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Filtration principles and performance evaluation of primary filtration equipment
Filtration principles and performance evaluation of primary filtration equipmentI. Filtration mechanism1. Filtration start stage: At this stage, the impurity particles in the media will be deposited on the exterior of the screen when passing through the screen, which mainly relies on the mechanism of blocking and dispersing, and the loss of pressure drop is relatively small;2. Filtration two stages: here gradually formed a continuation of the filter layer, filtering pore size gradually reduced, for the media in the dust blocking effect also has a substantial increase, however, the effectiveness of filtration will also be reduced; 3. Filtration stable stage: this stage mainly relies on the filtering and sieving role of the filter layer, the screen plays the role of forming and supporting the filter layer, the principle of filtration is mainly sieving, and the pressure change at this time will be relatively slow; 4. Filtration blowback stage: with the use of the filter layer of thickening, it must be cleaned to a certain extent before it can be recycled, this time the effectiveness of the equipment filtration has declined, to achieve a complete filtration cycle. II. Performance evaluationThe performance evaluation includes three aspects of filter effectiveness, pressure drop, and residual pressure drop.1. Filtration effectiveness mainly refers to the ratio of the filter outlet to the inlet mass; 2. The pressure drop is due to the continuous deposition of particles on the screen surface, and when the pressure drop reaches a large value, we must clean and regenerate the equipment; 3. A residual pressure drop occurs because the particles deposited in the filter media are not completely removed after the filtration and regeneration cycle. From this, we can see that high filtration effectiveness means that the proportion of contaminated particles is blocked and the purity of the fluid after filtration is high, but if we simply pursue filtration effectiveness it will have a certain impact on the service life of the filter because the rise in pressure drop will lead to an increase in the cost of using the equipment. And a good solution is to clean the equipment when necessary so that it does not lead to a reduction in the remaining pressure drop, when the pressure is reduced to the limit the equipment is also very damaging, and can not solve the actual problem. |
