author
Bobby Brown
Post 2016-12-14
3 Key Things You Need to Know About Spray Angle and Coverage !

Contents


1. What is "Spray Angle"?

llustration of the Spray Coverage Area of the Nozzle

When we refer to the spray angle (spray cone angle), we are talking about the angle formed between the centerline of the nozzle outlet and the edges of the spray on both sides. After the liquid exits the nozzle, it cannot continue in a tangential direction due to the effects of gravitational acceleration and air resistance. As a result, the the "actual spray coverage" may be smaller than the "theoretical spray coverage"


2. How to Calculate the Spray Angle?

Currently, there is no internationally standardized method for measuring spray angles, but common measurement techniques include protractor-based measurement and optical measurement.

  • Traditional Protractor Measurement Method:  
      The nozzle is fixed and kept in a horizontal position. A protractor is used to align with the edges of the spray emitted from the nozzle center, and the spray angle is read. This method is low-cost but may be affected by human error.

  • Optical Measurement Method:  
      Using a stable light source, a high-resolution camera captures the shape of the spray. Specialized computer software, such as CAD or image processing software, is then used to calculate the spray angle. This method is highly accurate but requires expensive software and professional expertise. LORRIC employs the optical measurement method to ensure the quality of every nozzle before shipment.

3. How to Calculate the Theoretical Spray Coverage Area?

The spray angle is influenced by both the size of the nozzle’s spray orifice and the distance between the nozzle and the target surface. This relationship also determines the spray coverage area and the density of the liquid relative to the covered area.
Theoretical spray coverage of nozzles
To calculate the theoretical spray coverage area, we need to know both the spray angle and the distance between the nozzle outlet and the object. The formula for calculating the spray coverage area is as follows:
 Theoretical Spray Coverage =2⋅Distance⋅tan(Spray Angle/2)
 
Calculate the theoretical spray coverage of nozzles
In summary, the relationship between angle, coverage area, and distance is: generally, the larger the spray angle, the wider the coverage area, but the spray distance will be relatively shorter. Conversely, a smaller spray angle results in a narrower coverage area but allows the spray to reach farther distances.

4. Spray Angle and Coverage Area Reference Table

LORRIC provides a reference table showing the calculated spray angles and corresponding coverage areas based on the formula. It is important to note that due to factors like gravity and aerodynamic drift, the spray angle can only be maintained over a limited distance—typically up to 300 mm from the nozzle outlet.

Unit: inch


 
Spray Angle (°)
Theoretical Spray Coverage (Unit:inch)
40 55 60 65 70 75 80 90  100 120 170

Distance

(inch)

1.0 0.7 1.0 1.2 1.3 1.4 1.5 1.7 2.0 2.4 3.5 23
1.5 1.1 1.6 1.7 1.9 2.1 2.3 2.5 3.0 3.6 5.2 34
2.0 1.5 2.1 2.3 2.5 2.5 2.8 4.2 4.0 6.0 8.7 57
2.5 1.8 2.6 2.9 3.2 3.5 3.8 5.0 5.0 7.2 10 69
3.0 2.2 3.1 3.5 3.8 4.2 4.6 5.0 6.0 7.2 10 69
3.5 2.5 3.6 4.0 4.5 4.9 5.4 5.9 7.0 8.3 12 80
4.0 2.9 4.2 4.6 5.1 5.6 6 6.7 8.0 10 14 91
4.5 3.3 4.7 5.2 5.7 6.3 7 7.6 9.0 11 16 103
5 3.6 5.2 5.8 6.4 7 8 8.4 10 12 17 114
6 4.4 6.2 6.9 7.6 8 9 10 12 14 21 137
7 5.1 7.3 8.1 8.9 10 11 12 14 17 24 160
8 5.8 8.3 9 10 11 12 13 16 19 28 183
9 6.6 9.4 10 11 13 14 15 18 21 31 206
10 7.3 10.4 12 13 14 15 17 20 24 35 229
11 8.0 11.5 13 14 15 17 18 22 26 38 251
12 8.7 12.5 14 15 17 18 20 24 29 42 274
13 9.5 12 15 18 20 22 23 26 31 45 297
14 10 13 16 17.8 19.7 21.8 24 28 33 48 320
18 13 19 21 23 25 28 30 32 43 62 411
20 15 21 23 25 28 31 34 36 48 69 457
22 16 23 25 28 31 34 37 40 52 76 503
24 17 25 28 31 34 37 40 44 57 83 549
26 19 27 30 33 36 40 44 48 62 90 594
28 20 29 32  36 39 43 47 52 67 97 640
30 22 31 35 38 42 46 50 56 72 104 686
32 23 33 37 41 45 49 54 60 76 111 732
34 25 35 39 43 48 52 57 64 81 118 777
36 26 37 42 46 50  55  60 60 86 125 823

Unit: mm



Spray Angle (°)
Theoretical Spray Coverage (Unit:mm)
55 60 65 70 80 75 90 100 120

Distance

(mm)

 

30 31 35 38 42 50 46 60 72 104
40 42 46 51 56 67 61 80 95 139
50 52 58 64 70 84 77 100 119  173
60 62 69 76 84 101  92 120 143  208
70 73 81 89 98 117  107 140 167  242
80 83 92 102 112 160  123 160 191  277
90 94 104 115 126 180 138 180 215 312
100 104 115 127 140 200  153 200 238  346
110 115 127 140 154 220 169 220 262  381
120 125 139 153 168 240 184 240 286  416
130 135 150 166 182 260 200 260 310  450
140 146 162 178 196 280  215 280 334  485
150 156 173 191 210 300  230 300 358  520
200 208 231 255 280 400  307 400 477  693
250 260 289 319 350 500  384 500 596  866
300 312 346 382 420 600  460 600 715  1039
350 364 404 446 490 700 537 700 834  1212
400 416 462 510 560 800  614 800 953  1386
450 469 520 573 630 900  691 900 1073  1559
500 521 577 637 700 1000  767 1000 1192  1732
550 573 635 701 770 1100  844 1100 1311  1905
600 625 693 764 840 1200  921 1200 1430  2078
650 677 751 828 910 1300  998 1300 1549  2252
700 729 808 892 980 1400  1074 1400 1668  2425
750 781 866 956 1050 1500  1151 1500 1788  2598
800 833 924 1019 1120 1600  1228 1600 1907  2771
850 885 981 1083 1190 1700  1304 1700 2026  2944
900 937 1039 1147 1260 1800  1381 1800 2145  3118
950 989 1097 1210 1330 1900 1458 1900 2264  3291
1000 1041 1155 1274 1400 2000  1535 2000 2384  3464

 


5. About Angles and Coverage Areas

About Angles and Coverage Areas

At a distance of 300 mm, theoretical spray area:

  • 90° angle: 60cm, 0.28㎡ per unit
  • 170° angle: 150cm, 1.76㎡ per unit (approximately 6.3 times)

4. 3 Key Distance Decisions for Choosing Nozzle Angles

1 ) Distance to Target

The distance between the nozzles and the target area, such as a plant canopy, significantly affects spray deposition. Optimal distance settings ensure efficient coverage while minimizing drift and wastage. Adjustments should consider the type of spray and the specific application requirements to maximize efficacy.

Schematic diagram of  Distance to Target

2 ) Distance Between Adjacent Nozzles

Maintaining the right distance between adjacent nozzles is crucial for achieving uniform coverage across the target area. Incorrect spacing can lead to overlapping spray zones or missed areas, affecting the overall effectiveness of the application. This distance varies depending on the nozzle type and the desired coverage pattern.

3 ) Distance Between Spray Bars

For non-fan nozzles, such as solid cone, hollow cone, and spiral nozzles, the distance between spray bars plays a critical role in angle selection and, consequently, in the coverage pattern and effectiveness of the spray. Proper adjustment ensures optimal spray overlap and uniform distribution across the target.

Schematic diagram of Distance Between Spray Bars
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