Vacuum Fittings Feedthroughs - Granzow

General
Introduction
According to DIN 28400, the term
“Ultra-high Vacuum (UHV)” designates
the pressure range below 10 -7 mbar.
Several physical quantities, such as
mean free path, monolayer time, flow
density of the particles impinging on
the walls, leak rate and the degassing
rate are of significance in the characterization
of this pressure range. For the
definitions of these quantities refer to
technical publications on this subject.
In order to attain or maintain pressures
below 10 -7 mbar, the following preconditions
must be met:
- The vapor pressure of the pump
fluid or lubricant should be in
accordance with the desired
ultimate pressure
- the leak and degassing rates of
the entire apparatus including its
installations must be extremely
low.
Generally, both leak rate and backstreaming
effects through the pump can
be kept at sufficiently low levels by
using suitable UHV sealing materials
and pumps.
However, a sufficiently low outgassing
rate can only be achieved by baking
out the entire apparatus at temperatures
of about 300 °C for a longer period
of time. It is only under these conditions
that the mono-layers of atoms or
molecules, which attach quite firmly to
the surfaces of the vacuum apparatus
including its installations, are desorbed.
Consequently, components for UHV
systems are generally made of stainless
steel. Metal gaskets, ceramic
feedthroughs and bakeable observation
windows are used exclusively.
For applications in the extreme UHV
range (XHV) the outgassing rate of the
CF flanges and the UHV components
can be reduced by about two orders
of magnitude by a special degassing
process.
The high standard of development and
manufacture combined with the use of
high quality materials guarantee that
UHV components from Oerlikon
Leybold Vacuum are able to meet even
the most demanding requirements.
Advantages to the User
- Stabilized Oerlikon Leybold
Vacuum knife-edge
- High reliability
- Special knife edge profiles ensure
the highest degree of leak
tightness
- Flange connection can be baked
out up to 450 °C
- Easy to assemble, helium-tight
- Symmetrical flange connection
- Equal sealing profiles
- Small outside diameter with
respect to the nominal width
- Can be joined by welding or
brazing using any desired
process, also with other nickel
chromium steel grades
- For use either with a flat gasket
made of OFHC copper (oxygenfree)
or FPM O-ring
- Self-centering
- Fixed and rotary flanges in almost
any size
Oerlikon Leybold Vacuum Full Line Catalog
03 C13