Flowserve SMB Series Electric Actuators - Manual (Page 92)

SMB Series/SB Series Installation and Maintenance FCD LMENIM1401-04-AQ – 01/15
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a. Place the actuator in hand operation.
b. Rotate the Handwheel in the direction to effect a downward movement of the stem—usually
the close direction. The Stem Nut will climb up the stem until it clears its splines.
c. Rotate the Stem Nut off the stem.
8.4.2 SB-2 Reassembly/Stem Nut Installation
Piece numbers refer to Figure 8.4.
1. Replace the Stem Nut (piece #20).
a. If the actuator is not on the valve, the Stem Nut will drop in the Drive Sleeve (piece #11) until it
bottoms out on the shoulder of the Drive Sleeve. Ensure splines are engaged.
b. If the actuator is mounted on the valve, thread the Stem Nut (piece #20) down the stem until
the splines hit. Put the actuator in manual operation. Rotate the Handwheel in the direction to
move the stem upward—usually the open direction. The Stem Nut will lower as the Handwheel
turns, until it bottoms out on the shoulder in the Drive Sleeve and the stem starts to move up.
2. Replace the Thrust Sleeve (piece #168) and the Bearing Cup and Cone (piece #169, 170). Ensure
the Quad Ring (piece #194) and the O-Ring (piece #176) are properly installed. Ensure the Thrust
Sleeve engages the splines on the top of the Stem Nut—the Thrust Sleeve will not rotate if
engaged improperly.
3. Clean the Housing (piece #2), flange, and mounting flange of the Spring Housing (piece #163).
4. Install the Spring Housing without any gasket. Measure the gap between the Spring Housing
(piece #163) and the Housing (piece #2).
5. Remove the Spring Housing (piece #163). Install a gasket between the Housing and the Spring
Housing. The gasket thickness should be the same as the gap measured in Step 4, plus an
allowance for the compressibility of the gasket material used. If an exact gasket thickness can not
be obtained, use the next higher thickness gasket available.
6. Install Spring Housing (piece #163).
7. Replace Spring Cartridge (piece #173) as an assembly. Install O-Ring (piece #197) in Spring
Cartridge Cap.
8. Install Spring Housing Cover (piece #161) using a gasket of sufficient thickness, including
allowance for compressibility, to fill any gap between the Spring Housing Cover and the Spring
Housing.