Instruction manual

A31A Valve
Instruction Manual
Form 5291
March 2008
5
the limits given in this manual or on
the nameplates.
D Use pressure-relieving devices as
required by government or accepted
industry codes and good engineering
practices to protect from
over-pressurizing the system.
D Check with your process or safety
engineer for any additional measures
that must be taken to protect against
process media.
D If installing into an existing
application, also refer to the WARNING
at the beginning of the Maintenance
section in this instruction manual.
CAUTION
When ordered the valve configuration
and construction materials were
selected to meet particular pressure,
temperature, pressure drop, and
controlled fluid conditions.
Responsibility for the safety of
process media and compatibility of
valve materials rests solely with the
purchaser and end-user. Since some
body/trim material combinations are
limited in their pressure drop and
temperature range capabilities, do not
apply any other conditions to the valve
without first contacting your Emerson
Process Management sales office.
1. Isolate the control valve from the line pressure,
release pressure from both sides of the valve body,
and drain the process media from both sides of the
valve. If using a power actuator, shut off all pressure
lines to the power actuator, release pressure from
the actuator, and disconnect the pressure lines from
the actuator. Use lock-out procedures to be sure that
the above measures stay in effect while you are
working on the equipment.
WARNING
See the WARNING at the beginning of
the Maintenance section for more
information before removing the valve
from the pipeline.
2. Install a three-valve bypass around the control
valve assembly if continuous operation is necessary
during inspection and maintenance of the valve.
3. Inspect the valve to be certain that it is free of
foreign material.
CAUTION
Damage to the disc will occur if any
pipe flanges or piping connected to
the valve interfere with the disc
rotation path. If piping flange has a
smaller inner diameter than specified
for schedule 80 piping, measure
carefully to be certain the disc rotates
without interference before placing
the valve into operation. Minimum
inside diameters for flanges or pipe
mating with valves are shown in tables
3 and 4.
Be certain that adjacent pipelines are
free of any foreign material, such as
pipe scale or welding slag, that could
damage the valve sealing surfaces.
Valve Orientation
The valve can be installed in any orientation,
however, it is recommended that the valve drive
shaft be horizontal and the actuator vertical as
shown in figure 5.
Install the valve with the high-pressure shutoff side
in the direction noted by the flow arrow for proper
installation, and see figure 4 for more information.
Before Installing the Valve
WARNING
The edges of a rotating valve disc
(key 2, figure 9) close with a shearing,
cutting motion. To avoid personal
injury, keep hands, tools, and other
objects away from the disc while
stroking the valve.
If the Type A31A valve is equipped
with a fail-open actuator, cycle the
valve into the fully closed position.
Ensure the valve cannot open during
installation by using travel stops, a
manual actuator, a constant supply
pressure to the pneumatic actuator, or
other steps as necessary.