Richter NKLP-C Series Butterfly Valves - Manual (Page 16)

Series NKS-C, NKSP-C, NKL-C, NKLP-C
Page 16
9520-072-en Revision 03
TM 8668 Edition 10/2012
8 Malfunctions
♦ Flange connection ball valve/pipe is leaking
Retighten the flange screws to a tightening torque
according to Section 1.3. If this does not remedy
the leak, the recommended torques may be ex-
ceeded by 10%.
If this also fails to stop the leak, dismantle and in-
spect the ball valve.
Dismount and inspect the valve.
♦ Stem passage leaking
With no safety stuffing box:
Dismount valve and repair.
With safety stuffing box:
First of all, the packing gland follower can be tight-
ened. For torques see Section 1.3.
Then dismount the valve as quickly as possible
and repair.
♦ Medium leaking at the partition between lower and
upper halves
Dismont valve and repair, probably the stem seal
is not tight.
♦ Valve does not switch
Has the locking plate been dismounted?
See Section 5.4.
Is the actuator supplied with power?
Has a directional control valve been correctly con-
nected?
Is there foreign matter in the valve?
♦ The bore of the valve is leaking
Wear at the valve actuation ?
Do limit stops have to be adjusted?
Is the shaft deformed?
Deformation, damage or wear to body lining or
disc?
9 Maintenance
♦ All repair work is to be performed by qualified per-
sonnel using the appropriate tools.
♦ For the arrangement, designation and item num-
bers of all parts of the valve, see Section 10.
♦ Spare parts are to be ordered with all the details in
acc. with the valve identification.
♦ Only original spare parts may be installed.
♦ To prevent leaks, a regular check of the connec-
tion screws should be made in line with the operat-
ing requirements.
For torques see Section 1.4.
♦ When disassembling and assembling the valve,
attention is to be paid to the tables and drawings in
Section 1 and 10.
♦ As the body lining 409 is drawn over the disc/stem
unit 221 while warm, this work should only be car-
ried out by the manufacturer.
♦ Has the pump been shut down, drained and
flushed according to the regulations?
See also Section 7.3.
If assembled incorrectly, individual compo-
nents of the valve may be damaged and this
can result in malfunctions during operation.
9.1 Notes for assembly
 The flexible inlay 521 expands during assembly.
Do not cut off the overhang, but push back into the
lower and upper part of the shell 120.
 Before tightening the body screws 914/1 align the
disc/stem unit 221 centrally in the closed position.
 Mark the position of the disc/stem unit 221 against
body lining 409 at the hub, so permitting switching
only to this point during later test switching.
 With disc/stem unit in closed position, tighten the
body screws (914/1, as well 918/1 and 929/2) until
the gap between the upper and lower part of the
shell 120 is ca. 5 mm.
 Open the valve several times counterclockwise
(when viewing the stem unit) and close again in
the opposite direction. A sealing edge can form in
this way.
Never switch in the other direction of
rotation over the sealing edge!
 Tighten the body bolts 1-2 mm when disc in closed
position.
 Repeat the previously described process once or
twice.
 When finally tightening the body bolts, pay atten-
tion to the torques provided in Section 1.4.