PIETRO FIORENTINI ASX 176, Translation Of Original Instructions

Page: 49 / 254

49
ASX 176
Use, maintenance and warning instructions
HIGH PRESSURE REGULATOR | DESCRIPTION AND OPERATION | REV. 00
EN
13
4
5
A
8
16
B
6
15
10
1
11
9
2
C
17
18
U
pstream pressUre
D
ownstream pressUre
L
oaDing pressUre
Fig. 4.9. ASX 176 with built-in slam-shut valve SSX/176
OPERATION:
At no pressure, the valve plug (1) is kept in the shut-off position by the spring (10) and rests on the reinforced gasket (11).
The upstream pressure (Up) reaches the HP2/2 bypass device (4) and the upper head (A) of the R44/SS regulator (6) to
prevent inappropriate resetting of the valve. By adjusting the activation button (13) of the bypass, the pressurised gas is
filtered and feeds the AR100 lamination valve (5), which in turn supplies:
• the chamber of the adjustment spring (B);
• the R44/SS regulator (6), calibrated at a pressure of 4.5 bar to overcome the force of the shut-off spring (15) of the
main valve.
Pressing the reset lever (16) acts on the pressure switch coupling system (9), so as to allow, through the 3/2 valve (8):
• the chamber (C) of the slam-shut valve to be pressurised by the R44/SS regulator (6);
• the plug (1) to open.
In the event that the slam-shut valve is required to trip, the pressure switch coupling system acts on the 3/2 valve to:
• discharge the pressure from the chamber (C) into the atmosphere through the 3/2 valve (8);
• allow the spring (10) to bring the plug (1) to the shut-off position.