Gas bearings
OFTTech's unique gas bearing technology
enables the operation of rotors to run on a thin film of self-generated pressurised
air, resulting in a 'zero friction' load bearing interface between surfaces
which would normally be in contact. By virtue of this 'non-contact' technology,
air bearings avoid the following traditional bearing-related problems:
- Friction
- Wear
- Lubricant, financial and environmental
costs
- Imprecise rotor location, excessive
rotor movement
- High speed instability, vibration
and noise.
Gas bearings fall into two categories:
- Externally pressurised or
Aero-Static. In these
bearings a supply of high pressure gas is necessary at all times, giving
the advantage of low speed load capability, but the disadvantage that if
the supply pressure fails so does the bearing. These are commonly used today
in many machine tool applications.
- Self acting or Aero-Dynamic.
These bearings generate their own high pressure to support the loads
using the rotation of the rotor. Hence these bearings will not support high
loads at low speeds, but have the major advantage that no gas need be supplied.
There are several other additional
advantages to the OFTTech gas bearing technology:
- Rotors can run up to 500,000
rpm without vibration, stability or thermal problems
- In most cases, a very long,
maintenance-free life, can be expected
- Costly down time, dismantlement
and replacement fitting costs can all be minimised
- The silence of gas bearings
makes them especially suitable for medical environments
- No external supply of gas is
required
- Precise motion: non-contact
air bearings average out any errors due to surface finish or irregularities
- As well as air, gas bearings
can operate in other process gases, such as helium, xenon, air-conditioner
refrigerants, oxygen, or nitrogen
- Temperature variations: operation
is possible over wider range of temperatures compared to that of other bearings,
even cryogenic temperatures.
OFTTech has over 20 years of personnel
experience in gas bearing design and use with examples of rotors running up
to 400000 rpm in compressor, expander and cooling applications.
Gas bearings are highly complex
components and must be carefully integrated into the application.
gas bearings
