Consolidated 1811 Series Safety Valve Instruction Manual
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© 2020 Baker Hughes Company. All rights reserved.
XIV. Setting and Testing (Cont.)
valve. Continue repeating this procedure until
the valve opens at, or below, the set pressure
recorded on the nameplate.
c. If the valve opens at a pressure below the
recorded set pressure, allow the valve to close
and the boiler pressure to reduce to 85% of
set pressure. Increase the compression on
the spring by turning the compression screw
clockwise 1/6th of a turn. Tighten the adjusting
screw lock nut and replace the cap and lifting
lever assembly. Retest the valve as described
in Step 6. If the valve continues to open below
the required set pressure, calculate how many
turns to move the adjusting screw to cause
the valve to open at the correct set pressure.
Adjust as necessary.
d. If the valve opens and closes rapidly, (called
“chattering”) hold the valve open to prevent
damage to the valve.
Reduce the fire in the
boiler
and allow the boiler pressure to reduce
to approximately 85% of the set pressure.
Gag the valve, and reset the adjusting rings
according to presetting instructions, see
Section XIV.C.
e. If the valve indicates simmer at a pressure
greater than 1% of the set pressure of the valve,
allow the valve to reseat and the boiler pressure
to reduce to 85% of set pressure.
Gag the
valve
to prevent accidental lifting while making
adjustments. Remove the lower adjusting ring
pin and raise the lower adjusting ring. As viewed
through the ring pin hole, move the adjusting
ring from left to right one or two notches.
Remove the gag, retest and note when simmer
occurs and repeat as necessary.
Note: The lower adjusting ring should
be adjusted to the notch that provides a
minimum of simmer and does not interfere
with the blowdown of the valve.
f. If the valve “pops” open then drops out of lift,
like it was going to close, but remains open
at a very low lift, this is called a “hang up”
and indicates that the position of the lower
adjusting ring is interfering with the blowdown
of the valve. To correct a hang up,
gag the
valve
, remove the lower ring pin and lower the
adjusting ring one notch (as viewed through
the ring pin hole, move the adjusting ring from
the right to the left to lower the adjusting ring).
Remove the gag, retest and note the reseating
pressure of the valve it should close sharply at
a higher pressure.
g. If the valve closes sharply but the reseating
pressure is too low in comparison to the
standard in Table 8, blowdown is excessive.
Gag the valve, remove the upper ring pin,
raise the upper adjusting ring 10 notches,
replace the ring pin, remove the gag and
retest the valve. If the reseating pressure
has not risen enough to meet the blowdown
standard, repeat the procedure until the
blowdown standard is achieved.
Note: It may be possible that in raising
the upper adjusting ring to reduce the
blowdown, the valve may develop a hang
up, correct it as described in step f. above,
and then continue if necessary to reduce the
blowdown.
h. If the blowdown is less than the standard
required, the reseating pressure can be
lowered by gagging the valve, removing the
upper ring pin and lowering the upper adjusting
ring 10 notches (as viewed through the ring
pin hole, move the adjusting ring from the
right to the left.) Remove the gag, replace the
adjusting ring pin and retest the valve. If the
reseating pressure is not reduced enough to
meet the standard, repeat this procedure until
the standard is achieved. The upper adjusting
ring should be positioned to provide no more
blowdown than that indicated in the ASME
Code Standard.
8. Once the valve has tested in compliance with
the appropriate standard, conduct two more
verification tests. All external adjustments should
be sealed after completing final setting.
9. Proceed to the next valve to be tested.
B. Hydrostatic Testing &
Gagging
B.1 General Information
During any hydrostatic test all safety valves on the unit
must be gagged. This gagging procedure prevents the
possibility of damage to the safety valve internals in the
event that the test pressure exceeds the safety valve set
pressure.
When hydrostatic pressure will exceed the set
