4 KH 70 en
9
5.3
Replacing the packing seal
1.
Make sure there is absolutely no pressure and fluid in the
installation.
2.
Place the valve in closed position.
3.
Loosen the screws that connect the stem or rod to the
gate.
4.
Release the connection between the support plates (8)
and the body (1).
5.
Release and remove the packing gland (3) and the
safety guards where present.
6.
Remove the old packing seal (4) and greased packing
using a pointed tool, taking care not to damage the sur-
face of the gate (2).
7.
Carefully clean the packing and make sure that there
are no residues anywhere so that the new greased
packing (5) and the pacing seal (4) fit correctly.
8.
Insert the new greased packing (5) and the new pack-
ing seal (4) correctly lubricated, impregnating their
inner cavities with plenty of Vaseline.
9.
Place the packing gland in its original position (step 5),
making sure it does not touch the gate, carefully
tighten all the nuts crosswise and make sure the same
distance is left between the gate and the packing gland
on both sides.
10. Screw down the support plates and the stem, in the
reverse order to what is described in steps 3 and 4.
11. Perform several manoeuvres with no load, checking the
correct operation of the valve and ensuring the packing
gland is correctly centred.
12. Pressurise the valve in the line and tighten the packing
gland crosswise, enough to prevent leakages to the
atmosphere.
Note:
The numbers in brackets refer to the components list
in Table 5.
Fig. 7
5.4
Maintenance of the pneumatic
actuator
The maintenance of these cylinders is simple, if your need
to replace any elements and you have any questions please
consult Metso. Below is an exploded diagram of the
pneumatic actuator and a list of the cylinder’s components.
The top cover and the support cover are usually made of
aluminium, but from pneumatic cylinders greater than
Ø 200 mm, they are made of cast iron GJS‐400.
The maintenance kit normally includes: The socket and its
joints and the scraper, and if the customer wishes the
piston is also supplied. Below we show the steps to follow
to replace these parts.
1.
Position the valve in closed position and shut off the
pneumatic circuit pressure.
2.
Loosen the cylinder air input connections.
3.
Release and remove the cylinder cap (5), the cylinder
tube (4) and the tie rods (16).
4.
Loosen the nut (14) which connects the piston (3) and
the rod (1), remove the parts. Disassemble the cir‐clip
(10) and remove socket (7) with its joints (8,9) .
5.
Release and remove the cylinder head (2), in order to
remove the scraper (6).
6.
Replace the damaged parts with new ones and assem-
ble the actuator in the opposite order to that described
for the disassembly.
