P/N: A-22075/6, Rev. 1.1
Page 22 of 45
WARNING: Valve-Stem Eccentricity
. Excessive valve-stem eccentricity will cause
binding that can result in high start-to-discharge pressure settings, reduced valve
capacity and/or low vapor-tight pressures.
WARNING: Valve-Stem Failure.
Cracks and corrosion of pressure relief valve
stems can result in stem failure and uncontrolled venting.
WARNING: Valve-Stem Straightening.
Straightening of the stem by bending it in a
press may result in the buildup of uneven stresses in the stem, which may result in
valve malfunction.
4.1.4
O-ring Retainer Grooves
4.1.4.1 The grooves (Figure 4-6) 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.
Figure 4-6 Retainer
4.1.5
Valve Body
4.1.5.1 The sealing surface is the crown of the seat, (see Figure 4-7). 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.
Figure 4-7 Valve Body
NOTICE:
Repair work is limited to cleaning and polishing. See Paragraph A4.11.2 of
the Tank-Car Specifications.
WARNING
NOTICE
Check Surfaces of Grooves for
Nicks, Corrosion and Gouges
Crown of the Seat
