e. The major diameter of the conical seat cavity in the flange must be
within +0.002/-0.000 in. of nominal value.
f. The external diameter of the flat disc window shall be within +0.000/
-0.01 in. (+0.000/-0.25 mm) or +0.000/-0.03 in. (+0.000/-0.75 mm) of the
nominal value depending on whether the window will be sealed with an O-ring
or a flat gasket seal, respectively.
g. The diameter of the seat cavity for a flat disc window shall be
within +0.01/0.000 in. (+0.25/-0.000 mm) or 0.03/-0.000 in. (+0.75/-0.000 mm)
of the nominal value depending on whether the window will be sealed with an
O-ring or a flat gasket seal.
h. The bearing surface of the window shall be no rougher than 32 rms.
12. FABRICATION OF WINDOWS.
a. Windows must be fabricated only from acrylic plastic casting
satisfying the requirements of paragraph 6.
b. During the fabrication process, each window must be identified with
identification and fabrication verification documents containing pertinent
material and fabrication data.
c. The windows must be annealed at least once during the fabrication
process. The mandatory annealing must take place prior to final installation
after all forming, machining, and machine polishing operations have been
already completed by the fabricator. Annealing schedule shown in Table 3-6
must be followed. Handlapping and hand polishing after annealing is allowed.
d. No fabrication process, solvent, cleaner, or coolant must be used
during the fabrication that degrades the original physical properties of the
acrylic casting.
13. INSTALLATION OF WINDOWS.
a. The window cavity seat in the flange must be thoroughly cleaned.
Aliphatic naphtha and hexane are suitable for cleaning.
b.
The window cavity seats for all window shapes possessing conical
bearing surfaces must be thoroughly coated with grease prior to placement of
window inside the window cavity so that the greased surfaces will act as
secondary seals. Silicone greases are suitable for this purpose.
c. After placement of window inside the window cavity, the primary
elastomeric seal will be placed on the high pressure face of the window, and
the retainer tightened until the seal compression reaches the minimum value
specified in paragraph 10.
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