OLGAS-H
– High pressure spring return hydraulic actuator
Use and maintenance manual
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Pag. 18
Contents may change without notice
3) Clean the actuator flange and remove anything that might
prevent a perfect adherence to the valve flange and especially all
traces of grease.
4) Lift the actuator near to the valve in such a way that the insert
bush, assembled on the valve stem, enters the actuator drive
sleeve without forcing the coupling . When the insert bush has
entered the actuator drive sleeve, check the holes of the valve
flange. If they do not meet with the holes of the actuator flange or
the stud bolts screwed into them, the actuator drive sleeve must
be rotated; feed the actuator cylinder with air at proper pressure,
indicated on data-sheet for actuator.
5) Tighten the nuts of the connecting stud bolts even
l
y with the
torque prescribed in the table. The stud bolts must be made of
ASTM A320 L7 steel; the nuts must be made of ASTM A194
grade 2 steel.
6) If possible, operate the actuator to check that it moves the valve
smoothly.
2.4 HYDRAULIC CONNECTIONS
Check that the values of hydraulic supply available are
compatible with those reported on the identification plate of the
actuator.
The connections should be made by qualified staff.
Use pipes, fittings and connections appropriate as for type,
material and dimensions.
Connect the actuator to the hydraulic feed line with fittings and pipes
in accordance to the plant specifications. They must be sized
correctly in order to guarantee the necessary oil flow for the
operation of the actuator, with pressure drops not exceeding the
maximum allowable value. The shape of the connecting piping must
not cause excessive stress to the inlets of the actuator. The piping
must be suitably fastened so as not to cause excessive stress or
loosening of threaded connections, if the system undergoes strong
vibrations. Every precaution must be taken to ensure that any solid or
liquid contaminants, which may be present in the hydraulic pipe-work
to the actuator, are removed to avoid possible damages to the unit or
loss of performance. The inside of the pipes used for the connections
must be well-cleaned before use: wash them with suitable
substances and blow through them with oil or nitrogen. The ends of
the tubes must be well debarred and cleaned. Once the connections
are completed, operate the actuator and check that it functions
correctly, that the operation times meet the plant requirements and
that there are no leakages in the hydraulic connections.
