ARI Armaturen STEVI 446 EN - Manual (Page 14)

Page 14 Rev. 0040301000 0410
Operating and installation instructions
Str. thr. control valves - STEVI
®
440 / 441, 445 / 446
7.1.3 Bellows seal design
If the stem leaks, the bellows seal (pos. 20.3) is defective. The leak can initially be stopped
by tightening the screw joint (pos. 20.17).
Stem and bellows (pos. 20.3) can only be replaced together.
Replacement of bellows seals:
- Remove actuator.
(Refer to operating instructions for actuator!)
DN15-150:
- Loose nuts (pos. 11).
- Detach bellows assembly (pos. 20).
- Slacken screw joint (pos. 20.17) by about one turn.
- Press stem/bellows unit (pos. 20.3) down.
- Drive pin (pos. 4) out with a drift.
- Unscrew plug (pos. 3).
- Loose nuts (pos. 20.8).
- Detach mounting bonnet (pos. 20.2).
- Extract stem/bellows unit (pos. 20.3) from the
bellows housing (pos. 20.1).
- Bolt new parts together and drill them.
- Replace 2 gaskets (pos. 20.6) and 1 gasket (pos. 9).
- Assemble in reverse order.
- Secure with nuts (pos. 10 u. 20.8) and tighten them
crosswise.
(For tightening torques refer to item 7.3.1)
- Tighten screw joint (pos. 20.17) gradually up to
tightness of the stuffing box packing (pos. 20.10).
ATTENTION !
Refer to item 10.0 and 11.0 before
dismantling the valve.
Fig. 22: Series 441/446