Patent Number: 048440493
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 schematically illustrates, in longitudinal cross-section, a water heater device, generally denoted as the numeral 10, having a generally cylindrical inner water tank 12 for containing water and a generally cylindrical outer shell 14 concentrically surrounding the inner water tank 12. The outer shell 14 is of a larger diameter than the water tank 12 and they cooperate to define an annular space 16 therebetween. As illustrated, the water heater device 10 is of the electrically heated type having, for example, an electrical resistance unit (not shown) projecting into the interior of the water tank 12 to heat the water therein. The bottom of the inner water tank 12 is formed with a concavity 18. The top end of the water heater device 12 is closed by a cap 20, which may be a separate component or may be unitary with the outer shell 14. The bottom end of the water heater device 10 is typically closed by a floor 22. With further reference to FIGS. 1, an insulating thermal collar 24 is located in the annular space 16. The collar 24 includes an enclosing envelope 26 filled with a thermal insulation material 28. The enclosing envelope 26 is fabricated of a fluid impermeable, pliable material such as, for example, polyethylene film, vinyl film, metalized polyester, metal foil, and the like. The thermal insulation material 28 can be a fibrous batt, such as interwoven fiberglass, or a loose, discrete, divided material, such as for example non-interengaged fiber glass, mineral wool, steel wool, cellulose, ceramic fiber, discrete particles or beads of plastic foam, and the like. It is contemplated, that in some applications, it may be necessary to cohesively hold the loose, discrete, divided insulation material together inside the envelope 26 to prevent the insulation material from shifting or settling within the enclosing envelope 26. In this event, a binder material is homogeneously dispersed throughout the mass of the insulation material 28 to cohesively hold the insulation material together, and possibly adhesively affix the insulation material to the wall of the envelope 26, to prevent the insulation material 28 from shifting or settling within the envelope 26. The binding material used is a function of the type of insulation material 28 and can be a thermosetting adhesive, thermoplastic adhesive, cold setting adhesive, ambient setting adhesive, or hot setting adhesive. For example, a suitable adhesive for use with fiber glass and mineral wood is phenolic or sodium silicate, and a suitable adhesive for cellulose is polyvinyl acetate. The collar 24 extends circumferentially around the inner water tank 12 in the annular space 16 proximate the bottom end of the water heater device 10. The collar 24 has a width greater than the radial width of the annular space 16 so that the collar 24 is radially compressed between the interior wall surface of the outer shell 14 and the exterior wall surface of the inner water tank 12 sufficiently to tightly seal the interface of the collar 24 and inner wall surface of the outer shell 14 and to tightly seal the interface of the collar 24 and exterior wall surface of the inner water tank 12. In addition, the collar 24 is in abutment with the water heater device floor 22. With reference to FIGS. 2, the enclosing envelope 26 of the collar 24 is in the form of an elongated generally cylindrical tube closed at both of its ends 27 and 29. The tubular collar 24 is circumferentially wrapped around the perimeter of the water tank 12 with the ends 27 and 29 thereof brought together into mutual abutment. The abutting ends 27 and 29 can be secured together by, for example, adhesive tape if necessary. With reference to FIG. 3, an alternative construction for the enclosing envelope 26 of the collar 24 is illustrated. Envelope 126 is in the form of an elongated generally cylindrical tube having one of its ends 127 closed and the other of its ends 129 open. The tubular collar 124, formed in part by envelope 126 is circumferentially wrapped around the perimeter of the water tank 12 and the closed end 127 is inserted into the open end 129. The ends 127 and 129 can be secured together by, for example, adhesive tape, if necessary. With reference to FIG. 4, a further alternative construction is illustrated. The enclosing envelope 226 of the collar 224 is in the form of an elongated generally cylindrical tube having both of its ends 227 and 229 open. The tubular collar 224 is circumferentially wrapped around the perimeter of the water tank 12 and one of the open ends 227 is inserted into the other of the open ends 229. The ends 227 and 229 can be secured together by, for example, adhesive tape, if necessary. With reference to FIG. 5, a still further alternative further construction is illustrated. The enclosing envelope 326 of the collar 324 is in the form of a closed toroid. The envelope 326 is filled with a suitable insulation material as previously described relative to collar 24. The toroid collar 324 is concentrically slid over the water tank 12. With reference once again to FIG. 1, the annular space 16 above the collar 24 is filled with an expanded foam thermal insulation material 30 such as urethane, polyethylene, polystyrene and the like, which functions as a thermal insulation surrounding the inner water tank 12. With reference to FIGS. 1, an insulating disc 32 is located at the bottom end of the inner water tank 12. The insulating disc 32 includes an enclosing envelope 34 filled with a thermal insulation material 36. The enclosing envelope 34 has a peripheral configuration matching that of the bottom end of the water heater 12 and a thickness preferably at least as great as the depth of the concavity 18. As shown, the envelope 34 has a generally circular perimeter to correspond to the perimeter of the bottom end of the inner water tank 12 so that the disc 34 overlays the bottom end of the tank. The enclosing envelope 34 is fabricated of a fluid impermeable, pliable material such as, for example, polyethylene film, vinyl film, metalized polyester, metal foil, and the like. The thermal insulation material 36 is either a fibrous batt such as interwoven fiberglass, or a loose, discrete, divided material such as, for example, non-interengaged fiber glass, steel wool, mineral wool, cellulose fibers, ceramic fibers, discrete particles or beads of plastic foam, and the like. It is contemplated that in some applications it may be necessary to cohesively hold the loose, discrete, divided insulation material together inside the envelope 34, and possibly adhesively affix the insulation material to the wall of the envelope 34, to prevent the insulation material from shifting or settling within the enclosing envelope 34. In this event, a binder material is homogeneously dispersed throughout the mass of insulation material 36 to cohesively hold the insulation material together and prevent the insulation material from shifting or settling within the envelope 34. The binder material used will be a function of the type of insulation material 36 and can be a thermosetting adhesive, thermoplastic adhesive, cold setting adhesive, ambient setting adhesive, or hot setting adhesive. For example, a suitable adhesive for use with fiber glass and mineral wool is phenolic or sodium silicate, and a suitable adhesive for cellulose is polyvinyl acetate. With reference to FIG. 7, an alternative construction for disc 32 is illustrated. Insulating disc 132 includes an enclosing envelope 134 having a peripheral configuration generally matching that of the bottom end of the water tank and a thickness preferably at least as great as the depth of the cavity 18. The envelope 134 includes a central inner circular pocket 138 concentrically surrounded by a perimeter outer pocket 140. The envelope 134 is fabricated of a fluid impermeable, pliable material such as, for example, polyethylene film, vinyl film, metalized polyester, metal foil and the like. The central circular pocket 138 is separated from the perimeter pocket 140 by a circular seal 142. The central circular pocket 138 is filled with a fibrous batt of insulation material, such as interwoven or interengaged fiberglass, and the perimeter pocket 140 is filled with a loose, discrete, divided insulation material such as, for example, non-interengaged fiber glass, mineral wool, steel wool, cellulose fibers, ceramic fibers, discrete particles of beads of plastic foam, and the like. However, it is contemplated that the central circular packet 138 be filled with the loose, discrete, divided insulation material and the perimeter pocket 140 be filled with the fibrous batt. It is contemplated that in some applications, it may be necessary to cohesively hold the loose, discrete, divided insulation together inside of the pocket. In this event, a binder material is homogeneously dispersed throughout the mass of insulation material within the pocket to cohesively hold the insulation material together, and possibly adhesively affix the insulation material to the wall of the pocket to prevent the insulation material from shifting or settling within the pocket. The binder material used will be a function of the type of insulation material used within the pocket and can be thermosetting adhesive, thermoplastic adhesive, cold setting adhesive, ambient setting adhesive, or hot setting adhesive. For example, a suitable adhesive for use with fiber glass and mineral wood is phenolic or sodium silicate, and a suitable adhesive for cellulose is polyvinyl acetate. With reference to FIGS. 8 and 9, there is illustrated, in schematic format, the results of various steps for manufacturing the water heater 10. The insulation collar 124 (or one of the alternative constructions) is circumferentially fitted around the perimeter of the inner water tank 12 proximate the bottom end thereof. The collar 124 can be secured to the wall of the water tank 12 by an adhesive, or tape. The insulating disc 32 (or the alternative construction) is disposed in overlaying relationship to the bottom end of the water tank 12, and can be secured in place by an adhesive or a tape. The outer shell 14 is coaxially moved over the inner water tank 12, the floor 22 is positioned over the bottom of the water tank 12 and the outer shell 14 assembly to close the bottom of the water heater device 10. An expandable foam insulation material 30 is injected into the annular space 16 between the inner water tank 12 and outer shell 14 above the collar 124 and allowed to expand in situ filling the annular space 16 above the collar 124. The collar 124 is radially compressed between the inner wall surface of the outer shell 14 and outer wall surface of the inner water tank 12 to form a seal at the interface of the collar 124 and outer shell 14 and a seal at the interface of the collar 124 and inner water tank 12, and functions as a stop or block to the expanding foam. The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention and scope of the appended claims.