ANDERSON GREENWOOD SERIES 400 PISTON PILOT POPRV
InstallatIon and MaIntenance InstructIons
Emerson.com/FinalControl
1 GENERAL VALVE DESCRIPTION AND
START-UP
1.1 General
The Anderson Greenwood Series 400 valve is
designed for modulating action. The main valve
will open at nameplate set, but only an amount
proportional to the relieving capacity required.
As process pressure increases, the valve will
open more and be in full lift at 110% of set.
The main valve uses the principle of
pressurizing the top or large area of a
differential area piston with line pressure
to hold the piston closed up to set
pressure. At set pressure, the pilot relieves,
depressurizing the volume above the piston,
the main valve dome, and the piston lifts
permitting discharge from the main valve.
1.2 Installation
Either or both inlet and outlet may be
standard ANSI flanges or ANSI pipe threaded
connections and are to be installed in
accordance with accepted piping practices.
When remote pressure pick-up is used the pilot
supply tube is connected to a remote location
rather than to the inlet neck of the valve. A
block valve in the remote pilot supply line is not
recommended. If one is used it must be opened
before pressurizing the main valve.
NOTE
Remote pressure pick-up piping must have the
equivalent flow area of 3/8” tubing for lengths up to
100 feet. For lengths greater than this, consult factory.
1.3 Start-up
There must be pressure at the valve inlet or at
the pilot inlet/sense port for valves with remote
sense to establish a differential force across
the piston and ‘load’ it in the closed position.
Pressure must pass through the pilot and exert
force on the top of the piston. On normal plant
start-up the valve will close itself as pressure
increases.
Block valves are often used under safety valves
to isolate them when maintenance is required.
When putting the safety valve in service be sure
the block valve is fully opened. If the block valve
is opened after system start-up, the safety
valve may briefly vent before the dome gets
pressurized to close the main valve seat.
Before installation these instructions must be fully read and understood
TABLE OF CONTENTS
1 General valve description and start-up ...... 1
2 Main valve maintenance .............................. 2
3 Pilot maintenance ........................................ 7
4 Pilot set pressure adjustment .................. 14
5 Valve assembly testing .............................. 20
6 Pilot set pressure field test procedure .... 24
7 Soft goods repair kits................................. 25
8 Pilot accessories ........................................ 26
9 Assembly and maintenance equipment ... 26
Engineering Doc. #05.9040.270 Rev. K
VCIOM-06020-EN 18/02
As capacity relief of thesystem is satisfied,
system pressure will begin to decrease. When
it does, the pilot will actuate and direct system
pressure to the main valve dome. This closes
the main valve.
The pilot is the non-flowing type. With the main
valve open and relieving at steady pressure,
no process gas or fluid flows through the pilot.
When process pressure changes, the pilot
actuates to change the lift of the main valve
piston. During these actuations a small amount
of gas or fluid from the main valve dome flows
through the pilot and is discharged thru the
pilot exhaust.
The set pressure range is 100 psig to 1480 psig.
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