Edwards STP-iX455, Инструкция по эксплуатации

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STP-iX455/iXL455 Series Instruction Manual
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2 Operation Principle of the STP Pump
The STP-iX455/iXL455 series pump is a series of a magnetically-levitated turbomolecular
pumps, featuring the following:
Oil free
Compact size (Integrated control unit)
Low vibration
High reliability
Figure 2.1 shows the cross sectional view of the STP pump. The STP pump is configured
so that rotor blade (1) and stator blade (2) are aligned alternately in the axial direction.
The rotor blade (1) is supported by the magnetic bearing without mechanical contact.
Therefore, the STP pump requires no lubrication oil, unlike conventional turbomolecular
pumps using ball bearings.
The magnetic bearing consists of 5 pairs of active magnetic bearings. The rotor is
supported in the radial direction by 4 pairs of active magnetic bearings that consist of
radial electromagnet (3). A pair of axial electromagnets (4) supports the rotor in the axial
direction.
Because the rotor is entirely magnetically supported, it rotates with low vibration.
Moreover, STP-iXL455 series, with which the structure of low vibration and low noise (6)
and (7) are equipped, suppresses vibration and noise more than STP-iX455 series.
There is less heat generated from magnetic bearings because there is no friction.
Therefore the STP pump requires no cooling. However, the STP pump does require
water-cooling or air-cooling during baking and gas pumping.
Taking into consideration an unexpected failure of the magnetic bearings, touch-down
bearings (5) coated with solid lubrication have been installed. They do not contact the
rotor during normal operation.
The status of the rotor and magnetic bearing is continuously monitored via circuits
detecting rotor displacement, rotational speed and pump temperature. If an
abnormality/error occurs, the rotor will stop.