Abstract: A method of producing a foam insulated vessel, such as a water heater. The water heater includes a tank to contain water to be heated and a jacket is spaced outwardly of the tank to provide a cavity therebetween. A band of self-supporting, gas entrained, foamable resin is applied to either the outer surface of the lower end portion of the tank, or to the inner surface of the jacket. The band of foamable resin expands radially to form a closure or dam that divides the cavity into a pair of isolated spaces. A liquid foamable resin composition is then introduced into one of the spaces and expands to fill the space and provide an insulating layer between the tank and the jacket.

Abstract: A common source of DC potential is utilized to simultaneously provide power to the protective anode in an electrically heated hot water heater and to the circuit used to bias the heating element jacket to reduce the current load the jacket would otherwise impose on the protective anode. By utilizing a common DC power source, the desired voltage relationship between the protective anode, the positively biased heating element jacket and negatively biased tank wall may be maintained, regardless of changes in the supply. The need for a second separate power supply is obviated and overall construction of the system substantially simplified. The DC power source may comprise a battery or rectified AC current from the power to the heating element.

Abstract: A foam insulated vessel, such as a water heater. The water heater includes a tank to contain water to be heated and a jacket is spaced outwardly of the tank to provide an annular cavity therebetween. An annular flexible strip is secured to the surface of one of said members, and is in sealing relation with the other of said members, thus forming a closure or dam at the lower end of the cavity. In a preferred form, the strip includes a flange secured to the tank and a body portion extends outwardly from the flange and terminates in a downwardly extending lip, which is located at an acute angle with respect to the body portion. The lip is in sealing engagement with the jacket. When a liquid foamable resin is introduced into the upper end of the cavity, the pressure acts to force the body portion of the seal downwardly, increasing the sealing effect against the jacket to retain the liquid resin within the cavity.

Abstract: A water heater includes a lower skirt ring (10, 50) supporting and spacing an inner storage tank (2) above a support surface (10a), and an outer jacket (42, 54) spaced outwardly therefrom to define an annular cavity space (22) therebetween. The outer jacket is slid along the inner storage tank during assembly. A seal (46) on the inner surface of the outer jacket, preferably in the form of a rolled-in dimple, engages the inner storage tank and/or the lower skirt ring, either at a seal (44) or a flange (52), and forms a dam (48) during sliding of the outer jacket along the inner storage tank. The dam prevents leakage of liquid therepast during foaming insulation. The rolled-in dimple (56) may extend all the way through the annular space to engage the tank wall or skirt ring.

Abstract: A cathodically protected water heater which eliminates the need of a conventional anode rod. The water heater tank includes a cylindrical shell enclosed by upper and lower heads and a flue which is mounted within openings in the lower and upper heads. The outer surface of the flue as well as the upper surface of the lower head is coated with a metal anodic to steel, and the metal coating on the flue extends continuously from the lower head to a location above the upper head. The remainder of the inner surface of the heater is also coated with the anodic metal. The anodic metal is applied in a sufficient thickness at least at the junction of the lower end of the peripheral flange of the upper head and the shell to bridge and seal the crevice opening which typically exists between the free end of the upper head flange and the shell wall.

Abstract: A cathodically protected water heater which eliminates the need of a conventional anode rod. The water heater tank includes a cylindrical shell enclosed by upper and lower heads and a flue which is mounted within openings in the lower and upper heads. The outer surface of the flue as well as the upper surface of the lower head is coated with a metal anodic to steel, and the metal coating on the flue extends continuously from the lower head to a location above the upper head. The remainder of the inner surface of the heater is also coated with the anodic metal. The anodic metal is applied in a sufficient thickness at least at the junction of the lower end of the peripheral flange of the upper head and the shell to bridge and seal the crevice opening which typically exists between the free end of the upper head flange and the shell wall.

Abstract: A method and apparatus for providing foam resin insulation for a vessel, such as a water heater. The water heater includes a tank to contain water to be heated and has a plurality of openings to receive components of the water heater. A jacket is spaced outwardly of the tank to provide a space therebetween to receive foam resin insulation. Prior to introducing the resin into the space, an elongated member, such as a rod, is engaged with the opening in the tank and the rod extends outwardly through an aligned opening in the jacket. A resilient pad, which is movable on the rod, is compressed against the outer surface of the jacket to seal the space between the jacket opening and the rod. A liquid foamable resin is introduced in the space between the tank and the jacket and expands to fill the space and provide an insulating layer.

Abstract: A cathodically protected water heater which eliminates the need of a conventional anode rod. The water heater tank includes a cylindrical shell enclosed by upper and lower heads, and a gas burner is located beneath the lower head. The waste products of combustion are discharged upwardly through the tank via a flue which is mounted within openings in the lower and upper heads. The outer surface of the flue as well as the upper surface of the lower head is coated with a metal anodic to steel, and the metal coating on the flue extends continuously from the lower head to a location about the upper head. The inner surface of the shell and the upper head are coated with a corrosion resistant coating, such as glass or metal anodic to steel as well, and the upper edge of the flange in the upper head bordering the opening is welded directly through the metal coating to the flue while the outer periphery of the lower head is welded to the lower edge of the shell.

Abstract: A clamping apparatus for use in applying foam resin insulation between the tank and the outer jacket of a water heater. The jacket of the water heater is spaced outwardly of the tank to provide a space that receives a foamable resin, such as polyurethane. The upper end of the jacket is enclosed by a thin, sheet metal cover. To clamp the cover to the jacket and prevent deformation of the cover due to the pressure of the resin foam, a clamping mechanism is utilized which includes a plate or clamping member that is positioned flatwise against the cover, and a clamp assembly secures the clamping plate to the upper end of a flue, or other tubular opening in the tank. In a preferred form, the clamping mechanism consists of a resilient, expandable plug which is inserted within the opening in the tank and is expanded outwardly into tight engagement with the wall bordering the opening to secure the clamping plate to the tank.