WÄRTSILÄ RT-flex50-D, Maintenance Manual

Page: 484 / 522

Maintenance
9403−4/A1
RT-flex50-D
Wärtsilä Switzerland Ltd
2/ 2
3. Working procedure for tensioning
⇒
Use a felt pen and mark the positions of the nuts, which already have been
firmly seated against their landings on the part. The marks are later a refer-
ence for judging the correct pre-tensioning.
⇒
Thread on by hand the pre-tensioning jack onto the protruding thread end of
the bolts/studs until it is fully seated without any clearance between the jack
and the part i.e. the piston is seated on the cylinder without any clearance. On
a pre-tensioning jack with round nut tighten it lightly.
⇒
It may be necessary to turn the jack back a little to gain easy access through
the slot in the jack cylinder for manipulating a round bar to tighten the nut.
⇒
Connect HP oil pump and pre-tensioning jack by the HP hose.
⇒
Open the vent screw on top of the pre-tensioning jack a little.
⇒
Shut relief valve at the HP oil pump and actuate it. As soon as oil flows out
bubble-free close the vent screw at the pre-tensioning jack.
Never move the piston of the pre-tensioning jack further up than to the red limiting
groove ’BN’.
⇒
Raise the pressure with the HP oil pump, in accordance with the indication on
the tightening of important screwed connections (see
0352−1 ).
⇒
Maintain the oil pressure constant at the adjusted value and use the round bar
to tighten the nut onto its seating surface until firmly seated.
Check with the feeler gauge whether actually no clearance remains between nut
and seating.
Check with the referenced markings, whether all the nuts of a screwed connection
have been turned by the same value as mentioned in 0352−1. If big differences are
noted their causes have to be investigated and the tensioning procedure must be
repeated.
⇒
Release the pressure at the HP oil pump and remove the pre-tensioning
jacks.
D
For operation and maintenance of the HP oil pump we also refer to the
manufacturer’s documentation.
Hydraulic Pre-tensioning Jacks: General Application Instructions
2010
CHECK