VERDER JEC JRZW Series, Operation And Maintenance Manual

Page: 13 / 23

13
ROTOR CLEALANCE
Rotor clearance must be precisely maintained to provide maximum pumping efficiency, yet prevent
contact between rotors, rotor housing, and front cover during operation. If pumping efficiency is
below expectations, or if parts contact has occurred during operation (Within rated differential
pressure), check, rotor clearances and adjust if incorrect.
Shims Rotor to Housing
Radial Top & Bottom
Back Face Front
Face
Rotor to
Rotor
Radial Sides
Standard Rotor Clearances (mm)
Model Back Face Front Face Radial Sides
Radial Top &
Bottom
Rotor to
Rotor
JRZW120-031-06 0~0.05 0~0.05 0~0.05 0~0.05 0~0.05
There are two areas of rotor clearances as illustrated following:
Rotor tip clearance – not adjustable set by manufacturer
Front and back face clearance – adjustable by shim
Rotor width and body depth are fixed at manufacture. Therefore, with the correct rotor size selected,
the only maintenance adjustment that can be made is the proportion of front and rear clearance.
Measure the front clearance as follows:
1. The rotor to rotor housing back face clearance is maintained by the shim (60).
2. Check that the rotor housing is tight to gearbox (1). And check the rotor bolts (6) are tight.
3. Measure the clearance between the back face of the pump housing and the back of the rotor with
a feeler gauge. Check the reading with the recommended back face clearance.
4. If incorrect, adjust by adding or removing shim plates (60) from behind the pump housing.
5. Check each rotor and adjust as necessary.