Improvement of pulse-jet cleaning of industrial filters

Abstract

Research on the improving the function of industrial air filters with pulse-jet cleaning has been running at our Department since 1996, and various projects have been carried out. Recently, research has focused on problems of geometry optimisation of the elements of pulse-jet cleaning. This paper deals with an investigation of the influence of the volumes of both the dirty and the clean part of the filter unit on the pulse-jet cleaning efficiency. Cleaning efficiency has received no attention in the literature in this area till now. The research was carried out on an experimental filter unit with a single filter bag, built in our laboratory from real filter parts - 5 filter bag diameter, 2 730 mm bag length. In order to evaluate the tested versions a point evaluation system was developed. The evaluation system reflects the main cleaning criteria, and consists of 6 evaluation factors following from the pulse-jet pressure signals, screened in the filter bag at three different distances from the mixing nozzle, built in the outlet of the filter bag. Three different versions of the inlet (dirty) filter volume and two versions of the outlet (clean) filter volume formed the 6 different versions that were tested. The version with the highest filter volume both on the dirty and the clean filter part received the best evaluation. A very strong positive influence of an increase in the volume of the dirty filter part on the total evaluation was found in the case of the enlarged volume of the clean filter part. The most efficient pulse-jet cleaning can be therefore expected for filters with sufficiently high volumes of both dirty and clean filter parts. This conclusion is unfortunately in contradiction with the practice of filter designers, who aim at minimising the filter volume per filtering area.