Emerson Process Management 1051 - Manual (Page 16)

Instruction Manual
D100320X012
1051 and 1052 H & J Actuators
October 2012
16
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.
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.
Disassembly
The following procedure describes how the actuator can be completely disassembled. When inspection or repairs are
required, perform only those steps necessary to accomplish the procedure. Do not under ordinary circumstances
remove the cap screws (keys 7, 8, and 21).
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 body or other operated equipment beyond its fully open or
closed position. This could cause damage to the operated equipment.
1. Bypass the valve or other operated equipment. Relieve all actuator loading pressure, and remove the tubing or pipe
from the top of the actuator.
2. Remove the positioner, if one is used.
3. Mark the orientation of the travel indicator (key 37) with respect to the travel indicator scale (key 35). Then,
unscrew the cap screws and washers (keys 34 and 63), and remove the cover (key 33).
4. Remove the retaining ring (key 30), and then remove the hub (key 29) from the cover.
5. Check the condition of the bearing (key 31). If replacement of the bearing is necessary, the travel indicator scale
(key 35) must first be removed by removing the self-tapping screws (key 36). Mark the orientation of the travel
indicator scale on the cover before removing it.
CAUTION
When removing the actuator from the valve body, do not use a hammer or similar tool to drive the lever (key 27) or
actuator off the output shaft (key 87). Driving the lever or actuator could damage operated equipment. For valves, driving
the lever (key 27) could move the valve disc and bearings away from the centered position causing subsequent damage to
valve parts.
If necessary, use a wheel puller to remove the lever. It is permissible to tap the wheel puller screw lightly to loosen the
lever, but hitting the screw with excessive force could also damage operated parts or disrupt the centered position of a
valve disc or other equipment.
6. For an actuator with an H mounting adaptation and a 22.2 through 38.1 mm (7/8 through 1-1/2 inch) output shaft,
unscrew the cap screws (key 78) and remove the actuator from the operated equipment. Mark the orientation of
the lever (key 27) with respect to the output shaft (key 87). This marking is used during reassembly to allow for
proper lever/output shaft positioning.