الفهرس 
Introduction
Fibrous raw materialsOnly 14 pages are availabe for public view
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Abstract
Rapid industrialization, indirectly or directly, endangers our environment through pollution. Every day our industries discharge tone of solid particles in the air. This imposes strict control of pollution by installing highly efficient gassolid separators. The filter media are necessary in cement industry for two reasons, firstly to protect the environment from pollution and secondly to minimize the loss of costly cement dust. Hence the decision for selection of filter media involves analysis of various criteria such as, suitability to the purpose, quality of filtration required, filtration efficiency, durability and economy. Needle felt fabrics proved to be the most suitable kind of filter media for depth filtration. To obtain the best performance characteristics, fabricmanufacturing variables, in particular, must be optimized, such as: needling density , needling depth of penetration, weight, type of fibre , dimensions of fibre and needle gauge. In this study, nine nonwoven needle punched filter fabrics from 100 % polyester fibres were prepared with different constructional parameters (three levels of needling density and three levels of needling penetration). Assessment of the quality of there filter fabrics was made by monitoring their capability to forming dust cake through the gaseous stream promptly. Thus it was decided to subject these filter to thermal and/or chemical treatments in order to improve their filtration performance. Both treatments were found to improve breaking strength, bursting strength, air permeability, filtration efficiency, and cleaning efficiency of tested filter fabrics. Filter pore size was measured by the image analysis technique, which is believed to be faster, more accurate, and more economical. Stereology techniques was used to determine depth of filtration and density of dust inside filter fabrics. Also this method used in measuring pore size. Results obtained were in good results and agreement with those of image analysis techniques.