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A301-51-880 Issue T
5.5
Change the pump oil
WARNING
Changing the oil in an EH pump from hydrocarbon to PFPE (Fomblin) could potentially cause a
safety hazard. Fomblin EH pumps are generally used in hazardous applications which may involve
the pumping of gases with high concentrations of oxygen. If hydrocarbon oil comes into contact
with gases with an oxygen concentration greater than 25%, an explosion can occur.
Therefore, if you want to convert an EH pump that has been used with hydrocarbon oil to use PFPE
(Fomblin) oil, you cannot simply flush the EH pump with new PFPE oil. You must return the EH
pump to a Edwards Service Centre for overhaul and cleaning by qualified Edwards service
engineers. The change in oil type requires a complete strip down of the EH pump, and thorough
cleaning of all parts, so that all traces of hydrocarbon oil are removed.
WARNING
Ensure that the correct grade of oil is used and that the oil-levels in the pump are correct. If an
incorrect oil is used or if an oil-level is incorrect, EH pump performance may be affected and the
EH pump may be damaged, which will compromise its constructional safety.
Replace the pump oil as described below. Refer to
Figure 1
and
2
for the location of the oil-filler and drain-plugs.
1. Switch off the EH pump, vent it to atmospheric pressure and allow it to cool.
2. Remove the hydrokinetic drive/gearbox oil filler-plug.
3. Remove the hydrokinetic drive/gearbox oil drain-plug from the underside of the hydrokinetic drive/gearbox and
allow the oil to drain into a suitable container.
4. Remove the shaft-seal vented oil filler-plug. Use a suitable pump to suck the oil out of the shaft-seal reservoir.
5. Refit the hydrokinetic drive/gearbox oil drain-plug.
6. Refer to
Section 3.4
and fill the hydrokinetic drive/gearbox and shaft-seal reservoir with oil.
7. Refit the hydrokinetic drive/gearbox oil filler-plug and the shaft-seal reservoir oil filler-plug.
8. On all EH1200, EH2600 and EH4200 model pumps only:
Remove the oil filler-plug on the gear-cover.
Remove the oil drain-plug from the underside of the gear-cover and allow the oil to drain into a suitable
container.
Refit the oil drain-plug and refer to
Section 3.4
to refill the gear-cover with oil.
Refit the oil filler-plug.
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
A301-51-880 Issue T
5.7
Overhaul the pump
The EH pump can only be overhauled by Edwards service engineers: contact your supplier or Edwards for advice.
Figure 23 - Lubricate the rear bearing (EH250, EH500 and EH500IND pumps only)
1. Pump-body
5. 'O' ring
2. Bearing
6. End-cover
3. Spacer
7. Socket-head screw
4. Shims
8. Cover-cap
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Page 47
Page 49
A301-51-880 Issue T
5.6
Lubricate the rear-bearing (All EH250 and EH500 model pumps
only)
WARNING
When you remove the end-cover, take note of the exact locations of the spacers and shims
(Figure
23, items 3 and 4) inside the end-cover. You must refit these items correctly in order to
ensure that the rotor clearance settings remain correct. Altering the rotor clearance settings may
compromise the constructional safety of the pump and, if the pump is part of an ATEX system, may
invalidate the system certification.
Use the following procedure to replace the grease in the rear-bearing. Refer to
Section 2.6
for the correct type/grade
of grease.
1. Switch off the EH pump and isolate it from the electrical supply. Vent the EH pump to atmospheric pressure.
2. Refer to
Figure
23. Remove the four plastic cover-caps (8) from the bearing end-cover (6).
3. Undo and remove the socket-head screws (7) located under the four plastic cover-caps.
4. Remove the end-cover (6) and 'O' ring (5). Dispose of the 'O' ring safely.
5. Note the exact location of the shims (4) and spacers (3) inside the end-cover (6). Clean off all visible grease from
the end-cover taking care not to misplace or damage the shims and spacers.
6. Use a soft, clean, lint free cloth or a plastic or wooden spatula to remove all visible grease from both bearings
(2).
7. Fill the visible side of each bearing (2) with clean grease, then lightly force the grease into the bearing.
8. Refill the visible side of each bearing (2) with clean grease.
9. Apply a light wipe of high-vacuum grease to the new 'O' ring (5) and fit into the groove in the end cover (6).
10. Check that the shims (4) and spacers (3) are correctly located in the end-cover (6).
11. Refit the end-cover (6) and secure it with the four socket-head screws (7). Tighten the screws evenly and refit
the plastic cover-caps (8).
12. Leak test the system and seal any leaks found.
Page 48
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
A301-51-880 Issue T
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Page 50
© Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
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