How to choose the primary air filter?

31/07/2020

    The primary air filter is suitable for pre-filtration of central air conditioning and centralized ventilation systems, pre-filtration of large air compressors, clean return air systems, pre-filtration of local high-efficiency filtration devices, and pre-filtration of high-temperature air filters. Mainly used to filter dust particles above 5μm.

    The primary air filter has three styles: plate type, folding type, and bag type. The outer frame materials include paper frame, aluminum frame, and galvanized iron frame. The filter material includes non-woven fabric, nylon mesh, activated carbon filter material, metal mesh, etc. The protective net has double-sided plastic-sprayed wire mesh and double-sided galvanized wire mesh.

    The advantages of the primary air filter are low price, lightweight, good versatility, and compact structure.

    This kind of efficiency filter is often used in the primary filtration of air conditioning and ventilation systems and is also suitable for simple air conditioning and ventilation systems that only require primary filtration. So what kind of primary air filter do we choose?

    One is the inlet and outlet diameter: in principle, the inlet and outlet diameter of the filter should not be smaller than the inlet diameter of the matching pump, and it is generally the same as the inlet pipe diameter.

    The second is the nominal pressure: the pressure level of the filter is determined according to the high pressure that may appear in the filter pipeline

    The third is the selection of the number of holes: the main consideration is the particle size of the impurity to be blocked, which is determined according to the process requirements of the medium. The particle size that can be blocked by various specifications of screens can be found in the following table "Filter Specifications".

    Furthermore, the filter material: the filter material is generally the same as the material of the connected process pipeline. For different service conditions, you can consider choosing a filter made of cast iron, carbon steel, low alloy steel, or stainless steel.

    Then there is the calculation of the filter resistance loss: the water filter, under the general calculation of the rated flow rate, the pressure loss is 0.52 ~ 1.2kpa.

    The primary air filter should be configured according to the performance requirements of different occasions, which depends on the choice of the primary air filter. There are four main characteristic indicators for evaluating air filters: air filtration speed, air filtration efficiency, air filter resistance, and air filter dust holding capacity.