Adjust the Atomization

1.Do not turn on atomizing air supply. Fluid pressure is controlled by the air pressure supplied to the pump (pump air regulator). Set fluid pressure at low starting pressure. For low viscosity fluids (less than 25 sec, #2 Zahn cup) with lower percent solids (typi- cally less than 40%), start at 300 psi (2.1 MPa, 21 bar) at pump outlet. For fluids with higher viscosity or higher solids content, start at 600 psi (4.2 MPa, 42 bar). Refer to the following example.

Operation

Adjust the Spray Pattern

Packages with Airless Guns

The spray tip orifice and spray angle determine pattern coverage and size. When you need more coverage, use a larger spray tip rather than increasing fluid pressure.

Align guard horizontally to spray a horizontal pattern. Align guard vertically to spray a vertical pattern.

Packages with AA Guns

1.See FIG. 6. Close off pattern adjustment air by turn- ing knob (AA) clockwise (in) all the way. This sets gun for its widest pattern.

Example:

 

 

 

 

 

Pump Air

 

Approximate

Pump

 

Regulator Setting

 

Fluid Pressure

Ratio

 

psi (MPa, bar)

 

psig (MPa, bar)

 

 

 

 

 

15:1

x

20 (0.14, 1.4)

=

300 (2.1, 21)

30:1

x

20 (0.14, 1.4)

=

600 (4.2, 42)

2.

Hold gun perpendicular and approximately

 

12 inches (304 mm) from surface.

3.

Move gun first, then pull gun trigger to spray onto

 

test paper.

4.

Increase fluid pressure in 100 psi (0.7 MPa, 7 bar)

 

increments, just to the point where a further

 

increase in fluid pressure does not significantly

AA

OUT (narrower pattern)

FIG. 6. Pattern Air Knob

AA

IN (wider pattern)

TI6559A

improve fluid atomization. Refer to the following

example.

Example:

 

 

Pump Air Regulator

 

Incremental

Pump

 

Increment

 

Fluid Pressure

Ratio

 

psi (MPa, bar)

 

psi (MPa, bar)

 

 

 

 

 

15:1

x

7 (.05, 0.5)

=

100 (0.7, 7.0)

30:1

x

3.3 (0.02, 0.2)

=

100 (0.7, 7.0)

2.See FIG. 7. Set atomizing air pressure at about 5 psi (0.35 bar, 35 kPa) when triggered. Check spray pat- tern, then slowly increase air pressure until tails are completely atomized and pulled into spray pattern.

Do not exceed 100 psi (0.7 MPa, 7 bar) air pressure to gun.

313255F

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Graco Inc 313255F Adjust the Atomization, Adjust the Spray Pattern, Packages with Airless Guns, Packages with AA Guns