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ANDERSON GREENWOOD SERIES 96A VACUUM BREAKER
INSTALLATION, OPERATION AND MAINTENANCE INSTRUCTIONS
5 INLET PIPING
No inlet piping is required. The 96A vacuum
breaker is a weighted pallet vent designed to
breathe in atmospheric air.
6 DISCHARGE PIPING
Connect this valve as direct and close as
possible to the vessel being protected. The
valve should be mounted vertically in an upright
position either directly on a nozzle from the
pressure vessel or on a short connection
fitting that provides a direct, unobstructed
flow between the vessel and the valve. Refer to
Figure 1. Installing a safety valve in other than
this recommended position will adversely affect
its operation.
The valve should never be installed on a fitting
having a smaller inside diameter than the
vessel or line connection of the valve. Fittings
or pipe having a smaller inside diameter than
the valve outlet connections must not be used.
This piping should be designed to carry the
weight of the valve and should be properly
braced to withstand reactive thrust forces
when the valve relieves. The valve should also
be supported to withstand any swaying or
system vibrations.
After installation, there must be positive
pressure at this piping to establish a differential
force across the moving member and "load"
the valve in the closed position. On normal
start-up, the vent loads itself without incident
as pressure increases.
7 VACUUM BREAKER REPAIR (See Figure 2)
7.1 Disassembly
7.1.0 Remove the retainer ring bolts, retainer
ring and inlet screen. Remove the seat ring
and seat plate/guide tube assembly, being
careful not to damage the sealing surfaces.
7.1.1 To disassemble the seat plate/guide
tube assembly, insert a .250 [6.35 mm]
diameter or smaller rod through the
cross drilled hole in tube to prevent it
from rotating while removing the lower
nut. Remove the nut, weight if used, and
spacer. Remove retainer and O-ring
from seat plate bolt. The guide tube
may be removed from the seat plate
bolt by placing the tube in a "VEE" block
and driving out the spring pin with a ⅛"
(3.17 mm) diameter punch for 4"-12"
valves or a
for 16" valves.
7.1.2 Remove the guide rod bolt, guide rod, and
guide rod seal. To facilitate disassembly
insert a .250 (6.35 mm) diameter rod
through the cross drilled hole.
7.1.3 Remove sponge seat from seat ring.
(The sponge seat is cemented in place
with an adhesive)
7.1.4 Remove O-ring seat from seat ring.
7.1.5 Discard all soft goods (seats, seals and
gaskets).
Capped Series 96A
" (4.76 mm) diameter punch
3
/
16
Series 96A with
pressure relief valve
7.2 Repair and assembly
7.2.1 Clean all metal parts. Any particles of
elastomer adhering to the metal parts
should be removed to facilitate proper
seating and adhesion of the new seats.
7.2.2 Inspect seat plate sealing surface for
scratches. If damaged, replace seat
plate. It may be polished with fine sand-
paper and crocus cloth, but it must be
recoated with PTFE to prevent adhesion
of the plate to the elastomer seat.
7.2.3 Inspect guide tube for wear at spring
pin holes. If holes are excessively worn,
replace tube.
Figure 1
3
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