An air filter suitable for temporary or interim use is configured to be removeably affixed over or inside the return air duct boot of a building under construction. In one embodiment, the air filter comprises a piece of air filtration material having a resilient, shaped, stretchable perimeter and further comprising integral magnetic strips suitable to adhere the invention to a metal return air duct boot. In a preferred embodiment, one or more layers of air filtration material are affixed to a shaped frame and may further comprise a plurality of magnets and billowable fabric to retain the invention sealably in position in the return air duct boot.

A device for filtering a gas stream, having a vessel partitioned into a first stage and a second stage, with an opening between stages. A filter element is positioned in the opening, with ends of the filter element extending into the first and second stages. The first member is removable from the second member while the filter element is positioned in the opening, to allow for replacement with a new clean member.

A magnetic vent filter that is washable and readily removable from a grill or vent register. The filter includes a first frame, a second frame, a filter, adhesive and fasteners. The first and second frames each have a planar perimeter rim with first and second sides. The filter is secured between the first side of the planar perimeter rim of the second frame and the second side of the planar perimeter rim of the first frame by adhesive. The first and the second frames are secured together in the same manner, the adhesive preventing movement of the second frame relative to the first frame, and securing the filter therebetween. Magnetic fasteners are attached to the vent filter, to a side of a planar perimeter rim of the first and the second frame, and then attach to a register or grille of a vent.

An air purifier includes a ventilation cover, a filtering component, and a sterilization component. The ventilation cover has an air inlet and an air outlet. The filtering component is fixed at the air outlet. The sterilization component is disposed between the air inlet and the air outlet. An air ventilation device may include the air purifier.

A portable air filtration system for efficiently installing an air filtration system to a barrier which may be easily removed or replaced. The portable air filtration system generally includes a filtration unit which is adapted to be secured to a barrier over an opening in the barrier. The filtration unit includes a first connector which may include a fastener or a magnetic element. A second connector is provided to secure the filtration unit to the barrier, with the second connector including a fastener or a magnetic element on its first side to engage with the first connector and an adhesive on its second side to engage with the barrier. The filtration unit may also include a removable one-way valve such as a flap and an optional secondary filter.

An apparatus for retaining a filter element in a filter holder frame in a HVAC system is provided where the apparatus is a retainer clip that is inserted between the filter element in the filter holder frame and magnetically held in place by a magnet on the retainer clip. A grip/stop on the retainer clip holds the filter element against a filter seating surface on the filter holder frame.

A filter equipment includes a main body portion which has a hollow columnar structure with an open upper portion and a closed lower portion, and has a plurality of air inlets formed on a side surface to be spaced apart at regular intervals; a top cap which is detachably attached to an upper opening surface of the main body portion, and has a doughnut structure having a width corresponding to that of the filter portion in a plan view, a magnetic member attached to a lower surface of an air vent by a magnetically detachable structure being mounted on an upper surface of the top cap; a filter portion which has a hollow columnar structure corresponding to an inner peripheral surface of a main body portion, has a doughnut structure having a width corresponding to the lower surface of the top cap, has a structure that is in close contact with the lower surface of the top cap, purifies the air drawn in from the air inlet of the main body portion and then makes the purified airflow through a central opening portion of the top cap to the air vent; and a safety wire which is mounted inside the main body portion and extends by a predetermined length to be combined with one side of the top cap.

A filtration system for a fuel cell hybrid propulsion system includes a first stage filter, a second stage filter positioned downstream of the first stage filter, and a third stage filter positioned downstream of the second stage filter and configured to be positioned upstream of a fuel cell system. The first stage filter has first pores with a first mean pore size. The second stage filter has second pores with a second mean pore size. The third stage filter has third pores with a third mean pore size. The second mean pore size is less than the first mean pore size. The third mean pore size is less than or equal to the second mean pore size. The first, second, and third stage filter are structured to filter an airflow prior to being received by the fuel cell system.

An assembly having a first body coupled to a second body via a hinged connection to rotatably couple the first and second bodies together. The assembly also has a releasable connection releasably coupling the first and second bodies together. The assembly also has a filter coupled to at least one of the first and second bodies and configured to prevent solids from flowing through the filter while allowing fluid flow through the filter. The assembly is configured to be coupled to a dispensing pipe of a dosing device and a fill pipe of a packaging system.

An air cleaner can include a first body including an intake port, configured to intake air, and a discharge port, configured to discharge the air to an outside, a fan disposed inside the first body between the intake port and the discharge port, the fan being configured to transfer the air from the intake port to the discharge port, and a second body disposed above the discharge port, spaced apart from the discharge port, and detachably coupled to the first body. In addition, a width of the second body can be larger than a width of the discharge port.