Emerson Fisher 634, Fisher 634M Instructional Manual

Instructional Manual
D100638X012

December 2018

Types 634 and 634M

Types 634 and 634M High-Pressure Shutoff Valves

W4128

TYPE 634M SHUTOFF VALVE WITH

STANDARD PIPE PLUGS IN BODY SIDE TAPPINGS

Figure 1. Typical Constructions

WARNING

!

Failure to follow these instructions or
to properly install and maintain this
equipment could result in an explosion,

re and/or chemical contamination

causing property damage and personal
injury or death.

Fisher™ shutoff valve must be installed,
operated and maintained in accordance
with federal, state and local codes, rules
and regulations and Emerson Process
Management Regulator Technologies,
Inc. instructions.

If a leak develops or if the outlet
continually vents gas, service to the
unit may be required. Failure to correct
trouble could result in a hazardous

condition. Only a qualied person shall

install or service the unit.

Call a qualied service person to service

the unit. Installation, operation and
maintenance procedures performed

W4156-1

TYPE 634 SHUTOFF VALVE WITH

OPTIONAL TANK VALVE IN UPSTREAM BODY SIDE TAPPING

by unqualied person may result

in improper adjustment and unsafe
operation. Either condition may result in
equipment damage or personal injury.

Only a qualied person must install

or service the Types 634 and 634M
shutoff valves.

Introduction

Scope of the Manual

This manual provides installation, maintenance, and
parts information for the Types 634 and 634M high­pressure shutoff valves. Refer to separate instruction
manuals for information on regulators used with these
high-pressure shutoff valves.

Product Description

Types 634 and 634M high-pressure shutoff valves
(Figure 1) serve to provide overpressure protection by
containment. The Type 634 shutoff valve with internal
registration is installed between a pressure-reducing

Types 634 and 634M

Specications

The Specications section on this page provides the ratings and other specications for the Types 634 and 634M.
Factory specications such as type, maximum inlet pressure, maximum temperature, maximum outlet pressure,
spring range and orice size are stamped on the nameplate fastened on the regulator at the factory. The

manufacture date and original fracture disk range are printed on the disk retainer (key 3, Figure 6).

Body Size and End Connection Style

3/4 or 1 NPT internal

Maximum Inlet Pressure

(1)

1500 psig / 103 bar

Maximum Body Outlet Pressure

(1)

Type 634 Shutoff Valve: 150 psig / 10.3 bar

Type 634M Shutoff Valve: 1500 psig / 103 bar

Maximum Diaphragm Pressure

(1)

Operating: 150 psig / 10.3 bar

Emergency

(2)

: 225 psig / 15.5 bar

Outlet Pressure at which Fracture Disk Shatters

See Figure 5

Temperature Capabilities

(3)

-20

to 180°F / -29

Vent Connection

1/4 NPT internal with removable Type Y602-12
vent assembly

Downstream Pressure Registration Connection
(Type 634M Shutoff Valve Only)

1/4 NPT internal

Approximate Weight

13 lbs / 6.0 kg

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

2. A pressure exceeding this value can cause failure of, or leakage from, pressure containing components.

3. Low temperatures may stiffen elastomers and prevent normal shutoff.

regulator and a downstream system or equipment
as shown in Figure 2. The Type 634M shutoff valve
with external registration requires a control line and is
installed upstream of a pressure-reducing regulator as
shown in Figure 3.

of accumulated gas. To avoid such
conditions, use qualified personnel
to install a high-pressure shutoff
valve where:

• Service conditions are within the
limits specied in the Specications

Principle of Operation

Regulator outlet pressure registers on the side of the
diaphragm opposite the fracture disk. An excessive
rise in outlet pressure provides enough force on the
diaphragm to drive the stem through the fracture disk.
This lets the plug close, and stay closed until upstream
and downstream pressures are relieved and a new
fracture disk is installed.

1. Before installing, inspect the shutoff valve for

section, and

• The valve is protected from
exposure to physical damage and/or

corrosive substances.

any damage and foreign material that may have
collected in the body.

2. Make certain that the body interior is clean and

Installation and Startup

All key numbers mentioned in this section appear
in Figure 6.

that piping is free from debris.

3. A Type 634 or 634M shutoff valve may be
installed in any position as long as the direction
of flow complies with the flow arrow on the side

WARNING

!

of the body (key 1). Typical positions as shown
in Figure 2 or 3 are with the disk retainer (key 3)

Installing a Type 634 or 634M high­pressure shutoff valve where its

pointing down. This position eases removal of
broken fracture disk pieces.

capabilities can be exceeded or where
proper operation might be impaired
may cause personal injury, property
damage or leakage due to bursting of
pressure-containing parts or explosion

4. The Type 634 shutoff valve installation shown in
Figure 2 does not shut off inlet pressure to the
upstream reducing regulator and thus does not
provide overpressure protection to that regulator.

(1)

(3)

to 82°C

2

Types 634 and 634M

REDUCING
REGULATOR

FRACTURE DISK

INLET PRESSURE

OUTLET PRESSURE

STEM

DIAPHRAGM

PLUG ASSEMBLY

INTERNAL
REGISTRATION
TAP

OPTIONAL TOKEN
RELIEF VALVE

VENT
TAPPING

Figure 2. Type 634 Shutoff Valve Installation

TYPE 627 PRESSURE
REDUCING REGULATOR

W4263*

DOWNSTREAM
CONTROL LINE

OPTIONAL TYPE H120
TOKEN RELIEF VALVE

TYPE 634M
SHUTOFF VALVE

Figure 4. Typical Installation Showing Token Relief Valve

Therefore, inlet pressure to the upstream
reducing regulator must not exceed the maximum
emergency outlet pressure rating of that regulator
or 1500 psig / 103 bar, whichever is less.

5. The Type 634M shutoff valve installation shown
in Figure 3 will shut off flow to the downstream
reducing regulator. Thus, inlet pressure to that
regulator is limited by its maximum allowable
inlet pressure rating or by the Type 634M
maximum inlet pressure of 1500 psig / 103 bar,
whichever is less.

PLUG ASSEMBLY

REDUCING
REGULATOR

STEM

FRACTURE DISK

INLET PRESSURE

OUTLET PRESSURE

VENT
TAPPING

DIAPHRAGM

OPTIONAL TOKEN
RELIEF VALVE

Figure 3. Type 634M Shutoff Valve Installation

6. Both types can be used along with a token

relief valve (Figure 4) to minimize unnecessary

shutoff. The relief valve is set to open before the
Type 634 or 634M shutoff valve activates. This
arrangement allows the relief valve to handle
minor overpressure problems such as gas thermal
expansion or seat leakage due to dirt moving
through the system which may move out of the
regulator during the next operating cycle. The
shutoff valve does activate if the regulator has a
major malfunction with excessive gas flow that
exceeds the token relief capacity.

WARNING

!

In case the diaphragm leaks, a Type 634
or 634M shutoff valve can vent gas from
the vent assembly (key 22, not shown)
in the upper casing (key 2). If a Type 634

or 634M shutoff valve in ammable or

hazardous gas service is installed in

an enclosed space or a conned area,

personal injury or property damage

may occur due to re or explosion of

accumulated gas. To prevent such injury
or damage, provide piping or tubing to
remove the vented gas to a safe, well­ventilated area at atmospheric pressure.

CONTROL
LINE

CAUTION

To avoid a pressure surge that may
shatter the fracture disk due to impact,
start up the system slowly.

7. A self-threading vent assembly (key 22, not
shown) is screwed into the 1/4 NPT tapping of
the casing. This vent assembly may be removed
and obstruction-free piping or tubing installed
for remote venting of the casing. If kept in the
casing, the vent assembly must be pointed down
if possible or otherwise protected from blockage

such as insects, snow or freezing rain.

3