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Prineiples of collision and holding-up
The dust particles in the air make inertia movements along with air current,or movements,or move under the effects of certain field.When colliding with obstacles particles will be adhered onto the obstacles by the gravitation between their surfe.
Inertia principles
Large particles make inertia movement in the airflow.The air current detours when meeting obstacles and the particles bump into the obstacles due to deviation form the direction of airflow because of inertia. The larger the particles,the stronger the inertia will be and there will be and there will be more possibilities of bumping into obstacles and therefore this will lead to better filtering effects.
Pervasion prineiples
Minor particles make irregular movement. The theory of pervasion on mass transfe making mathematic treatment on irregular movement and this is the origin of the saprinciples. The smaller the particles,the more strenuous the irregular movement will be more possibilities of bumping into obstacles and there fore this will lead filtering effects.
Fiber filtering materials
The fiber filtering materials should be able to hold up dust particles while not producing too big resistance toward the airflow. Non-woven fiber materials and special paper just come up with such a requirement. The interlaced fiber builds up millions of barriers toward particles and the broad space between the fiber allow the fluent passing of airflow.
Effieieneies vary according to defferent sizes of dust granules.
The ratio of powder and dust quantity between that caught and collected by fill existing in the unfiltered air is called"filtering efficiency". The particles under mainly make pervasion movement. In this case,the smaller the particles, the higher to be. Particles above 0.5um mainly make inertial movement and the larger the particl efficiency will be. Beteen 0.1um and 0.5um, there existed a lowest point of efficieneies.
Resistance
The fiber makes airflow detour, thus producing resistance. The sum of mumerous resistance of filters.
The resistance of filters increses with the airflow volume. Through the augmet filtering material surface area, the comparatively wind speed passing through filter be lowered in order to reduce the resistance of filters.
Dynamic capability
The caught dust powder produces additional resistance toward the airflow. Thus increses gradually in the working filters. The dust powder that has been caught but obstacles and therefore the filtering efficiency is slightly improved.
The caught dust powder mostly gathers on the windward surface of filtering mate the filtering material area is, the more dust powder it can hold and the longer the will be.
Filters rejecting
The more amassed dust the filter materials have, the greater the resistance will resistance reaches the level that's not allowed by the designing, the production line be ended. At times, overlarge resistance can scatter the dust on filters that has all caught. When such a dangerous thing happens, the filters should be rejected.
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