8
3L.P. GAS s.r.l.
TECHNICAL MANUAL ICM
4.2
GAS INPUT, CONTROL OF EXTERNAL
TIGHTNESS AND SETTING
External tightness is guaranteed if no bubbles form
when a foam medium is applied on the element under
pressure.
The slam-shut valves are normally supplied already
set for the desired setpoint. It is possible for various
reasons (e.g., vibration during transport) for the
settings to be changed while remaining within the
values permitted by the springs used.
We therefore recommend checking the settings using
the procedures illustrated below.
Before commissioning the valves you must check
that all the on-off valves (inlet, outlet, any by-pass)
are closed and that the gas is a temperature which
will not lead to malfunction.
4.3
CHECKING THE SETTING
Check and adjust the intervention of the slam-shut
1 as follows:
A) For slam-shuts connected to the downstream piping
by a three-way deviator “push” valve proceed as
follows (Fig. 9):
- connect a controlled auxiliary pressure to C;
- stabilise this pressure at the notch, pressing the knob
1 completely;
- reset the slam-shut device by means of the provided
lever;
- keep the knob 1 pressed:
a)
safety devices which intervene for maximum
pressure: slowly increase the auxiliary pressure and
check the intervention value. If necessary, increase
the intervention value by turning the adjustment ring
12 clockwise, or anticlockwise to reduce the
intervention value.
b)
safety devices which intervene for pressure
increase and reduction: slowly increase the auxiliary
pressure and record the intervention value. restore the
pressure to the setpoint established for the regulator,
and carry out the slam-shut reset operation.
Check intervention for pressure reduction by slowly
reducing the auxiliary pressure.
If necessary, increase the intervention values for
pressure increase or decrease by respectively turning
the rings 12 and 13 clockwise and vice versa to redu-
ce the intervention values.
- check proper operation by repeating the operations
at least 2-3 times.
