A filter including a filter media pack, first and second preform members and first and second adhesives is provided. The first preform member is disposed over the media pack. The first preform member has a wall defining a well. The wall defines a notch. The first adhesive in the well attaches the first preform member to the filter media pack. The first adhesive has a contact region disposed in the notch. The second preform member is disposed over the first preform member. The second adhesive bonds the first preform member over the first preform member. The second adhesive engages with the first adhesive at the contact region.

An HVAC system that utilizes an air-to-air heat exchanger includes an HVAC ductwork section including a fan, and a filter assembly in fluid flow communication with the HVAC ductwork section. The filter assembly has a filter compartment having an opening oriented generally transverse to a direction of air flow through the filter assembly. A compressive member is provided on at least a portion of a perimeter extending around the opening. The compressive member is adjustable between an installation configuration in which the compressive member is spaced from a position that is to be occupied by a filter when the filter is installed in the filter compartment and an installed configuration in which the compressive member engages at least a portion of one of an upstream and a downstream face of the filter when the filter is positioned in the filter compartment.

A filter device has a filter element with filter medium body and surrounding frame with opposed lateral faces. A filter housing has opposed wall sections with two engagement counter elements for receiving with form fit an engagement element, respectively. The engagement counter elements are grooves in the wall sections with an insertion section and a blocking section connected to the insertion section and angled thereto. The insertion section permits insertion of the engagement element along a flow direction through the filter element. In the mounted state, the engagement element is arranged at one of the lateral faces of the frame, extends away from the filter medium body, and is held in the blocking section. One or several of the engagement elements are separate parts fastenable detachably to the filter element. A vehicle with such a filter device and a method for mounting the filter element with engagement elements are provided.

A filter device has a filter element with filter medium body and surrounding frame with opposed lateral faces. A filter housing has opposed wall sections with two engagement counter elements for form fit engagement of an engagement element, respectively. The engagement counter elements are grooves in the wall sections with an insertion section and a blocking section connected to the insertion section and angled thereto. The insertion section permits insertion of the engagement element along a flow direction through the filter element. When mounted, the engagement element is arranged at one of the lateral frame faces, extends away from the filter medium body, and is held in the blocking section. Two of the engagement elements are connected by a connection piece. A vehicle with such a filter device, a set of filter element and engagement elements, and a method for mounting the filter element with engagement elements are provided.

A framed air filter in which at least one portion of the frame is provided by a spiral-wrapped frame piece in which a terminal segment of the spiral-wrapped frame piece serves as a reinforcing strut.

An enclosure (100) of an electric device includes an enclosure wall (105) and a flame arrestor filter (130) integrated into the enclosure wall (105), wherein the flame arrestor filter (130) is configured to filter a stream (160) of hot gases and particles occurring during an arc fault event inside the enclosure (100) such that the hot gases and particles are absorbed by the filter (130) and a filtered stream (170) of cooled gases exits the filter (130) to an outside of the enclosure (100).

A monitoring clip to be secured to the edge of a filter cartridge includes a channel connecting both sides of the filter through which air will flow in response to the filter becoming clogged. Air flow within the channel will eventually be strong enough to pivotally move a flow vane. Controlling circuitry is used to detect the angular movement of the flow vane. When the flow vane moves to a triggering position, it is determined that the filter is clogged and requires replacement. Controlling circuitry will sound and illuminate a local alarm, and send a signal by Bluetooth or WiFi, to a smartphone. Although a clip format is preferred, the measuring and controlling circuitry of the monitoring clip can be also built into new filters.

A filter bellows with zigzag-folded filter medium has first and second fold edges extending between opposite end edge faces of the filter medium. The filter bellows has opposite end faces with an end fold. The filter bellows in use has a raw fluid-side surface and a clean fluid-side surface. First fold edges are positioned at the raw fluid-side surface and second fold edges are positioned at the clean fluid-side surface. The filter bellows has a passage extending between raw fluid-side surface and clean fluid-side surface. The passage has a first opening at the raw fluid-side surface provided with a first cross section and a second opening at the clean fluid-side surface provided with a second cross section. When projecting the first and second openings onto each other, one cross section, at least with sections thereof, is arranged outside of the other cross section.

A portable air filter and method of use are provided. The portable air filter includes a semi-permeable air filter, optionally disposed within a frame. An attachment surface, such as an adhesive, is disposed on the frame, for attaching the portable air filter to an air vent. In certain embodiments, a second air filter and frame are slidably connected to the frame. If the portable air filter is not disposed within a frame, the portable air filter is cut to fit over an air vent, and an adhesive, such as tape, is provided for a user to attach the cut filter to fit over the air vent. The method includes attaching the portable air filter to an air vent by pressing the adhesive to a wall, ceiling, or floor such that the portable air filter covers the air vent. The invention is useful for improving air quality in a variety of spaces, including in an airplane, in a hotel, on a cruise ship, on a travel bus, and other public spaces.

An air filter unit for purifying air. The air filter unit includes a filter body extending along an axis, a first filter frame and a second filter frame arranged on opposite ends of said filter body. Each of the first and second filter frame includes four elongated frame members turnably secured to each other. The four elongated frame members are turnably secured to each other such that the filter body could be arranged in a first and a second state. The first state is such that the filter body is folded to reduce the volume of the filter unit and the second state is such that the filter body is assembled.