Description
1.2 Compatibility with
pumped media
The MAG (W) 1600/2000 C/CT are specifically designed
for the needs of the semiconductor industry.
Corrosion protection
To protect the pump from corrosive gases it is mandatory
to use dry Nitrogen purge during operation of the
pump.The purge gas protects the bearing section and
the motor from corrosive gases.
The rotor and the stator of the pump are KEPLA-coated
to prevent corrosive attack caused by the process gases.
The corrosion protection of the pump is effective only
when the pump is protected from moisture during
standstill and storage. If the process gas contains moi-
sture, contact Leybold for recommendations.
Sublimation
Some media (e.g. AlCl
3
) can sublimate in the pump and
form deposits. Thick coatings can infringe on the requi-
red operating clearence and ultimately cause the pump
to seize.These deposits can also react with moisture and
generate corrosive gases (e.g. HCl).This can become
very critical when the pump is exposed to air. Deposits
can be avoided in many processes by heating the pump
with TMS (Temperature Management System).
The TMS is integrated in all CT-versions. The purpose of
the TMS is to keep the baseflange temperature in a con-
stant range. To achieve the temperature the pump is
equipped with a heaterband.
Some media ( e.g. metall organic compounds ) can
decompose at the hot surface of the pump and build lay-
ers. Please direct any inqueries to the manufacturer.
Ignition danger
During operation the pressure inside the MAG is so low
that there is no danger of ignition (at pressures below
about 100 mbar). A hazardous condition will be created
if flammable mixtures enter the hot pump at pressures
above 100 mbar. During operation the pump can reach
temperatures as high as 120°C (248°F). If the pump is
damaged, sparks could occur which could ignite explosi-
ve mixtures.
Please consult us regarding the media which can safely
be handled with this unit, with or without purge gas.
4
GA 05.130/3.02 - 05/98
1.3 Design of the MAG
The MAG comprises basically the pump housing, the
multistage rotor with the stator package, the drive, and a
magnetic bearing.
Rotor
The rotor is made from a high strength aluminium alloy.
The rotor and the lower stator plates are protected with
a special ceramic layer ( KEPLA-coat ). The standard
rotor is a multi-stage axial-flow turbine. In addition to the
turbine stage the wide range rotor has a screw stage.
Both rotors are machined from one piece and the geo-
metry of the the blades is optimized for high compressi-
on and pumping speed of the typical gases used in semi-
conductor manufacturing processes ( e.g. SF
6
, Ar, BCl
3
).
Bearings
The MAG 1600/2000 has a built-in precision 5-axis con-
trolled magnetic bearing. The rotor is suspended by
trouble-free magnets:
• along two orthogonal axes in each of two radial planes
• and completely in the axial direction
The bearing concept allows for low vibration operations
and insures operation of the pump in any mounting posi-
tion. Magnetic bearings also guarantee ultra-clean vacu-
um because no grease is used for lubrication of bea-
rings.
Two touch down bearings are provided to stabilize the
rotor mechanically if impacts occur during operation.
They are only used in case of the breaking of the power
supply cable during operation, strong shocks, or faulty
electronics.
Motor and control
A DC motor without commutator is used to power the
rotor.
Drive voltage for the motor and the operating voltage for
the magnetic bearing are supplied by the MAG.DRIVE
frequency converter. It also handles the automatic moni-
toring of these systems.
The pump is equipped with a data storage device which
stores the important operating parameters during the
complete operation time of the pump.
The converter monitors continously all important opera-
ting parameters and provides warning and alarm signals
in case the operating conditions exceed the specification
or the set threshold.
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