Abstract: An air filter medium reduces a decrease in collection efficiency in the case where a main collection layer and a pre-collection layer having a lower collection efficiency than the main collection layer are used. An air filter medium that collects dust in gas includes a main collection layer and a pre-collection layer that has a lower collection efficiency of NaCl particles having a particle size of 0.3 ?m than the main collection layer, is disposed on an upstream side of an air flow with respect to the main collection layer, and has water repellency.

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.

Abstract: An air filter medium reduces a decrease in collection efficiency in the case where a main collection layer and a pre-collection layer having a lower collection efficiency than the main collection layer are used. An air filter medium that collects dust in gas includes a main collection layer and a pre-collection layer that has a lower collection efficiency of NaCl particles having a particle size of 0.3 ?m than the main collection layer, is disposed on an upstream side of an air flow with respect to the main collection layer, and has water repellency.

Abstract: A filter medium for an air filter includes a pre-collection member, a first porous film, and a second porous film arranged in order from the side that is upstream of the air current. Each of the first porous film and the second porous film has a pressure loss of 30 Pa or more and 90 Pa or less when air is passed through each porous film at a flow rate of 5.3 cm/s, and has a collection efficiency of 95% or more and 99.9% or less for NaCl particles having a particle diameter of 0.3 ?m when air containing the NaCl particles is passed through each of the porous films at a flow rate of 5.3 cm/s. The pre-collection member has a pressure loss of 5 Pa or more and less than 55 Pa when air is passed through the pre-collection member at a flow rate of 5.3 cm/s, has a collection efficiency of 15% or more and less than 85% for NaCl particles having a particle diameter of 0.3 ?m when air containing the NaCl particles is passed through the pre-collection member at a flow rate of 5.3 cm/s, and has a thickness of more than 0.

Abstract: A filter medium for an air filter includes a pre-collection member, a first porous film, and a second porous film arranged in order from the side that is upstream of the air current. Each of the first porous film and the second porous film has a pressure loss of 30 Pa or more and 90 Pa or less when air is passed through each porous film at a flow rate of 5.3 cm/s, and has a collection efficiency of 95% or more and 99.9% or less for NaCl particles having a particle diameter of 0.3 ?m when air containing the NaCl particles is passed through each of the porous films at a flow rate of 5.3 cm/s. The pre-collection member has a pressure loss of 5 Pa or more and less than 55 Pa when air is passed through the pre-collection member at a flow rate of 5.3 cm/s, has a collection efficiency of 15% or more and less than 85% for NaCl particles having a particle diameter of 0.3 ?m when air containing the NaCl particles is passed through the pre-collection member at a flow rate of 5.3 cm/s, and has a thickness of more than 0.

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.

Abstract: A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 ?m when air containing the particles is passed through at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be in a filter pack or filter unit, and produced by integrating the films and the pre-collection member using heat lamination.

Abstract: Provided are a filter medium for an air filter capable of having extended life even when composed of embossable material. The filter medium (1) has a tensile elongation of 10% or greater, and includes a main collection layer (30) having a filing rate of 5% to 15%, a thickness of 0.35 mm to 0.70 mm, and a peak in a fiber diameter distribution at less than 1.0 ?m and a peak at 1.0 ?m or greater. An average fiber diameter of small fiber diameters of less than 1.0 ?m is from 0.1 ?m to less than 0.8 ?m, and an average fiber diameter of large fiber diameters of 1.0 ?m or greater is from 1.2 ?m to less than 3.0 ?m. A volume ratio of the fibers having the small fiber diameter to the fibers having the large fiber diameter is from 30:70 to 80:20.

Abstract: A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 ?m when air containing the particles is passed through at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be in a filter pack or filter unit, and produced by integrating the films and the pre-collection member using heat lamination.

Abstract: A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The second film is downstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 ?m when air containing the particles is passed hrough at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. The PF value={?log((100?collection efficiency (%))/100)}/(pressure drop (Pa)/1000). A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be used in a filter pack or filter unit, and may be produced by integrating the first and second films and the pre-collection member using heat lamination.

Abstract: Provided are a filter medium for an air filter capable of having extended life even when composed of embossable material. The filter medium (1) has a tensile elongation of 10% or greater, and includes a main collection layer (30) having a filing rate of 5% to 15%, a thickness of 0.35 mm to 0.70 mm, and a peak in a fiber diameter distribution at less than 1.0 ?m and a peak at 1.0 ?m or greater. An average fiber diameter of small fiber diameters of less than 1.0 ?m is from 0.1 ?m to less than 0.8 ?m, and an average fiber diameter of large fiber diameters of 1.0 ?m or greater is from 1.2 ?m to less than 3.0 ?m. A volume ratio of the fibers having the small fiber diameter to the fibers having the large fiber diameter is from 30:70 to 80:20.

Abstract: A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The second film is downstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 ?m when air containing the particles is passed hrough at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. The PF value={?log((100?collection efficiency (%))/100)}/(pressure drop (Pa)/1000). A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be used in a filter pack or filter unit, and may be produced by integrating the first and second films and the pre-collection member using heat lamination.

Abstract: A filter medium for an air filter collecting dust in an air flow has a principal collection layer including a porous polytetrafluoroethylene film. A surface of the filter medium is provided with a plurality of embossed projections. Preferably, a processed filter medium maintains a zigzag shape by pleating an unprocessed filter medium to create mountain folds and valley folds. Preferably, an air filter unit includes such a processed filter medium and a frame body holding the processed filter medium.

Abstract: A filter medium for an air filter collecting dust in an air flow has a principal collection layer including a porous polytetrafluoroethylene film. A surface of the filter medium is provided with a plurality of embossed projections. Preferably, a processed filter medium maintains a zigzag shape by pleating an unprocessed filter medium to create mountain folds and valley folds. Preferably, an air filter unit includes such a processed filter medium and a frame body holding the processed filter medium.