Edwards STP-301 Series, Инструкция по эксплуатации

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STP-301/451 Series Instruction Manual
2-1
Installation
2 Operation Principle of the STP Pump
The STP-301/451 is a series of magnetically-levitated turbomolecular pumps, featuring
the following:
•
Oil free
•
Low vibration
• High reliability
The STP pump is configured so that rotor blade (1) and stator blade (2) are aligned
alternately in the axial direction. Gas molecules are pumped from the inlet port to the
outlet port by the high speed rotation of the rotor.
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 3 pairs of active magnetic bearings. The rotor is
supported in the radial direction by 2 pairs of radial direction active magnetic bearings
that consist of radial sensor (3) and radial electromagnet (4). A pair of axial direction
active magnetic bearings consists of axial sensor (5) and axial electromagnet (6) to
support the rotor in the axial direction. Because the rotor is thus supported without
mechanical contact, it can rotate with low vibration.
There is less heat generated from magnetic bearings because there is no friction.
Therefore the STP pump requires no cooling. However, the STP pump requires water
cooling or air cooling during baking and gas pumping.
Taking into consideration a breakage of magnetic bearings, touch down bearings (7) and
(8) coated with solid lubrication have been installed. They do not contact the rotor
during the rated operation.
A radial sensor, an axial sensor, a rotational speed sensor and a temperature sensor
always monitor the magnetic bearing as well as the rotor. If an abnormality/error
occurs, the rotor will stop.