IM-P184-09
CMGT Issue 4
8
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TRANSLATION RUN OVER
After installation or maintenance ensure that the system is fully functional. Carry out tests on any alarms
or protective devices.
5.1
The bellows sealed isolation valve plays an important role in the conservation of energy by eliminating
fugitive stem seal emissions.
5.2
The valve is operated manually by handwheels. Special care must be taken to ensure that the
movement is made in the correct direction.
To open the valves fully, it is recommended to turn the handwheels until the shafts are raised to the
maximum position, indicated by the (+) on the bonnet, then turn the handwheel clockwise 1/8 to ¼
turn to remove any backlash. This action prevents any force being applied to open a valve, which is
already fully open, resulting in damage to the stem, bellows unit or other components. Spirax Sarco
bellows sealed isolation valves are fitted with a position indicator, which can be found on the stem,
and should align with the (+) or (-) on the bonnet support pillars. (+ = fully open and - = fully closed).
5.3
If valve ‘keys’ are used care must be taken not to use excessive force when opening or closing the
valve.
5.4
A Valve Integrity Test must be undertaken prior to each double isolation of the system. Refer to
Figure 3 and the Table below for correct sequence of operation.
Flow from Left to Right (L-R)
Flow Right to Left (R-L)
1.
All valves closed
1.
All valves closed.
2.
Open bleed/drain valve
C
.
2.
Open bleed/drain valve
C
.
3.
Open downstream valve
B
.
3.
Open downstream valve
A
.
4.
Upstream valve
A
should remain closed.
4.
Upstream valve
B
should remain closed.
5.
Af ter initial disc harge of downstream
depressurisation from the bleed valve
C
,
no further steam/fluid should be observed
(integrity proved).
If fluid is observed check valve A is fully closed,
if fluid is still evident contact Spirax Sarco and
Do Not Use.
5.
Af ter initial disc harge of downstream
depressurisation from the bleed valve
C
,
no further steam/fluid should be observed
(integrity proved).
If fluid is observed check valve B is fully closed,
if fluid is still evident contact Spirax Sarco and
Do Not Use.
It is advisable to place a copy of the above table in close proximity of the Spirax SafeBloc
TM
valve.
4. Commissioning
5. Operation
