Air holes0 pages

透气孔(呼吸器)
Air Vent Gland
In order to choose the right ventilation plug unit (pressure balance
elements) for a specific application, the working principles of the unit must
be known first.

AVG-M12 IP66

Ventilation plugs are permeable to "gases and vapours, e.g. air" but
impermeable to "liquids and dust, e.g. water". The permeability resistance
to liquids depends on the pore size and structure of the membrane inside
these devices.

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If the working conditions of water (the most common liquid) are studied, it
is possible to say that the water intrusion pressure goes down as air
permeability increases. The relevant specifications are collected in
tabulated data.

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Of the relevant parameters, the "Pressure Balance" function depends on
the differantial pressure between the inner and the outer environnements
of the enclosure. As a reference pressure, 70 mBar (70mBar = 1 Psi) value
is choosen to present data. Under normal conditions, air circulation exists
for all differential pressure levels. But the volume flow rate is very low for
smaller values and obviously increases with increasing pressure values.
Of course the air flow rate also depends on the properties of the
membrane (classified as standard, medium, high and ultra high
permeability types).

AVG-M16 IP66
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If there is no water pressure danger (if the device is not immersed in the
water), it is always better to choose highly permeable elements for good
circulation even for low differantial pressure levels.

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In essence, there is air circulation in the enclosure from the inside to the
outside when the device is heating up due to its operation. Similarly, a
circulation in reverse direction occurs during the cooling period. It should
also be noted that there is always a level of humidity in air, hence some
water in the form of vapour is also circulated with air. However condensed
water is blocked by the water repellent membrane unless the differential
pressure exceeds the intrusion pressure threshold.

AVG-M20 IP66
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After this technical overview, the utility of the "Ventilation Plugs" can be
listed as follows:

Prevention of pressure increase inside the enclosure. The
pressure sensitive elements are not threatened.

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Limiting of temperature increase by the air circulation. The
temperature sensitive elements are not threatened.

AVG-M40 IP66

Added flexibility for maintenance. In traditional units, when
the enclosures are heated, generaly the dilated air goes out from
the seals but can not return back when the device is colder.
Because of the vacuum formed inside the enclosure, the gaskets
are exposed to large pressure levels. In result, it is very difficult
to open the covers for maintenance. Especially in“luminaires” it is
obligatory to change the bulbs when the device is cold. The
ventilation plugs in our system prevent these kind of limitations.

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Prevention of accidental water suction into the system.
During the cooling period, we know that there is air circulation
from the outside to the inside. Hence, if the enclosure is wet from
rain or due to other reasons, some water may be sucked inside
the enclosure if there is no ventilation plug.

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AVG-M40 IP55

Prevention of exposure to hot, humid, compressed gases.
There is always a level of humidity in the enclosure due to
atmospheric conditions. Hence when the device is hot, all the
components will be exposed to a hot, humid and compressed
environment without the ventilation plug.

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To conclude, the ventilation plug can reduce and even fully
eliminate the adverse effects of humidity in the environment. Water drops
on the bottom of the enclosure are normal,but the inherent damage
becomes insignificant due to the existence of a ventilation plug.

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