02-05-2012, 05:02 PM
Centrifugal Compressors with Magnetic Bearings
[attachment=21096]
Features
Use of non-contact bearings
There is no contact between the body of the compressor and the rotor, so there are no parts that wear.
The bearings can be used semi-permanently without maintenance.
No need for lubricating oil or oil seals
There is no need for lubricating oil or oil seals because non-contact gas seals are used, so there is no need to change oil filters or inspect pumps.
Parts related to lubricating oil and oil seals are responsible for 60-70% of normal compressor breakdowns. These parts aren't used with magnetic bearings, so this means higher reliability and a dramatic reduction in breakdowns.
Internal operating status can be constantly monitored
Internal operations, such as increases in the rotor balance load and changes in labyrinth gaps due to changes in axial thrust force can be accurately and easily monitored.
We use various types of analysis techniques, including high-pressure fluid vibration analysis technology.
We aim for more advanced products through the use of an integrated system of design and manufacturing using 3D CAD.
Higher speeds and smaller size
Magnetic bearings use dry gas seals and rotate without contact, so higher speeds than conventional compressors can be used.
The shaft system, which was limited to the secondary critical speed, can be operated at or above the tertiary critical speed, so a large number of impeller stages can be accommodated per casing, which means that size can be reduced by reducing the number of casings.
Running costs can be greatly reduced
Because there is no contact, mechanical losses at bearings and seals can be reduced to a range of 1/10 to 1/100 of that with conventional bearings.
By also using non-contact gas seals, utility costs such as steam, electrical power, cooling water, process gas, oil, etc. can be reduced.
Principle of magnetic bearings
Radial bearings
A pair of electromagnets provided circumferentially opposite each other with the shaft in the center create a magnetic field between the rotor. This magnetic field attracts the rotor, which is held suspended in the air. However, the magnetic field varies as the surface of the rotor rotates, which generates eddy current losses. In order to minimize these losses, a laminated structural sleeve is press-fitted to the rotor.
The rotor position is detected by 4 or more position sensors, and deviation from the rotor positional standard is transmitted to a control circuit, which controls the strength of the magnetic field to restore the rotor position to its standard position.
[attachment=21096]
Features
Use of non-contact bearings
There is no contact between the body of the compressor and the rotor, so there are no parts that wear.
The bearings can be used semi-permanently without maintenance.
No need for lubricating oil or oil seals
There is no need for lubricating oil or oil seals because non-contact gas seals are used, so there is no need to change oil filters or inspect pumps.
Parts related to lubricating oil and oil seals are responsible for 60-70% of normal compressor breakdowns. These parts aren't used with magnetic bearings, so this means higher reliability and a dramatic reduction in breakdowns.
Internal operating status can be constantly monitored
Internal operations, such as increases in the rotor balance load and changes in labyrinth gaps due to changes in axial thrust force can be accurately and easily monitored.
We use various types of analysis techniques, including high-pressure fluid vibration analysis technology.
We aim for more advanced products through the use of an integrated system of design and manufacturing using 3D CAD.
Higher speeds and smaller size
Magnetic bearings use dry gas seals and rotate without contact, so higher speeds than conventional compressors can be used.
The shaft system, which was limited to the secondary critical speed, can be operated at or above the tertiary critical speed, so a large number of impeller stages can be accommodated per casing, which means that size can be reduced by reducing the number of casings.
Running costs can be greatly reduced
Because there is no contact, mechanical losses at bearings and seals can be reduced to a range of 1/10 to 1/100 of that with conventional bearings.
By also using non-contact gas seals, utility costs such as steam, electrical power, cooling water, process gas, oil, etc. can be reduced.
Principle of magnetic bearings
Radial bearings
A pair of electromagnets provided circumferentially opposite each other with the shaft in the center create a magnetic field between the rotor. This magnetic field attracts the rotor, which is held suspended in the air. However, the magnetic field varies as the surface of the rotor rotates, which generates eddy current losses. In order to minimize these losses, a laminated structural sleeve is press-fitted to the rotor.
The rotor position is detected by 4 or more position sensors, and deviation from the rotor positional standard is transmitted to a control circuit, which controls the strength of the magnetic field to restore the rotor position to its standard position.