VAG Operation and Maintenance Instructions • 5
- Never stand under a suspended load!
- Only use hoists and slinging tackles which are safe to sup-
port the load!
- Lift the valve carefully until it is freely suspended.
- Balance the valve carefully. Consider the center of mass!
- The valve can now be hoisted and cautiously transported to
the installation site.
2.2 Storage
Caution:
The VAG EKN
®
Butterfly Valve type AWWA type should
be stored with its disk slightly open.
Picture 4: Storage of the VAG EKN
®
Butterfly Valve type AWWA
tion. If required, the profile seal ring can be disassembled without
having to dismantle the valve.
In case of epoxy-coated VAG EKN
®
Butterfly Valves type AWWA,
the sealing seat is made corrosion-resistant by high-alloy weld
overlay and is also resistant to mechanical damage. In the steel-
welded type of the body, the sealing seat is made of stainless
steel.
3.2 Applications
In its standard version, the VAG EKN
®
Butterfly Valve type AWWA
is equipped with EPDM seals.
The VAG EKN
®
Butterfly Valve should only be used in media in
which there is no risk of clogging.
The butterfly valve can be used for the following media:
• Water,
• Raw and cooling water (with appropriate corrosion protection)
• Weak acids and alkaline solutions (with according corrosion
protection)
Caution:
The use of the valve with media containing gas or oil
may result in the destruction of the EPDM seals (rubber lining) and
O-rings and is therefore not permissible.
VAG EKN AWWA Butterfly Valves are designed acc. AWWA 504
standard with maximum working pressure of 150 psi g and a ma-
ximum full open velocity of 16 ft / sec. Temperature range acc.
AWWA is 33° - 125° F.
In case of differing operating conditions, the manufacturer needs
to be consulted. If in doubt, consult the manufacturer to inquire
about the appropriate sealing materials for your application.
3.3 Performance limits
3.3.1 Cavitation
Caution:
VAG EKN
®
Butterfly Valves are mainly used to shut off
flow. If a VAG EKN
®
Butterfly Valve is used to control flow, the
operational limits of the maximum flow velocity as well as the ca-
vitation limits must be observed. However, in this case VAG will
void any warranty issues, unless VAG authorized the operating
mode in writing.
The operational limits can be calculated either using the VAG
UseCAD
®
or the following calculation rules:
Cavitation limits
After the upstream and downstream pressures of the valve as well
as the flow rate have been determined, the cavitation value is cal-
culated as follows:
Calculation of the
σ
-Value acc. AWWA M49:
σ
=
cavitation index
[dimensionless]
Pd
=
downstream pressure
[psig (kPa)]
The elastomeric parts (seals) must be protected against direct
sunlight and/or UV light as otherwise their long-term sealing
function cannot be guaranteed. Store the valve in a dry and well
aerated place and avoid direct heat. Protect any assembly units
important for proper function such as the disk and the body seal
against dust and other dirt by adequate covering.
Do not remove the protective caps of the connections / flanges
and the packaging materials until immediately prior to assembly
into the pipeline.
The valve can be stored in ambient temperatures ranging from
-4° F to 122°F (-20 °C to +50 °C) (protected by adequate covers).
If the valve is stored at temperatures below 32° F (0 °C), it should
be warmed up to at least 41° F (+5° C) before installation and be-
fore it is put into operation.
3 Product features
3.1 Features and function description
The VAG EKN
®
Butterfly Valve type AWWA is a fully flanged but-
terfly valve and can therefore be used both between two flanges
and as an end-of-line valve without counter-flange and at full ope-
rating pressure.
The design of the VAG EKN
®
Butterfly Valve is that of an offset
valve with a double offset bearing of the disk. In closed position,
the disk is perpendicular to the direction of flow. To close or open
the valve, the disk must be turned by 90°.
The body is sealed with an endless profile seal ring which in the
standard version is fixed by a retaining ring.
In closed position, the elastic profile sealing ring is pressed to the
conical seat surface inside the body and safely seals in both flow
directions. Due to the double offset bearing of the disk, the profile
seal ring is completely unstressed when the valve is in open posi-
