Baker Hughes Spring Diaphragm Actuators 87/88 Series

Replacing diaphragm air to close actuator (Model 87), size 3 without handwheel A. Shut off air supply to the actuator and remove air piping from the upper diaphragm case (24).

B. Check the travel indicator on stem flange (2) against the travel scale (9) to ensure that the plug is up (off the seat).

D. Re-tighten lock nuts (1) against each other so they will lock at a point that is not against the stem flange (2).

E. Turn the stem lock nut (1) counterclockwise and loosen the plug stem until it disengages from the actuator stem (10).

F. Remove four diaphragm case cap screws and nuts (27 and 28) leaving the other four installed on the case equally spaced.

G. Remove tension bolts (four remaining 27 and 28) in multiple steps to relieve spring tension gradually. Remove upper diaphragm case (24).

H. Remove hex nut (23) and spacer (14).

I. Replace the new diaphragm (25) on the diaphragm plate (26).

Replace diaphragm seal and stem seal, air to open (Model 88) actuators A. Shut off air supply to the actuator, isolate the control valve process pressure to eliminate the valve from moving with spring tension removed

B. If valve is equipped with a handwheel, rotate handwheel to a free position

C. Remove diaphragm case cap screws and nuts (20 and 19)

D. Remove tension bolts (27 and 28) in multiple steps to relieve spring tension gradually. Remove upper diaphragm case (24)

E. Note position of springs (21) and spring spacers (18) [if equipped] in the diaphragm plate (26)

F. Remove springs (21) and spring spacers (18) if used.

G. Loosen lock nuts (1). Re-tighten lock nuts against each other so they will lock at a point that is not against the stem flange (2). By means of a wrench, hold the lock nuts (1) and plug stem. Turn the actuator stem (10) subassembly until it disengages from the plug stem and remove completely from actuator.

On size 10,16 and 23 actuators

Replace or repack handwheel bearing, size 6 and 10 actuators

A. Rotate handwheel to a free position.

B. Remove handwheel cap screw (20) and washer (42).

C. Remove handwheel (41) and lock nut (43).

D. Remove lock pin (91), cap screw (93), and washer (94) to release handwheel cover (57). Remove cover.

E. Remove pivot pins (33) from the yoke which hold the handwheel pivot (36).

F. Remove snap rings (46) and remove lever pin (45) to release handwheel assembly.

G. Turn handwheel stem (39) until it clears traveling nut (40).

H. Remove snap ring (38) and bearing ring (37) to release the handwheel stem (39) from the bearing.

Replace or repack handwheel bearing size 16 and 23 actuators A. Rotate handwheel to a free position.

B. Remove lock pin (91), cap screw (93), and washer (94) to release handwheel cover (57).

C. Remove pivot pins (33) which engage the handwheel pivot (36) thru the yoke.

D. Remove snap rings (46) and remove lever pin (45) to release complete handwheel assembly.

E. Remove cap screw (97) and end flange (96) to release the handwheel stem (39) from the bearing.

F. Remove snap ring (35) to release bearing (34).

G. Replace or clean to repack the bearing with new grease.

H. Pack bearing (34) with Mobilux No. 2 grease or equal.

I. For remounting, reverse removal procedures from step (F) through (B).;

Replacing diaphragm air to open actuators (Model 88) with or without handwheel (Figure 5, 6 and 10)

A. Shut off air supply to the actuator, isolate the control valve process pressure to eliminate the valve from moving with spring tension removed.

B. If valve is equipped with a handwheel, rotate handwheel to a neutral position.

C. Remove diaphragm case cap screws and nuts (20 and 19). Tension bolts (27 and 28) must be removed last.

D. Remove tension bolts (27 and 28) in multiple steps to relieve spring tension gradually. Remove upper diaphragm case (24).

E. Note position of springs (21) and spring spacers (18)[if equipped] in the diaphragm plate (26), before you remove these parts.

F. Remove hex nut (23) [size 3] or jam nut (23) [all other sizes]. Also remove spacer (22) [size 3] and diaphragm washer (22) [all sizes].

G. Remove diaphragm plate (26) and diaphragm (25).

H. Replace the new diaphragm (25) on the diaphragm plate (26).