Dungs FRM-NOC 100025 HD, Instruction Manual, Page: 27 / 76

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MC • Edition 2022.08 • No
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10. Function Safety Shut off Valve (SAV+ASE)
SAV protects downstream fittings or lines against pres -
sures that are too high or too low. As soon as the pre-set
trip pressure falls below or exceeds a limit due to a fault,
the SAV automatically interupts the gas flow. Under normal
operating condition the SAV is open.
If the equipment downstream of the regulator, including
any pipework, cannot safely operate or contain a pressure
equal to the highest supply pressure (inlet to regulator), a
SAV must be installed. The SAV is designed to shut down
the gas supply in the event of a fault condition.
The SAV complies with the requirements of EN 14382 as
safety shutoff valve.
Main components
A Valve disc
B Closing spring
C Ball catch / trigger mechanism
D Chamber with the pressure to be monitored
E Working diaphragm
F Push rod
G Setpoint spring for p
do
H Setpoint spring for p
du
I Protective cap
Function
Chamber D is connected to the outlet pressure via a
pulse line.
The pressure to be controlled acts on the working mem -
brane E. The force of the set point springs G and H acts
as a counter force.
In case of an unbalance of forces (overpressure or un -
derpressure), the SAV is actuated and the gas supply is
blocked.
A
B
C
D
E
F
G H
I