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

An air-filtering medium that is used in a pleated state in which a mountain fold and a valley fold are provided, comprising:

• a main collecting layer that includes an upwind-surface embossed protrusion protruding in a thickness direction of the main collecting layer;
• a downwind-surface interval maintaining structure;
• and
• an upwind-surface interval maintaining member, wherein
• 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 is a structure that 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, and
• in the pleated state, the downwind-surface interval maintaining structure and the upwind-surface interval maintaining member are provided at locations where the downwind-surface interval maintaining structure and the upwind-surface interval maintaining member at least partly overlap each other when viewed in a direction perpendicular to the direction of airflow and perpendicular to a mountain fold line and a valley fold line.

An air-filtering medium that is used in a pleated state in which a mountain fold and a valley fold are provided, comprising:

• a main collecting layer that includes upwind-surface embossed protrusions protruding in a thickness direction of the main collecting layer;
• a downwind-surface interval maintaining structure;
• and
• an upwind-surface interval maintaining member, wherein
• in the pleated state, the upwind-surface embossed protrusions are 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 protrude towards an upwind-surface side,
• in the pleated state, the downwind-surface interval maintaining structure is a structure that 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,
• in the pleated state, the upwind-surface embossed protrusions are provided such that protrusion heights become lower towards the downstream side, and
• in the pleated state, the upwind-surface interval maintaining member is provided only on the downstream side with respect to the upwind-surface embossed protrusion whose protrusion height in the thickness direction is larger than a thickness of the air-filtering medium.

An air-filtering medium that is used in a pleated state in which a mountain fold and a valley fold are provided, comprising:

• a main collecting layer that includes an upwind-surface embossed protrusion protruding in a thickness direction of the main collecting layer;
• a downwind-surface interval maintaining structure;
• and
• an upwind-surface interval maintaining member, wherein
• 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 is a structure that 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, and
• in the pleated state, the upwind-surface interval maintaining member contacts each of facing upwind surfaces so as to maintain an interval between the 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.