The technology disclosed herein relates to filter assemblies and methods of making filter assemblies. One filter assembly has a first sheet of filter media having a first perimeter region and a second sheet of filter media having a second perimeter region. The first perimeter region and the second perimeter region are bonded in a rim region. A plurality of adsorbent beads are disposed between the first sheet of filter media and the second sheet of filter media, and a substantial portion of the plurality of adsorbent beads are unbonded. Other embodiments are also described.

A substrate for use in a filter media including, for example, in a hydrocarbon fluid-water separation filter; methods of identifying the substrate; methods of making the substrate; methods of using the substrate; and methods of improving the roll off angle of the substrate. In some embodiments, the substrate includes a hydrophilic group-containing polymer or a hydrophilic group-containing polymer coating.

Fiber webs that may be used as filter media are provided. In some embodiments, the filter media may include multiple layers. Each layer may be designed to have separate functions in the filter media. For example, a first layer may be provided for improving dust holding capacity, a second layer for improving efficiency, and a third layer for providing support and strength to the media. By designing the layers to have separate functions, each layer may be optimized to enhance its function without negatively impacting the performance of another layer of the media.

Filter elements are described. In an example embodiment, the filter element has a support framework and media defining a closed end and an open end. A non-circular radial seal is depicted, in an example. Variations for particular applications are described.

A nonwoven filtration medium that includes a fibrous base media including synthetic and/or natural fibers and micro fibrillated cellulose fibers.

An air filter including a filter support that supports porous, polymeric sorbent particles that comprise a divalent metal impregnated therein.

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.

Provided is a fiber structure having a high dust holding capacity. The fiber structure includes a thick fiber group composed of fibers A each having a single fiber diameter larger than 5 ?m and a thin fiber group composed of fibers B each having a single fiber diameter of 5 ?m or smaller, and has an intermingled region in which the thick fiber group and the thin fiber group are intermingled.

An air filter medium includes a first porous PTFE membrane and a second porous PTFE membrane. The air filter medium (10) has a first main surface and a second main surface, and the first porous PTFE membrane and the second porous PTFE membrane are arranged so that an air flow moving from the first main surface to the second main surface passes through the first porous PTFE membrane and subsequently through the second porous PTFE membrane. A thickness of the first porous PTFE membrane is in the range of 4 to 40 m and a specific surface area of the first porous PTFE membrane is 0.5 m.sup.2/g or less.

A filtration media with improved filtration, strength, tear resistance and air permeability in the form of a relatively thin and lightweight wet-laid fibrous web that has a wet Mullen ratio of 60% to 80% to ensure that the media is flexible enough to be formed into a fluted structure, and strong enough to retain the fluted structure when wound into a roll and to permit further processing without the media becoming too brittle. The filtration media comprises a blend of cellulose and synthetic fibers having a weight percent of 81 wt % to 87 wt % of a weight of the media and a resin binder having a weight of 13 wt % to 19 wt % (preferably about 16 wt %) of the weight of the media.