
6 EB 3009 EN
Design and principle of operation
The medium ows through the valve in the
direction indicated by the arrow. The posi-
tion of the valve plug (3) determines the dif-
ferential pressure over the cross-sectional ar-
ea released between the plug and seat (2).
At a differential pressure of
0.2bar/3.0bar1) (3psi/5psi)1), the valve
begins to open; at 0.35bar/0.55bar
(5psi/7psi), the valve is completely open.
At this point, the upstream pressure p1 must
be greater than the downstream pressure p2.
The regulator closes automatically when the
downstream pressure rises to or above the
value of the upstream pressure. The standard
plug is soft-seated to ensure tight shut-off
and to prevent backow from the plant into
the medium supply network.
The mounted control lines (14) transmit the
upstream and downstream pressures to the
actuator.
The actuator with two diaphragms (11)
offers increased safety and reliability of
functions. The operating diaphragm for
upstream pressure (11.1) is connected to the
valve input pressure, whereas the operating
diaphragm for downstream pressure (11.2)
is connected to the valve output pressure. A
bore with a mechanical diaphragm rupture
indicator (12) is located in the intermediate
ring located between the two diaphragms.
The pressure of response of the diaphragm
rupture indication is approximately
1.5bar/22psi. In the event of a diaphragm
rupture, the pressure in the space between
the two operating diaphragm starts to
1) DN200 and 250/NPS8 and 10 version
Legend Fig.1
1 Valve body
2 Seat
3 Plug
4 Plug stem
5Threaded connection for diaphragm
actuator
6Actuator stem
7 Diaphragm stem
10 Actuator housing
11 Two diaphragms
11.1 Operating diaphragm for upstream
pressure
11.2 Operating diaphragm for downstream
pressure
12 Diaphragm rupture indicator
13 Set point springs
14 Control line 8x1mm
15 Spacer bushing
16 Housing bolts (two long bolts opposite each
other, DN15 to 25/NPS½ to 1 only)
16.1 Top housing bolts
16.2 Bottom housing bolts
17 Diaphragm plate nut (outer)
17.1 Diaphragm plate nut (inner)
18 Pressure switch (optional)
19 Compensation chamber (optional)
20 Filler plug
increase. This causes the pin in the
diaphragm rupture indicator to be pushed
outwards and a red ring appears, indicating
the diaphragm rupture. The intact operating
diaphragm takes on the control task of the
ruptured diaphragm.
A pressure switch (18) can be optionally
mounted to the actuator to trigger an alarm.