Hitachi 308640 How the Air-Assisted Spray Gun Operates, Install a Spray Tip, Your application

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Operation

How the Air-Assisted Spray Gun Operates

The air-assisted spray gun combines airless and air spraying concepts. The spray tip shapes the fluid into a fan pattern, as does a conventional airless spray tip. Air from the air cap further atomizes the fluid and completes the atomization of the paint tails into the pattern to produce a more uniform pattern. The width of the pattern can be slightly adjusted by the pattern adjustment valve.

Note that the air-assisted spray gun differs from an air spray gun in that increasing the pattern air reduces the pattern width. To increase the pattern width, less pattern air or a larger size tip must be used.

The spray gun has a built-in lead and lag operation. When triggered, the gun begins emitting air before the fluid is discharged. When the trigger is released, the fluid stops before the air flow stops. This helps assure the spray is atomized and prevents fluid buildup on the air cap.

Install a Spray Tip

WARNING

INJECTION HAZARD

To reduce the risk of a fluid injection injury, follow the Pressure Relief Proce- dure on page 7 before removing or

installing a spray tip.

Install a spray tip in the gun. The air cap and spray tip position determines the direction of the spray pattern.

Rotate the air cap (the spray tip rotates with it) as needed for the desired spray pattern direction. See Fig. 3.

NOTE: If the gun has the AA RAC assembly, hand- tighten the air cap retaining ring, while holding the orange tip guard in the desired direction. If the retain- ing ring is over-tightened, the spray tip will be difficult to rotate.

Vertical Spray Pattern

Horizontal Spray Pattern

Select a Spray Tip and Air Cap

 

The fluid output and pattern width depend on the size

 

of the spray tip, the fluid viscosity, and the fluid pres-

 

sure. Use the Spray Tip Selection Chart, on page 22,

 

as a guide for selecting an appropriate spray tip for

05991

your application.

Fig. 3

8 308640

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Contents 308640 Part No , Series aPart No , Series B This manual contains important warnings and informationTable of Contents Equipment Misuse Hazard Installation Typical InstallationVentilate the Spray Booth T QConnect the Air Line Connect the Fluid LineObject being sprayed Ground it according to local code Ground the SystemFluid supply container Ground it according to local code Operation SafetyPressure Relief Procedure Install a Spray Tip How the Air-Assisted Spray Gun OperatesSelect a Spray Tip and Air Cap Your applicationAdjust the Spray Pattern Recoil HazardApply the Fluid Clean the Spray Gun and System Daily Check the Diffuser-seat Operation WeeklyFlush the Gun Daily 308640 Troubleshooting General TroubleshootingProblem SolutionSpray Pattern Troubleshooting Fluid Needle Cartridge Service ServiceAir Valve Service AIR Service Notes 10b 10aParts Part No , 238852, 238883,Description Qty 35Y 172479 TAG, instruction not shown Repair KitsDescription Qty 14a 10b 111517 RING, backup Ptfe r 238701 238755 NEEDLE, fluid, hi-flow Included with192096 239172Spray Tip Selection Charts Standard Spray Tips, for use with Air CapFluid output at 600 psi 4.1 MPa, 41 bar On the next 238402 238851 238852 238883 239001 241070 DimensionsMeasurements, inches mm Gun Technical Data Sound DataAccessories Graco Standard Warranty Graco Phone NumberManual Change Summary Manual changed per ECO