23
Use feeler gauges and a
depth micrometer to verify the back and radial clearances
between the rotors and the rotor case. A depth micrometer should be used to verify the
front clearance.
6.5 ROTOR CLEARANCE
Rotor clearance must be precisely maintained to provide maximum pumping efficiency, and to
prevent contact between rotors, rotor case, and front cover during operation.
If pumping efficiency is lower than expected or if parts contact has occurred during operation
(Within rated differential pressure), check the rotor clearances and adjust, if incorrect.
Standard Rotor Clearances (mm)
Model
Back Face
Front Face
Radial Sides
Radial Top &
Bottom
Rotor to
Rotor
ZL105
0.07
0.07
0.07
0.07
0.1
ZL110
0.07
0.07
0.07
0.07
0.1
ZL115
0.15
0.15
0.27
0.12
0.15
ZL120
0.15
0.15
0.3
0.13
0.13
ZL220
0.2
0.2
0.3
0.15
0.2
ZL225
0.2
0.2
0.4
0.2
0.2
ZL330
0.3
0.3
0.4
0.2
0.3
ZL340
0.3
0.3
0.45
0.25
0.3
ZL440
0.35
0.35
0.55
0.3
0.4
ZL450
0.45
0.45
0.7
0.45
0.4
There are two areas of rotor clearances as illustrated above:
-
Rotor tip clearance; not adjustable set by manufacturer
Fig. 26
