SMB/SB Installation and Maintenance Manual 140-11000 • July 2003 8-11
Flow Control Division
Limitorque Actuation Systems
8.4 SB-2
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-2 actuator is a basic SMB-2 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-2 is applicable (Sections 7.3.1, SMB-0, 1, 2, 3, 4, and 4T
Disassembly and Section 7.3.2, SMB-0, 1, 2, 4, and 4T Reassembly), with the following procedures replacing Step 11 and stem nut
removal procedure.
8.4.1 SB-2 Disassembly/Stem Nut Removal
Piece numbers refer to Figure 8.4.
1. Remove Spring Housing Cover (piece #161).
2. Remove Spring Cartridge (piece #173), complete with Belleville Springs (piece #179), Thrust Washers (piece #178), Thrust
Limit Sleeve (piece #199), and Spring Retainer Cap (piece #180).
NOTE: The spring assembly should not be disassembled unless absolutely necessary.
To disassemble the compensator spring cartridge:
a. Remove the Spring Retainer Cap (piece #180). Be careful to remove the set screws securing the Spring Retainer Cap to the
Spring Cartridge before trying to remove locknut.
b. Lift off the Thrust Washer (piece #178), the Belleville Springs (piece #179), and the Thrust Limit Sleeve (piece #199).
To reassemble the Spring Cartridge:
a. Position the Belleville Springs (piece #179) between the two Thrust Washers (piece #178) as shown in Figure 8.4.
b. Thread Spring Retainer Cap (piece #180) onto the Spring Cartridge (piece #173) until it hits the shoulder on the cartridge.
c. Reinstall set screws or drill and tap for new set screw locations.
3. Remove the Thrust Sleeve (piece #168), complete with the Bearing Cup (piece #169) and the Bearing Cone (piece #170).
4. Read Step 6. Remove the Spring Housing (piece #163).
5. Remove the Drive Sleeve 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, lift the Stem Nut (piece #20) directly from the actuator. If the actuator is on the valve,
bolt a support bar across the top of the actuator Housing to hold the Bearing Cone (piece #77) and the Bearing Cup (piece #78)
in place.
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.
To Next Page
Loading...
Need help?
General
