Maintenance - Alcatel I series User Manual

Maintenance frequency
Draining
Maintenance
An incorrect ultimate vacuum or a reduction in pumping speed are signs that the
oil has deteriorated.
The periodic inspection of the state of the oil is performed by comparison with
a sample of new oil in order to check the level of contamination or deterioration
of the lubricant.
The frequency at which oil is renewed is adapted to the type of operation:
- if the oil is cloudy, this indicates that condensables have been absorbed during
pumping. The oil can be regenerated using the gas ballast (see
page
77].
- a thickening of the oil, together with a blackish color and a "burnt" smell
indicate that the oil has deteriorated.
Drain the pump and flush it.
Normally, for a pump operating continuously at a pressure lower than 0.75 Torr
(1
mbar) with a clean gas (dry air), the oil should
be
changed every 6 months.
This value is given as a guide only. It may be extended to 1 year if the ultimate
vacuum required is sufficient (for primary vacuum pumps).
Similarly, if the pump is stopped frequently for long periods, the oil should be
changed at intervals of 6 months
to
a maximum of 1 year (oil may become
sticky).
Note: Every pumping operation is different. This oil must therefore be changed at
intervals adapted to each specific application. The use of certain accessories
(see
page
63) can reduce the frequency of these maintenance operations.
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The pump must be drained when hot and after the oil case has been vented to
atmospheric pressure. For this:
- switch off the pump;
- isolate the pump or disconnect from the
installation;
- tilt the pump;
- unscrew the draining plug on the side of
the oil case and the filling plug on the top
of the oil case.
When all the oil has drained, replace the
two plugs temporarily and run the pump
for about 10 seconds leaving the intake
open. Take care with the oil mist which
may appear at the exhaust. This operation
removes the oil from the functional block;
- drain this oil by removing the draining
plug; : . : ' " .
- replace the draining plug and fill with fresh oil to the appropriate maximum
of the oil case oil sight glass through the filling orifice
(see page 69).
87
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