6
E N G I N E E R E D V A L V E S
Open and Closed Viewports
Once the pipe plug and relief plug are removed from the valve mounting flange, the position of the keyshaft
stop relative to the valve stops can be observed on valves with nominal stem sizes of 3" and larger.
The valve is fully opened when the keyshaft stop butts against the valve stop as viewed through the
"open viewport" and is fully closed when the keyshaft stop butts against the valve stop as viewed through
the "closed viewport".
Figure 8 shows the viewport locations for valves with a 3" stem size and figure 9 shows the viewport locations
for valves with 4" and larger stem sizes.
Operating Times
Quick Operating Time
Opening or closing a valve quickly induces loads in
addition to the normal torsion load. It is therefore
necessary to limit valve operating times in order to
prevent over stressing of the valve.
Valves can be safely operated with an operating
time given by the formula:
*Quick operating time =
Valve nominal bore
2
If a faster operating time is required, please call your
Cameron Valves & Measurement Representative.
Longest Operating Time
When the valve is being operated, the seat face is
exposed. Therefore, to minimize the amount of time
in which the seat face is exposed, Cameron Valves
& Measurement group recommends a maximum
operating time as follows:
*Longest Operating Time = 5 x Valve nominal bore
(i.e., one minute
per foot of nominal
bore)
*The time is in seconds and the bore size is in inches.
CAUTION: Failure to follow these operating times
could cause damage to the valve.
Maintenance
The CAMERON T31 Fully Welded Body Ball Valve
requires a minimum of maintenance. In order to
optimize the life of the valve, the maintenance
procedures on pages 6 and 7 should be followed.
Operation
Operating the valve is an important part of routine
maintenance. Operation of the valve will help to
break-up any buildup on the seat face and/or ball
and, if so equipped, will rotate the seat rings 15°,
distributing the wear on the insert.
Figure 9 - Open
and Larger Stem Sizes: Valve shown in open Position.
and Closed Viewport Location for Valves with 4"
Figure 8 - Open and Closed Viewport Location for Valves
with 3" Stem Size: Valve shown in Open Position.
VALVE
STOP
KEYSHAFT
STOP
VALVE OPEN
OPEN VIEWPORT
CLOSED VIEWPORT
STEM SEALANT
PORT (REF.)
VALVE
STOP
KEYSHAFT
STOP
VALVE OPEN
OPEN VIEWPORT
STEM SEALANT
PORT (REF.)
CLOSED VIEWPORT
Installation, Operation and Maintenance Manual
IOM-CAM-BALL-T31
