Edwards B777-51-000, Инструкция по эксплуатации, Страница: 29 / 40

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Maintenance
B777-50-880 Issue D
5 Maintenance
5.1 Introduction
The maintenance operations for the EXT556H Turbomolecular pumps are described in the following sections.
The inlet-screen, the WCX water-cooler accessory and inlet-flange seals are available as spares (refer to
Section 7 ).
Fit the ISX inlet-screen as described in Section 3.3.1 . Fit the WCX water-cooler as described in Section 3.7.3 .
5.2 Bearing maintenance
When supplied, the pump contains sufficient lubricant to supply the bearings for life. No routine maintenance is
therefore required between bearing replacements. The bearings are not user-serviceable. The bearings will need to
be replaced when they reach the end of their service life. This is typically more than 20,000 hours, but may be less;
this depends on the type of pumping duty on which the pump is used.
When the bearings need replacement, Edwards recommends exchanging the pump for a factory reconditioned
replacement. Alternatively, the pump can be sent to an Edwards Service Centre to have the bearings replaced.
When returning EXT556H pumps to Edwards Service Centres please use the procedure included at the end of this
manual.
5.3 Rotor life
CAUTION
The fatigue life of EXT Turbo-pump rotors is typically 40,000 to 50,000 cycles. As a precautionary measure,
Edwards recommends that pumps are returned for a major service (rotor replacement) after 20,000 cycles of
rest to full speed and back to rest, or after 10 years use, whichever occurs first.
5.4 Clean the pump
CAUTION
Do not attempt to clean any parts of the pump other than external surfaces. Use of solvents may damage internal
pump components. Do not use abrasive materials on any surface of the HF variant.
If the EXT556H pump is contaminated inside, it may not be possible to achieve the specified ultimate vacuum, or
pump-down time may increase. The pump should be returned to a Edwards Service Centre where the pump will be
dismantled and cleaned. Use the procedure included at the end of this manual.
WARNING
Allow the pump rotor to stop, then disconnect the EXC Controller before removing the pump from
the vacuum system for maintenance or fault-finding procedures.
WARNING
Clean the external surfaces of the pump in a well-ventilated location. When using cleaning
solutions and solvents to clean the pump, observe all precautions specified by the manufacturer.
Avoid inhalation of any particulates which may be present in the pump.