Data Sheet

Bulletin 71.2:92S
4
• Lapped Seats for Tight Shutoff—The valve and
pilot use lapped seating surfaces that have been
proven to minimize seat leakage.
• Application Flexibility—Pilot with optional
tapped spring case is available for use either
with an air loading regulator for remote adjustment
of outlet pressure setting or, when all compression
is removed from the pilot control spring, with a
solenoid or switching valve for on-off service.
Principle of Operation
Pilot supply pressure is piped from the main valve inlet
(Figure 2) to the pilot inlet connection. Downstream
pressure registers on the main valve pistons through the
downstream control line and then on the pilot diaphragm.
When increased downstream demand lowers the
downstream pressure to a value below the setting
of the pilot control spring, this forces the pilot valve
plug to open increasing the loading pressure on the
main valve pistons. At the same time, the increased
demand lowers the downstream pressure on the
main valve piston(s). This opens the main valve plug,
increasing ow to the downstream system to satisfy
the increased demand and to restore downstream
pressure to the setting of the pilot control spring.
Decreased downstream demand increases the
downstream pressure registered on the pilot
diaphragm. The increased pressure overcomes the
force of the pilot control spring and allows the pilot
valve plug spring to close the valve plug. As the pilot
valve plug closes, excess loading pressure bleeds
to the downstream system through the pilot bleed
restriction. At the same time, decreased downstream
demand increases the downstream pressure
registered on the main valve piston(s). This allows
the main valve spring to close the main valve plug,
reducing ow to the downstream system in response
to the decreased demand.
With a pilot for pressure-loaded service (Figure 7), the
operation is the same as for a standard pilot except
that the pilot control spring force on the pilot valve
plug is aided by pneumatic pressure from the loading
device. With a pilot for on-off service, the only force
acting on top of the pilot diaphragm is pneumatic
pressure provided by the solenoid or switching valve.
Installation
The Type 92S regulator should be installed and
used in accordance with governmental codes and
regulations. Although this regulator minimizes
leakage under shutoff conditions, downstream
overpressure protection must be provided by the
user. The pressure and temperature limitations in
the Specications section must be observed and the
downstream equipment protected.
A Type 92S regulator may be installed in any
orientation, but should not be installed in a tall vertical
pipeline where condensate could collect and create
a pressure head affecting regulator performance.
To obtain maximum ow capacities in some instances,
outlet piping will have to be swaged up above the
given body size.
A downstream control line is required but is not
furnished with the Type 92S regulator. Additionally,
an adjustable loading pressure regulator and loading
pressure piping are required for pressure-loading pilot
regulators, while an on-off or solenoid valve is required
for on-off pilot regulators.
Dimensions are shown in Figure 9.
Table 3. Flow and Sizing Coefcients
(1)
BODY SIZE ORIFICE SIZE
REGULATING
C
s
WIDE-OPEN C
s
FOR
RELIEF SIZING
C
1
K
m
IEC SIZE COEFFICIENTS
NPS DN Inches mm X
T
F
D
F
L
1 25 7/8 22 16 17.5
34
0.62
0.73
0.51
0.791-1/2 40 1-1/8 29 30 33 0.47
2 50 1-29/64 37 48 52 0.48
2-1/2 65 1-5/8 41 74 78
0.71
0.48
0.84
3 80 2-1/16 52 100 110 0.47
4 100 2-3/8 60 140 145 0.46
6 x 4 150 x 100 2-3/8 60 150 155 0.46
1. C
v
= C
s
x 20 ÷ C
1