17
3.3 CONTROL OF THE INTERNAL TIGHTNESS
The valve internal tightness may be checked by placing the valve in full close position, keeping
the line pressure upstream from the valve and checking that there is not fluid leaks downstream
from the valve and from the pilot blowdown.
3. 4
COMMISSIONING ( INSTALLATION ACCORDING TO DIAGRAM IN FIG. 3 ).
a) On the data plate check that the required intervention value is within the listed limits ( Wao
value on the plate )
b) Fully tighten the adjusting ring nut of the setting on the pilot
c) make sure that the pressure upstream from the cut-off valve is lower than the intervention value
d) slowly open the cut-off valve
e) check the tightness of all the joints placed under pressure with the previous operation
f) increase the pressure up to the intervention value, slowly unscrew the ring nut until the pilot pipe
starts to discharge the gas.
h) very carefully carry on the previous operation until the valve opening
i) decrease the pressure and check that the pilot valve is close again and their tightness.
3. 5
COMMISSIONING ( INSTALLATION ACCORDING TO DIAGRAM IN FIG.4 )
a) With the same order carry out the operations a, b, c, d, e, of paragraph 3.4
b) Connect the C way of the three-way switch valve ( PUSH ) to a chamber with controlled
pressure
c) stabilize the test pressure in the chamber at the same value as the pressure at the safety valve
inlet
d) actuate the three-way valve by connecting the controlled pressure chamber to the pilot sensing
line.
e) increase the test pressure in the controlled chamber up to the intervention value of the safety
valve
f) with the same order repeat the operations g,h, of the previous paragraph.
g) decrease the pressure and check that the pilot valve is close again and their tightness.
h) restore the three-way valve position in order to connect the chamber to be controlled with the
pilot sensing line.
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