Pleated filter element comprising pleated filter media with edge dams, and method of making and using

A pleated filter element comprising:

• a pleated filter media comprising a major upstream face and a major downstream face and comprising a plurality of oppositely-facing pleats with a pleat direction and with a plurality of upstream pleat tips and upstream pleat valleys and a plurality of downstream pleat tips and downstream pleat valleys;
• wherein the pleated filter media comprises a first corrugated edge and a second corrugated edge;
• and, a first noncorrugated edge and a second noncorrugated edge;
• wherein the first corrugated edge of the pleated filter media comprises a first edge dam of hardened adhesive that occupies the upstream pleat valleys and the downstream pleat valleys of the pleated filter media at a location laterally inwardly proximate the first corrugated edge of the pleated filter media and that extends along an entire longitudinal extent of the pleated filter media, and wherein the second corrugated edge of the pleated filter media comprises a second edge dam of hardened adhesive that occupies the upstream pleat valleys and the downstream pleat valleys of the pleated filter media at a location laterally inwardly proximate the second corrugated edge of the pleated filter media and that extends along the entire longitudinal extent of the pleated filter media;
• wherein the pleated filter media is a multilayer filter media comprising a primary filtration layer laminated together with an additional layer, wherein the primary filtration layer comprises an organic polymeric nonwoven web that exhibits a Percent Penetration of less than 5 and wherein the additional layer is a prefilter layer that is disposed upstream of the primary filtration layer and that exhibits a Percent Penetration of greater than 70,
• wherein the first edge dam is a first edge seal that is configured so that the first corrugated edge of the pleated filter media is occluded by the first edge seal, and wherein the second edge dam is a second edge seal that is configured so that the second corrugated edge of the pleated filter media is occluded by the second edge seal,
• wherein the first and second edge seals are obtained by applying a liquid adhesive to an upstream major surface of a filter media in the form of a first elongate bead that extends along a longitudinal direction of a filter media at a location laterally inward from a first edge of the filter media and by applying the liquid adhesive to a downstream major surface of a filter media in the form of a second elongate bead that extends along the longitudinal direction of the filter media at a location laterally inward from a second edge of the filter media, then compressing the filter media along the longitudinal direction of the filter media to form the pleated filter media, and hardening the first and second elongate beads of liquid adhesive to form the first and second edge seals, so that the first edge seal is located from laterally inward from the first corrugated edge of the pleated filter media with no part of the first edge seal extending laterally outward beyond the first corrugated edge of the pleated filter media, and so that the second edge seal is located laterally inward from the second corrugated edge of the pleated filter media with no part of the second edge seal extending laterally outward beyond the second corrugated edge of the pleated filter media.
• and wherein the filter media is tightly pleated so that the filter media exhibits a pleat spacing of less than three millimeters and so that adjacent walls of pleats are at least substantially parallel to each other over at least 70% of the pleat height, on average, and wherein the edge dams maintain the tightly pleated filter media in the tightly pleated configuration.