Index revision : A
23
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8.2. Spraying rules
Regardless of the type of nozzle, the quality of spraying depends on both the supply pressure
and the product viscosity: as viscosity increases, pressure must also rise, yet the final outcome is
also influenced by the product’s dilution.
A few key points:
• Viscosity: 40 sec CA4: minimum product pressure of 70 bar.
• Viscosity: 60 sec CA4: minimum product pressure of 90 bar.
• Viscosity: 90 sec CA4: minimum product pressure of 130 bar.
The addition of more air serves to reduce the impact width by 25% at a 120-bar pressure; more-
over, the higher the product pressure, the smaller the influence being exerted by the additional
air. In order to limit the production of overspray, it is recommended to never exceed an air pres-
sure of 4 bar.
Using the nozzles with small impact width (XX-09 or 11), whenever the additional air is open, the
jet is practically round.
Table of impact widths in water at a gun/part distance of 25 cm (closed to any additional air).
Nozzles
Impact width
03-05
12 cm
04-05
03-07
17 cm
04-07
04-09
21 cm
06-09
09-09
12-09
14-09
04-11
25 cm
06-11
09-11
12-11
14-11
04-13
29 cm
06-13
09-13
12-13
14-13
06-15
33 cm
09-15
12-15
14-15
14-17
37 cm
