How is the filtration area of paper filter mediums primarily increased?

The primary method for increasing the filtration area of paper filter mediums is through pleating. Pleating involves folding the filter material in a series of sharp, parallel creases, which expands the surface area available for filtration without significantly increasing the overall size of the filter. This added surface area improves the filter's capacity to capture particles, thereby enhancing its efficiency.

While form winding and resin bonding are important processes in the construction and durability of filters, they do not primarily serve to increase the filtration area. Form winding is typically used in manufacturing cylindrical filters, and resin bonding can be involved in strengthening the filter material. However, it is pleating that directly enhances the effective filtration surface by creating more space for contaminants to be trapped.