| Energy-saving and low-cost of high efficiency particulate air filter (HEPA filter) is the key to its spread and popularization. But high pressure loss is the most difficult problem in developing new HEPA filter products. So, a groping experimental study on certain low pressure loss HEPA filter is a breakthrough point for further searching its potential market.For the sake of this, a new type of multi-tube HEPA filter is studied in the paper. This kind of HEPA filter can reduces pressure loss from two aspects. On the one hand, it chooses melt-blown tiny polypropylene electret filtration medium. Presently, the glass fiber filtration paper has been widely used as high efficiency filter medium. However, with rapid development of the polypropylene-fiber filter paper in recent years, the filtration efficiency (Na-flame method) can reach 99.999991% at the standard velocity (Icm/s), and its pressure loss is only one sixth of the glass fiber at the same range of efficiency. On the other hand, it applies multi-tube structure which is in triangle arrange to lower resistance of the structure. The studies of predecessors have proved that multi-tube structure has low pressure loss. Moreover, the polypropylene filter medium which can be stuck by hot pressure makes it possible to adopt the multi-tube structure. Therefore, this type of filter is characteristic of low pressure loss, high efficiency, light weight, non-agglutinant, low-request to humidity and non-completely throwing away (just needs change the filter tubes), thus it has fairly big market in the future.Firstly, the influence of the structure and work parameters on the performance of the filters is analyzed theoretically in the paper, and then deduces the resistance formulae of this multi-tube HEPA filter. After that, based on the experimental results of pressure loss and filtration efficiency for the filters in different sizes under different flow rates, the resistance formulae is further proved that can be applied in the engineering. And various factors which affect the performance of the filter is analyzed based on the experimental data. Furthermore, the test filters in the paper are of triangle arrange structure which are different from the Niexueli's. Meanwhile the experiment has enriched test types and conditions of this multi-tube HEPA filter and deducted the resistance of the system elbow more correctly, so can get more reasonable resistance formulae which establishes the foundation for the further economic optimization.Secondly, the efficiency and resistance under HEPA's nominal air flow rate which are affected by the diameter and length of the its tubes is obvious or not is analyzed in the paper based on the method of square error analysis. Then the best type which has the lowest pressure loss is picked out, meanwhile it can meet the requirement of high efficiency. The experimental results show that this type of filter is do a kind of highefficiency and low resistance, which under its nominal air flow rate( 1000m /h) and when the diameter of filter tube is 30mm and the length of it is 1.1m, its resistance is the lowest, only 50Pa.Nevertheless, it is not perfect to do these just from the energy consumption, which needs discuss from its compositive technical economy performance, thus will be accorded with practical using. Therefore, based on the resistance formulae which is obtained at the beginning of this paper, the mathematic model which sets the economic value as the objective function can be established, and then uses optimization method to get the best structure of the filter when its first invest, maintenance together with operating costs are most economical. And the different results gaining from resistance and economic analysis are compared at the end. Furthermore, the best economic type which fits different length condition of filter tube is got in the paper.
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