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Instruction Manual
Form 5062
May 2008
Principle of Operation
The diaphragm rod moves down as loading pressure
is increased on top of the diaphragm. As the loading
pressure is decreased, the spring forces the
diaphragm rod upward.
The spring and diaphragm have been selected to
meet the requirements of the application and, in
service, the actuator should produce full travel of the
valve with the diaphragm pressure as indicated on
the nameplate.
Consult the separate positioner instruction manual
for actuator principle of operation with positioner.
Maintenance
Actuator parts are subject to normal wear and must
be inspected and replaced as necessary. The
frequency of inspection and replacement depends
upon the severity of service conditions. Key numbers
are shown in figure 8 for Type 1051 actuators and in
figure 9 for Type 1052 actuators.
WARNING
Avoid personal injury or property
damage from sudden release of
process pressure or uncontrolled
movement of parts. Before performing
any maintenance operations:
D Always wear protective gloves,
clothing, and eyewear when
performing any maintenance
operations to avoid personal injury. Be
aware of pinching parts during
maintenance operations.
D Disconnect any operating lines
providing air pressure, electric power,
or a control signal to the actuator. Be
sure the actuator cannot suddenly
open or close the valve.
D Use bypass valves or completely
shut off the process to isolate the
valve from process pressure. Relieve
process pressure from both sides of
the valve. Drain the process media
from both sides of the valve.
D Vent the power actuator loading
pressure and relieve any actuator
spring precompression.
1051 & 1052 F & G Actuators
D Use lock-out procedures to be
sure that the above measures stay in
effect while you work on the
equipment.
D The valve packing box may
contain process fluids that are
pressurized, even when the valve has
been removed from the pipeline.
Process fluids may spray out under
pressure when removing the packing
hardware or packing rings, or when
loosening the packing box pipe plug.
D Check with your process or safety
engineer for any additional measures
that must be taken to protect against
process media.
CAUTION
To avoid parts damage, do not stroke
the actuator while cover (key 33) is off.
Disassembly
The following procedure describes how to
completely disassemble the actuator. When
inspecting and replacing parts, perform only those
steps necessary to accomplish the repair.
Do not, under ordinary circumstances, remove the
cap screws (keys 7, 8, and 21) at this time.
CAUTION
Cap screw (key 18) must be
disengaged from the lever (key 27)
before removing the diaphragm casing
(key 1). Failure to do so will allow the
spring precompression to rotate the
valve beyond its fully open or closed
position. This could cause damage to
the valve components and/or seal.
1. Perform the steps in the WARNING at the
beginning of the Maintenance section to isolate the
control valve and actuator.
2. Remove the tubing or piping from the top of the
actuator.
3. Remove the positioner, if used. If necessary,
refer to the positioner instruction manual for removal
instructions.
4. Unscrew the cap screws and washers (keys 34
and 63), and remove the cover (key 33).
9
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