How to Set Bench Range for an Air-to-Open Baumann Actuator


In this video we’ll show you how to
mount this size 32 Air-to-Open actuator on a 24000 series valve assembly and
properly set the bench range. In this case we’ll be setting a bench range of 5
to 15. Before performing any work, always be sure to read and follow all safety
precautions as they are outlined in the instruction manual. To get started we’ll
make sure that the stem nuts are installed and counter tightened on the
valve stem as shown at the bottom of the stem. Carefully lower the actuator onto
the valve assembly and install the yoke drive nut with the rounded side facing
down. Then install the travel indicator desk. Apply a small amount of anti-seize to
the valve stem threads. The valve stem needs to be carefully threaded on to the
actuator stem by one thread using the counter tightened nuts. Air will need to
be applied to the assembly before we make further adjustments to the stem.
Install a pressure connection into the lower diaphragm casing of the actuator
and apply 15 psi. As pressure is increased the actuator will move and
make contact with the bonnet. Be sure to keep your hands clear of the actuator
and the valve. With the actuator contacting the top of the bonnet, hand
tighten the yoke drive nut. Make sure the actuator is positioned correctly with
the travel scale on the left. Leave the air applied to the assembly and continue
to adjust the valve stem into the actuator stem using the lock nuts until
some resistance is felt. Back the stem off a half a turn. Continue to secure the
actuator to the valve body using a hammer and a blunt tipped cold chisel to
tighten the yoke drive nut. With the actuator mounted we’ll now perform the
bench range to set the proper spring compression and travel for the assembly.
Locate the assembly nameplate and verify the listed bench range for the assembly.
These are the pressure values that will move the assembly over it’s rated travel
span when set correctly. Start the bench range by removing all pressure to the
actuator so that the valve plug is making contact with the valve seat. Next
we’ll slowly increase the pressure looking for the initial movement of the
assembly. Movement should be detected at the lower bench range value if not we’ll
need to make some adjustments by threading the valve stem in or out of
the assembly. Before any adjustments are made, increase the actuator pressure to
15 psi to move the valve plug away from the valve seat to prevent damage. If the
movement was observed at a pressure below the lower bench range value, the
valve stem connection will need to be lengthened by turning the valve stem out
of the actuator stem. If the movement was observed at a pressure above the lower
bench range, the valve stem connection will need to be shortened by turning the
valve stem into the actuator stem. After making the needed adjustments, remove
pressure and monitor the travel again. Continue to make adjustments and test
for initial movement at the lower bench range value until the appropriate
settings are achieved. This may need to be repeated several times. At this point
apply 15 psi and adjust the stem nuts to secure the indicator disc below the
actuator stem. Loosen the screws holding the travel
scale and align the 100% travel marking to the indicator disc as needed. The last
thing we’ll need to verify is that the correct travel is achieved. Slowly
decrease the pressure to the actuator to 0 psi. The valve plug should make
contact with the valve seat and the travel indicator disc should now line up
with the 0% rated travel mark on the scale. Bench range and travel are
now properly set for this assembly. For more information visit Emerson.com/Fisher or contact your local Emerson sales representative. Thanks for
watching!

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