Edwards EXT250 Series, Инструкция по эксплуатации, Страница: 16 / 42

B722-01-880 Issue K
Page 10 © Edwards Limited 2007. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Technical data
2.4 Pumping media
CAUTION
Do not use an EXT to pump gases containing more than 20% oxygen unless the pump is gas purged. If you do, the
lubricant will polymerise and the pump will fail prematurely.
CAUTION
Do not use the EXT to pump mercury vapour and do not allow mercury (for example, from a Mcleod gauge) to
come into contact with the pump. If you do, the pump rotor may corrode and fail.
Note that concentrations of gases may be modified by the compression of the pump.
2.4.1 EXT70 and EXT250 pumps without gas purge
These pumps are designed to pump the following residual gases normally used in high-vacuum systems:
You can use the pumps to pump oxygen and water vapour, subject to the following conditions:
If you wish to pump a gas not in the list above, contact your supplier for advice. If you do not contact your supplier,
you may invalidate the warranty on the pump. EXT70 and EXT250 pumps are not suitable for pumping aggressive or
corrosive gases.
2.4.2 EXT250 pumps with gas purge
When purged with an inert gas, EXT250 pumps can be used to pump oxygen in concentrations above 20% by volume.
WARNING
Vent dangerous gases and gas mixtures safely. Do not expose people to these gases.
WARNING
Do not use EXT pumps to pump explosive gas mixtures as the pumps are not suitable for this
purpose.
z
Air
z
Carbon monoxide
z
Neon
z
Ethane
z
Methane
z
Nitrogen
z
Krypton
z
Argon
z
Propane
z
Carbon dioxide
z
Helium
z
Hydrogen
z
Butane
z
Oxygen The oxygen concentration must be less than 20% by volume.
z
Water vapour You must ensure that vapour does not condense inside the pump; refer to
Section 3.7.2 .