

cb

acb

a

0

0.5

1

1.5

2

2.5

3

Open 1 Port Plugged 2 Port Plugged

Perc

en

tag

e d

rop

lets

≤ 1

50 µ

m

Port

AI AIXR TDXL ULD TTI B

a b

c

b a a

b a

c

ab

a

b

a

400

500

600

700

800

900

Open 1 Port Plugged 2 Port Plugged

Dv50

(µ

m)

Port

AI AIXR TDXL ULD TTI A

Means comparison between nozzle*port by the same letter are not statically significant using Fisher’s Protected LSD at α=0.05

B

ab

c

a a b

a

a

a

ab

a

b

a

400

500

600

700

800

Open 1 Port Plugged 2 Port Plugged

Dv

50

(µ

m)

Port

AI AIXR TDXL ULD TTI B