Bluescope Steel at Port Kembla asked Cliff Harper of Vilair-AAF to investigate two problems with a large 4-stage filter bank servicing an electrical switch room for a plate-tinning line. Supply of conditioned air was unacceptably low; and there was significant contamination of equipment in the switch room due to dust particles passing through the filters.
The airflow deficiency was found to be due to high filter pressure drop – even with new filters. This was a result of a large axial fan in close proximity to the filter bank deforming pocket filters so as to restrict the media area. The ‘angled’ airflow would pull the filter pockets to one side, causing the pockets to fall onto each other – creating higher than normal filter resistance. The contamination issue was identified as being due to the relatively low efficiency of the installed filters, exacerbated by continual movement of the filter pockets.
The existing filters were replaced with a higher-efficiency two-stage system. The primary filters are high-capacity pads and the second stage are AAF F8 grade DuraCel XL90 D cells. The DuraCel filter-media cartridge is rigid, thus eliminating the problem of media deformation. The upgraded installation has accomplished the dual goals of increasing airflow and cooling for the switchboards together with the supply of cleaner air.