SMB/SB Installation and Maintenance Manual 140-11000 • July 20038-8
Flow Control Division
Limitorque Actuation Systems
8.3 SB-1
a WARNING: See Section 4.1 and 4.2 on Safety Precautions and Safety Practices before proceeding with
disassembly.
a WARNING: Extreme caution should be used in the disassembly and reassembly of the spring compensator
assembly.
The SB-1 actuator is a basic SMB-1 actuator with the housing cover, drive sleeve, and locknut modified to provide spring compression
to the stem nut. The disassembly/assembly procedure for the SMB-0 is applicable (Section 7.3.1, SMB-0, 1, 2, 3, 4, and 4T
Disassembly and Section 7.3.2, SMB-0, 1, 2, 3, 4, and 4T Reassembly), with the following procedures replacing Step 11 and stem
nut removal procedure.
8.3.1 SB-1 Disassembly/Stem Nut Removal
Piece numbers refer to Figure 8.3.
1. Remove the Spring Housing (piece #159).
2. Remove the Spring Housing Adapter (piece #156).
3. Remove the Thrust Spring Bearing Cartridge (piece #151). The Belleville Springs (piece #153), Seal Bushings (piece #160)
and Belleville Spring Shim (piece #154) will come off with the Thrust Spring Bearing Cartridge.
4. Remove the Thrust Sleeve (piece #147). Be careful not to loosen or damage the Quad Ring (piece #150). The Bearing (piece
#146) will come out with the Thrust Sleeve (piece #147).
5. Remove the Bearing Retainer (piece #155). Remove the Drive Sleeve (piece #11) in accordance with Step 12 of Section 7.3.1,
SMB-0, 1, 2, 4, and 4T Disassembly. If only the Stem Nut (piece #20) is to be removed, see Step 6.
6. If the actuator is not on the valve, the Stem Nut (piece #20) is accessible. If the actuator is on the valve, bolt the Bearing Retainer
(piece #155) to the housing using two 5/8” x 11 UNC x1-1/4” long bolts.
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.
8.3.2 SB-1 Reassembly/Stem Nut Installation
Piece numbers refer to Figure 8.3.
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 in
the bottom 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 bottom and the stem starts to
move up.
2. Replace the Thrust Sleeve (piece #147) and the Bearing (piece #146). Ensure O-Ring (piece #148) and Quad Ring
(piece #150) 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. Replace the Thrust Spring Bearing Cartridge (piece #151) along with the Belleville Springs (piece #153) and Belleville Spring
Shim (piece #154). Ensure the Belleville Springs are stacked as indicated in Figure 8.3. Ensure the O-Ring (piece #162) is
installed in the Thrust Sleeve.
4. Install the Spring Housing Adapter (piece #156) using a 1/32" gasket.
5. Ensure the Seal Bushing (piece #160) and the O-Ring (piece #161) are properly installed in the Spring Housing (piece #159).
6. Install the Spring Housing (piece #159) using a 1/32" gasket.
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