Page 164 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

146 Major Process Qutpment Maintenance and Repair

14. Place support blocks on the bed of an arbor press. Set the blower,
gear end pointing down, on the two blocks. Make sure the blocks
support the rotor housing (3). Press the gear end plate (4) and ro-
tors (1 & 2) out of the rotor housing (3) simultaneously.
15. Lift the housing off the rotors and remove the nondrive end plate
(5) by tapping the end plate from the inside of the housing. Place
the rotor housing back over the rotors.
16. Set the unit on support blocks with the gear end pointing upward.
Do not extend blocks into the rotor bores. Press the rotors out
from the gear end plate. Mark each rotor and note the position of
the keyways.
17. Remove the bearing retainers (14) on drive end plate and push the
bearings (9) from the end plates.
18. Remove lip seals from the end plates.
19. Clean all parts with clean solvent.

Assembly

Here is a typical assembly sequence and rule-of-thumb dimensions:

1. Install lip seals in end plates. Ensure the lip is towards the bearing
side.
2. Install rotors in drive end plate.
3. Stand rotors on free end in arbor press. Keyways must be in line.
4. Place drive end plate (4) with lip seals installed, over rotors.
5. Press gear end ball bearings (9) on rotor shafts and into bearing
bores in end plate.
6. Install gear end bearing retaining ring (14), and screws (62).
Caution: The bearings used have flush ground faces and should
be installed with manufacturer’s bearing number toward
the gear side. Do not use standard bearings which have
not been flush ground within .001 in. tolerance.
7. Install timing gears.
8. Insert the gear keys in their proper location.
9. Install drive gear first. Press gear on drive rotor. To prevent jam-
ming, timing marks must be arranged as shown on Figure 4-2B.
Secure gears with lock plate (65) and hex screw (66). Check face
runout not to exceed .001 in. TIR.
10. Check clearance between face of the drive end plate and the rotor
lobe ends (.006 in. to .009 in.).
1 1. Install rotor and drive end plate assembly in rotor housing (3). Se-
cure with 4 hex screws (26). Be sure dowel pins (63, 58) are in