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Regulator Operation
Regulator Operating Principle
The fluid coming from the upstream pipe enters the inlet
chamber (4), passes through the opening of the valve (3)
and then expands in the outlet chamber (18) flowing into
the downstream pipe.
The downstream pressure, which from the chamber (18)
through the pipe (17) enters the regulation diaphragm
housing (14), exerts a force on the surface of the dia-
phragm (9) balancing the Ioad oft the calibration spring
(12), enabling the valve plug (5) to find an optimum posi-
tion, ensuring good regulation and the required flow rate.
The series 3200 pressure regulator is fitted with a balan-
ced compensation system, which allows constant downs-
tream pressure regardless of variations of upstream pres-
sure. If during the operation the flow rate increases, due
to a demand, or the inlet pressure decreases, the pressure
values in the chambers 18 and 14 will tend to decrease.
Consequently the force of the spring (12) moves the dia-
phragm assembly (15) downwards and by means of the
lever system (16) adjusts the position of the valve plug
(5), thus resetting the pressure and the flow rate to the
required values. The reverse occurs when the flow rate
demand decreases.
At zero flow, rate the regulator guarantees full tightness.
The regulator is also fitted with a relief valve built into
the diaphragm bolder assembly (15) which, calibrated by
means of the spring (13), serves to discharge externally,
through the vent (10), possible over-pressure created in
the chambers 14 and 18.
The capacity of this valve is limited.
Regulator Calibration
The regulator is supplied with calibration values specified
in the order. If a different outlet pressure is required, select
the correct spring to obtain this set pressure.
Once the suitable spring (12) is installed, proceed as fol-
lows:
• to increase the outlet pressure value:
rotate in a clockwise direction the screwing ring (11)
until the required value is read on the downstream
manometer;
• to reduce the outlet pressure value:
proceed likewise but rotate the screwing ring in an
anticlockwise direction.
It is recommended to proceed slowly waiting for the
pressure to stabilize after each movement of the scre-
wing ring.
These operations can be done either with the regulator
in operation or with the downstream stop valve closed
(ensuring a small vent is open downstream to give a small
flow).
Shut-off Valve Operation
Operating Principle of the Shut-off Valve
The pressure regulator can be fitted with an independent
shut-off valve consisting of a shutoff valve casing (21) and
a diaphragm assembly (29), which controls a mechanical
ball system enabIing the release of the valve.
The shut-off valve is triggered when the pressure value in
the chamber (22) increases or decreases beyond the pre-
set values established and thus moves the entire assem-
bly(29) from a balanced position. The stem (27), which is
connected to the valve plug (19) is triggered under the
force of the spring and comes immediately into contact
with the orifice (2), cutting automatically the flow of the
fluid.
For series 3211 the shut-off valve operates only for. over-
pressure shutoff; for series 3212 it operates for both over
and low-pressure shut-off.
Adjustment of the Shut-off Valve
If the set values of the shut-off are to be modified, pro-
ceed as follows:
(A) over-pressure shut-off operation:
Rotate the outside shut-off screwing ring in a clock-
wise direction to increase the pressure values, or
anticlockwise to reduce it.
(B) low-pressure shut-off operation:
Likewise but on the central shut-of screwing ring.
Resetting of the Shut off Valve
The shut-off valve must be reset only after verifying the
reasons far the intervention and after having re-establis-
hed normal operating conditions, proceeding as follows:
(A) close the downstream stop valve;
(B) remove the cover (25), unscrewing it (see fig. B1);
(C) screw it upside down into the stem (23), until it comes
into contact with the cover (see fig. B2);
(D) continue to screw it slowly; this causes the valve to
open slowly and pressure fills the downstream pipe
piece;
(E) pull the cover outwards to permit seating of the balls
on the stem: this operation ensure resetting (see fig.
B3);
After these operations, screw the cover to its housing (see
fig. B4) and open slowly the downstream valve.
Caution: for safety reasons, the cover must absolutely be
screwed to its housing, as shown in the schematic sec-
tion.
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