The following is a list of the most likely causes of
butterfly valve seat leakage and suggested solutions:
Valve is not being fully closed.
Make sure the valve is being closed fully, but do not
use cheaters.
Valve seat or disc is dirty or has a visible oxide layer
(rust).
Prior to hydrotesting the valve, inspect the seat and
disc. If there is a visible oxide layer, polish the area with an emery
cloth and suitable solvent such as acetone. Wipe clean both the seat
and disc prior to testing or installation.
Line debris accumulated around the seat is preventing
the disc from closing fully.
Cycle the valve and then flush to remove the debris
or obstruction.
If the valve has a powered actuator, the stops may be
set incorrectly. This can stop the disc while the valve is still partially
open.
Accumulated line debris around the seat may be increasing the closing
torque and setting off the trip prematurely. Try flushing the valve.
Please contact Velan Field Engineering Services for any assistance
in actuator adjusting.
The seal is damaged.
Remove the valve from service and replace the seal. Make sure to
follow safety instructions when operating on valve.
The seat is damaged.
Remove the valve from service. Contact Velan Field Engineering Services.
