Debris trap and filter cover for vent opening
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A temporary debris trap and air filter which may be installed on floor vent openings in the early stages of home or commercial construction. After the floors are cut open for vent openings, the trap and filter is laid over the opening and easily affixed by adhesive strips on the flanges. The screen on top prevents construction debris from entering the duct boots and duct system and the filter below prevents dust and fine particles from entering the system while simultaneously allowing the free flow of cooled or heated air to enter the room area. The air will not be obstructed so the building and construction materials can be acclimatized during the construction period, the HVAC system can be tested and adjusted for proper air balance and the construction workers can breath filtered and conditioned air.

Fontana, Richard G. (Scarsdale, NY, US)
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1. The purpose of this invention is (1) to prevent both construction debris and fine compound dust and saw dust from falling into the boot and the floor duct system and infiltration the air ducts during construction and before the permanent grille is put in place; (2) to permit the easy flow of hot air (in winter) or cool air (in summer) into the construction area so that ambient room temperature is maintained during construction to acclimate the wall boards, wood trim, flooring materials and wall coverings during any season in the construction process and (3) the device will be inexpensive to make, very easy to install, sturdy enough to last six to twelve months during the construction phase and easily disposable in an environmentally friendly way.



This application claims the benefit of Provisional Application Ser. No. 60/877,980 filed Jan. 2, 2007.


Not applicable.


Not applicable.


In modern home building construction, HVAC systems typically sheet metal ducts that are routed to communicate with one or more vent openings in the floor of a given room. A preformed sheet-metal “boot” is fitted inside the perimeter of each opening for connection with the duct work. Two common sized of floor vent openings are 4 in. by 10 in. and 4 in. by 12 in. FIG. 1 illustrates a typical floor boot and duct installation.

It is not unusual for workers to allow the floor boot to remain uncovered during construction, and it is customary to operate the HVAC system to control the ambient temperature in the rooms under construction to permit the new materials (wood, flooring, wall boards, tiles, etc.) to become acclimatized to the heated air and cooled air during the construction period. As a result, wallboard dust, sawdust, nails, wood, metal and wire fragments, and other construction debris will often enter the boots and accumulate inside the ducts and associated HVAC equipment. Unless thoroughly removed when construction is finished, the accumulated debris will impair the operation of the HVAC system by restricting the flow of conditioned air below the rate for which the system was designed. Moreover, debris particles and dust will be expelled from the vent openings during system operation be inhaled by the building occupants to the detriment of their health and cause undesirable odors. Government publications suggest to home owners that the ducts be thoroughly cleaned when “ducts are clogged with excessive amounts of dust and debris”. EPA-402-K-97-002 October 1997. The EPA also advises that to prevent duct contamination “during construction or renovation work that produces dust in your home, seal off supply and return registers and do not operate the heating and cooling system until after cleaning up dust”.

This invention concerns particle traps and filters, particularly a trap/filter device that prevents construction debris and dust from infiltrating the ducts of heating, ventilating and air conditioning (HVAC) systems during home building or renovation while permitting air flow.

U.S. Pat. No. 6,461,235 B2 (Oct. 8, 2002) discloses a temporary vent opening cover for covering a vent opening in a floor during building construction. A cover plate permitting air passage is secured above the opening by fasteners which are inserted through mounting holes in a peripheral flange, and into the surrounding floor surface. A filter material is attached underneath the cover plate to prevent dust from entering the duct work through the air passages in the cover plate, according to the patent.

As mentioned, the cover of the '235 B2 US patent requires the use of nails, screws or other fasteners to secure the cover properly over a vent opening. Accordingly, workers may not wish to expend the time needed to install such covers over a number of vent openings during the course of their work. Further, because nail or screw holes are formed in the surrounding floor surface to receive the cover fasteners, additional time is needed to refill these holes when construction work is finished and the covers are removed.

U.S. Pat. No. 4,712,343 (Dec. 15, 1987) embodies a re-usable shield to temporarily cover interior vent openings in residential and commercial HVAC systems. This embodiment is a vent cover only to prevent scrap construction debris from falling into the floor opening. It does not permit air, heated or cooled, to come out of opening and will prevent the operation and testing of the HVAC system during the construction period.

U.S. Pat. No. 6,835,129 B1 (Dec. 28, 2004) embodies an HVAC duct boot sealing device that covers the duct boot during construction and when removed provides an improved vent seal after construction is finished. The cover of '129B1 is a solid cover that stops debris from entering the duct system but permits no “breathing” during the construction period.

U.S. Patent #US 2004/0074214A1 (Apr. 22, 2004) is a filter devise to be mounted upon a register or air grille that will permit a slidable air filter to be replaced from time to time. It is a housing that goes over a register, grille or diffuser and that can accept a filter of various sizes. US '4A1 is a permanent air filter fixture that is used on floors, walls and ceilings with a raised top portion a variously shaped apertures to permit air flow. This devise is not designed for nor suitable for construction because it is a consumer product to be added after construction, is a permanent two-part product that has a raised permanent housing that allows replacement of the filter. Because it is mounted over the grille or vent opening can be a tripping hazard for construction workers.

U.S. Pat. No. 4,829,886 (May 16, 1989) is a thermoplastic guard device that is a permanent debris or liquid catcher to be placed over vent openings. Because the air must pass around the recess and can enter or exit the vent only around the edges of the vent openings, the device fundamentally alters the movement of air through the duct boot. It requires different channels for different air and heat requirements. US '886 does not filter air or acts as a filter against compound or construction dust but operates as a debris catcher only.

U.S. Pat. No. 6,908,115 B2 (Jun. 21, 2005) is a register opening cover to be used until the boot is installed. The devise is only used during a short time in construction (until the boot is installed), is a complete cover that permits no air flow and has no air filter ability.


The invention is a temporary debris trap and air filter for floor openings. The device will be utilized during the construction or remodeling of residential and commercial buildings that use a forced-air system for heating, ventilation and air-conditioning (HVAC).

The frame of the device is made of disposable material, such as corrugated fiberboard or re-enforced paperboard, and within the frame is a pleated, medium to high efficiency, air filter that stops small particles and fine construction dust from entering the boot and ducts while permitting large volume of air to flow out the vent opening and into the room. The top of the frame will have a screen to block large items and construction debris from falling into the ducts. The flanges on the device will have a peel away strip and a glue base for simple installation.


FIG. 1 is a section view of a typical floor opening that shows the duct boot and floor open customarily left uncovered during construction.

FIG. 2 is a top view of the invention with cut-away showing the screen and filter underneath.

FIG. 3 is a sectional view of the present invention in the floor opening.

FIG. 4 is a bottom view of the invention demonstrating the filter, the frame holding the filter and revealing the peel away, self-adhesive bottom of the flanges.

FIG. 5 shows the H frame of second embodiment.

FIG. 6 shows the top (screen side) of one of the two trap/filter sections to be inserted into the H frame of FIG. 5.

FIG. 7 shows the bottom (filter side) of one of the two trap/filter sections to be inserted into the H frame of FIG. 5.


The collective views in FIGS. 2 through 4 show the invention apparatus, generally denominated 10, comprises a debris trap and filter to cover floor vent openings to be used during construction of residential or commercial buildings that use a forced air HVAC system. Device 10 prevents common construction debris (e.g. pieces of wood, wire, wallboard scraps, nails, bottles, paper and cups) as well as compound dust, sawdust and sweeping compound from entering the duct boots through the floor vent openings and settling in the duct work.

FIG. 1 is a sectional view of a typical floor (1) and vent opening (2) with connecting duct boot (3) and the HVAC duct (4).

FIG. 2 shows the various components of device 10. The device 10 blocks relatively large debris pieces including sawdust, plasterboard shavings, nails, and the like by way of a screen or mesh 5 (made of paper or wire) disposed across an upper portion of the device. Smaller debris and fine particulates are entrapped within a filter material 8 disposed across a lower portion of the device. The filter is held in the frame of device 10 by cross supports 9. The filter material 8 is a high air flow material such as, for example, a micron polyester sheet or a HEPA-like material. The filter material will be pleated in an accordion style in and across the body of device 10. The foregoing examples for the filter material 8 are not intended to be limiting, and other materials permitting a high rate of air flow with at least a medium efficiency filter may also be used. The screen or mesh 5 and the filter material 8 are therefore sufficiently porous to allow the conditioned air to flow upward and through the device 10 to circulate freely throughout the room under construction.

The device 10 may be constructed with relatively inexpensive material (without limitation e.g. cardboard or reinforced paper board), and it can be easily disposed of at the end of its temporary term of use. The filter material 8 may be arranged to have a pleated, accordion like profile, so that dust and fine particulate will be trapped in valleys of individual pleats, while conditioned air flows upward and out through peaks of the material. The device 10 may be constructed in several sizes so as to fit a given standard floor vent opening having a width of, e.g. 2, 4, 6 or 8 inches, and a length of 8, 10, 12 or 14 inches.

In FIG. 3 the device 10 is shown sitting on the floor opening above the duct boot 3. The mesh screen on top 5 blocks the larger materials while the filter 8, held in place by the central and perimeter supports 9 of the frame of device 10, captures the fine particulates and dust 11 in the accordion valleys while permitting the free flow of cooled (in summer) or heated (in winter) air 12 to flow into the room and construction area.

Device 10 is shown on FIG. 4 from the bottom. Here, the peel and seal self-adhesive strips on the underside of the flanges 13 are shown for the easy installation of the device in the floor opening. The filter 8 in its pleated form can be seen deposed across the length of device 10 while held by the central and perimeter supports 9.

FIG. 5 shows a second embodiment of the invention. In FIG. 5 and FIG. 6 views, inventive device is constructed and arranged to be expandable and contractible to fit either one of two standard vent openings, e.g., openings having a width of 4 inches, and a length of either 10 inches or 12 inches. The device 14 includes a frame 15 having a generally “H” shape, wherein the long sides 16, 17 of the frame 15 are approximately 9 inches in length. The device 14 also utilized two trap/filter sections, each having an upper mesh FIG. 6 and a lower filter material FIG. 7 similar to the device 10 of FIG. 2 and each approximately 5 inches in length. The two trap/filter sections are retained for sliding movement between the long sides 16, 17 of the frame 15.

A central spring loaded mechanism, e.g., leaf springs 18 are fixed to corresponding inner short sides 19, 20 of the H frame. The springs 18 are operative to urge the two sections FIG. 6 apart a sufficient distance so that the device 50 will cover either one or two standard floor vent openings, for example, 4 by 10 inches or 4 by 12 inches. Specifically, the device 14 may be used by (1) manually retracting the two sections of FIG. 6 toward one another within the frame 15 against the action of the springs 18 associated with the sections, (2) inserting the device 14 inside the perimeter of the vent opening with the wire meshes of the two sections FIG. 6 facing up, and (3) releasing the sections so that their outer short sides 21, 68 are urged by the springs 18 against the facing short sides of the vent opening.

The device 14 is also retained in the vent opening by friction between the outer short side 21 of the trap/filter sections FIG. 6, 7 and the sides of the vent opening against which the sections are urged by the springs 18. Either device 10, 14 may therefore be installed conveniently and with relative ease, and without having to create holes in the floor surface which later must be refilled.

Flanges 6 are provided preferably on all four sides of either of the devices 10, 14 and a self-adhesive glue is provided on each of the flanges with peel off cover strips 13. Accordingly, either device 10 or 14 can be secured to the floor surface surrounding the vent opening simply by peeling off the adhesive cover strips 13 and pressing the flanges 6 on the device against the surrounding floor surface. The flanges may be hinged on either device 10, 14 so that they can be folded to a storage position atop the screen 6.