Richter NKLP-C Series Butterfly Valves - Manual (Page 15)

Series NKS-C, NKSP-C, NKL-C, NKLP-C
Page 15
9520-072-en Revision 03
TM 8668 Edition 10/2012
7 Operation
7.1 Initial commissioning
Normally, the valves have been tested for leaks with
air or water. Prior to initial operation check body bolt-
ing. For torques see Section 1.4.
Unless otherwise agreed, there could be
residual amounts of water in the flow section
of the valve; this could result in a possible
reaction with the medium.
To prevent leaks, all connection screws should be
retightened after the initial loading of the valve with
operating pressure and operating temperature.
For torques see Section 1.4.
7.2 Improper operation and their
consequences
♦ Do not operate the butterfly valve without valve
actuation. Otherwise the disc will be uncontrollably
set in motion by the medium flow.
♦ Butterfly valves with a hand lever should never be
abruptly opened or closed. This can lead to water
hammer effects.
♦ Dissipate thermal expansion volumes in shut-off
pipes.
♦ If the plastic swells up due to the effect of the me-
dium, this can result in the functional parts jam-
ming.
♦ Operation with solids leads to increased wear.
♦ There must be no foreign matter on the sealing
surfaces.
♦ Operation during cavitation leads to increased
wear.
♦ Non-observance of the pressure-temperature dia-
gram can lead to damage of the plastic lining.
♦ If no monitoring is provided by the warning connec-
tion, do not tighten safety stuffing box. Otherwise
any leak cannot be seen.
♦ Do not apply heavy loads to the lever; the lever or
butterfly valves may be damaged.
♦ Do not use a lever extension as this could cause
damage.
7.3 Shutdown
Before loosening the flange bolts:
♦ ensure plant to be free of pressure
♦ flush out medium
♦ observe safety regulations
Prior to starting any repair work, the valve is to be
thoroughly cleaned. Even if the valve has been
properly emptied and rinsed, residual medium may
still be found in the valve,
In addition to suitable protective clothing, wear work-
ing gloves and goggles for assembly and mainte-
nance work.
After dismantling, immediately protect the valve flang-
es against mechanical damage with flange caps. See
also Section 6.2.
7.3.1 Additional advice for shut-off and
control butterfly valve with actuator
Ensure that a remotely actuated quarter-turn
actuator cannot be accidentally switched on.
 Having dismounted the valve, mount the locking
plate 507 and screw in with hex. screw 901/1.
See also Section 6.4.1 and drawing in Section 5.4.