Air holes
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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. 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. 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. 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). 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. 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. 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. Limiting of temperature increase by the air circulation. The temperature sensitive elements are not threatened. 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. 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. 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. 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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透气孔(呼吸器) Air Vent Gland PRESSURE BALANCE ELEMNTS 为了为特定的应用程序选择合适的通气塞装置压力平衡元素必须先知道该单位的工作原理。通气塞可渗透“气体和蒸气比如空气”但不能渗透“液体和灰尘比如水”。这些装置的内膜的孔径大小和结构决定了液体渗透性阻力。如果水最常见的液体的工作条件的研究可以说水入侵的压力下降空气渗透率增大。相关规格的测试数据在表格中可以查到。有关的参数“压力平衡”功能取决于内、外壳的所处环境之间的不同压力。作为一个参考压力 70毫巴 70mBar=1 PSI 值的选择呈现的数据。在正常条件下空气流通存在于所有不同的压力水平.但体积流率是非常低的较小的值随着压力的增加值明显增加。当然空气流动速度也取决于膜的性能分类为标准中高和超高渗透型。如果没有水压力的危险如果装置没有浸在水里那么对于好坏不同程度的环境来说高渗透性的良好循环始终是较好的选择在本质上来讲由于这种操作当设备在加热时伴随着装置外壳由内到外的空气流通。同样在冷却期间会产生反向循环。还应指出的是总会有一定湿度水平的空气中水是以蒸汽的形式与空气流通着。除非压力差超过入侵的阈值压力否则冷凝水会被防水性膜阻止。...

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Air holes 2Pages

Catalog excerpts

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Air holes
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