Emerson Daniel 788DVC User Manual page 77

User manual
P/N 3-9008-556
Table 9-2: Valve cylinder head to cylinder (socket head screws) torque specifications
(continued)
NPS
4
4
6
6
8
8
9.4.2 Standard cylinder reassembly
Reassembly of a control valve without a position indicator
Procedure
1. Place the cylinder in an upright position with the ports on the bottom. Lubricate the
2. Insert the O-ring into the groove inside the bottom of the cylinder. This will require
3. Insert the seat ring into the cylinder; placing it on top of the O-ring.
4. Using the piston as your tool, place it nose end down into the cylinder on top of the
5. Remove the piston from the cylinder.
6. With the piston in a vertical position, nose end down, place the O-ring into the
7. Place the indicator stem retaining ring into the counter bore of the piston. Place the
8. Insert the piston into the cylinder, nose end down.
9. Insert the spring into the piston.
10. Turn the jack-out screws in the cylinder head to their original position.
11. Place the O-ring into the groove in the cylinder head.
12. Place the cylinder head on top of the spring, and use an arbor press against the top
User manual
Class
150
300
150
300
150
300
inside of the cylinder wall with a suitable lubricant.
some effort.
seat ring. Using a hammer handle or similar device, press down on the piston to
force the seat ring into position against the lip in the cylinder.
groove on the piston. (If the valve is a high-pressure model, the piston will require
PTFE backup rings on either side of the O-ring.
washer on top of the indicator stem retaining ring. Using retaining ring pliers, place
the retaining ring on top of the washer.
of the cylinder head to press the spring into the cylinder.
Planned maintenance
Socket head screw Torque (ft-lb)
size
1/4"-20 5
1/4"-20 5
1/4"-20 5
1/4"-20 5
5/16"-18 11
5/16"-18 11
October 2019
77