July 2020
Installation, Operation and Maintenance Manual
MAN 573 Rev. 8
Prior to reassemble:
1.
Check that the actuator components are in good conditions and clean.
2.
Substitute the gaskets and the O-Rings if worn or damaged.
3.
Assemble all the components, taking care not to damage the seals.
5.3
Lubrication of Mechanism
For normal duty the rack and pinion mechanism of the actuator is lubricated "for life".
In case of high load and high frequency of operation, it may be necessary to periodically restore
lubrication: it is advisable to apply a generous coating of grease on the contact surfaces of moving
parts, especially on the surface of the rack in contact with the thrust bearing sliding block and on the
teeth of the rack and pinion.
For this operation, proceed as follows:
1.
Disassemble the actuator from the valve.
2.
Measure the protrusion of the stop screw (30) with reference to the end flange surface (4),
so as to be able to easily restore its setting once the maintenance procedures have
been completed.
3.
Loosen the locknut and unscrew the stop screw until it is removed.
4.
Remove the nuts (25) from the tie rod (14) at the end flange side: they must be gradually
unscrewed all at the same time so as to release the thrust of the spring against the flange.
5.
Slide off the end flange (4) and the cylinder tube (13).
6.
Measure the protrusion of the thrust- bearing screw (15), with reference to the housing
surface, so as to be able to restore the right working position of the thrust bearing sliding
block with reference to the rack once the maintenance procedures have been completed.
7.
Remove from the actuator the complete spring module, the main components of which are
the piston (3), the spring (16), the rack spacer rod (12), the spring retainer disk (11) and the
rack (5).
8.
Remove the spacer tube (33).
9.
Lubricate abundantly the teeth of the rack and pinion and the surface of the rack in contact
with the thrust bearing sliding block. Use recommended grease.
Maintenance
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Section 5: Maintenance
