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External-Style Pressure Relief Valve A-1402C Series
4.1 INSPECTION PROCEDURES
4.1.1
Top Guide
4.1.11
The Top Guide (Figure 4-1) is principally a structural part. There should
be no paint on any components covered by the cap, or between
adjacent surfaces on the top guide and valve body. The vent area of
the valve body must be unobstructed by foreign matter that would
hinder free flow of discharging fluid.
4.1.2
Adjusting Screw Threads
4.1.2.1
The threads of the adjusting screw (Figure 4-1) should be clean and
lightly lubricated.
4.1.3
O-Ring Retainer Grooves
4.1.3.1
The grooves (Figure 4-2) must be free of gouge marks, corrosion, pits and rust. Since the O-rings must seal against
these surfaces, any irregularities can cause the valve to leak. Clean the groove by sanding it lightly with emery paper
(400 grit). If this does not effectively clean the groove, replace this part.
4.1.4
Valve Body
4.1.4.1
The sealing surfaces are the crown of the seat and rupture disc, sealing surface (Figure 4-3). Clean the seat with
emery paper (400 grit) then wipe it clean with a cloth and a suitable solvent. Run your fingernail around the surface
to detect any flaws.
NOTE:
Repair work is limited to cleaning and polishing. See Paragraph A4.11.1 of the Tank Car Specifications.
NOTE
Figure 4-3 Valve Body Seat
Figure 4-4 Valve Plug
Figure 4-2 Retainer O-ring Grooves
