JABSCO Hy-Line, Installation, Operating, Maintenance And Spares Manual

Page: 34 / 52

07/03
Hy~Line
and
Ultima
Lobe Pumps
a) With the pump assembled, the end
cover (122) removed and the rotors (56
& 57) and rotorcase (1) fully secured to
the correct torques. Measure the rotor
front end clearances (X) using a depth
gauge or feeler gauge and straight
edge.
b) If the clearance is incorrect, remove
the rotors (56 & 57) see section 6.02.
Remove the O rings (31) and shims
(30), the shims are cut to allow them to
slide over the shaft. Tri-bolt shaft shims
are uncut.
c) If mechanical shaft seals are fitted take
great care not to scratch, chip or
damage the seal faces.
d) Measure the thickness of the shim
pack for each shaft and calculate the
thickness of shim to add or remove on
each shaft to give the front clearance
specified in the Performance Data
Sheet. Shims are available in
increments of 0.025 mm (0.001 inch).
(See Figure 18).
e) To fit the shims open them slightly and
slide onto the shaft up to the shoulder
(A) - see figure 19. NOTE: New shims
are not cut, this will need to be done
with scissors prior to fitment.
(LH32
and LH34 shims are not split)
f) Fit the shims and retain them with the
O-ring (31).
(No O-ring on LH32 and
LH34 models)
g) Refit rotors and tighten retaining bolts
(59) to correct torque. Recheck end
clearance and re-adjust if necessary.
If any side-to-side movement of the rotors
can be detected or if the radial clearance is
incorrect, check the condition of the
bearings and their pre-load. (see section 7
Inspection and repair of gearbox.)
There is no adjustment for radial clearance -
replace shafts and/or bearings if worn.
When re-assembling the pump always
tighten screws to the correct torque
specified on the Performance Data Sheet.
6.12 END COVER RELIEF VALVE
Disassembly:
Before dismantling the relief valve assembly
it is advisable to measure the distance from
the end of the housing (133) to the end of
the adjusting screw (155). This will enable
the correct pressure setting to be re-set
without having to go through the set up
procedure.
New relief valves are not supplied
factory set. This pressure setting
should be done when the valve is fitted
to the pump. See section 2.12
Page 32
Figure 19 - Fitting Shims