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Danger
The valves should not be installed with the stem pointing downwards to prevent dirt
deposits between the folds of the bellows which might cause valve failure.
In steam service, the valve must not be installed with the stem pointing downwards
(risk of steam hammer due to condensate collecting in the valve neck).
Shut-off valves must be installed in the line so that the fluid enters the valve beneath
the disc and flows out above the disc. However, they can also be installed in lines with
alternating flow.
If the valves are to be used for throttling applications, a throttling valve disc (standard
variant DN 5 – 00) must be used.
In valves with pilot plug, the flow direction must correspond to the direction indicated by
the arrow on the valve. Valves with pilot plug must always be installed so that the pressure
to be sealed off lies above the plug.
Installation
- continued -
GAV 54F
Prior to commissioning / start-up compare the material, pressure and temperature data
on the valves with the operating conditions of the piping to check the material's chemical
resistance and stability under load.
Danger
Venting the valve by undoing the bonnet / cover bolting or removing the stuffing box
packing is dangerous and therefore not permitted.
It is generally not allowed to use lamellar graphite cast iron (EN-JL040) in systems where
surge pressures might develop, since this material does not withstand pressure surges
and, therefore, the valves may be damaged or destroyed. In such cases valves made of
nodular cast iron (EN-JS05) or steel shall be used.
In new systems and particularly after repair, the complete piping must be thoroughly
flushed with the valves fully opened so that particles and/or welding beads that might
damage the seat/disc interface are removed.
Valve actuation
Viewed from above, the valve is closed with a clock-wise turn of the handwheel, and
opened with a counter-clockwise turn.
Direction symbols are found on the top of the handwheel.
Commissioning Procedure
