Australian Pipeline Valve - Installation, Operation and Maintenance Manual
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API6D THROUGH CONDUIT EXPANDING GATE VALVE - AP400-405 SERIES
8.3.2
To protect the seats, ensure the slab is above the closed position prior to actuation installation.
8.4 TROUBLE SHOOTING GUIDE
8.5 BODY BLEED PROCEDURE
Whilst through conduit valves are block & bleed capable, the valve needs to be ordered and tested as a
block & bleed valve. A special bleed system should be specifically plumbed as per diagram below.
This characteristic is used to:
a- Ensure that the seats are providing an effective seal, or
b- Drain or flush the body cavity of an in-service gate valve.
Problem
Possible Reason
Action
Difficult to OPEN or CLOSE
Valve has not been opened or closed for a
long time, the seats and gate tied tightly
OPEN and CLOSE the valve rapidly several times
till the gate is loosened, then OPEN or CLOSE
the valve to the required position
Dry stem
Inject lubricant as necessary
Medium frozen in the cavity
Heating
Pipeline distorted
Eliminate the distorting restriction of pipeline
The gate will not CLOSE
Medium frozen in the bottom
Heating
Debris obstruction in bottom of valve
Remove debris through bottom drain plug
Sealing incompletely to upstream and
downstream (the pressure in middle
cavity cannot relieve to low pressure)
The gate is not CLOSED completely
CLOSE the valve
Damage to sealing surface
Replace the damaged sealing element
Damage to O-ring
Replace O-ring
Stem packing leakage
Damage to packing
Inject stem packing
Imbalance of operation
Dry bearing
Inject the distorting as necessary
Possible damage to drive nut or bearing
Replace the damaged parts
Leakage in bonnet flange
Bonnet bolts loose
Tighten bonnet bolts as necessary
Damage to gasket
Replace the gasket
Leakage in grease injection and waste
valve
Damages to ball, spring and sealing ring
Replace the damaged components
Screw cap is not tight
Tighten screw cap as necessary
Note
To relieve pressure from the internal cavity (body) of the valve while under
pressure, please follow this procedure carefully. Operate the valve into the full
torqued CLOSED position.
Note
If actuation is to be installed after shipment from APV, IT IS CRITICAL THAT THE SLAB
DOES NOT DROP TO THE BOTTOM OF THE VALVE DURING ACTUATION INSTALLATION! THIS
MAY RESULT IN SEAT DAMAGE.
