6 Technical data
All dimensions in mm unless otherwise stated.
6.4
Specific conditions for safe use
The media properties has influence on the mechanical shaft seal properties and must not be change from what the agitator was
designed for without advising with Alfa Laval.
The operating limits of the shaft seal must not be exceeded from below table.
NOTE
The rpm of the gear box can be the limiting factor.
6
Pressure max. [Barg]
Øshaft
90
Media temp. max. [°C]
Ø30
500
Ø40
500
Max. speed [rpm]
The shaft seal must always be submerged during operation since dry running will result in a temperature increase in the seal
faces and a potential ignition source can become effective. With the Agitator’s seal submerged the agitator is not subjected to
any gas or dust inside the tank and is therefore outside any classification zone – even though the inside of the tank can be
Atex classified to zone 0, 1 or 2 for Gas zones or 20, 21 or 22 for Dust zones.
To prevent dry running a level switch must be installed to shut down the agitator and depending on the zone classification inside
the tank, the level switch must correspond to different safety levels:
-
Zone 0/20 inside the tank – the level switch must correspond to b2 according to EN 80079-37
-
Zone 1/21 inside the tank – the level switch must correspond to b1 according to EN 80079-37
-
Zone 2/22 inside the tank – the level switch does not need to correspond to a specific safety integrity level.
The level switch must ensure a liquid level of minimum 500mm above the seal faces to prevent dry running.
The gear box ATEX validation is depended on the forces applied to it and must therefore have values for FR2, FA2 and XR2
stated on the gear box name plate that are higher or equal to the values from the supplied ATEX addendum. See picture
example of the gear box name plate below.
The oil level in the gear is adjusted to the agitator mounting angle and must be meet /-5°. The angle is to be found
on the agitator name plate.
NOTE
The axial force FA2 is depended on the density of the media and must therefore not be higher than the density stated in
the ATEX addendum.
Operating with variable speed please pay special attention to section 6.7 Use of frequency converter drive (VLT).
4303-0021
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