Nordson-EFD-741V-Maintenance-Guide.pdf

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™
Electronic pdf files of Nordson EFD
manuals are also available at
www.nordsonefd.com
IMPORTANT!
Save this Sheet.
Forward to
Maintenance or
Tool Crib Supervisors
741V Series Needle Valve
Maintenance & Parts Guide
741V Series Needle Valve | Maintenance & Parts Guide
2 www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide.
Valve Disassembly and
Reassembly Procedures
To prevent damage, the valve must be disassembled
starting at the fluid outlet end of the valve.
CAUTION
Valve Maintenance
To thoroughly clean the fluid body and replace needle
packings:
1. Remove the needle stroke control knob and
spring.
2. Remove the inlet fitting and tip adapter/seat
assembly.
3. Remove the fluid body from the air cylinder body,
then remove the O-ring.
4. Use extraction tool #7021552 to remove the
needle packings from fluid body.
5. Remove any remaining packings and remove the
spring from the needle.
6. Clean the needle with a cloth dampened in
solvent, and lubricate the needle with Nye
Lubricant #865, included in the Maintenance Kit.
7. Replace the O-ring and reassemble the valve in
the reverse order of disassembly.
NOTE: Ensure that the lower cylinder needle
O-ring is back in place before reinstalling the
packing spring.
Replacing the Piston and Needle
Assembly or Piston O‑Ring
8. Remove the needle stroke control knob.
9. Remove the piston return spring and thrust
washers.
10. Remove the snap ring.
11. With small pliers on the spring pilot, pull the
piston and needle assembly out of the air cylinder.
The piston and needle assembly are one unit and
cannot be disassembled.
12. Clean the air cylinder body wall and replace the
piston O-ring. Lubricate the O-ring with Nye
Lubricant #865, included in the Maintenance Kit.
13. Reassemble the valve in the reverse order of
disassembly.
14. Leak test the valve (see “Leak Testing”).
Tip adapter/
seat assembly
#7007026
Fluid inlet fitting
#7021499 for 1/4" OD
tube (installed)
#7007038 for 3/8" OD
tube (supplied)
Needle packing assembly
#7007014
SafetyLok
™
collar
#7007027
Fluid body
#7021252 (stainless steel)
#7021250 (hard-coated aluminum)
Packing spring
#7014683
3
2
7
17
16
O-ring (Buna-N)
#7014718
O-ring (Buna-N)
#7014684
Retaining
washer
#7014685
O-ring
(Buna-N)
#7018502
4
Screws
#7023632
741V Series Needle Valve | Maintenance & Parts Guide
3www.nordsonefd.com info@nordsonefd.com +1-401-431-7000 Sales and service of Nordson EFD dispensing systems are available worldwide.
Maintenance Tools
6" adjustable wrench
Snap-ring pliers
Packing extraction tool #7021552
Leak Testing
15. Set the needle stroke control at two turns open.
16. Shut off the actuating air. Install an air hose in the
fluid inlet and connect it to a 7.0 bar (100 psi) air
supply.
17. Submerge the tip adapter/seat assembly in water.
If air bubbles appear, reseat the parts (see next
steps).
Reseating the Needle and Tip
Adapter Assembly
18. Disconnect all air to the valve.
19. Rotate the stroke adjustment knob to the closed
position.
20. To compress the needle into the tip adapter,
further rotate the stroke adjustment clockwise one
additional reference mark.
21. Return the stroke adjustment to the normal setting
and cycle the valve. If a slight leak remains, repeat
steps 1 and 2.
22. If the leak persists, replace the tip adapter.
General Maintenance Kit
#7007030
Includes all O-rings, needle packing
assembly, and lubricant
Valve Disassembly and
Reassembly Procedures
(continued)
Air cylinder body
#7021245 (aluminum)
Piston and needle
assembly #7007025
Air input hose #7007036
Piston return spring
#7014688
9
5
11
10
6
Needle stroke control
#7021256 (aluminum)
Snap ring
#7014757
Thrust washers
#7014862
O-ring
(Buna-N)
#7014687
12
O-ring #7014686
1 8 15
19 20 21
18
Part # Description
7007029 741V-SS valve
7021239 741V-SS-TR valve
7015584 741V-SS-BP valve