Richter NKLP-C Series Butterfly Valves - Manual (Page 17)

Series NKS-C, NKSP-C, NKL-C, NKLP-C
Page 17
9520-072-en Revision 03
TM 8668 Edition 10/2012
9.2 Valve actuation
The disc/stem unit has a 2-surface pivot point on DN
50-150 (2"- 6") and a 4-surface pivot point on DN 200-
1000 (8"- 40") for mounting a hand lever or coupling.
Hand lever or 2/4-surface pivot point parallel to the
pipe axis:
 Valve open
Hand lever or 2/4-surface pivot point at right angles to
the pipe axis:
 Valve closed
In the case of a coupling, 2 red marks indicate the
position of the disc on them.
Marks parallel to the axis of the pipeline:
 Valve open
Marks at right angles to the axis of the pipeline:
 Valve closed
9.2.1 Actuated with lever
The throttling plate 519 permits a fixing of the lever at
10° intervals. It is lockable with a commercially availa-
ble padlock.
9.2.2 Actuated by means of worm gear
In the standard version, the manufacturer normally
provides worm gears with a special pick-up for the
stem pivot.
The bracket and the coupling are thereby not re-
quired.
9.2.3 Remotely actuated
Richter butterfly valves can be remotely actuated by
means of pneumatic, hydraulic or electric quarter-turn
actuators equipped with a connection as per DIN EN
ISO 5211.
Couplings and brackets are available as accessories
in the Richter range of products.
9.2.4 Required breakaway torque
The breakaway torque of the actuator must
be at least as high as the breakaway torque
of the butterfly valve, about 20% higher being
better however.
Media of higher viscosity and/or those with solids may
require an increased factor of safety when calculating
the size of the actuator. This is particularly true for
non-Newtonian fluids such as high polymer substanc-
es, suspensions, pastes, lubricants, resins, lacquers
etc.
Admissible factors of safety lie in the range of 20 -
50% of the breakaway torque.
To prevent damage to the valve, particular attention
must be paid to the torque Mdmax in Section 1.8.
9.3 Tests
Following tests would be done after the assembly.
Measurement of the breakaway torque
The breakaway torque required for opening and clos-
ing the valve is to be ascertained. The maximum
torque should not exceed the values given in Section
1.8.
Tightness of valve opening and shaft bushing
The completed valves have to undergo a „leak test of
the closure with air“.