21
MT 235 – EN ed.2015 (Rev.A)
B)
For devices not equipped with "push" valve (fig. 20), it is recommended to separately connect the control head to a
controlled auxiliary pressure and repeat the operations described above.
CAUTION
At the end of the procedure, connect the control head
again to the pressure sensing point downstream.
NB.
: It is recommended to repeat the tripping tests at least every
6 months
.
At the end of the slam-shut device check operations, proceed as follows:
Make sure that the slam-shut device is in closed position;
Partially open the relief valve 6 located on the outlet piping;
Very slowly, open the on-off valve V1;
Very slowly open the slam-shut valve, by pulling the proper bushing;
Increase the calibrations of the main regulator 2 until the monitor regulator 1 trips, acting on the proper internal ring
nut, turning it clockwise;
Using the pressure gauge 4 and 5, check that the outlet pressure shows the calibration value preset for the monitor
regulator 1. Should this not be the case, adjust the calibration by acting on the proper internal ring nut, turning it
clockwise to increase and counterclockwise to decrease;
Close the relief valve and check the lockup pressure value of the monitor regulator 1;
Let the slam-shut valve trip and partially open the relief valve 6;
Very slowly open the slam-shut valve, by pulling the proper bushing;
Decrease the calibrations of the main regulator 2 until bypassing the monitor regulator 1, acting on the proper ring nut,
turning it counterclockwise;
Set the calibration of the main regulator 2 to the set calibration values; then, using the pressure gauge 5, check the
calibration values;
Close the relief valve and check the lockup pressure value of the main regulator 2;
With a foamy substance, check the tightness of all the joints present between the on-off valves V1 and V2;
Very slowly open the outlet on-off valve V2 until reaching the complete filling of the piping;
