Abstract:
A vessel of substantially uniform curvilinear shape comprising at least one area of a different curvilinear shape that is adapted to closely conform to and engage a number of commonly contoured curvilinear segments on a housing member constructed and arranged to receive an outer covering panel in close fitting relation therewith is disclosed. In addition a method of manufacturing a vessel which comprises at least one area of a different curvilinear shape is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is drawn to a curvilinear structure formed integral to a vessel for containing fluids that permits the attachment thereto of a standardized fitting regardless of the nominal diameter of the vessel. Specifically, the present invention is drawn to the formation of a standard radius in the sidewall of the vessel wherein the radius of the remainder of the circumference of the vessel may differ from the standard radius. The standard radius is common to a plurality of vessels of varying diameter and is arranged to be complementary with a standard fitting or fittings which may be mounted to the vessel in a flush manner. 
     In the fabrication of vessels for containing fluids, it is often necessary to mount a fitting to the sidewall of the vessel. These fittings may comprise access panels, junction boxes, or gauges. In addition, it is often very desirable to mount the aforementioned fittings to the sidewall of a vessel in a flush manner so as to prevent the infiltration of liquids into or out of the vessels. Presently, when manufacturing vessels such as for water heaters, it is necessary to have on hand numerous fittings with mating surfaces of varying radii to fit each of the plurality of vessels of varying diameter. The variation in size between fittings has resulted in higher inventory costs and higher fabrication costs. The use of standardized fittings reduces the total inventory costs, lowers the fabrication costs associated with the manufacture of both the fittings and the vessels, and lends itself to modern just-in-time manufacturing techniques. 
     Therefore, it is an objective of this invention to provide a structure or structures for mounting a standard fitting upon any of a series of vessels of varying size. 
     SUMMARY OF THE INVENTION 
     The present invention provides a structure which permits a standard fitting or housing to be mounted upon any of a number of variously sized vessels, thereby obviating the need to maintain stocks of various sized fittings or housings. Though the present invention is herein described as being used with a vessel for containing fluids, namely a water heater, it is to be understood that the invention can easily be adapted to other types of vessels of varying application and materials. Furthermore, it is contemplated that the present invention may have applications outside the field of fluid containment vessels. 
     A vessel incorporating the present invention typically has a substantially uniform curvilinear shape and comprises at least one area that has a different curvilinear shape that is adapted to closely conform to and engage commonly contoured curvilinear segments on at least one housing member constructed and arranged to receive an outer covering panel in close fitting relation therewith. 
     The vessel may be the outer shell of a water heater having an inner, water containing shell positioned inside it in a spaced apart relation thereto so as to form an annular space between the vessel and the shell. An insulating material substantially fills the annular space between the vessel and the shell in surrounding relation to the housing member. The housing member is typically an electrical junction box for making an electrical connection to at least one electric heating element that extends into the inner shell. The curvilinear segments of the housing member are curved mounting flanges on opposing sides of the housing member that are arranged to mate with the area of different curvilinear shape. 
     The outer covering panel has curved, peripheral edges formed to substantially conform to the curvilinear shape of the area of different curvilinear shape. The outer covering panel typically comprises an intermediate bracket and a covering panel. The intermediate bracket has a curvilinear shape arranged and constructed to conform to the area of different curvilinear shape of the vessel and is also arranged to be secured to the housing member in such a way as to secure the wall of the vessel therebetween. The intermediate bracket also has formed therein attachment means for releasably attaching the covering panel over the intermediate bracket. 
     The present invention also comprises a method of manufacturing a vessel which is integral to the practice of the invention disclosed herein. A first step in this method involves forming a vessel having a substantially regular curvilinear shape, the vessel being any one of a number of predetermined sizes. Integral to this vessel is formed a geometric discontinuity having a curvilinear shape different from the remainder of the vessel. The curvilinear shape of the geometric discontinuity is identical for all of the predetermined sizes for the vessel. A housing member having a mating surface complementary to the curvilinear shape of the geometric discontinuity is also provided. The housing member is identical for all of the predetermined sizes of the vessels. The provided housing member is then secured to the geometric discontinuity in a manner that is identical for all of the predetermined sizes of the vessel. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a water heater embodying the standard radius of the present invention; 
     FIG. 2 is an exploded perspective view of a housing constructed and arranged to mate with the standard radius of the present invention; 
     FIGS. 3 a - 3   d  are top plan views of the outer shell of a water heater illustrating the offset relationship between the area of standard radius and various water heater tank diameters; and 
     FIG. 4 is a partial top sectional view taken along section lines  4 — 4  of FIG. 1 illustrating the housing mated to the area of standard radius of water heater tanks of various sizes. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a front, elevational view of a water heater  5  comprising an outer shell  6  and an inner tank  6   a  as shown in FIG.  4 . The outer shell  6  of the water heater  5  has a substantially uniform curvilinear shape, which is in this embodiment substantially cylindrical. The top portion  8  of the outer shell  6  has a large radius fillet and acts as a gradual transition between the substantially cylindrical central portion  10  of the outer shell  6  and the substantially flat top  9  of the outer shell  6 . The bottom portion  12  of the outer shell  6  is also substantially cylindrical and contains at least one recess  13 . Recess  13  has disposed therein a spigot  14  which may be a drain for the inner tank of the water heater  5 . The top  9  of the outer shell  6  is arranged to have pass therethrough an inlet  15 , an outlet  16 , and a pressure relief valve  17 , all arranged to be in fluidic connection with the inner tank  6   a  of the water heater  5  and arranged in known manner to convey and control the flow of water through the water heater  5 . 
     An electrical connection box  18  is mounted at the top portion  8  of the outer shell  6  and is arranged to receive electrical conductors (not shown) which power the heating elements (not shown) of the water heater  5 . The water heater  5  illustrated in FIG. 1 also has attached thereto two junction boxes  19 . For the purposes of the present invention all junction boxes  19  are identical, irrespective of the size or shape of the water heater  5 . Use of a standard junction box  19 , capable of being mounted upon any of a series of water heaters  5  having varying sizes, reduces the number of variously sized junction boxes that would otherwise be required to be kept on hand. The use of a standard junction box  19  therefore reduces overhead expenses and manufacturing costs associated with the production of the water heaters  5 . It must also be kept in mind that the box  19  may be arranged for uses other than as an electrical junction box. For instance, box  19  may be arranged to conceal or protect a valve, gauge, or spigot. For the purposes of this application the term “electrical junction box” should be construed to include boxes which may be mounted integral to and used in conjunction with a vessel for containing fluids as disclosed herein. 
     FIG. 2 illustrates in detail the construction of the junction box  19 . The junction boxes  19  are comprised of a housing member  20  and a cover  24 . The cover  24  is in turn comprised of an intermediate plate  26  and a cover panel  28  that is arranged to be releasably attachable to the intermediate plate  26 . As can be seen, the housing member  20  is comprised of a substantially rectangular housing  21  having an open outer surface defined by a plurality of curvilinear segments which form a flange  22 . The flange  22  of the housing member  20  is arranged to be complimentary with the inner surface of an area  32  of the wall of the outer shell  6  that is geometrically discontinuous, i.e. has a different curvilinear shape from the remainder of the outer shell  6 . The purpose of the area of geometric discontinuity  32  is to provide a common mounting surface on the outer shell  6  of a water heater  5  to which a junction box  19  may be attached. Identical areas of geometric discontinuity  32  that are complementary to the flange  22  of the housing member  20  are formed into the outer shell  6  of each of a series of variously sized water heaters  5 , such that a standard junction box  19  that is identical for each distinctly sized water heater  5  may be attached thereto. This purpose is furthered by providing junction box  20  with an inner curved surface  25  having a radius permitting it to abut against inner shell  6   a  in conforming relation thereto. Insulation  11  fills the annular space between inner and outer shells  6   a  and  6 . 
     In order to facilitate the addition of necessary electrical components, the housing  20  of junction box  19  is provided with electrical conduit ports  35  at its top and bottom. Conduit ports  35  permit electrical conductors (not shown) to be strung from the electrical connection box  12 , to the housing(s)  20 . Where a water heater  5  has more than one junction box  19 , electrical conductors may be strung between the housings  20  of the junction boxes  19 . The electrical conductors are required to power electrical components such as heating elements (not shown) that may be mounted through component port  36  at the back of the housing  20  of the junction box  19 . 
     Referring next to FIG. 4, a junction box  19  is seen as mounted to the outer shell  6  at an area of geometric discontinuity  32 . Housing member  20  is mounted against the inner surface of the outer shell  6  at the area of geometric discontinuity  32  in registration with an opening  7  that is formed through the wall of the outer shell  6 . The opening  7  formed through the outer shell  6  is roughly the same size and shape as open face  23  of the housing member  20  bounded by the flange  22 . The opening  7  through the outer shell wall  6  permits communication between the exterior of the outer shell  6  and the interior of the rectangular housing  21  of the housing member  20 . The cover  24  is affixed to the outer surface of the outer shell  6  of the water heater  5  at the area of geometric discontinuity  32  in registration with the opening  7  through the outer shell wall  6  and the housing member  20  of the junction box  19 . 
     Typically, intermediate plate  26  is attached to the outer surface of the outer shell  6  by means of a mechanical fastener or an appropriate adhesive so as to secure the wall of the outer shell  6  between the flange  22  of the housing member  20  and the intermediate plate  26  as shown in FIG.  4 . Intermediate plate  26  has formed therein attachment means arranged to permit releasable attachment of the cover panel  28  to the intermediate plate  26 . The attachment means may comprise a plurality of apertures  27  arranged to mate with a plurality of tabs  29  extending from the cover panel  28 . Hooks  30  formed on the distal ends of the tabs  29  extend through the apertures  27  of the intermediate plate  26  and engage the inner surface of the intermediate plate  26  to secure the cover panel  28  thereto. Gentle prying pressure applied to an aperture  31  is sufficient to remove cover panel  28  from intermediate plate  26 . It is to be understood that the structure of the apertures  27 , tabs  29 , and aperture  31  may be altered significantly without exceeding the scope of the present invention. 
     FIGS. 3 a - 3   d  are a series of top plan views of the outer shell  6  illustrated in FIG.  1 . FIGS. 3 a - 3   d  illustrate the radially offset relationship between the area of standard radius and various water heater tank diameters. As indicated above, the outer shell  6  of a water heater  5  is a curvilinear substantially cylindrical shape having a substantially circular cross section as indicated in FIGS. 3 a - 3   d . In the preferred embodiment of the present invention, the area of geometric discontinuity  32  comprises a curvilinear shape having a fixed radius R 1  with a center point C 1  that is offset from the center C 2  of the outer shell  6  of the water heater  5 . Depending upon the requisite volume of the outer shell  6  of the water heater  5 , it is possible that the radius R 2  and center point C 2  of the outer shell  6  may be the same as the radius R 1  and center point C 1  of the area of geometric discontinuity  32 . The outer shell illustrated in FIGS. 3 a - 3   d  has been variously labeled with the reference numerals  6 ,  6 ′,  6 ″, and  6 ′″, respectively, to distinguish the variously sized shells of differing embodiments. Note that in FIGS. 3 a  and  3   b  that the radii R 1  of the areas of geometric discontinuity  32  are larger than the radii R 2  of outer shell embodiments  6  and  6 ′ of the water heater  5  and that in FIGS. 3 c  and  3   d  that the radii R 1  geometric discontinuity  32  are smaller than the radii R 2  of outer shell embodiments  6 ″ and  6 ′″ of the water heater  5 . 
     Though the shape of the water heater  5  and area of geometric discontinuity of the present invention are, in conjunction with the preferred embodiment, described as being essentially circular in cross section, it is to be understood that various curvilinear shapes that are not essentially circular in cross section may be utilized without exceeding the scope of the present invention. For example, the present invention may be readily adapted to the outer shell of a water heater that has an elliptical cross-sectional shape or an irregular curvilinear shape. Likewise, the cross-sectional shape of the area of geometric discontinuity need not be circular, but instead could be elliptical, parabolic, or even an irregular curvilinear shape. 
     The substantially circular cross section of the outer shell  6  is modified near the area of geometric discontinuity  32  so as to create a smooth transition T therebetween. One advantage to utilizing a substantially circular area of geometric discontinuity  32  with the substantially cylindrical outer shell  6  of the water heater  5  is that the area of transition T between the area of geometric discontinuity  32  and the remainder of the outer shell  6  may be made in a manner that is unobtrusive and generally pleasing to the eye. 
     In FIG. 1, the outer shell  6  of the water heater  5  is illustrated as having a single vertically oriented area of geometric discontinuity  32  which extends from below the lower junction box  19  to above the upper junction box  19 . While the embodiment of FIG. 1 is the preferred embodiment of the present invention, it is to be understood that an area of geometric discontinuity  32  need only be large enough to permit a single junction box  19  to be mounted thereto. Therefore, the areas of geometric discontinuity  32  may be varied in size, number, and location, depending upon the desired number and arrangement of junction boxes required for a given water heater  5  without exceeding the scope of the present invention. For example, the water heater outer shell  6  may comprise a single vertically oriented area of geometric discontinuity  32  that extends over substantially the entire height of the outer shell  6 , as illustrated in FIG. 1, or, the water heater outer shell  6  may comprise a plurality of areas of geometric discontinuity  32  that are slightly larger than the junction boxes  19  and which are disposed in a predetermined pattern upon the surface of the water heater  5 . Another example of a water heater  5  according to the present invention has areas of geometric discontinuity  32  formed on a front side and a back side of the water heater  5  or in the four quadrants of the water heater  5  and extending either the entire height of the outer shell  6  of the water heater or some portion thereof. 
     Forming an area of geometric discontinuity  32  into an outer shell  6  of a water heater  5  is an integral part of a method of manufacturing a water heater  5 . A vessel incorporating the present invention such as the outer shell  6  of a water heater  5  may be formed of plastic as by blow molding, fabricated from metals such as steel or aluminum, or formed of a composite material such as fiber glass or the like using fabrication techniques appropriate to the chosen material. In the preferred embodiment of the present invention, a vessel having a substantially regular curvilinear shape and having any one of a number of predetermined sizes is formed in a blow molding procedure utilizing a mold appropriate to the desired final shape and size of the vessel. Areas of geometric discontinuity  32  are formed into the vessel in a desired arrangement by replacing portions of the mold used to form the vessel with mold portions which have formed thereon a negative image of the areas of geometric discontinuity  32  and transition areas T. It is important to reiterate that the areas of geometric discontinuity  32  are of uniform size and shape irrespective of the size or arrangement of the vessel into which they are being formed. In this manner, the areas of geometric discontinuity  32  of a vessel of a particular size will be identical to the areas of geometric discontinuity  32  formed into vessels of different sizes. Where the vessels are formed of steel or other materials not suitable for a molding process, identical areas of geometric discontinuity may be formed using any number of well known stamping, rolling, replacement by welding or other suitable fabrication techniques. 
     Housing members  20  of junction boxes  19 , having mating surfaces defined by flange  22 , are next attached to the inner surface of the areas of geometric discontinuity  32  of each outer shell  6  such that the flange  22  is in mating contact with the inner surface of an area of geometric discontinuity  32 . It is preferred that the flange  22  be sealingly mated to the area of geometric discontinuity  32 . Openings  7 , which allow access to the interior of the housing member  20 , may be preformed in the areas of geometric discontinuity  32  of the vessel or may be formed once the housing members  20  have been secured to the outer shells  6 . It is to be understood that a single, standard junction box  19  design is mounted to the identical areas of geometric discontinuity  32  of each of the outer shells  6  of varying size. In addition, the manner whereby a junction box  19  is attached to an outer shell  6  of a water heater  5 , i.e. by use of mechanical fastener or adhesive, is identical for the outer shells  6  of varying size. Once the housing members  20  have been attached to the inner surface of the outer shells  6  at the areas of geometric discontinuity  32 , the cover  24  is secured to the exterior surface of the outer shells  6  over the housing members  20 . The intermediate plate  26  of the cover  24  is secured directly to the exterior surface of the outer shell  6  by means of mechanical fasteners or adhesives and cover panel  28  is releasably secured to the intermediate plate  26  by apertures  27  and tabs  29 . In the embodiment shown in FIG. 2, aligned apertures  33  and  34  are provided in housing member  20  and plate  26 , respectively, to receive threaded fasteners. 
     By forming identical areas of geometric discontinuity  32  into vessels of varying size, it is possible to utilize a standard configuration of a junction box  19  for each of the vessels of varying size, thereby obviating the need to maintain stocks of variously sized junction boxes  19  each usable for specific sizes of vessels only. While the preferred embodiments of the present invention have been described, it is to be understood that various changes, adaptations, and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.