Air-filtering medium, air filter pack, and air filter unit

Abstract

An air-filtering medium, an air filter pack, and an air filter unit, which are capable of reducing the number of portions where filtering functions can no longer be exhibited while suppressing an increase in pressure drop are provided. An air-filtering medium is used in a pleated state and includes a main collecting layer, a downwind-surface interval maintaining structure material, and an upwind-surface interval maintaining member. The main collecting layer includes an upwind-surface embossed protrusion protruding in a thickness direction of the main collecting layer. In the pleated state, the upwind-surface embossed protrusion is provided at least on an upstream side of a center of the air-filtering medium in a direction of airflow passing through the air-filtering medium, and protrudes towards an upwind-surface side. In the pleated state, the downwind-surface interval maintaining structure maintains an interval between facing downwind surfaces at least at a portion on an air-flow downstream side of the center of the air-filtering medium in the direction of airflow. In the pleated state, the upwind-surface interval maintaining member maintains an interval between facing upwind surfaces at least at a portion on the downstream side of the center of the air-filtering medium in the direction of airflow.