Sharp R-880D Manual de Instruções descarregar pdf (Página 98)

STP-200/300/400 Series Instruction Manual

11 Operation Principle of the STP Pump

(See Figure 11.1.)

The STP-200/300/400 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 supported without mechanical contact, it can rotate at 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

air cooling during baking and gas suction. 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 with the rotor during the

rated operation.

A radial sensor, an axial sensor, a rotation sensor and a temperature sensor

always monitor the magnetic bearing as well as the rotor. If an

abnormality/error occurs, the rotor will stop.

11-1

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Sharp R-880D Manual de Instruções Página 98