5
IOM-3200
Using match marks align seat rings (16) with body
and re-position seat rings back in body, resting on
tape seals.
Re-install pallet guides (22,29) around the seat rings
as previously marked. Install cap screws (15) - apply
15 ft.-lbs. (20.3 Nm) torque to tighten.
Place pressure and vacuum pallet stem assemblies
on the correct seat rings (16).
WARNING
When assembling a P/V vent, always put the pressure
(long stem) and vacuum (short stem) pallet assemblies
back in their original location and ensure that the
stem is straight and fits into the guide in the cover.
If the pressure and vacuum pallet assemblies are mixed
at assembly, the settings will be changed and the flow
for the vacuum side will be restricted.
If the stem is cocked at an angle, pallet lift may be
completely blocked. An over-pressure can occur if
any of these three conditions happens. This can cause
a tank failure, severe personal injury and material
damage.
Select the appropriately tagged set of weights
(21,28) and carefully lower each set of loading
weights on the pallet stem assembly, Exercise care
so as not to damage the pallet diaphragm and seat
surfaces.
NOTE:
When installing the pressure and vacuum
covers, ensure the pressure stem assembly(30)
and vacuum stem assembly (23) are inserted in the
cover guides.
Place a new piece of TFE tape / rope seal (34, 34.0)
on the face of the body cover flanges. See Figure 9
.
Place covers (8) over stem of pallet assembly, align
bolt holes with the body (1) and install cap screws
(10). Using a star crossing pattern, tighten nuts to
15 ft. lbs. (20.3 Nm).
For FRP material - install
(10,33)
and tighten to 50 in. - lbs. (5.6 Nm).
To Remove Flame Screen:
Rotate cap screws (42)
CCW and remove cap screws and ring (41). Inspect
and clean screen (40), replace as necessary. Re-
secure screen and ring to body with cap screws.
See Figure 10.