Trade-marks
PERFORMANCE CHARACTERISTICS OF VENTS
1. Cautionary Note
Reference is made to the following
statements in para 9.3.8 of the UN
Recommendation on the Transport of
Dangerous Goods. ‘Where pressure
may develop in a package by the
emission of gas from the contents (as a
results of a temperature increase or
other cause), the packaging may be
fitted with a vent provided that the gas
emitted will not cause danger on
account of its toxicity, flammability, the
quantity released, etc. Venting of the
package should not be permitted for air
transport’ Where the risk exists of
ingress of foreign material into the drum
the packager should verify whether this
is acceptable for the to be filled product.
The performance of vents may be
impaired if contaminated by the filling
product (see also para. 5.1 and 5.2).
2. Purpose of Venting
The purpose of venting a package can
be: - To relieve overpressure caused by
gassing of the filling product (e.g.
hydrogen peroxide)
- To relieve under pressure caused by
cooling down of a drum after hot filling
(e.g. high viscosity liquids)
- To prevent unsafe stacking conditions
of light weight packages as a result of
pressure
changes
caused
by
temperature variations.
3. Range of Standard Vents
3.1 Valve Type Vents
The standard valve type vents are made
of a rubber (e.g. Silicones etc.) and is
available fitted in G2 Plastic and G2
Steel Tri-Sure plugs. The operation of
this type of vent is based on pretensioning of the stem of the vent to
ensure that the ‘umbrella’ or ‘mushroom’
shaped head of the vent closes off the
venting hole(s) in the plug. The opening
pressure of this type of vent is
determined by the design of the head of
the vent and the tension in the stem of
the vent.
3.2 Membrane Type Vents
The standard membrane type vent
consists of a microporous film of
polypropylene with P.T.F.E. (Teflon) and
is available fitted in G¾ Tri-Sure plastic
plug. This in turn can be assembled into
a 56x4 Buttress or G2 Tri-Sure
combination plug (Other executions are
also
available).
Microporous
membranes vent in both directions (“in”
and “out”). By their nature the
membranes are “open” to gases at
extremely low pressure differentials.
Issued by: Product Management / www.tri-sure.com
®
®
Tri-Sure
metal
closures, Tri-Sure
plastic
®
TM
®
closures, Tab-Seal caps, SambaCap , UNI-GRIP
®
TM
spouts, PLASTIPLUG
spouts, ULTRA-BOND
TM
TM
plugs, Push-Lock caps, PLASTICAP screw caps,
®
®
PLASTIROB taps, CDS dispense closures
Average
Opening
Pressure in Bar
Average Air
Flow Rate in
ml/min. at 0.2
Bar Pressure
Step 3
Check if venting is required
below the threshold opening
pressure of a valve type
vent.
Umbrella or
Mushroom
0.1
1000
Step 4
Microporous
Membrane
(almost) 0
1500
minimum
Check
the
maximum
temperature requirements. For
hot-filling of highly viscous
products, where venting-in
during cooling
down of the
drum is required, a steel plug
with a valve type vent is
advised when the filing product
is not sensitive to ingress of
foreign material. When the
ingress of foreign material is
not acceptable the PACKSURE® System should be
considered
(for
details
contact your local Tri-Sure
Sales Organization)
Step 5
Check
the
chemical
compatibility (see para. 5) in
combination
with
the
required venting performance.
Vent Type
4. Performance
When located above the liquid surface and
not affected by the contents of the drum or
any
other
foreign
materials,
the
performance of the standard vent is as
indicated in the table above.
5. Compatibility
For all types of vents the user should
check the compatibility of the vent with the
filling product and the transportation
conditions. Chemical compatibility tests
should not only be conducted under
laboratory but also under practical
conditions.
5.1 Valve Type Vents
Rubber used for valve type vents may be
sensitive to chemicals and solvents; even
a few percent absorption/swelling could
dramatically change the pre-tension in the
stem of the vent and consequently the
venting/closing characteristics.
7. Tri-Sure® Tab-Seal® Caps
For vented plugs special Tri-Sure Tab-Seal
caps with a venting hole must be used to
allow the flow of gas, while still reducing
considerably the risk of ingress of foreign
materials.
Cautionary notes:
Always; store upright, store under cover,
air transport is not permitted and check
National
Regulations
for
local
requirements.
5.2 Membrane Type Vents
Basically the polypropylene / P.T.F.E.
(Teflon) membranes have excellent
chemical/solvent resistance. However
membranes can become blocked by
viscous liquids (liquids which do not dewet) and eventually by particulate matter.
Oleophobic membrane material can be
supplied.
6. Selection Guidelines
Step 1
Verify whether the relevant
Regulation/
Recommendations permit
venting of the package in the
specific intended application.
Step 2
Issue no.: WEB-100005
Determine
whether
the
requirement of venting is uni- or
-directional. When bi-directional
venting is not allowed the
membrane type vents are not
suitable.
Version: 2
Date: 30-11-2008
Page 1 of 1
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