ARI Armaturen STEVI 446 EN - Manual (Page 17)

Rev. 0040301000 0410 Page 17
Operating and installation instructions
Str. thr. control valves - STEVI
®
440 / 441, 445 / 446
Series 441/446:
For replacement of plug and stem with bellows sealing (Series 441/446) refer to item 7.1.3.
7.2.2 Replacement of seals of pressure balanced plugs
- Remove actuator.
(Refer to operating instructions for actuator!)
- Remove plug as described in item 7.2.
- Prise worn piston seal (pos. 32) out of groove in
plug with suitable tool (e.g. screwdriver).
- Insert new piston seal (pos. 32), taking care that
it is in the correct position (refer to Fig. 27).
- Replace guide ring (pos. 31).
- Clean sliding surface of guide bush (pos. 30);
smooth with fine abrasive if necessary.
- Replace 2 gaskets (pos. 9).
- Assemble in reverse order.
- Secure with nuts (pos. 11) and tighten them
crosswise.
(For tightening torques refer to item 7.3.1.)
7.2.3 Replacement of the seat ring
Only with control valves series 445 / 446 the seat ring is screwed in.
- Remove actuator. (Refer to operating instruction for actuator!)
- Loose nuts (pos. 11).
- Detach valve top part.
- Unscrew seat ring (pos. 2) with a special wrench (can be obtained from the manufacturer).
- Clean thread and seat ring taper in body (pos. 1).
- Replace respectively recondition and clean seat ring (pos. 2).
- Apply sealing taper (body / seat ring) with suitable lubricant (e.g. Epple 37).
- Install seat ring (pos. 2). (For tightening torques refer to item 7.3.2.)
- Replace gasket (pos. 9).
- Assemble valve top part.
- Secure with nuts (pos. 11) and tighten them crosswise.
(For tightening torques refer to item 7.3.1.)
ATTENTION !
Refer to item 10.0 and 11.0 before dismantling the valve.
ATTENTION !
Refer to item 10.0 and 11.0 before dismantling the valve.
Fig. 27: Pressure balanced plug