Abstract:
A sealable electrical junction box of one piece unitary construction which incorporates one or more sealing chambers through which one or more electrical wires can pass before they reach the main chamber of the inside of the box. These chambers may then be filled with an expandable foam sealant to form an airtight seal around wires. A flange around the outside of the box allows a vapor barrier to be sealed to the box, so that an airtight seal may be formed around the outside of the box. When properly installed, no air or water vapor can pass from the inside of a building to the outside around or through the sealable electrical junction box.

Description:
BACKGROUND OF THE INVENTION 
     Residential and commercial building codes have been changing in recent years to require higher levels of efficiency in the heating and cooling of buildings. The most effective way to lower heating and cooling costs is to raise the level of insulation in walls and ceilings and to suppress the movement of air known as infiltration. In typical residential construction, insulation, generally batts of fiberglass insulation, is used to fill the space between the studs, thereby creating small pockets of immobilized air, which decrease the thermal conductivity of the walls. A vapor barrier, often a sheet of polyethylene, is then secured to the inside of each wall. In order to be completely effective, the vapor barrier must suppress the movement of air and water vapor through all of the walls, ceilings and floors of the building structure or residence so that a separate environment or envelope is created within the building structure. However, any penetrations or openings in the vapor barrier provide passage ways for water vapor or conditioned air. Because of the number of electrical outlet boxes that are used in modern homes, and the need to penetrate the vapor barrier to provide electricity using state of the art electrical outlet and electrical junction boxes, there is great potential for the creation of a significant number of passage ways in the vapor barrier for infiltration or escape of water vapor or conditioned air, resulting in an inability to adequately provide such a separate environment and an inability to adequately provide for efficient control of the environment within the building structure. 
     In building energy efficient housing, one faces many obstacles. The main obstacle is being able to find affordable and readily available components with which to complete the assembly of the structure. As noted above, one area requiring attention to detail is electrical outlets in exterior walls. The average new home has probably at a minimum 25 such exterior wall outlets and maybe as many as 50. Using conventional outlet boxes  5 , shown in FIGS. 10 and 11, with air leaking in or out at all wiring perforations  8  and all around the front edge of the outlet box the inevitable heat loss is considerable. 
     Air flow, or the passage of air from one environment to another, occurs whenever there is a pressure gradient across a wall and a path for air to follow. Air is generally lost outwardly through the walls during heating seasons because, as the air inside the building is heated, the air pressure increases, creating a pressure differential which forces the heated air through any perforations in the vapor barrier. Just the reverse happens when it is warm outside and air conditioning is used on the inside to lower the temperature and, perhaps, the humidity. In this case, the inside of the building will actually have a negative pressure differential in relation to the outside environment, such that warm outside air may pass inside or infiltrate through any openings in the vapor barrier to balance the pressure differential. Whenever the inside air is heated or cooled, a pressure differential will be created between the inside environment and the outside environment causing a movement of air either inwardly or outwardly through any openings or penetration in the vapor barrier. This movement is further exacerbated by wind creating a positive pressure on the windward side and a negative pressure on a leeward side of a building. 
     Moisture, generally conveyed by the air, passes through walls in the same manner. Whenever there is a difference between the outside humidity and the level of humidity inside, a vapor pressure is established. This vapor pressure can be significant, especially during winter months in colder climates when the outside air is extremely dry. Under such conditions, the moisture inside the building is generally driven outside through any existing penetrations in the walls in response to a differential in the humidity level, regardless of the actual air pressure inside and outside of the building. In northern climates, where the outside temperature is below freezing, the effects of moisture passing through the walls can be very detrimental. As water vapor passes through a wall, the temperature in the wall will drop to the temperature outside of the building, from a temperature equal to that of inside the building, over the distance from the inside to the outside of the wall. Following the downward sloping temperature gradient, the moisture in the air first condenses into water droplets. At some point in the wall, the temperature drops below freezing and an ice barrier forms. This wall of ice not only results in destructive forces due to the expansion of the water as it freezes, but it also contributes moisture to rotting processes through moisture retention which continues to destroy wooden structures in the warmer periods of the year. 
     During warmer months, air movement through the walls can also result in the retention of moisture in some building materials due to their hygroscopic nature. Moisture passes through the walls and the backside of the siding material and often stops when it gets to painted surfaces. The moisture can then build up between the paint and the backside of the siding, causing the paint to blister and peel. Damage of this kind, along with the increased heating and cooling costs associated with air and water vapor infiltrations and escapes of the kind seen in typical residential housing, have led to many of the changes in building codes which have occurred in recent years. 
     It will be understood therefore, that in order to efficiently control the temperature and moisture levels in both residential and commercial building structures, and in order to prevent damage to structural aspects of the respective buildings, there is a need for a way to stop the passage of air and moisture through the walls of building structures . More specifically, in order to do this, there is a need to prevent the loss of vapor barrier integrity through and around electrical outlet and electrical junction boxes. Many attempts have been made to effectively and efficiently stop air movement at electrical outlet boxes. 
     Some builders use conventional electrical outlet boxes in conjunction with a separate poly box with a flange to provide a means to fasten the vapor barrier to the outlet box. This system requires two separate components, however. Another method is an outlet box with a ring that makes a seal between the vapor barrier and the electrical box, and the wiring penetrations are sealed with a neoprene strip. The problem with this system is that drywall applicators typically use a router to cut outlet openings and the vapor barrier will be cut and destroyed around the entire perimeter of the outlet box. Still another method is a one piece electrical box with a flange for making the connections between the vapor barrier and outlet box. This system does not adequately address the electrical penetrations at the rear of the box where a significant amount of air leakage can occur. These attempts have been largely unsuccessful at either stopping the air flow near the wiring or around the box, or at providing a cost-effective solutions which can be installed quickly and easily, so as to be more likely to be effectively used. 
     A number of patents disclose similar solutions to these problems. Balkwill et al. (U.S. Pat. No. 4,158,420) disclose the use of conventional electrical outlet boxes in conjunction with a thin flexible cover. After the outlet box is installed, the thin plastic cover is placed over the box and nailed to a stud. Holes are then punched through the thin plastic to receive the wires. A true vapor seal is not achieved either around the box or around the wires. 
     Lentz U.S. Pat. No. 4,757,158) teaches the use of rigid boxes with flanges that cover a conventional electrical outlet box. The flanges provide a surface on which the vapor barrier can be glued, providing an effective seal around the boxes. However, like the Balkwill solution, air can still flow where the wires penetrate the boxes. Furthermore, each of these solutions require two components, resulting in increased installation time. 
     Schuldt (U.S. Pat. No. 4,673,097) discloses a single component system which attempts to address the vapor barrier problem by providing an integrally molded flange to which a sheet of polyethylene can be sealed. Unfortunately, this system does not provide any measure for eliminating the air flow adjacent to the wires passing through the knockout opening in the back of the box. 
     Rye (U.S. Pat. No. 4,952,754) teaches a unitarily constructed outlet box with a front opening that can receive a flexible ring after the vapor barrier has been placed over the opening. The ring is used to attach the vapor barrier to the outlet box. The problem with this solution is, with the absence of a flange, the vapor barrier is forced through the rough, hole routered in the drywall to allow access to the outlet, and is often damaged in the process. In addition, the outlet box does a poor job of forming a seal around the wires. This system relies on the use of a neoprene strip to cover the knockout holes. When the wiring is installed, the strip is to be cut to allow the wires to pass through. The discretion of the wiring installer is the determining factor in the size of the perforations, leaving significant room for installer error or non-performance. Furthermore, this is a relatively labor intensive system which makes it more expensive to the consumer, raising the cost of new housing and thereby creating incentives for unscrupulous installers and/or builders to neglect the attention to detail required to properly utilize this system to minimize air infiltration in the envelope created in the new building structure. 
     It will be appreciated from the foregoing that prior art devices present problems which are in need of solutions. The present invention provides solutions for these and other problems. 
     SUMMARY OF THE INVENTION 
     This has lead to the development of a unique electrical junction enclosure device that will be a one piece structure, preferably provide a flange on which to seal the vapor barrier, and provide a first chamber and a second chamber through which the electrical wires will pass near the rear of the outlet box for the electrical junction. The first chamber can be filled with an expanding foam after the wiring has been passed through the chamber. The preferred device provides a flange and a plurality of chambers including a main electrical junction chamber and a sealing chamber. Preferred embodiments will have separate sealing chambers at the top and bottom of the outlet box, which when filled with the proper sealing medium, will provide an airtight seal between the electrical wires and the outlet box thus eliminating air movement through the device. This one device will have an ease of installation similar to that of any conventional outlet box, will accommodate standard building practices, and allow the user to easily provide an airtight seal at all electrical outlet boxes. Because this device is of one piece construction, it can be manufactured economically, and because it installs like conventional outlet boxes, it will provide for economy in the installation. Once in place, the installer will find making the airtight seal at the outlet box a simple procedure using commonly used materials. Typically, TREMCO™ Acoustical Sealant, 3M® tape, or the like would be used to seal the vapor barrier to the flange and an expanding foam made by any number of companies, would be used to fill the first chamber, or a plurality of sealing chambers in preferred embodiments, through which the electrical wires pass. This device will be manufactured economically, easily installed and provide the highest level of air tightness. 
     It is a primary object of this invention to provide a sealable electrical junction box which is formed from a single mold. 
     It is another object to provide a sealable electrical junction box which is a one component system. 
     It is a further object to provide a sealable electrical junction box that can be installed like a conventional outlet box. 
     It is another object to provide a sealable electrical junction box that utilizes a typical knockout structure that is familiar to those in the field and will require no special handling or tools when installing the wiring. 
     It is also an object to provide a sealable electrical junction box that utilizes a flange which has been commonly used and proven effective to seal the vapor barrier around the outside of the box. 
     The instant invention comprises an electrical junction box which is of unitary construction and shaped to allow an airtight seal around the front opening and around the wire penetration areas when the box is fully installed. The outlet box is installed like conventional boxes and requires no special tools or training. 
     The electrical junction box has a closed back and sides and a front side with a front opening. The sides are closed by side walls with interior and exterior surfaces. The back is closed by a rear wall also with an interior and exterior surface. First walls define the top and bottom of the box. Alternatively, these first walls can be an upper wall and a lower wall, each with interior and exterior surfaces. Dividing or second walls are used to create small cavities through which the wires must pass when the box is installed. 
     With the wires in place, the cavities can be filled with a sealing substance in order to create an airtight seal around the wires. The box incorporates first chamber access points and second chamber access points which comprise access openings, openings covered by tape or the like similar to that disclosed by Rye or most preferably, knockout areas which can be easily destroyed in order to form openings or holes for the wires. The knockout areas are defined by areas of reduced wall thickness as compared to the surrounding areas of the respective wall. 
     The box has side flanges which extend upwardly and downwardly from one of the side surfaces. These side flanges allow the box to be fastened to the side of a stud in the wall and will preferably have notches or holes to accommodate a fastening means such as nails or screws. 
     The box preferably includes a flange proximate the front opening which can be used to form an airtight seal with the vapor barrier around the front opening of the box. The plane of the flange is substantially parallel to the plane of the front opening and provides a flat surface onto which the vapor barrier may be glued. After the box is fastened to the side of a stud such that the front opening of the box faces into the room, the vapor barrier is applied to the wall and sealed to the outlet box or boxes. Most commonly, sheet rock is then applied to the wall over the vapor barrier, closing the wall. A hole cut through the sheet rock is aligned over the outlet box to accommodate the front opening. The flange proximate the front opening is set back from the front opening approximately the same distance as the width of the sheet rock such that, once the sheet rock is installed, the back face of the sheet rock is substantially flush with the flange and the front face of the sheet rock is substantially flush with the front edge of the box which defines the front opening. 
     In alternate embodiments, the box will be a round or “circular” box preferably for ceiling fixtures, or “double-gang” or “side by side” “double” box. it will be appreciated that any number of “side by side” boxes are envisioned within the present invention. 
     The above described features and advantages, along with various other advantages and features of novelty, are pointed out with particularity in the claims of the present application. However, for a better understanding of the invention, its advantages, and objects attained by its use, reference should be made to the drawings which form a further part of the present application, and to the accompanying descriptive matter in which there is illustrated and described preferred embodiments of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings, where like reference numbers refer to like parts through the several views: 
     FIG. 1 is a perspective view of an installed junction box of the present invention with portions of the wall cut away to show how the box is mounted to the stud, how the vapor barrier seals to the front flange, how the wires extend through the knockout areas, and how the sheet rock sits against the vapor barrier and the front flange and is flush with the edge of the front opening; 
     FIG. 2 is a perspective view of the uninstalled junction box of the present invention shown in FIG. 1; 
     FIG. 3 is a front plan view of the uninstalled junction box of the present invention shown in FIG. 1; 
     FIG. 4 is a partially cut-away side view of the uninstalled junction box shown in FIG. 1 with a cut-away view of a knockout area; 
     FIG. 5 is a rear view of the uninstalled junction box shown in FIG. 1; 
     FIG. 6 is a top view of the uninstalled junction box shown in FIG. 1; 
     FIG. 7 is a close-up partial side view of the knockout area of the uninstalled junction box shown in FIG.  1 . 
     FIG. 8 is a close-up partial cross-sectional side view of generally from along lines  8 — 8  of FIG. 1, but after the box has been installed, showing how the wires pass through the knockout areas and how the first chamber is filled with sealant, forming an airtight seal around the wires; 
     FIG. 9 is a close-up partial front view of an installed box of the present invention similar to the box shown in FIG. 1 showing a wire in place with sealant sealing the wire within the box and cutaway portions of vapor barrier and sheet rock against the front flange; 
     FIG. 10 is a close-up partial cross-sectional side view corresponding to the view shown in FIG. 8, but showing a prior art box; 
     FIG. 11 is a partial close-up front view of the installed prior art box shown in FIG. 10, but in a view similar to that shown to that shown in FIG. 9; 
     FIG. 12 is a perspective view of an alternate circular ceiling box of the present invention when secured to a ceiling joist; 
     FIG. 13 is a bottom plan view of the alternate circular ceiling box shown in FIG. 12 but turned 90° from the general direction of the view shown in FIG. 12; 
     FIG. 14 is a side view of the alternate circular ceiling box shown in FIG. 13; 
     FIG. 15 is a perspective view of a preferred circular ceiling box of the present invention; 
     FIG. 16 is a bottom plan view of the circular ceiling box shown in FIG. 15; 
     FIG. 17 is a side view of the circular ceiling box shown in FIG. 16; 
     FIG. 18 is an enlarged partial side cut-away of the area within the highlighted circle shown in FIG. 17; 
     FIG. 19 is a perspective view of a preferred “double gang” junction box of the present invention; and 
     FIG. 20 is a plan view of open side of the box shown in FIG.  19 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings, and first to FIGS. 1 through 9, there is shown a sealable electrical junction box  10 , comprising a rear wall  20 , two side walls  22   a  and  22   b , an upper first wall  24 , and a lower first wall  26 . These walls are interconnected to form a substantially box-shaped exterior wall  28 . 
     A chamber formed by the exterior wall  28  is divided into at least one first chamber  12 , and a second chamber  14 , by at least one dividing second wall  30 . In the preferred embodiment shown in the drawings, there are two second walls,  30   a  and  30   b  forming two first chambers  12   a  and  12   b . The second chamber  14 , defined by the rear wall  20 , the side walls  22   a  and  22   b , and second walls  30   a  and  30   b , is open opposite the rear wall  20  thereby forming front opening  16 . 
     Junction box  10  further comprises a front flange  34  which extends outwardly and substantially perpendicularly from exterior wall  28 . Front flange  34  is substantially parallel to the plane of the front opening  16  and is preferably set back therefrom to accommodate a layer of sheetrock  50 . Front flange  34  may have one or more attachment holes  42  for the purpose of securing the box  10  to a stud  60  using nails, screws or other securing means. Front flange  34  is preferably wide enough to receive an adhesive  52  used to seal a vapor barrier  56  to the front flange  34 . 
     A side flange  36  extends rearwardly from the front flange  34  and is flush with side wall  22   a . Side flange  36  is at least long enough to have at least one attachment notch  40  which can be used to fasten the box  10  to the side of a stud  60 . The attachment notches  40  may be used in conjunction with or instead of attachment holes  42 . It is important to note that the terms notches and holes are used strictly for clarification and that the securing arrangements in either the front flange  34  or the side flange  36  or both, may be openings, notches, indentations, or any other configuration commonly used to accommodate securing means such as nails, screws, or the like. 
     The first walls  24  and  26  have first knockouts  32   a  which may be destroyed and removed by striking the knockout in a manner well known in the art in order to form one or more first access openings  33   a  through which the wires  62  could pass. These access openings  33  would then lead from the exterior to the first chamber  12 . Note that this first chamber  12  could be toward the top or bottom of the box  10 , or even toward the rear or sides of the box  10 . The preferred embodiment shown in FIGS. 1-9 includes a first chamber  12   a  toward the top of the box  10  and a first chamber  12   b  toward the bottom of the box  10 . All first chambers in any alternate embodiments would have either destroyable knockouts  32  or access openings  33  for receiving wires. 
     The second walls  30   a  and  30   b  also have destroyable second knockouts  32   b , although they could have access openings for receiving wires. The second knockouts  32   b  can be destroyably removed to form one or more second access openings  33   b  which allow the wires  62  to pass from the first chamber  12 , through the second wall  30 , into the second chamber  14 . Preferably, the first knockouts  32   a  substantially align with second knockouts  32   b  so that the wires  62  can pass through both without having to turn or bend, thereby simplifying installation. 
     The preferred junction box  10  includes attachment busses  43  adjacent the front opening  16  for receiving a conventional outlet cover (not shown). Preferably the box  10  has opposing busses  43  extending inwardly from the top and bottom of second chamber  14 , and fixture holes  44  extending therethrough. These fixture holes  44  are preferably threaded to receive screws, or, alternatively, could be narrower than the intended screws used to fasten the outlet cover thereto such that the screws cut their own threads when screwed into the holes  44 . 
     In preferred embodiments of the present invention, junction boxes  10 ,  110 ,  210 , and  310  are injection molded out of a non-combustable, flame-retardant resin material such as the modified P.P.O. (polyphenylene oxide) resins sold by GE under the mark NORYL, or other similar resins which are known in the art. 
     It is envisioned that the preferred installation process would begin with placing the outlet box  10  against a stud  60  of an incomplete wall such that the side flange  36  abuts the side of the stud  60 , the front flange  34  abuts the front of the stud  60  and the front opening  16  faces the inside of the room in which the outlet is to be used. In preferred embodiments, screws or nails would then be used to fasten the box  10  to the stud  60  through the attachment holes  42  and the attachment notches  40 . 
     First knockouts  32   a  and second knockouts  32   b  would then be destroyed in order to form access openings  33   a  and  33   b  from the exterior of the box  10 , so that the wire  62  can pass through the respective first wall  24  or  26 , into the respective first chamber  12   a  or  12   b , through respective second wall  30   a  or  30   b  and into the second chamber  14  for each wire  62  to be joined in the box  10 . After the knockouts  32   a  and  33   b  are destroyed, the wires  62  are inserted through the respective access openings  33   a  and  33   b  so that the ends of the wires  62  extend well into the second chamber  14  leaving some excess for joining wires  62  as appropriate. 
     With the wires  62  in place, a sealant  54  is injected into the first chamber or chambers  12   a  and/or  12   b , as appropriate where access openings in the box would allow air to pass through the box, thereby forming a substantially airtight seal around the wires  62  as shown in FIG.  8 . Only those first chambers  12   a  and/or  12   b  having wires passing through them would need sealant  54  assuming the knockouts  32  remain intact where no wires are received. In alternate embodiments (not shown) where the boxes have preformed access openings in the place of knockouts then all first chambers  12  would require sealant  54  to provide an airtight box. 
     The next step in the preferred installation procedure is to apply a vapor barrier  56  over the wall. The vapor barrier  56  is secured to the outside of the front flange  34  with an adhesive or sealant  52 . It is important that the sealant  52  be applied continuously around the perimeter of the flange  34  so that no air leaks form between the flange  34  and the vapor barrier  56 . A hole is then cut in the vapor barrier  56  to substantially conform to the front opening  16 . 
     Finally, sheetrock  50  with holes cut to conform to the box  10  and front opening  16  is placed over the vapor barrier  56  and secured to the studs, substantially completing the construction of the unfinished wall. An outlet fixture or cover (not shown) can be secured to the box  10  using the fixture holes  44  to receive screws or the like, presumably after the wall is finished. Installation according to this preferred procedure, should result in a virtually airtight seal across the vapor barrier  56  proximate the outlet box  10 . This procedure is essentially the same for other embodiments of the sealable outlet and/or junction box of the present invention, unless access openings are pre-existing boxes. In that case, it would not be necessary to break the knockouts to create the access openings and care would need to be taken to seal all of the first chambers. 
     Referring now to FIGS. 12-20, an alternate circular ceiling box  110  is shown in FIGS. 12-14; a preferred circular ceiling box  210  is shown in FIGS. 15-18; and a preferred “double-gang” junction box  310  is shown in FIGS. 19-20. Each of these additional junction boxes  110 ,  210  and  310  have many of the same elements as junction box  10  shown in FIGS. 1-9. The circular ceiling junction boxes  110  and  210  are designed for attachment to a ceiling joist  70  in a ceiling. The respective ceiling junction boxes  110  and  210  are configured somewhat differently, but each has a main chamber  114 ,  214  and opposing first chambers  112 A and  112 B,  212 A and  212 B, respectively. In addition, each of the respective ceiling boxes  110 ,  210  have corresponding knockouts  132 A and  132 A,  232 A and  232 B, which can be destroyed in the same manner as the knockouts  32 A and  32 B are destroyed. In addition, the installation of the ceiling boxes  110 ,  210  is generally similar to that of the installation of junction box  10  with the exception that the junction boxes  110 ,  210  are attached to a ceiling joist  70  in the process of completing construction of an unfinished ceiling (not shown). The preferred ceiling boxes will also have side flanges  136 ,  236  for attachment to a ceiling joist  70 , front flanges  134 ,  234  to provide a surface to which to secure the vapor barrier (not shown), attachment busses  143 ,  243  having fixture holes  144 ,  244  and the like for securing outlet cover (not shown) or other fixture covers. It is appreciated that the ceiling junction boxes of the present invention may be used as a housing of one kind or another for any type of electrical junction where code requires an enclosure, including, without limit, a simple electrical junction between separate wires, a junction between electrical wires and a switch, a junction between electrical wires and an electrical outlet or outlets, a junction between an electrical wire and an electrical device which is powered by electrical power, such as a siren or other noise generating device, a light bulb and bulb socket or other light generating device, other like. 
     The “double-gang” junction box  310 , shown in FIGS. 19-20 also has similar features to those associated with junction box  10  shown in FIGS. 1-9. The “double-gang” junction box  310  is installed in a manner which is almost identical to the manner in which the junction box  10  is installed, except that it is a double box and can, therefore, accommodate more than one junction or switch, etc. The “double-gang” junction box  310  has a front flange  334  which provides a surface to which the vapor barrier (not shown) may be sealed in a manner similar to which the vapor barrier is sealed to the other junction boxes  10 ,  110 ,  210  of the present invention. The “double-gang” box  310  also has a side flange  336  including notches  340  for securing the box  310  to a stud or joist (not shown). The “double-gang” box also includes a pair of side by side first chambers  312   a ,  312   b  on each side of the second or main chamber  314 . The respective side by side first chambers  312   a ,  312   b  are separated from one another by a separating wall  313   a ,  313   b , respectively. In this way, if the first and second knockouts  332   a  and  332   b  associated with only a single one of the side by side first chambers  312   a ,  312   b  are destroyed to form access openings (not shown), only one of the first chambers  312   a ,  312   b  in which the knockouts are destroyed to provide access openings for wires coming into the main chamber  314  through the access openings and the first chamber, will need to be filled with sealant (not shown) in order to seal the box  310  and provide the desired air tight vapor barrier. 
     It will be appreciated that the sealable junction box of the present invention envisions boxes which may accommodate even more junctions, switches, outlets or other electrically functioning devices then the “multiple-gang” junction boxes are well within the scope of the present invention. 
     It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only and changes may be made in detail, especially in matters of shape, size and arrangement of parts, within the principles of the present invention, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.