XIV. Maintenance Instructions
A. General Maintenance Information
After the valve has been disassembled, a close
inspection should be made of the seating surfaces.
In a majority of cases, a simple lapping of seats is all
that is necessary to put the valve in first class working
order. If an inspection of the parts shows the valve
seating surfaces to be badly damaged, machining will be
required before lapping. O-Ring seat seal valve nozzles
can only be reconditioned by machining, not lapping.
(For specific information concerning the machining of
nozzle and disc seating surfaces, see The Re-Machining
Nozzle Seats and Bores and Re-Machining the Disc Seat
sections.)
The seating surfaces of the metal seated Consolidated
Safety Relief Valve are flat. The nozzle seat is relieved
by a 5° angle on the outside of the flat seat. The disc
seat is wider than the nozzle seat; thus, the control of
seat width is the nozzle seat (see Figure 27).
Reconditioning of the seating surfaces of the nozzle
and disc is accomplished by lapping with a cast iron lap,
and lapping compound.
Anytime the V or W orifice valve is disassembled,
be sure to inspect the Guide Rings for wear. If worn,
replace before reassembly.
ATTENTION!
In order to establish leak free valve seats,
the nozzle seating surface and the disc
seating surface must be lapped flat..
B. O-Ring Seat
The nozzle must not have any defects to prohibit the
O-Ring from sealing properly, especially the OD of the
seat where the surface must maintain a minimum of
32 RMS finish. See Figure 27 and Table 2 for reworking
O-Ring Nozzle.
The O-Ring Retainer must also maintain a flat surface
for it to sit on the Nozzle. Only polishing of surface can
be done since material removal from this surface will
cause the Nozzle to over engage O-Ring. Polishing
paper or some other light abrasive can only be used
since the part cannot function properly if its overall
dimensions are changed significantly. If significant
corrosion or damage has occurred on O-Ring retainer,
discard and replace.
K
L
D
J
45°
Nozzle
Bore
B
A
M
F
H
D
N
E
P
5°
Nozzle
Bore
L
G
Figure 27a: Metal Seat Nozzle
Figure 27b: Soft Seat Nozzle
Figure 27: Main Valve Nozzle Critical Dimensions
Consolidated 2900 Series POSRV Maintenance Manual
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