Engineering manual - SAB 193-233-283 S A-frame (including ATEX)
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008831 en 2022.02
It is very important that the vibration dampers are fitted correctly as shown in the drawing as
the load on the foot plates varies. Fig. 80 illustrates the different types of vibration dampers for
stationary and marine units.
To check that the vibration dampers are adjusted for the correct load, make a note of the meas-
urement, H or h, in the unloaded state for each individual damper. After loading of the vibration
dampers, H’ or h’ should be reduced by typically 1 to 2 mm. When the adjustment is correct,
tighten the lock nut. The alignment of the unit against the foundation is now completed. See al-
so subsection
7.18 Alignment of unit against foundation
. At standstill, the motor and compres-
sor vibration levels caused by external forces must not exceed 1 [mm/s] RMS.
The vibration dampers for stationary units are made with a rubber surface underneath so that
they can be positioned directly on the concrete foundation without needing to be fastened. This
means that pockets in the foundation are not required.
Further, vibration dampers for stationary use can be adjusted in height and thus equalise minor
deviations that may occur in the foundation level. Vibration dampers for marine use, however,
cannot
be adjusted, which makes a level foundation even more important. Read more about
this below under
Marine plant
.
Fig. 80: Vibration dampers
Stationary plant
The machine room floor or foundation where the unit should be positioned must have the nec-
essary bearing strength.
It must be plane within a maximum of 5 mm from the horizontal level so that the difference in
height between the foundation plates does not exceed the scope of adjustment on the vibration
dampers.
The vibration dampers are installed on the unit in their unloaded state while the unit is sus-
pended from a crane; the unit is then placed in its final position and aligned with the aid of
wedges positioned close to the vibration dampers.
When the unit is horizontal, both longitudinally and laterally, the screws in the vibration damp-
ers are tightened exactly enough to release the wedges.
It is very important that the vibration dampers are fitted correctly as shown in the drawing as
the load on each foot plate varies.
The vibration dampers have been selected to compress between
1.0 and 2.0 mm
below the
expected load calculated at the point of support.
Marine plant
The vibration dampers for marine use cannot be adjusted in height. This means that the foun-
dation must be plane and horizontal within a
maximum deviation of 2 mm
.
Marine type
1
2
1
2
H
h
h’
H’
Not adjusted
Adjusted
Stationary type