Dungs FRM 100025 HD, Instruction Manual, Page: 124 / 174

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Edition 10.15 • No
. 270 442
10. Integrated SSD
SSD protects downstream fittings or lines against pressures
that are too high or too low. As soon as the pre-set trigger -
ing pressure falls below or exceeds a limit due to a fault, the
SSD interrupts automatically the gas flow. Under normal
operating condition the SSD is open.
If the outlet side of the gas pressure regulator and/or the
fittings and devices of the succeeding gas line section, inclu -
sive its equipment until the gas-consuming device, are not
designed for the highest supply pressure (inlet pressure to
the gas pressure regulator in case of an error), a SSD must
be installed to shut down the gas supply before the gas pres -
sure becomes too high:
The SSD complies with the requirements of EN 14382 as
safety shutoff valve with standard strength range (IS).
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 checked acts on the working diaphragm
E . The force of the setpoint springs G and H acts as counter -
force.
In case of an unbalance of forces (overpressure or un -
derpressure), the SSD is actuated and the gas supply is
blocked.
A
B
C
D
E
F
G H
I
10.1 Function