Series NKS-N, NKSP-N
Page
15
9520-021-en
Revision 17
TM 10477
Edition 05/2022
9.4 Valve actuation
The valve stem has a pivot to attach a hand lever
respectively a coupling.
Hand lever respectively pivot parallel to the axis of the
pipeline:
→
Valve open
Hand lever respectively pivot at right angles to the
axis of the pipeline:
→
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
9.4.1 Actuated with lever
The throttling plate
519
permits a fixing of the lever at
15° intervals. It is lockable with a commercially
available padlock.
9.4.2 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
510
and the coupling
804
are thereby not
required.
Commercially available worm gears equipped with a
connection as per ISO 5211 can also be connected.
These require a bracket
510
and a coupling
804
however.
Couplings and brackets are available as accessories
in the Richter range of products.
9.4.3 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 ISO
5211.
Couplings and brackets are available as accessories
in the Richter range of products.
9.4.4 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 M
dmax
in
Section 1.8
.
When disassembling and assembling the valve,
attention is to be paid to the tables and drawings in
Section 1
and
9
.
9.5 Tests
Following tests would be done after the assembly.
Measurement of the breakaway torque
The breakaway torque required for opening and
closing 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“.
The tightness of the shaft bushing of each valve is
tested.
The holding time begins once the residual air has
escaped from the valve dome.
Tightness is verified according to DIN EN 12266-1
respectively MSS SP-67.
For detailed installation and inspection regulations for
shut-off and control butterfly valves, see QM No.
0910-08-1005, available from ITT Richter on request.
