This invention relates to an air filtration assembly, specifically, a reversed cube filter assembly having a reusable frame that allows replacement filter media to be easily exchanged for dirty filter media.
An air filter assembly is a device used for removing particulate material from an air stream. Simply stated, a filter assembly is made up of media through which the air passes, and a frame to hold the media in place. The media allows air to pass through while capturing and holding particulate material traveling in the air stream. A filter""s ability to remove particulates is known as xe2x80x9cefficiencyxe2x80x9d, while the amount of particulate a filter can hold in its useful life period is known as xe2x80x9cdust holding capacityxe2x80x9d. The amount of restriction to the air flow that is caused by the media is known as xe2x80x9cresistancexe2x80x9d.
The simplest filter is a flat sheet of media. This filter has a certain face dimension and contains a certain amount of media that offers a certain efficiency, dust holding capacity and resistance. By increasing the surface area of media in that filter assembly (using the identical media) while allowing the filter to have the same face dimension, the efficiency of the filter would generally increase, the dust holding capacity would increase and the resistence would decrease. Conventional ways to add media to a given face dimension are to pleat the media or to allow the media to extend out of the back or downstream side of the filter assembly. When the media extends out the back of the filter assembly, this type of filter is typically known as a cube filter, or a single pocket filter.
When a conventional cube filter is used, the filter assembly requires enough space on its downstream side for the filter assembly to fit with no interference downstream. Sometimes, there is not enough space to use a cube. For instance, in some situations, second stage filters may be placed directly behind a first filter, or coils or some other mechanical device are located directly behind an initial filter. In still further cases there may not be any room on the downstream side to add additional filters.
One type of reversed cube assembly is also known. In these known assemblies, filter media is integrally, permanently reinforced with a support frame that allows the assembly to protrude from the upstream side of an intake duct whether it be a single unit for the duct or multiple units mounted in a filter rack for a larger system. The drawback with these existing assemblies is the cost, because the original and replacement filters include the integral frame and will be disposed along with the dirty filter media. The cost of the filter media/frame unit can be substantially higher than other filter media options available.
Accordingly, as an object of the present invention to overcome the foregoing drawbacks and provide a reversed cube filter assembly having a replaceable filter media so that air may be efficiently and inexpensively filtered through use of this reverse cube structure.
In one embodiment, a reversed cube air filter assembly includes a frame and a filter media adapted to be removably mounted around the frame. The frame is adapted to be attached to and surround an air intake duct wherein the duct has an intake side and the frame is adapted to protrude outwardly from the intake side. The frame may further include a hook and loop fastener (VELCRO(copyright)) which is adapted to removably attach to the filter media mounted around it. Also, the filter media may be a graduated density filter media.
In a further embodiment, a reversed cube air filter assembly has a filter rack system header, wherein the header has an intake side. Filter media is removably attached around the header, and frame means for maintaining the shape of the filter are attached to the header and protrude outwardly from the intake side of the header. The header may further include a hook and loop fastener (VELCRO(copyright)) so that the filtered media is removably attached to the header through the engagement of the hook and loop fastener (VELCRO(copyright)) and the filter media.
In a still further embodiment, a reversed cube air filter assembly includes a rectangular filter rack system header wherein the header has an intake side. A box-shaped wire frame having at least one side that is substantially the same shape as the header is attached to the header and protrudes outwardly from the intake side. Filter media is mounted around the frame and removably attached to the header.