Channel-framed, pleated air filter with bridging filaments

A rigid, channel-framed, non-compressible, non-nestable, pleated air filter, consisting essentially of:

• a tightly-pleated air filter media with an upstream face and a downstream face and a generally rectangular perimeter with four major edges,
• wherein the tightly-pleated air filter media has a plurality of oppositely-facing pleats with a pleat direction and with a plurality of upstream pleat tips and upstream pleat valleys and downstream pleat tips and downstream pleat valleys,
• the tightly-pleated air filter media bearing a plurality of upstream linear bridging filaments that are all parallel to each other and are all oriented orthogonal to the pleat direction and are all extrusion-bonded to at least some of the upstream pleat tips,
• and,
• a channel frame comprising four major frame portions, with each major frame portion being mounted on one of the four major edges of the pleated air filter media;
• wherein the pleated air filter media comprises a spun-bonded nonwoven web comprising organic polymeric fibers at least some of which are of a composition that comprises electrets.