Piston Disk And Nozzle Sealing Face Repair - Emerson ANDERSON GREENWOOD 727 Installation And Maintenance Instructions Manual

ANDERSON GREENWOOD TYPE 727 DUAL PILOT MANIFOLD
INSTALLATION AND MAINTENANCE INSTRUCTIONS
General
1. 12 point sockets, nozzle retaining screw
removal/installation
¼" for 2 x 3, 3 x 4
" for 4 x 6
/
5
16
⅜" for 6 x 8, 8 x 10
2. " and ⅝" open end wrench
/
11
16
3. " and ¼" allen wrench
5 /
32
4. ¾", " and ⅞" crows foot adapter wrench
/
11
16
5. Brass hammer
6. 2" crescent wrench
7. Wood or plastic dowel rod
8. Optional tools
- Air impact tool w/socket set through
- Overhead crane or hoist
- Strap wrench
9. Housing-pilot lift indicator
Anderson Greenwood Part no. 06-1330-001
10. 2" dial indicator/.001 increments
.100 stem travel/1.00 stem extension
11. Brass shim stock
12. SST sealing tape Anderson Greenwood
Part no. 05-1124-001
13. Needle nosed pliers
14. Torque wrench capable of measuring
values in Table 1
Lubricant/sealants
1. Dow Corning-Silicone-33 grease
(or equivalent)
2. Hooker chemical "Fluorolube" LG-16
14 PISTON DISK AND NOZZLE SEALING
FACE REPAIR
The disk cannot be disassembled from the
2", 3" and 4" valve size piston. The 6" and 8"
size disk can be removed for replacement or
relapping. Loosen three disk assembly locking
screws located inside piston at spring stop.
Hold piston and unscrew disk assembly with
strap wrench (see Figure 3).
The piston disk and nozzle seat faces are
manufactured to close tolerances and
finishes. Care must be exercised in reworking
both mating surfaces to ensure a tight seat
after main valve assembly. Note that a good
machined surface finish will reduce lapping
time but in no case should the surface be
polished to improve the finish as this will
affect the flatness of the surface.
Refacing of both parts is limited to the
'mated' minimum heights and tolerances listed
in Table 3.
TABLE 3 - MINIMUM REMACHINED PISTON AND NOZZLE DIMENSIONS
Valve size
'A'
'B'
Lapping
The finer points of lapping should be
considered a mechanical art. The ability of
the average repair person to produce a good
lapped seat will require practice. No effort has
been made in this manual to establish an exact
lapping procedure. However, it is very important
to insure that the laps you are using (whether
donut laps or flat lapping plates) are flat within
2 light bands. Otherwise an uneven surface will
be transferred to the seat sealing area.
The following items are required when
lapping a piston disk or nozzle.
A. One flat lap per valve (see list below).
"
17 /
16
B. Clover compound 'C', 220 grit medium,
to remove, grooves, pits, and dents.
C. Clover compound, '1A', 320 grit, very fine, for
general smoothing of seats.
D. Clover compound, '3A', 500 grit, extremely
fine, for general smoothing of seats.
E. Clover compound, '6A', 1000 grit, micro fine,
for final finishing of seat.
F. Cotton rags, clean and lint-free.
Before lapping, chamfer the leading edge of
both disk and nozzle with sand paper. This
will break the inner and outer edges and
remove any small metal particles that might
be attached to the sharp corner surfaces.
1. Lap part numbers for ordering laps
Valve size
2 x 3
3 x 4
4 x 6
6 x 8
8 x 10
NOTE
Laps are pre-surfaced at Anderson Greenwood and
checked optically for flatness. Reconditioning of the
lap may be accomplished with a optically flat lapping
plate with all lap work verified through use of an
optical flat and monochromatic light source.
Remachining disk and nozzle
Removed material from disc or nozzle face
must not exceed .030 inches maximum and
height of reworked components must not be
less than dimensions shown in Table 3.
WARNING!
Mated heights less than the dimensions given
in Table 3 will result in seal ring damage and
potential failure of main valve function.
2 x 3 3 x 4
3.54 4.89
0.88 0.89
Part numbers
06.1595.001
06.1595.002
06.1595.003
06.1595.004
06.1595.005
4 x 6 6 x 8
5.305 7.72
1.310 1.64
8 x 10
11.13
2.17
34