Graco AKA 420 User manual

Continued on pages 1 to 11
Pneumatically operated automatic spray gun for airless atomization of liquid materials.
The original manufacturer’s nameplate is located
on the spray gun. Please compare the
specifications and complete if necessary.
Read and understand the operator manual and
the safety instructions before taking into
operation
In this manual important information is marked with
the following symbols.
Information affecting your safety
Important operational direction
Keep user information for future reference
CONTENTS OF THE USER INFORMATION
Page
OPERATING INSTRUCTIONS
CORRECT USE 2
FUNCTIONAL DIAGRAM 2
PRODUCT DESCRIPTION 3
SUITABILITY, MATERIAL 3
TECHNICAL DATA 4
Key
Data
Material in contact with the fluid
Dimensions, Connection thread
Mounting the gun
LIST OF TOOLS 6
START-UP 7
IMPORTANT INFORMATION CONCERNING START-UP AND OPERATION 8
OPERATION 8
MAINTENANCE AND INSPECTION, REPAIR 8
TORQUE MOMENTS 9
TROUBLESHOOTING 9
FOOTNOTE 10
REPAIR PARTS SET 10
ACCESSORIES 11
Includes:
TEST CERTIFICATE (final inspection)
DECLARATION OF CONFORMITY
Replacement for issue of 02.97
SPRAY GUN A KA 420
Subject to change
Part nbr. 7990 022001
Prepared 28.10.99 Stengele
Approved 12.11.99 Kuhn
Issued 10.99
B.2.30.95-B
*5$&2 6000330E, Rev.A
USER INFORMATION
- OPERATING INSTRUCTIONS -

B.2.30.95-B- 2 -
CORRECT USE
The spray gun A KA 420 is exclusively manufactured for normal use in surface technology
(for spraying coating substances) or for similar work.
Any other purpose above and beyond this, is considered as incorrect use. We are not liable for any
damage or injury resulting from this; the user will bear sole liability in such cases.
Correct use includes observing operating, maintenance and inspection conditions and regulations
laid down by us.
The spray gun A KA 420 may only be installed, maintained and repaired by personnel familiar with,
and trained to recognize the inherent dangers.
The relevant accident prevention regulations as well as safety and medical rules must be respected.
Unilateral changes to the spray gun will cause us to waive our responsibility for any damage or injury
caused.
The user is responsible for correct attachment/installation.
FUNCTIONAL DIAGRAM
Operating air
(control air)
A Automatic spray gun
B 3/2-way valve
C Air pressure regulator
D Pressure gauge
Coating substance
Fig. 1

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PRODUCT DESCRIPTION
The spray gun A KA 420 is operated pneumatically.
When switched on, the control air 1opens the fluid valve 2.
When switched off, the fluid valve is closed by the pressure spring 3.
The parts in contact with the fluid are suitable for water-based paints (stainless steel).
The needle 4is completely made of hardened steel.
The valve seat (diffuser) 5and the gun body 6are designed in such a way that a filter element 7of varying
mesh size can be incorporated, and that an additional filter element does not obstruct the flow of fluid through
the spray gun.
The spray gun is fixed centrally at the rear end 8.
The union nut 9belongs to the spray gun.
Fan jet nozzles, pre-atomizer, filter elements and connections should be specified separately by the operator.
COMPATIBILITY, MATERIAL
FLUID Compatibility
Neutral
Corrosive
Abrasive
Acidic
Inflammable 1)
highly suitable
highly suitable
suitable under
certain conditions
suitable under
certain conditions
highly suitable
1) Hazard classes AI, AII, AIII: the spray gun
should be properly grounded.
Please consult us when processing highly
abrasive and aggressive materials.
Fig. 2
switched air

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- 4 -
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Kinematic viscosity in
mm2/s Compatibility
up to 500
500 to 750
over 750
highly suitable
suitable
suitable under certain conditions
(application must be tested)
Solids content Compatibility
low
low to 1 %
medium 1 to 6 %
over 6%
over 50%
highly suitable
suitable
suitable under certain conditions
suitable under certain conditions
not suitable
TECHNICAL DATA
KEY TO DESIGNATION
Spray gun A KA 420 - 0
DATA
Spray gun AKA 420 (basic version) Part nbr.: 79331 006002
Fluid inlet pressure max. permissible 420 bar
Fluid temperature max. perm. 80 °C
Operating air pressure max. perm. 5 bar
Recommended switching frequency 160 Strokes/min
Mesh size of the filter elements 0.08 0.18 0.30
Weight of the spray gun without accessories 450 g
Without nozzles
Fluid inlet pressure
Conventional Airless
Automatic

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MATERIALS IN CONTACT WITH THE FLUID
Pos. Description Material
1
2
3
4
5
6
7
8
Gun body
Valve seat (diffuser)
Needle
Seat
Profile sealing ring
Spacer
Grooved ring
Filter element
SST 1.4305
SST 1.4305
Hardened steel
Hardened steel
POM
POM
PE
SST
Materials that contain chlorinated hydrocarbons such as trichloro-ethane or methylene chloride
react with aluminum to form metal-organic compounds.
These compounds are explosive and extremely caustic.
– The use is not permissible
GROUNDING, CONNECTION THREAD
Nominal diameter of the pressure air hose preferred DN 6; hose length < 1.5 m DN 4.
Fig. 3
Air pressure connection G 1/8, 7 deep
Thread M 10 for gun
fastening, 10 deep
Fig. 4
for positioning pin
Fluid connection G 1/4, 9 deep, on both sides

B.2.30.95-B- 6 -
MOUNTING THE GUN
- centrally at the rear end
LIST OF TOOLS
Tools for the spray gun in its basic version
Allen Screw
DIN 911
Open-end spanner
DIN 895
Spanner
DIN 3116
Drift
Part nbr.
70641 001002
SW 4 SW 27 A 20 Special tool
Tools for the spray gun accessories
Open-end spanner DIN 895
SW11 Air pressure connection (plug-in screw connection for DN 4)
SW12 Air pressure connection (plug-in screw connection for DN 4)
SW15 Fluid connection (angle)
Allen Screw DIN 941
SW6 Fluid connection (screw plug)
Position of the leakage hole
Positioning pin ø3
- on a bracket,
- on a reciprocating arm
- by means of a rod
- on a stationary support
Fig. 5
Fig. 6

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START-UP
Fasten spray gun
The threaded connection M 10 must be locked.
The leakage holes should point downwards.
Connect hoses and hose line(s)
Then check for tightness.
Install the in-line filter element
Automatic spray guns are delivered without filter elements.
Filter elements must be installed later (the choice of mesh size depends on spray tip used).
Before removing the valve seat (diffuser) the needle must be brought into the opened
position.
Switching on the control air (Pos. 1, page 3), does this.
Then - Screw out the valve seat (diffuser)
- Put the filter element 3 on to the valve seat (diffuser) 1
Note the mounting position of the profile sealing ring 2
- Install the valve seat (diffuser) with the filter element
The needle is in the opened position
Install the nozzles
- Put the nozzle in the union nut, align at the gun and tighten (pay attention to the tightening
torque).
Do not use any additional seals (The nozzle with pre-atomizer is self-sealing).
With older nozzles without pre-atomizers, a sealing washer should be installed instead of the
pre-atomizer.
Fig. 7

B.2.30.95-B- 8 -
IMPORTANT INFORMATION CONCERNING START-UP AND OPERATION
During prolonged operating pauses and/or during shutdown, no energy potential (fluid and/or
air pressure and/or electricity) should be present at the spray gun.
The working area of the spray gun must be protected.
The recommendations of the manufacturer of the fluid should be observed.
OPERATION
Do not exceed the specified technical data (page 4).
MAINTENANCE AND INSPECTION
- The automatic spray gun A KA 420 requires little maintenance.
• Flush thoroughly before operating pauses.
• Drain the condensed water every day from the filter or filter regulator if there is no automatic
water drainage in the compressed air supply to the spray gun.
• Regularly dismantle the filter element and thoroughly clean.
- The cleaning interval depends on the coating substance and must be determined by the
user.
• Check leakage behavior (air or material escaping from the leakage hole) at regular intervals –
e.g. once a week.
- The seals should be replaced if substantial amounts of air and fluid are escaping.
Loosen the sealing plug (cover) with spanner DIN 3116-A20.
By screwing in a tapping screw DIN 7981-ST4,2 the complete bearing bushing. 1and the
grooved ring 2can be simply removed.
The complete bearing bushing 1and the grooved ring 2are installed using the drift 3,
Part nbr. 70641 001002.
Fig. 8

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The parts should be lightly greased before assembly.
– We recommend “grease OKS 270” (Tube 100g, Part nbr. 70950 003001).
• The service life of the hose lines is adversely affected, and thus shortened, by surrounding
influences (oxygen in air, temperature, light, etc.), even if correctly handled.
It is recommended that they undergo regular visual checks and occasional checking of
performance.
As a precaution, the hose lines should be replaced by new ones at intervals set by the operator
(after 2 to 3 years).
NEVER dismantle a spray gun that is under pressure.
TIGHTENING TORQUE
Pos. Thread Material Tightening
torque
1 M24 x 1.5 X12CrMoS17 25 Nm
2 M 5 8.8 7 Nm
TROUBLESHOOTING
BREAKDOWN ANALYSIS
Component group Nature of defect Defect symptoms Possible cause Counter measure
Nozzle, filter
element Irregular fluid delivery Change in the spray pattern, no
application of fluid
Nozzle or pre-atomizer
obstructed, filter
element clogged up.
Clean nozzle, pre-
atomizer and filter
element
Sealing system
(needle seal, piston
seal)
Leakage at the
body of the gun Air or fluid escaping from the leakage
holes
Seal(s) worn Replace seals
Air connections Spray gun does not
work No switching Air supply interrupted Check the plug connection and air
hose
Fig. 9

B.2.30.95-B
- 10 -
FOOTNOTE
The spray gun is intended for attachment/installation to/in a machine for surface technology. The
start-up is prohibited until it has been established that the machine in/to, which the spray gun is to be
installed/attached, conforms to the provisions of the EU directive on machines in the version
93/44/EEC.
LIST OF REPAIR PARTS
Replacement part set, fluid valve Part nbr. 79978 040001
Pos. 10
Pos. 20
Pos. 30
1 off
1 off
1 off
Valve seat (diffuser) complete
Profile sealing ring
Needle complete
M 16 x 1 x 38.5
9.5 x 14 x 3.2
D 3 L 66.5
Repair kit
Pos. 40 1 off Union nut M 24 x 1.5 76089 080002
Replacement part set, seals Part nbr. 79978 041001
Pos. 10
Pos. 20
Pos. 30
Pos. 40
Pos. 50
Pos. 60
1 off
1 off
1 off
1 off
1 off
1 off
Spacer
Grooved ring
Seal
Bearing bushing complete
O-ring
Bearing
6 x 7.5 x 0.6
3 x 7.5 x 3.35
15 x 12 x 1.5
3.1 x 7.6 x 11
36 x 2.5B
4 x 1.55 x 118
Fig. 10
Fig. 11