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 (e) Maintain fluid pressure and temperature within the valve rating.
( f ) Do not jam valve shut while hot, or binding may result when the
v a l v e cools.
( g ) Do not jam valve open while cold. Valve may bind open when hot.
T h i s is prevented by closing the valve one-fourth turn after it is wide open.
P e r f o r m the following procedures.
3 INSPECTION AND MAINTENANCE OF VALVES.
( a ) M o n t h l y . I n s p e c t for leaks and damage to insulation. Check for
d e f e c t i v e operation.
( b ) Q u a r t e r l y . Operate any valve which has not been used frequently.
T h i s w i l l p r e v e n t s t i c k i n g . Lubricate exposed threads and valve stem gearing.
P e r f o r m the following
4 PREVENTIVE MAINTENANCE INSPECTION OF VALVES.
inspections.
( a ) Q u a r t e r l y . L o o s e n and lift the packing follower. Lubricate the
p a c k i n g with graphite-bearing oil or grease. Replace packing followers and
t i g h t e n as required to prevent packing leakage without causing binding.
(b) Yearly.
Disassemble and clean the valve, and Inspect the following
i terns:
q Valve
leaks
q Damaged seats and disks:
w e a r , wire-drawing, and grooving
q Deposits
of
foreign
matter
q Lodging of foreign matter between disk and seat
q Scoring
and
pitting
q Worn out, corroded, or damaged stems, disks, and seats
q Damaged
insulation
q Defective
parts
q Damaged gaskets
q Packing
condition
P e r f o r m the following
5 PREVENTIVE MAINTENANCE INSPECTION OF RELIEF VALVES.
inspections.
( a ) M o n t h l y . I n s p e c t for leakage through the valve which may indicate
d e f e c t i v e seats or lodged scale. Make sure exhaust piping is in good
condition, adequately supported, and valve discharge cannot endanger personnel.
7-16
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