Fisher HPA Instruction Manual page 19

Instruction Manual
D101634X012
Figure 9. Typical Balanced TSO Trim, Large Port Designs (2.6875 Inch and Larger Port Diameters)
A7096
Table 10. Actuator Groups by Type Number
71 & 90 mm (2‐13/16 & 3‐9/16 Inch) Yoke Boss
4. Attach a handle, such as a piece of strap iron secured by stem locknuts, to the valve stem. Rotate the handle
alternately in each direction to lap the seats.
5. After lapping, disassemble as necessary (you may mark the position of the seat ring and cage with a soft tip
marker). Clean the seating surfaces, replace the gaskets, reassemble (taking care to return the seat ring and cage to
their original positions), and test for shutoff. Repeat the lapping procedure if necessary.
VALVE PLUG
SEAL
PROTECTED
SOFT SEAT
Group 1
472 & 473
585C
1B
644 & 645
655
657 & 667
685SE & 685SR
1008
HP and HPA Valves
Group 100
127 mm (5‐Inch) Yoke Boss
472
473
474
476
585C
657
Group 101
127 mm (5‐Inch) Yoke Boss
667
July 2017
19