Emerson FL User manual

Bulletin 71.2
D103067X012

August 2020

Type FL Pressure Reducing Regulators

Features

• No Atmospheric Bleed—Eliminates nuisance and

wasteful bleed gas to atmosphere by utilizing a
self-contained control system, which bleeds 100%
of the gas to the downstream system.

• Quiet Operation—Multiple noise attenuation options
available which reduce noise by up to 25 dBa at
the source, eliminating the need for expensive path
treatments such as insulation, buried valves and
enclosures which only mask noise.

• High Capacity—The highly e󰀩cient axial ow

design produces exceptionally high capacities.

• Long Life in Severe Service Applications—The

metal plug design deects particles and debris

away from the soft-seat, which gives excellent
particle erosion resistance.

• Precise Pressure Control—Provides accurate
downstream pressure control regardless of inlet
pressure variations or demand changes.

• Easy In-Line Maintenance—Outlet ange spacer

allows trim parts such as the disk holder to be
inspected, cleaned and replaced without removing
the body from the pipeline.

• Bubble-Tight Shuto󰀨—A knife-edged metal plug

and soft seat provide bubble tight shuto󰀨 for use
in applications where positive shuto󰀨 is required

such as dead-end systems.

• Full Pressure Rating—The equal inlet and outlet

pressure rating of 1480 psig / 100 bar, which

allows easier selection and requires no special

startup or shutdown procedures.

• Versatility—Ideal for a wide variety of

applications such as natural gas transmission and
distribution stations and power plant feeds.

• Travel Indicator—Simplies in-service inspection

and system troubleshooting.

• High Turn Down Capability—The oversized

diaphragm and unique piloting system allow

for high turn down, providing superior pressure
control in systems with large variations in

downstream ow demand.

Figure 1. Type FL Regulator with Type PRX Pilot

• Disk Design—The FL series o󰀨ers disks

for the main body made from Nitrile (NBR),
Fluorocarbon (FKM), and Polyurethane (PU).
Polyurethane (PU) provides better abrasion
resistance properties and a high durometer rating

to extend the working life of the disk in di󰀩cult

applications such as high pressure drop and

low ow.

Introduction

The Type FL is an accurate, pilot-operated regulator
designed for high-pressure transmission/city gate,
large capacity distribution systems and power plant

feeds. Type FL provides smooth and quiet operation,
tight shuto󰀨 and long service life. The regulator is

comprised of a main valve actuator, a Type PRX
pressure reducing pilot and a Type SA/2 pilot supply
pressure regulator.

Type FL

North America Only

Type FL

Specications

The Specifications section gives some general specifications for the Type FL regulators. The nameplates give
detailed information for a particular regulator as it comes from the factory.

Available Conguration

Type FL: Pilot-operated pressure reducing

regulator from 14.5 to 1160 psig / 1.00 to 80.0 bar
outlet pressures

Body Sizes

Type FL: NPS 1, 2, 3, 4, 6, 8 and 10 /

DN 25, 50, 80, 100, 150, 200 and 250

Type FL with Type SRS Silencer (Inlet x Outlet):

NPS 1 x 4, 2 x 6, 3 x 10, 4 x 10, 6 x 12 and 8 x 16 /
DN 25 x 100, 50 x 150, 80 x 250, 100 x 250,
150 x 300 and 200 x 400

Main Valve End Connection Style and
Pressure Ratings

CL300 RF: 740 psig / 51.0 bar

CL600 RF: 1480 psig / 102 bar

(1)

(3)

(3)

Maximum Inlet and Outlet (Casing) Pressure

1480 psig / 102 bar

(3)

Minimum Operating Di󰀨erential Pressure

Start Open:

NPS 1 to 4 / DN 25 to 100: 7.3 psid / 0.50 bar d
NPS 6 and 8 / DN 150 and 200: 3 psid / 0.21 bar d
NPS 10 / DN 250: 2.9 psid / 0.2 bar d

Full Open

NPS 1 to 4 / DN 25 to 100: 14.5 psid / 1.00 bar d
NPS 6 and 8 / DN 150 and 200: 7.3 psid /

0.50 bar d
NPS 10 / DN 250: 8.7 psid / 0.6 bar d

Outlet (Control) Pressure Ranges

See Table 1

Flow and Coe󰀩cients

See Table 2

Pilot and Filter-Regulator Flow Coe󰀩cients

Type PRX Pilot: C

: 10.5; Cv: 0.36; C1: 29

g

Type SA/2 Filter-Regulator: Cg: 19

Pressure Registration

External

Process Temperature Capabilities

(1)(2)

Nitrile (NBR), Fluorocarbon (FKM) or
Polyurethane (PU) Disk

ANSI/FCI 70-3 Class VIII: -4 to 140°F / -20 to 60°C

Nitrile (NBR) or Polyurethane (PU) Disk

ANSI/FCI 70-3 Class VI: -20 to 140°F / -29 to 60°C

Approximate Weights (Including Pilot)

See Figure 7

(1)

Construction Materials

Type FL Main Valve

Main Body and Flanges: Steel
Sleeve and Disk Holder: Steel
Diaphragm Plates: Steel
Diaphragm: Nitrile (NBR) with PVC coating
Disk O-rings: Nitrile (NBR) or Fluorocarbon (FKM)
Disk: Nitrile (NBR), Fluorocarbon (FKM)

or Polyurethane (PU)

North America Only

Type PRX Pilot

Body: Steel
Trim: Stainless steel
Diaphragm: Nitrile (NBR) or Fluorocarbon (FKM)
Disk O-rings: Nitrile (NBR) or Fluorocarbon (FKM)
Disk: Polyurethane (PU) or Fluorocarbon (FKM)

Type SA/2 Supply Pressure Regulator

Body: Steel
Diaphragm: Nitrile (NBR) with PVC Coating
O-rings: Nitrile (NBR) or Fluorocarbon (FKM)
Disk: Polyurethane (PU) or Fluorocarbon (FKM)

1. The pressure/temperature limits in this Bulletin and any applicable standard or code limitation should not be exceeded.

2. Types PRX and SA/2 Fluorocarbon (FKM) elastomer are limited to 0°F / -18°C.

3. At average ambient temperature.

2

Type FL

E0822

TYPE SR

Figure 2. Noise Abatement Construction

110

100

90

80

NOISE, dB (A)

70

60

TYPE SRII

STANDARD

TYPE SR OR SRII

TYPE SRS

TYPE SRS

North America Only

50

0

187,567 /

5000

373,134 /

10,000

FLOW RATE IN SCFH / Nm3/h

559,701 /

15,000

Figure 3. Typical Sound Emission Comparison among the Different Configurations

746,269 /

20,000

3

Type FL

The regulator’s superior performance is due to the

amplifying e󰀨ect of the pilot and two-path control system.
Changes in outlet pressure act quickly on the actuator

diaphragm to provide fast response to system change.

Then the pilot amplies any small system changes to

position the main valve for precise pressure control.

Type PRX Pilot Descriptions

The Type FL pressure reducing regulators include a
PRX Series pilot mounted on the main valve.

Type PRX/120: Outlet pressure range of 14.5 to
435 psig / 1.00 to 30.0 bar. Type PRX/120 can be
used as the pilot on single stage pressure-reducing
regulators, as the monitor or working pilot in wide-open
monitor systems or as the working pilots in working
monitor systems.

Type PRX/120-AP: Outlet pressure range of 435 to
1160 psig / 30.0 to 80.0 bar. The Type PRX/120-AP
can be used as the pilot on single stage pressure­reducing regulators, as the monitor or working pilot in
wide-open monitor systems or as the working pilots in
working monitor systems.

Type PRX/125: This pilot is identical to the
Type PRX/120 except that the restriction screw is
removed. Type PRX/125 can only be used as the
monitor override pilot on working monitor applications.

Type PRX/125-AP: Identical to the Type PRX/120-AP
except that the restriction screw is removed.
Type PRX/125-AP can only be used as the monitor
override pilot on working monitor applications.

Type PRX/131: Outlet pressure range of 14.5 to
435 psig / 1 to 30 bar. The Type PRX/131 is used as a

booster or quick dump pilot on a single stage pressure

reducing regulator or with the monitor pilot on the
monitor regulator in Wide-Open Monitor systems. It
is installed as standard on the regulator for NPS 10 /
DN 250 and can be used on any other size to increase
its closing speed.

Type SA/2 has an integral 5 micron lter. This integral
lter acts only as an emergency lter; gas must be

cleaned upstream of the regulator.

Noise Abatement

At elevated pressure drops and ow rates, regulators

with standard trims can produce unacceptable noise
levels. Several options are available to reduce the
noise generated.

Type SR: Type SR (Figure 2) multi-path noise
abatement device is incorporated into the regulator
on the seat area. It consists of plated Stainless steel
wires containing no sound deadening materials.

Depending on ows and pressure drop, the silencer

can reduce noise levels as much as 20 dB (A) with an
approximate 3% Cg reduction. Type SR is available
only in NPS 1 through 6 / DN 25 through 150 and is
not recommended for high velocity applications.

Type SRII: The Type SRII (Figure 2) noise abatement
device is the next generation of Type SR and is
used in case of extreme service conditions (dirty
gas, high pressure drops and high gas velocities).
Noise characteristics are very similar to the standard
Type SR.

Type SRS: A second noise reduction device may be
added to the Type FL regulators. Type SRS (Figure 2)
consists of a Type SR or SRII plus a widened outlet

ange in which a second silencer is tted. Noise

reduction is based on the principle of stream splitting
and gradual expansion in several stages. By using a

wider outlet ange the silencer can be mounted integral

to the regulator body which allows installation of the
regulator directly into the downstream piping without
an expansion joint. Noise reduction up to 25 dB (A)
is reached without limiting the velocity in the outlet

ange with a Cg reduction of about 15%. Type SR/SRS

Silencer is available only in NPS 1 through 6 / DN 25
through 150.

North America Only

Type PRX/131-AP: Outlet pressure range of 435
to 1160 psig / 30 to 80 bar. This pilot is used as a

booster or quick dump pilot on a single stage pressure

reducing regulator or with a monitor pilot on the
monitor regulator in Wide-Open Monitor systems.

Type SA/2 Pilot Supply Filter Regulator

The PRX Series pilots are usually used together

with the Type SA/2 pilot supply lter regulator. The

Type SA/2 acts as a pressure stabilizer that provides a
constant supply pressure to the PRX Series pilots: that
is approximately 45 psi / 3.1 bar over set pressure.

4

Principle of Operation

The pilot-operated Type FL (Figure 4) uses inlet
pressure as the operating medium, which is reduced
through pilot operation to load the actuator diaphragm.
Outlet pressure opposes loading pressure in the
actuator and also opposes the pilot control spring.

When outlet pressure drops below the setting of the
pilot control spring, pilot control spring force on the
pilot diaphragm opens the pilot valve plug, providing
additional loading pressure to the actuator diaphragm.

Type FL

TYPE

TYPE
SA/2

M

R

B

V

PRX/120

S

L

A

E0827_01/2016

INLET PRESSURE

OUTLET PRESSURE

ATMOSPHERIC PRESSURE

LOADING PRESSURE

PILOT SUPPLY PRESSURE

Figure 4. Type FL Operational Schematic

Table 1. Outlet (Control) Pressure Ranges

OUTLET PRESSURE RANGE

TYPE

PRX/120
PRX/125
PRX/131

PRX-AP/120
PRX-AP/125
PRX-AP/131

psig bar Spring Color Part Number

14.5 to 26
23 to 44
41 to 80

73 to 123

116 to 210
203 to 334
319 to 435

435 to 1160 30.0 to 80.0 1% Clear M0273790X12 0.335 0.85 3.93 10.0

1.00 to 1.8

1.6 to 3.0

2.8 to 5.5

5.0 to 8.5

8.0 to 14.5

14.0 to 23.0

22.0 to 30.0

(ACCURACY

AC

CLASS)

2.5%

2.5%

2.5%

2.5%

1%
1%
1%

TYPE FL

Yellow
Green

Blue

Black

Silver

Gold

Aluminum

M0255240X12
M0255230X12
M0255180X12
M0255220X12

M0255210X12
M0255200X12
M0255860X12

8 TO 10

PIPE

DIAMETER

PILOT CONTROL SPRING INFORMATION

Wire Diameter Free Length

In. cm In. cm

0.110

0.126

0.138

0.157

0.177

0.197

0.236

0.28

0.32

0.35

0.40

0.45

0.50

0.60

2.16 5.49

2.16

2.00

2.00

5.49

5.10

5.10

North America Only

5

Type FL

M1204_01/2016

M

M

TYPE
SA/2

TYPE
SA/2

R

V

TYPE
PRX/125

R

B

V

TYPE
PRX/120

S

B

L

A

TYPE
SA/2

M

R

V

TYPE
PRX/120

S

B

L

A

8 TO 10

PIPE

DIAMETER

TYPE FL WIDE-OPEN MONITOR

TYPE
PRX/120

S

B

L

A

S

L

A

TYPE
SA/2

M

R

V

TYPE
PRX/120

S

B

L

A

M1201_01/2016

INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
LOADING PRESSURE
INTERMEDIATE PRESSURE
PILOT SUPPLY PRESSURE

Figure 5. Typical FL Installation Schematics

8 TO 10

PIPE

DIAMETER

TYPE FL WORKING MONITOR WITH TYPE PRX-125

North America Only

8 TO 10

PIPE

DIAMETER

6

Type FL

TYPE
PRX/120

TYPE
SA/2

M

TYPE
PRX/131

M1216_01/2016

R

B

V

S

L

A

S

L

B

A

8 TO 10

PIPE

DIAMETER

TYPE FL WITH TYPE PRX/131 QUICK DUMP PILOT

TYPE
PRX/120

TYPE
SA/2

M

R

V

S

B

L

A

TYPE
PRX/131

S

B

L

A

TYPE
SA/2

M

R

V

TYPE
PRX/120

S

B

L

A

North America Only

M1212_01/2016

INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
LOADING PRESSURE
INTERMEDIATE PRESSURE
PILOT SUPPLY PRESSURE

TYPE FL WIDE-OPEN MONITOR WITH TYPE PRX/131 QUICK DUMP PILOT

Figure 5. Typical FL Installation Schematics (continued)

8 TO 10

PIPE

DIAMETER

7

Type FL

This diaphragm loading pressure opens the main valve

plug, supplying the required ow to the downstream

system. Any excess loading pressure on the actuator
diaphragm escapes downstream through the exhaust
restriction in the pilot.

When the gas demand in the downstream system

has been satised, the outlet pressure increases.

The increased pressure is transmitted through
the downstream control line and acts on the pilot
diaphragm. This pressure exceeds the pilot spring

setting and moves the diaphragm, closing the orice.

The loading pressure acting on the main diaphragm
bleeds to the downstream system through the
exhaust restriction in the pilot.

Installation

Type FL regulators are installed in a horizontal or

vertical pipeline. An optional outlet ange spacer

(Figure 6, page 8) is available to be installed
downstream of the regulator. Once the spacer and

outlet ange are removed, the disk holder and trim

parts are easily accessed. See Figure 5 for typical
piping installations. Dimensions are given in Figure 7.

Type FL may be installed in any position, but is
normally installed in a horizontal pipeline with the pilot
or pilots above the body. The optimal location for the
sense and bleed lines is between the Type FL and
the downstream block valve. If the sense and bleed
lines cannot be located between the Type FL and
downstream block valve, contact your local Sales

O󰀩ce for Startup assistance. See Figure 5 for typical

piping installation.

pressure at a higher value than normal pressure.
During an overpressure situation, monitoring keeps
the customer online. Also, testing is relatively easy
and safe. To perform a periodic test on a monitoring
regulator, increase the outlet set pressure of the
working regulator and watch the outlet pressure to
determine if the monitoring regulator takes over at the
appropriate outlet pressure.

Wide-Open Monitoring Systems
(Figure 5)

There are two types of wide-open monitoring systems:

upstream and downstream. The di󰀨erence between

upstream and downstream monitoring is that the
functions of the regulators (monitor and worker) are
reversed. Systems can be changed from upstream
to downstream monitoring and vice-versa, by simply
reversing the setpoints of the two regulators. The
decision to use either an upstream or downstream
monitoring system is largely a matter of personal
preference or company policy.

In normal operation of a wide-open conguration,

the working regulator controls the system’s outlet
pressure. With a higher outlet pressure setting, the
monitor regulator senses a pressure lower than its
setpoint and tries to increase outlet pressure by going
wide open. If the working regulator fails, the monitoring
regulator assumes control and holds the outlet
pressure at its outlet pressure setting.

Working Monitoring Regulators
(Figure 5)

North America Only

Note

To prevent damage to the pilot during
Startup, the sense and bleed lines
should be located on the same side of
the downstream block valve.

Monitoring Systems

Monitoring regulation is overpressure protection by
containment, therefore, there is no relief valve to vent
to the atmosphere. When the working regulator fails
to control the pressure, a monitor regulator installed in
series goes into operation to maintain the downstream

8

In a working monitoring system, the upstream regulator

requires two pilots and it is always the monitoring

regulator. The additional pilot permits the monitoring
regulator to act as a series regulator to control an
intermediate pressure during normal operation.

In this way, both units are always operating and can be
easily checked for proper operation.

In normal operation, the working regulator controls
the outlet pressure of the system. The monitoring
regulator’s working pilot controls the intermediate
pressure and the monitoring pilot senses the system’s
outlet pressure. If the working regulator fails, the
monitoring pilot will sense the increase in outlet
pressure and take control.