Using X-ray Computerized Tomography for Characterization of Defects in Cartridge Filters

摘要

Cartridge filter manufacturers conventionally use air permeability and bubble point tests for the evaluation of integrity and filtration rating of their filter elements. These tests reveal information only upstream and downstream of the filters. If a region of low density and a region of high density (compared to the mean density of the filter) exist in the interior of the element, these two regions may be superimposed and the results of the test may cause acceptance of an imperfect filter. The present paper shows the use of an X-ray computerized tomography scanner for visualization of internal defects in the cartridge filter elements used in industrial and domestic applications. Tomographic images with good contrast were obtained. The images clearly revealed cracks in the activated carbon filter and regions of high density in the fibrous filter (melt-blown type). Finally, the main objective of this paper is to show that X-ray computerized tomography can be used successfully within the filter industries as a potential tool in the evaluation of existing products, and as a support in new product development.