Fisher Instruction Manual: C402, C421 and C427 Internal Valves LP | Fisher Manuals & Guides

Instruction Manual
MCK-1104

January 2009

Types C402, C421, and C427

Types C402, C421, and C427 Internal Valves

WARNING

!

Failure to follow these instructions or to
properly install and maintain this equipment

could result in an explosion and/or re

causing property damage and personal injury
or death.

Fisher® equipment must be installed,
operated, and maintained in accordance with
federal, state, and local codes and Fisher
instructions. The installation in most states
must also comply with NFPA No. 58, and
ANSI Standard K61.1.

Only personnel trained in the proper
procedures, codes, standards, and
regulations of the LP-Gas industry should
install and service this equipment.

The internal valve must be closed except
during product transfer. A line break
dowstream of a pump may not actuate the

excess ow valve. If any break occurs in the
system or if the excess ow valve closes, the

system should be shut down immediately.

Introduction

TYPE C427

TYPE C421

Figure 1. C400 Series Internal Valves

Scope of Manual

This manual covers instructions for the Types C402, C421,
and C427 threaded internal valves.

Description

The valves are typically used on the inlets and outlets of
bobtail and transport trucks and on large stationary storage
tanks. They can also be installed in-line. Designed for
propane, butane, or NH3 at ambient temperatures, the valves
can be used on other compressed gases, but the user should
check with the factory to make sure the valves are suitable for

the particular service.

www.emersonprocess.com/regulators/lp

Specications

Refer to Specications for Types C402, C421, and C427
internal valves.

DOT Internal Self-Closing Stop Valve Requirement —
U.S. Department of Transportation (DOT) regulations
49CFR§178.337-8(a)(4) require each liquid or vapor
diskharge outlet on cargo tanks (except for cargo tanks used
to transport chlorine, carbon dioxide, refrigerated liquid, and

certain cargo tanks certied prior to January 1, 1995) to be
tted with an internal self-closing stop valve. Fisher’s

“C” Series internal valves comply with the internal self­closing stop valve requirement under the DOT regulations.

D450022T012

Types C402, C421, and C427

Specications

Body Sizes and End Connection Styles

Inlet: 2 or 3-inch NPT external

Outlet: 2 or 3-inch NPT internal

Number of Outlets

Type C402: 3 (side)

Type C421: 2 (side and straight through)

Type C427: 1 (straight through)

Excess Flow Springs

Half Coupling Flows:

2-inch Sizes (DN 50): 100, 150, and 250 GPM
(378, 568, and 946 l/min)

3-inch Sizes (DN 80): 150, 200, 250, 400, and 500 GPM
(568, 757, 946, 1514, and 1893 l/min)

Full Coupling Flows:

2-inch Sizes (DN 50): 60, 90, and 130 GPM
(227, 341, and 492 l/min)

3-inch Sizes (DN 80): 100, 125, 165, 235, and 325 GPM
(378, 473, 625, 890, and 1230 l/min)

Principle of Operation

Refer to the schematic drawing, Figure 2. In view #1, the

valve is held closed by both tank pressure and the valve’s

closing spring. There is no leakage past the resilient seats in
the poppet to the valve outlet.

The valve is opened by moving the operating lever to
approximately mid-point in its 70° travel (view #2). This
allows the cam to place the rapid equalization portion of the
valve stem in the pilot opening, permitting a larger amount of
product to bleed downstream than if the operating lever were
moved to the full open position.

When tank and downstream pressure are nearly equal after

a few seconds, the excess ow spring pushes open the main

poppet (view #3) and the operating lever can be moved to
the full open position.

If tank pressure is greater than the valve’s outlet pressure,

the main poppet will remain in the closed position. If valve
outlet piping is closed off by other valves, however, product
bleeding through the pilot will increase until it nearly equals
tank pressure and the main poppet opens.

Note

The main poppet will not open if valve outlet
piping is not closed off so that the outlet
pressure can approach tank pressure.

Maximum Allowable Inlet Pressure

400 psig (27,6 bar) WOG

Temperature Capabilities

-20° to 150°F (-29° to 66°C)

Body Materials

Types C421 and C427: Ductile Iron

Type C402: Cast Steel WCC

Approximate Weights

2-inch Sizes (DN 50):

Type C402: 15 pounds (7 kg)
Type C421: 11 pounds (5 kg)
Type C427: 9 pounds (4 kg)

3-inch Sizes (DN 80):

Type C402: 38 pounds (17 kg)
Type C421: 21 pounds (10 kg)

Type C427: 16 pounds (7 kg)

Once the main poppet opens, a ow greater than the valve’s
excess ow spring rating or a sufcient surge in ow forces
the main poppet closed against the excess ow spring

(view #4). The pilot valve allows a small amount of product
to bleed, but much less than view #2 where the rapid
equalization portion of the stem is placed in the pilot opening.
When the operating lever is moved to the closed position, the
valve closes completely and seals tightly (view #1).

Installation

Mounting and Piping

The internal valves can be installed in either a half or full

coupling. Excess ow spring closing ow rates vary in half
and full couplings, refer to specications.

CAUTION

Excess ow valve closing ow rates are not

the same for half and full couplings. Verify

the coupling for the desired excess ow rate.

Do not install the valve in any piping tending
to restrict the valve inlet because this may

prevent the excess ow valve from closing.

Do not install the valve with such extreme
torque that the coupling can cut threads into
the valve. This could cause valve distortion
and affect the internal working parts.

2

Types C402, C421, and C427

BLEED BLEED

VALVE CLOSED

T80174

RAPID BLEED OPEN

Figure 2. Operational Schematic

Do not use Polytetrauoroethylene (PTFE)

tape as it may cause thread galling to occur.

Use an appropriate pipe compound, on the male threads of
the internal valve and pipeline. Pull the valve into the coupling
hand tight, and then wrench tighten it for approximately two
additional turns. Larger size valves may require an additional
amount of torque to obtain a leak-free connection.

Keep piping from the valve outlet to the pump full size and
as short as possible with a minimum number of bends.
Reduction in pipe size to suit smaller pump inlets should
be made as close to the pump as possible using forged
reducers (swage nipples) or venturi tapers rather than

bushings. This assures minimum ow resistance and
efcient pump operation.

The valves have a break off section below the inlet pipe
thread which is intended to permit the lower valve body
to shear off in an accident, leaving the valve seat in the
tank. The break off section is designed for container

installations and will probably not provide shear
protection if the valve is installed in a pipeline.

A hydrostatic relief valve does not need to be installed
adjacent to the valve since the internal valve relieves
excessive line pressure into the tank.

FLOW FLOW

VALVE OPEN

LIMITED
BLEED

EXCESS FLOW VALVE

CLOSED

LIMITED
BLEED

Actuators

The remote operating control system for the valve is
extremely important, and it must be installed to conform
with the applicable codes. DOT MC331, for example, most
generally applies for trucks.

Fisher® offers both cable controls and air cylinder systems
to operate the C400 Series internal valves. It may also be
possible to use cable controls from other manufacturers or to
fabricate a linkage mechanism.

Any control system requires thermal protection (fuse links)
at the valve, at the remote control point and, if necessary,
near the hose connections. The instruction manuals for
Fisher Controls actuator systems show how to install the
fuse links.

Installation instructions on Fisher Types P650, P163A, and
P164A cable controls, are in Form MCK-1083. Air cylinder
actuator installation is covered in Form MCK-1137. Type P340
latch/remote release instructions are on Form MCK-2048.

The operating linkage must allow the operating lever to
move from the fully closed position to within 2° of the fully
open position. The linkage should not apply strong force
to the lever past the fully open position or the valve could
be damaged.

Selectively Filling Manifolded Tanks

Fisher® internal valves provide positive shutoff only in one
direction, from out of the tank to downstream of the valve.

The internal valves are designed to allow gas to ow into

a tank when the downstream line pressure exceeds tank

pressure. If you want to selectively ll one or more of the

other tanks in a tank manifold system, you must place a
positive shutoff valve downstream of the internal valve,

otherwise, all tanks will be lled at the same time and at

about the same rate.

CAUTION

The internal valve’s closing spring is
not designed to overcome drag in the
control linkage in order to close the valve.
Depending upon the control system used,
an external spring (such as Fisher drawing
number 1K4434) or positive closing linkage
may be needed. Be sure the control system
is installed to prevent binding that could
cause the valve to stick in the open position.

3