Ssv 8500: Description, Resetting - ITRON RB 4000 Instruction Manual

SSV 8500
(for RB 4000 models with integrated SSV 8500)
Operating principle of the shut-off valve
The shut-off device is a safety device that goes
off when the pressure value in the downstream
pipe increases or decreases beyond the prefixed
calibration values, cutting automatically the flow of
the gas�
Shut-off valve with screw reset
These device consists of a valve body 10, a control
head, a diaphragm assembly 4 - 15 and a stem
–valve plug assembly 12 – 18, which remain in a
balanced position through a mechanical ball sys-
tem� The shut-off valve is triggered when the pres-
shown body is for single SSV, for integrated SSV
in one body with the regulator all described items
are identical
sure value in the control chamber 5, that from the
downstream pipe flow into this chamber through
the impulse intake 14, increases or decreases be-
yond the established pressure values, thus moving
from its balancing position the diaphragm assem-
bly 4 – 15� The stem 18 connected to the valve
plug 12 triggers under the force of the spring 13,
coming immediately into contact with the valve 8
cutting automatically the flow of the gas�
NOTE: The schematic section refers to a safety
valve installed of series 8500, but the operating
principle is valid even for other safety valves in-
stalled of series 8200 and 8300�
Item Description
1
2
3
4
5
6
7
8
9
10 Valve body
11 Body outlet
12 Valve disc
13 Valve plug spring
14 Diaphragm plate
15 Impulse intake
16 Balls
17 Max calibration spring
18 Stem
19 Cover
20 Screwing ring
21 Min calibration spring
Screwing ring
Cover
Vent
Diaphragm
Motorisation chamber
Flange
Valve plug plate
Valve seat
inlet chamber
7