Emerson FRM-2 User Manual

CASH VALVE TYPE FRM-2 CRYOGENIC BACK PRESSURE OR ECONOMIZER VALVE

INSTALLATION, OPERATION AND MAINTENANCE INSTRUCTIONS

Before installation, these instructions must be carefully read and understood.

DESCRIPTION

The Type FRM-2 is designed to function as
a Back Pressure or Economizer valve in
Cryogenic Circuits. The Back Pressure function
is to open at a preset pressure and relieve inlet
pressure to the discharge side into a lower
pressure. The Economizer function is to open
at a preset pressure, above the Pressure Build
set pressure, and continue to open as gas
head pressure from heat leak builds during
non-use periods of the system. The Economizer
by-passes gas head pressure directly to the
Final Line circuit, when system draw resumes,
to draw down the excess pressure rapidly and
recloses before the Pressure Build regulator
opens. These valves are small and compact, yet
highly efficient, making it suitable for numerous
applications that call for a small, accurate back
pressure regulator. Type FRM-2 incorporates a
"floating ring" design that provides for smooth
even pressure control.

SPECIFICATION DATA

Service: Cryogenic liquids and
gases. Well suited for
use in the Economizer
circuit as a heat leak
economizer valve in
systems having
medium flows.
Sizes: ¼" (6.4 mm), ⅜" (9.5 mm)
and ½" (13 mm)

Connections: NPTF
Body: Brass
Material: Brass
Maximum
Temperature: -320 to 150°F (-195 to 65°C)
Maximum
Set Pressure: FRM-2: 600 psig (41.4 barg)

CONSTRUCTION

Threaded ends; 2-way, side inlet-side outlet;
2-way, side inlet-bottom outlet; 3-way,
2 side inlets-bottom outlet; brass body;
brass spring chamber; stainless steel seat
disk, seat ring and pressure spring; bronze
diaphragms; Polytetrafluoroethylene (PTFE)
diaphragm gasket.
Also available with stainless steel body, spring
chamber and diaphragms.

All parts commercially cleaned for
cryogenic service.

INSTALLATION INSTRUCTIONS

When installing the valve, connect the
supply line to the inlet connection. The outlet
connection should be connected to the bypass
or final vaporizer line. Valves with 2 opposite
side inlets and a bottom outlet may be installed
as an angle valve with one inlet plugged, or
alternatively used as an in-line valve with
regulated pressure on both the inlet and
process sides of the valve.

It is recommended that Type FRM-2 valve be
installed in the horizontal position with the
spring chamber upright. For ease of operation
and maintenance, it is suggested that manual
shut-off valves be installed upstream and
downstream from the valve. Use a compatible
sealant on the male pipe threads and do not
overtighten the valve connections.

Other considerations in making a good
installation are:

1. The valve should be sized properly for the
service conditions.

2. Type FRM-2 valve is a diaphragm operated
valve designed for the continuous
operating pressure control of a system.
All series FRM-2 valves are fitted with a
diaphragm stop to prevent the diaphragms
from extending beyond their limit; however,
should a diaphragm fail, the valve will fail in
the closed position. As a safeguard, it may
be desirable to protect the system against
damaging high pressures by a safety relief
valve or some other type of safety device.

Emerson.com © 2019 Emerson. All rights reserved. VCIOM-14770-EN 20/08

CASH VALVE TYPE FRM-2 CRYOGENIC BACK PRESSURE OR ECONOMIZER VALVE

INSTALLATION, OPERATION AND MAINTENANCE INSTRUCTIONS

OPERATION INSTRUCTIONS

Adjusting the Back Pressure

The regulator's back pressure setting is
adjusted by turning the adjusting screw (1) at
the top of the spring chamber after loosening
the adjusting screw lock nut (2). To obtain a
higher pressure setting, turn the adjusting
screw clockwise (into the spring chamber). To
lower the pressure setting, turn the adjusting
screw counter-clockwise (out of the spring
chamber). Tighten the adjusting screw lock nut
after the adjustment has been made and install
the closing cap.

MAINTENANCE INSTRUCTIONS

The following procedures are provided for
servicing the Type FRM-2 back pressure relief
valve. Repair parts can easily be installed
without removing the valve from the line.

CAUTION

Before attempting to replace any spare parts, be
sure to shut off all pressure connections to the
valve. With the valves closed, however, system
pressure could still be locked between the shut
off valve and the inlet and/or outlet sides of the
relief valve. Before proceeding with any valve
service, be certain to relieve the pressure from
BOTH sides of the valve.

Refer to the valve exploded view for
parts identification.

Servicing the Pressure Spring (5),
Diaphragms (10), Seat Disk (13), and
Seat Ring (14)

4. The Diaphragm assembly, consisting
of the pressure plate nut (7),
lock washer (8), diaphragm pressure
plate (9), diaphragms (10), seat disk
gasket (12) and seat disk (13), can now
be lifted off the body (15). Disassemble
the parts by unscrewing the pressure
plate nut (7) from the seat disk (13).
Inspect all parts and replace if necessary.
The diaphragm gasket (11), below the
diaphragm, should be replaced when new
diaphragms (10) are installed.

IMPORTANT

Excercise care to ensure that the surface of
the seat disk (13) is not scratched, marred or
damaged during disassembly and reassembly.

5. Once the diaphragm assembly has been
removed, the seat ring (14), which is sitting
loosely in a recess of the valve body, can
be removed.

IMPORTANT

Handle the seat ring carefully to avoid damage
to the seat ring surface which contacts the
seat disk (13).

NOTE

Be sure to install the seat disk, with the machined
groove around the outer edge of the flat face, so that
this face is up (away from the body).

6. Inspect all parts and replace if necessary.
Reassemble in reverse order. After placing
the valve back in service, adjust the
delivery pressure setting as detailed under
Operation Instructions.

1. Loosen the lock nut (2) ¼ turn and turn
the adjusting screw (1) counter-clockwise
until the pressure spring (5) is no longer
under tension.

NOTE

When installing the adjusting screw during
reassembly, turn the screw clockwise untl the lock nut
just touches the spring chamber. When the valve is
placed in service, the pressure setting should be very
close to the original setting.

2. Unscrew the spring chamber (3) from the
valve body (15). During reassembly, tighten
the spring chamber securely.

3.

Remove the spring seat (4), pressure spring (5),

and the diaphragm stop (6) from the
valve body.

REPAIR PARTS INFORMATION

Refer to the Type FRM-2 exploded view for
parts identification.

SPECIFICATIONS

Each Type FRM-2 back pressure valve is
supplied with a pressure spring selected to
provide the desired pressure setting. The range
of adjustment or satisfactory "working range"
of individual springs is shown below for each
valve size. Each valve has the "set" pressure
and range of adjustment stamped on a tag
fastened to the valve.

LIST OF MATERIALS

Item No. Description

1 Adjusting Screw
2 Lock Nut
3 Spring Chamber
4 Spring Seat
5 Pressure Spring
6 Diaphragm Stop
7 Pressure Plate Nut
8 Lock Washer
9 Pressure Plate
10 Diaphragm
11 Diaphragm Gasket
12 Seat Disk Gasket
13 Seat Disk
14 Seat Ring
15 Body

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