Repair
58
WBV.PU.002.EN VX136Q V2.0
9.3
Rotary lobe change
Fig. 22: Rotary lobe change
When assembling, replace the O-rings, strain bolts and strain bolt cover.
1.
Open the Q cover (2)
Chap.
"Opening the Q cover".
2.
Remove cover (4) from the strain bolts and undo strain bolts (5). Pull off the pressure discs (7) using a
suitable bolt (strain bolt) or with the threaded rod of the lobe puller. Remove O-rings (6,8).
Notice: VVA series
With the VVA series with rubberised lobes (not with solid material lobes), the lobe core is protected by an
additional sealing ring in which the pressure disc and spring washer are located. Dismount this sealing ring
and reinstall it after the lobe change.
3.
Use a lobe puller to pull the rotary lobes (10) from the upper and lower shafts in pairs
Chap.
"How
the lobe puller works".
4.
Before installing the new lobes, thoroughly clean the contact surfaces of lobes and seal components!
5.
Install the new rotary lobes in reverse order
Fig.
"Arrangement of HiFlo and HiFlo
plus
".
Notice: solid material lobes
When assembling solid material lobes, fit an O-ring (12) on the gearbox side of each lobe. When installing
two lobe pairs, also fit an O-ring (11) between each lobe pair. The O-rings shown in the figure (12, 11) are
not present with rubberised lobes (not solid material lobes).
6.
When installing the pressure discs and spring washers, make sure that the spring washers (9) are
positioned correctly in the pressure discs
Fig.
"Position of pressure disc and spring washer".
Carefully press the pressure discs and spring washers into the lobe groove. The spring washers must
not fall into the extracting groove. Tighten the spring washers and pressure discs with the strain bolt.
Install the strain bolt cover (4).