Instruction manual

Instruction Manual
D500248X012
A31D Valve
April 2014
4
CAUTION
Damage to the disk will occur if any pipe flanges or piping connected to the valve interfere with the disk rotation path. If
piping flange has a smaller inner diameter than specified for schedule 80 piping, measure carefully to be certain the disk
rotates without interference before placing the valve into operation.
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.
Installing Double-Flange Valves
WARNING
The edges of a rotating valve disk have a shearing effect that may result in personal injury. To avoid personal injury, keep
clear of the disk edges when rotating the disk.
CAUTION
To avoid damage to the valve disk during installation, the valve must be in the fully closed position. If the A31D valve is
equipped w ith a fail-open actuator, remove the actuator before installing the valve/actuator assembly or cycle the valve
into the fully closed position. Then, take appropriate steps to ensure that the actuator does not cause the valve to open
during installation.
1. See table 2 for flange bolt specifications.
2. Properly orient the valve according to the specific application. For optimum performance, install the valve so that
the shaft will be on the high pressure side of the valve at shutoff.
3. Position the valve between the flanges. Be sure to leave enough room for the flange gaskets. Install the lower flange
bolts.
4. Select the appropriate gaskets for the application. Flat sheet, spiral wound, or other gasket types, made to the
ASME B16.5 group standard or user's standard, can be used on the valve depending on the service conditions of the
application. Install the gaskets and align the valve and the gaskets.
5. Install the remaining bolts.
6. Tighten the flange bolts in an alternating criss-cross fashion to a torque value of one-forth of the final bolting
torque. Repeat this procedure several times increasing the torque value each time by a forth of the final desired
torque. When the final torque value has been applied, tighten each flange bolt again to allow for gasket
compression.
WARNING
An A31D valve body is not grounded when installed in a pipeline. To avoid personal injury or property damage, always
make sure that the valve body is grounded to the pipeline before putting the valve assembly into operation in a flammable
or hazardous atmosphere. To provide shaft and disk-to-body grounding, attach a grounding strap to the shaft w ith a clamp
and connect the other end of the grounding strap assembly to the valve body.
7. If necessary, attach a grounding strap from the valve body or pipeline to the valve shaft. For additional information
on grounding procedures, contact your Emerson Process Management sales office.