1-6940 and 1-4640 SERIES CONTROL VALVE
INSTRUCTION MANUAL - USE - MAINTENANCE
FOREWORD
Before installing 1-6940 and 1-4640 type valves
ascertain that the process operation pressures are not
higher than the ones allowable by the valve body rating
at the design temperature.
Furthermore the valve specific overall rating shall also
be considered (see general catalogue). The latter may
be more restrictive in some instances.
1. INSTALLATION
A straight pipe at least 6 DN long must be installed in
the piping upstream the valve and a further 3 DN length
must be installed downstream. Purpose of the above re-
quirements is to avoid stream deviations at body
connections, namely at the inlet one.
Reducers are allowed along above mentioned straight
lengths, provided that they are duly tapered and
concentric...
Before installing the valve in the line, namely the new
ones, clean piping and valves from all foreign materials,
such as welding chips, scale, oil grease or dirt.
Check piping connections arrangement for dimensions,
coaxiality and parallelism, to avoid tensile and bending
stresses, which could occur when fastening the valve to
the piping, namely in case of valves with flanged
connections.
If the valve body has butt welding connections the
installation in the pipeline should be done avoiding to
overheat the body wall.
If the valve plug is provided with a plastic seal insert it is
better to lift the plug over the seat when welding.
If excessive heating of the body is expected (small
valves, on line annealing, MIG welding, etc.) and the
trim is provided with plastic inserts, the body
temperature should be kept under control. The outside
surface temperature should not exceed 100°C at 70
80 mm distance from the welding bead.
In case of doubt it is better to remove the trim from
valve body before beginning to weld.
The face-to face dimensions of PARCOL valves are
according to IEC 534-3-1 standard, table 1.
Valves with threaded connections should be installed
with unions to allow their removal.
Control valves are normally installed with a by-pass to
allow their maintenance without shutting down the
process.The need of the by-pass must be stated for
each specific application.
The two shut-off valves located aside the control valve
must have the same port as the pipeline, not to cause
considerable head losses when completely open. The
by-pass valve should have the same port (full size or
reduced) as the control valve.
1-6940 and 1-4640 series valves are normally installed
in such a way that the flow action tends to open the
plug, unless otherwise specified.
The flow direction, according to what above specified, is
identified by the arrow printed on the indicating plate.
Valves are normally installed in vertical position with
upward oriented actuator.
Anyhow they may be installed and properly operate in
any other position. Valves should not be installed with
downward oriented actuator if the fluid holds solid
particles, which may then build-up into the packing.
2. VALVE DISASSEMBLY AND REASSEMBLY
When valves, typically over 6”, are installed
with plug in horizontal position it is necessary
to provide suitable tools, to correctly support
internal parts during disassembly and
reassembly operations (for further information
please contact Parcol).
