GB
6.2) DISASSEMBLY
When disassembly of actuator is required for maintenance,
firstly remove the actuator from the valve. Before
performing any disassembly operations it is important
to verify that the actuator is not pressurised.
Always use caution and double check that the ports 2 and
4 are vented and are free from any accessory and/or
device. When the actuator is a spring return unit, make
sure that the actuator is in the failed position and with
pistons completely inwards before disassembling.
A) Removal of position indicator and graduated ring
(Part N° 19,19.0,19.1), figure 01:
•
Remove cap screw (39) if
fitted.
•
Lift position indicator (19
or 19.1) off shaft, it may
be necessary to pry gently
with a screwdriver.
•
Lift, if necessary, the
graduated ring (19.0)
off the body, it may be
necessary to pry gently
with a screwdriver.
B) Removal of stop cap screws (Part N° 02), figure 02:
•
Remove both stop cap
screws together with nut
(04) and washer (03).
•
R e m o v e s t o p s c r e w
o-rings (11) and discard if
replacing all soft parts.
C) End caps disassembly (Part N° 30), figure 03:
•
End caps disassembly for spring return actuators
(disassemble one end cap at a time).
Unscrew the end cap bolts (13) in the sequence shown in
figure 03, until the end-caps are free from springs force
(for AT045U and AT051U 20-23 turns of the screws, for
AT101U to AT801U 4-5 turns of the screws).
Then completely unscrew the screws and remove the
end-cap and the springs.
If there is still force on the end-caps after unscrewing as
indicated above, this may indicate that spring cartridge is
damaged or that the pistons are not completely closed,
so any further disassembly should be discontinued.
Further disassembly of the end caps may result in injury.
•
End caps disassembly for double acting actuators
(disassemble one end cap at a time)
Unscrew the end cap bolts (13) in the sequence shown in
figure 03, until the screws are completely unscrewed and
the end caps are free.
8
•
Remove the o-rings (14) using a screwdriver. Discard soft
parts if replacing.
Fig. 01
•
Only for actuators with adjustment 50% or 100%, remove
the nut 04R, the washers 03R and o-rings 11R and
discard soft parts if replacing.
D) Pistons disassembly (Part N° 40), figure 04:
•
Holding the body (50) in a vice or similar device, rotate the
drive shaft (60) until the pistons (40) are released. Caution:
air pressure should not be used to remove the pistons from
the body.
•
Remove o-rings (16) using a screwdriver. Remove the
piston back (05) and piston head (15) bearings.
•
Discard bearings when replacing all soft components.
Fig. 02
E) Drive shaft disassembly (Part N° 60), figure 05:
•
If necessary, remove the graduated ring (19.0) with a
screwdriver, remove the spring clip (18) using snap-ring
pliers or screwdriver for spiral rings, remove the thrust
washer (10) and the external thrust bearing (08). Apply
downward force to top of drive shaft (60), until it is partially
out of the bottom of the body when it is possible to
remove the internal thrust bearing (08) and the octi-cam
(01), then push the pinion (60) completely out of the
body. If pinion is not easily removed, gently tap the top
of the shaft with a plastic hammer.
IMAT 4thGU-E
Fig. 03
Fig. 04
Fig. 05
