Richter NKP Series Butterfly Valves - Manual (Page 12)

Series NKL, NKLP, NKS, NKSP, NK, NKP
Page 12
9520-070-en Revision 04
TM 7113 Edition 05/2008
6.4.1 Additional advice for shut-off and
control butterfly valve with actua-
tor
For single-acting actuators a locking plate has
been fitted into the bracket, blocking the stem at a
disc opening of 10 – 15°.
Remove the locking plate before the first test ac-
tuation, screw in again hex. screw 901/1. Slightly
actuate the actuator.
Please pay attention to the drawing in Section
5.4.
6.5 Earthing
One end of the grounding rope 532 is attached with a
hex. nut 920/1 and a tooth lock washer 936/1 to the
underside of the head flange.
The other end is metallically secured in the plant.
Series NK, NKP
Butterfly valves with tapped bores are earthed by the
pipe screws.
At the customer's request a setscrew M6 with a hex.
nut and washer will be provided at each flange as an
additional grounding connection.
7 Operation
7.1 Initial commissioning
Normally, the valves have been tested for leaks with
air or water. Prior to initial operation check body bol-
ting. For torques see Section 1.3.
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 1.3.
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 pro-
perly emtied and rinsed, residual medium may still be
found in the valve,
After dismantling, immediately protect the valve flan-
ges 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.