Bakeout Operation - Agilent Technologies Miniature 913-0037 Notice De Mode D'emploi

4 Instructions for Use
Operating Notes
B akeout Operation
When a VacIon pump does not reach the desired base pressure, and
there are no leaks, it is necessary to bake the system to remove water
vapour. This is done by heating the pump and all the components in
the system.
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Heat the pump body and the system with a bakeout oven unit or
heating strips to temperatures between 150 °C and 250 °C
(250 °C is the maximum allowable for most bakeable high voltage
cables). This temperature is high enough to degas the pump
surfaces of water vapour without damaging the magnet and high
voltage connector. Note that the system components must be
compatible with the bakeout temperature. The heating must be
approximately even on all vacuum surfaces or water vapour can
recondence on the cooler surfaces preventing achievement of
UHV vacuum pressures.
Leave the pump control unit on and monitor the pressure. It
must never increase above 5x10
exceeded, turn the bakeout off and then on again when low
pressure is restored.
To control the heaters and to monitor to high pressure limit
during bakeaout in automatic mode, a pressure-sensitive relay
may be used.
Bake the VacIon pump for at least eight hours. Longer bakeout
periods are recommended when the pump has been used with
heavy gas load or when UHV pressure, 10
desired.
As the pump and system cool down to room temperature, a drop
in pressure should be observed.
Since VacIon pumps can be used in many different applications,
some are being used successfully in vacuum processing. The high
voltage feedthrough on the VacIon pump, can stand a limited
number of high temperature bakeout cycles (to +400 °C). Hence,
Agilent recommends only a few high temperature bakeouts to
+400 °C.
Miniature and 2 l/s VacIon Pumps User Manual 87-400-044-01 (E)
-5
Torr (mbar); if this value is
-9
Torr (mbar) or less is