Instruction manual

Issue H Oct 04
PAGE
32
GV Dry Vacuum Pumps
MAINTENANCE
32
6. Clean all of the sight-glass components and the
sight-glass recess in the gearbox (2) with a soft
lint-free cloth. If necessary, use a suitable
cleaning solution; if you use a cleaning solution,
ensure that all of the solution is removed before
you reassemble the sight-glass.
7. Refit the compression ring (6) in the sight-glass
recess in the gearbox (2).
8. Fit two new ‘O’ rings (7, 9) and the sight-glass
(8), then fit the bezel (10) and secure with the
four M5 screws (11).
9. Place a suitable funnel in the oil filler-port (1).
10. If the oil drained from the pump is very
discoloured, flush the gearbox with new or
clean oil two or three times, until the oil which
drains from the gearbox is clean.
11. Wipe clean the oil drain-plug (3), then fit a new
bonded seal (4) to the drain-plug.
12. Fit the oil drain-plug (3) and bonded seal (4) to
the oil drain-port (5).
13. Fill the gearbox through the funnel, with the
correct grade and quantity of oil. Allow the oil
to drain into the gearbox and then check the
level on the oil sight-glass (refer to Section 5.3).
14. Remove the funnel and refit the oil filler-plug
(12) and bonded seal (13) to the oil filler-port
(1).
15. Dispose of the used oil safely: refer to
Section 6.2.
5.8 Relubricate the high-vacuum
bearings
The frequency of relubrication of the high-vacuum
bearings depends on the operating temperature of
your pump; Table 12 shows the recommended
frequencies. For maximum pump reliability, we
recommend that you change the gearbox oil when
you relubricate the high-vacuum bearings: refer to
Section 5.3.
Use the following procedure to relubricate the high-
vacuum bearings:
1. Refer to Figure 11. Remove the three M8
bearing cap retaining bolts (5) which secure the
bearing cap (4) on the drive rotor shaft; ensure
that you do not accidentally remove one or
more of the bearing carrier bolts (8, see detail
A), which are next to the bearing cap retaining
bolts. Remove the bearing cap (4) and the
bearing cap ‘O’ ring (3).
2. Repeat Step 1 to remove the bearing cap (6)
and bearing cap ‘O’ ring on the driven rotor
shaft.
3. Use a clean lint-free cloth to remove as much
old grease as possible from the inside face of the
bearing caps (4, 6) and from the top of the
bearings (2). Do not use your fingers for this
operation.
4. Inspect the bearings (2) for obvious signs of
wear or the presence of debris. If the bearings
are worn, contact your supplier or BOC
Edwards for advice.
(Continued on page 34)
Pump operating temperature
(measured at the point shown
in Figure 1, item 3)
Recommended frequency
of high-vacuum bearing
relubrication
30 to 45
o
C, 86 to 113
o
F Every 18 months
46 to 60
o
C, 115 to 140
o
F Every 12 months
61 to 75
o
C, 142 to 167
o
F Every 6 months
76 to 90
o
C, 169 to 194
o
F Every 3 months
Table 12 - Recommended frequencies for high-vacuum bearing relubrication