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To remedy the problems, we recommend:
• Changing the back pressure
• Choosing a different place of installation
If the σ - value lies above the limit curves of σ k the noise is caused
by other things and the pipeline will have to be checked.
3.3.2 Kv values (valve fully open)
DN
50
65
80
100
125
150
200
250
300
350
400
450
500
600
Table 1: KV values
In case a valve is used in continuous control operation, the opera-
tion limits need to be coordinated in consultation with VAG be-
fore the valve is ordered and/or installed. Cavitation must always
be prevented.
Permanent operation in intermediate position will result in in-
creased wear of the valve. Operation limits need to be established
according to Section 3.3.1.
3.3.3 Maximum permissible flow velocity
VAG CEREX
300 Butterfly Valves are dimensioned to EN 593 for
®
the following flow velocities:
• Liquid media: 4m/s (for nominal pressure PN16)
• Gaseous media: 35m/s (for nominal pressure PN16)
The operating torque of butterfly valves greatly depends on the
differential pressure and the flow velocity. If you intend to oper-
ate the CEREX
300 Butterfly Valve at higher flow velocities, this
®
requires the recalculation of the valve by VAG.
If you have any questions on the design and dimensioning of the
valve, please contact your coordinator in charge at VAG-Arma-
turen GmbH.
3.4 Permissible and impermissible modes of
operation
The maximum operating temperatures and operating pressures
specified in the technical documentation (KAT-A 1331) must not
be exceeded.
The pressure applied to the closed valve must not exceed its rated
pressure.
Kv [m
/h]
ZETA-value
3
195
0,26
321
0,29
435
0,34
754
0,28
1264
0,24
1868
0,23
3128
0,26
4885
0,26
7026
0,26
9514
0,26
12426
0,26
15722
0,26
19415
0,26
27958
0,26
VAG CEREX
300 Butterfly Valves have to be equipped with an
®
actuator having a limit stop for the open and closed position.
Hand levers can be used as actuators for valves of a nominal di-
ameter of up to DN 200 and a nominal pressure of PN 16. Valves
with larger nominal diameters should not be equipped with hand
levers as it will not be possible for one operator only to handle the
operating torque.
The only types of gear units that may be mounted are self-locking
worm gears with limit stops in the open and closed position. Due
to the self-lock of the gear unit it suffices to locate the final posi-
tion of the gear unit (limit stop).
4
Installation into the pipeline
4.1 Conditions required on site
When installing the valve between two pipeline flanges, these
must be coplanar and in alignment. If the pipes are not in align-
ment, they must be aligned before installation of the valve, as oth-
erwise this may result in impermissibly high loads acting on the
valve body during operation, which may eventually even lead to
fracture.
When the valve is installed, the minimum diameters of the coun-
ter-flanges must be observed to ensure trouble-free opening and
closing of the valve and proper sealing on the pipeline flange.
Make sure that the valve is installed into the pipeline as stress-
free as possible. Wafer-type butterfly valves must not transmit any
pipeline forces. The distance between the flanges must be wide
enough to provide sufficient space for the face-to-face length of
the valve and the protruding profiled seal.
The lug-type VAG CEREX
®
end-of-line valve in closed position and without counter flange up
to the following operating pressure:
- DN 50 - 300: 16 bar
- DN 350 - 400: 14 bar
- DN 450 - 600: 10 bar
When used as an end-of-line valve, the butterfly valve
must not be operated without suitable counter-flange!
Figure 5: Operation of the VAG CEREX
valve only with suitable counter-flange
300 Butterfly Valve can be used as
300-L Butterfly Valve as end-of-line
®
VAG Operation and Maintenance Instructions • 6
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