4
IOM-3200
Tank or system protection is the primary function
of the weight loaded Pressure and/or Vacuum
Relief Vent. As a safety device, it is very important
that maintenance/inspection be done on a regular
interval. Maintenance should only be done by a
qualified technician. Valve Concepts recommends
that all service be performed at the factory or a
factory authorized repair center. For information on
repair centers in your area, please contact factory.
Maintenance procedures hereinafter are based
upon removal of the relief vent unit from the tank
where installed.
Owner should refer to Owner’s procedures for re-
mov al, handling and cleaning of non re us able parts,
i.e. gaskets, suitable sol vents, etc.
NOTE:
Item Numbers that are specific to FRP body
material are in parenthesis and underscored; i.e. (8).
See Figure 11. Item Numbers that are generic to all
body materials are
not
un der scored; i.e. (1). See
Figures 3 through 9 where applicable.
To Dis-assemble:
Remove cover cap screws (10)
(10 & 33), covers (8) the TFE tape /rope seals (34).
Inspect covers for corrosion, damage, or foreign
material. Clean with a suitable solvent, replace as
necessary.
NOTE:
During re-assembly, install new TFE tape /
rope (34).
For FRP material -
nuts (10) for covers
(8) should be tightened to 50 in. - lbs. (5.6 Nm).
Remove pressure and vacuum pallet assemblies,
including any loading weights (21 & 28) that may
be on the pallets (19,26).
NOTE:
As the pallets
are removed from the vent, identify each assembly
(including the stack of weights) by tagging as
“pressure” side or “vacuum” side.
Clean and inspect pallet assemblies. Inspect the
diaphragms (18,25) and replace if necessary.
To Replace Diaphragms - Std. Construction:
See Figure 4. Secure pressure or vacuum stem
assembly (23,30) in a soft-jawed vise with short,
threaded end up. Remove washer and nut (14).
For settings above 32oz/in
2
See Figure 5.
Remove machine screws (43) CCW
Lift up to remove diaphragm retainer (17,24) and
diaphragm (18,25) and pallet (19,26) and stiffener
plate (20,27). Clean parts with a suitable solvent,
replace as necessary.
NOTE:
Before re-assembly,
apply TFE paste to threads of the stem and around
center hole on the pallets (19,26).
Place stiffener plate (20,27) over threaded end of
stem. Set diaphragm (18,25) and diaphragm retainer
plate (17,24), over end of stem. Install washer and
nut (14) tight on stem.
For settings above 32oz/in
2
See Figure 5 for
assembly. Install machine screws (43).
Inspect and clean pressure / vacuum seat ring(s)
(16). Check seat surface for any nicks, corrosion,
pitting or foreign material. Seat surfaces must be
clean and smooth for vent to perform properly.
NOTE:
FRP seat surfaces are integral inside the
body.
SECTION V
V. MAINTENANCE
CAUTION
The pipeaway body (13) is no longer fastened securely
to the lower body (1) and could fall and cause severe
personal injury and material damage.
To Remove Seat Rings (except for FRP body
material):
Make a match mark between the lower
body and the upper body. Rotate cap screws (15)
CCW and remove. Remove guides (22,29). (Use the
slot on top of the guides and rotate CCW to remove.)
Mark the location of each guide on the seat ring (16)
flange for reference at re-assembly.
Lift up to remove seat rings (16) and TFE tape /
rope seal(s) (34.1). (There is no rope seal on FRP
material.) Inspect guides (22,29) and inside of the
body cavity for any corrosion or product build up.
Clean all parts as necessary.
To Remove Pipeaway Tape Seal:
Separate
pipeaway upper body (13) from lower body (1).
Remove TFE tape seals (34.1 & 34.2) and clean
sealing surfaces of both parts. Place new TFE tape
seals (34.1 & 34.2) in grooves in body (1). See
Figure 9.
Using match marks to align upper body with lower
body, lower pipeaway body on lower body, resting
on tape seals.
Place new seat ring TFE tape seals (34.1) in grooves
in upper and lower bodies (1,13). See Figure 9.
