CAUTION!
Stroke movement of the piston! There is a risk of crush injuries to hands. Do not reach into the piston area!
Work in the piston area may therefore only be carried out with the dosing pump switched off.
The piston can be replaced as follows:
1. Switch off the pump!
2. Loosen the clamping screws at the clamping flange with an appropriate tool (open-end spanner
SW10). (see Fig. 1)
3. Loosen the gland connection
?
(see fig. 11.1) with an appropriate tool.
With two cotter pin drives d6 inserted into two opposite bores in the gland connection, the connection
can easily be loosened. (see Fig. 2)
NOTE!
To loosen the gland connection and the piston, the following assembly kits are available (consisting of cotter
pin drives and open jaw wrenches): FEDOS E/DX 01…2 (A/N 37850), FEDOS E/DX 5…8 (A/N 37851) and
FEDOS E/DX 17…30 (A/N 37852)
4. The dosing head
a
is withdrawn from the holder in an axial direction.
IMPORTANT!
Slight rotary movements of the dosing head make dismantling easier.
5. The piston
g
is unscrewed from the piston rod with the help of 2 open jaw wrenches. Use one open-
end spanner to fix the piston rod and the other to unscrew the piston from the piston rod. Grease the
thread of the new piston with Molykote DX. The new piston
g
is now screwed into the piston rod. (see
Fig. 3)
6. To replace the packing
d
, unscrew the gland connection
f
completely from the dosing head.
Remove the gland
e
and the supporting disc
c
. The defective packing is removed using a packing
worm. Alternatively, a hook can be used to remove the old packing.
7. Clean the packing area. Install the new packing rings
d
with staggered gaps and observe the correct
sequence of support ring, supporting disc, packing rings and another supporting disc (see fig. 4). Install
the gland hand-tight. (see Fig. 5)
CAUTION!
The packing material must be coordinated to the purpose of use (system pressure) and the chemical
(chemical resistance).
8. The dosing head
a
is now pushed in alignment with the piston
g
and the seating flange and fixed in
the final position with the attachment screws.
IMPORTANT!
Make sure that the valves are aligned vertically. (see Fig. 4)
9. Carefully tighten the gland connection
f
, to start the bedding-in process of the new packing. For this
purpose the dosing pump is run dry first without connection to the medium. After a few strokes the
gland is tightened once more.
10. After connecting the dosing lines, the pump is started as described in the section entitled Startup.
For this the packing is to be prestressed further using the gland connection, until a minimum leakage
occurs.
ATTENTION!
If prestressing is too strong, the return movement of the piston might be restrained. In this case slightly
loosen the gland stud again.
11. If the piston wear is excessively high, try to find out the reason. For the possible causes, please refer to
"Troubleshooting" (Section 14).
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| Operating Manual FEDOS E/DX | Maintenance
