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OPERATION & MAINTENANCE INSTRUCTIONS - ORIGINAL VERSION
AVK DOUBLE ECCENTRIC BUTTERFLY VALVES
SERIES 756
Page 10/13
MI Butterfly756 rev. AC 2018
7.3 MAINTENANCE WORK AND REPLACEMENT OF PARTS
7.3.1 DESIGN
The below figure serves as a partial overview of the description for the below working steps. For information about spare
parts and their parts number, please contact AVK.
1. Bolt
2. End plate
3. Axial bearing
4. O-ring
5. O-ring
6. Stub shaft
7. Body
8. Drive pin
9. Valve shaft
10. Key
11. Self-lubricating bearing
12. Disc
13. Washer
14. Bolt
15. Seal retaining ring
16. Disc seal
17. Disc cover
18. Screw
7.3.2 RECOMMENDATIONS FOR THE REPLACEMENT PARTS
Replace disc seal and O-rings whenever necessary.
Intervals of replacement depend on the operating conditions.
7.3.3 CLEANING AND LUBRICATION
Remember to grease the disc seal and O-rings slightly during replacement. Only use lubricants approved for drinking
water applications according to local legislation.
7.3.4 REPLACEMENT OF THE DISC SEAL
The disc seal can be replaced without disassembly of the disc.
Disassembly of the disc seal (only with fixed disc on gearbox):
• Open the disc in fully open position (12).
• Detach the retaining ring screws (15).
• Remove the retaining ring (15) and the disc seal (16).
• Clean the disc (12) in the sealing zone.
• Check the seat ring in the body for damage or deposits.
• Insert the new disc seal (16) into the groove of the disc and grease it slightly.
• Insert the screws (14) and fasten them with a torque as specified in section 7.3.6.
7.3.5 REPLACEMENT OF THE O-RINGS IN THE SEAL HOUSING
Remember to grease the disc seal and O-rings slightly during replacement. Only use lubricants approved for drinking
water applications according to local legislation.
