Operating Manual
© Dürr Systems AG
EcoBell2 SL EC - Rotating Atomizer with External Charging
Operating principle
Document No.: MRA00001EN
Version:: 07
•
As of:: 01/2020
35 / 156
Fig. 9:
Guiding the shaping air in the turbine
LL1 Shaping air for the inner shaping air ring
4.4.2.3
Rotational SpeedControl
W A R N I N G
Fire Hazard
Too high a speed can deform the bell disk. This causes an imbalance
in the bell disk. The bell disk can abrade the housing. Housing and
bell disk heat up.
The maximum rotational speed of the bell disk must restricted to
70000 RPM ± 500 RPM.
The speed measurement is performed on the turbine wheel. The
turbine wheel has alternately reflective and non-reflective surfaces.
Four signals are generated per revolution.
Light is directed through an optical fiber and focused onto the turbine
wheel. The non-reflective surfaces absorb the light. The reflecting
surfaces send the light back into the light conductor.
An R/O converter must be placed at the end of the optical fiber. The
R/O converter converts optical signals into electrical signals. The
electrical signals are evaluated by the control. The control enables a
speed controller to regulate the speed of the turbine.
Pos: 26 /INP/ Bell2/04_03_03 Ve ntilblock @ 57\mod_1503928741643_20.docx @ 619993 @ 3444 @ 1
4.4.3
Valve block
The turbine is flanged to the valve block. A large swivel nut keeps the
turbine on the flange of the valve block.
In the hollow turbine shaft is the paint tube. The paint tube is flanged
to the valve block as well.
There are three channels in the paint tube. In one channel, the paint is
led to the main needle. In the second channel, the main needle is
inserted. In the third channel, the rinsing agent is fed to the bell disk.