Abstract: An electric water heater has a tank portion in which water to be heated is stored. The stored water is heated by a vertically spaced plurality of electric heating elements extending into the tank interior. The heating elements are of unequal wattages, and serve unequal volume water zones, but provide equal heating wattage densities in each of the water zones.

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.

Abstract: Access to the interior of a vessel during fabrication and assembly of the vessel is provided by a channel structure formed around the circumference of the vessel. The channel structure comprises an outer surface that is radially inwardly offset from the exterior surface of the vessel around the circumference of the vessel. The outer surface of the channel structure is bounded by upper and lower circumferential transition areas which join the outer surface of the channel structure to the surface of the vessel. The channel structure is arranged such that when an upper portion of the vessel is separated from a base portion of the vessel by removing the material comprising the upper transition area, the upper portion of the vessel will receive within its inner diameter the outer surface of the channel structure.

Abstract: A method of manufacturing a double walled vessel is herein disclosed. The method involves the steps of forming an outer vessel having at least one reassembly channel formed therearound and forming an inner vessel having at least one element fitting formed integral thereto. At least one control housing is secured to the outer surface of the inner shell in registration with the element fitting. Heating elements and other control apparatus are installed in the element fittings within the control boxes. The outer vessel is sectioned at the reassembly channel, thereby allowing the inner vessel to be inserted into the outer vessel. The outer vessel is reassembled to enclose the inner vessel therein and a curable foam material is injected into the space between the inner and outer vessels to maintain a constant spatial relationship therebetween and to ensure the structural integrity of the outer vessel.

Abstract: A port assembly for a non-metallic pressure vessel is joined to a boss which is molded into or otherwise joined to the vessel wall. A bayonet type accessory mount is insertable therein for sealing passage through the vessel wall. The mount includes a simple semicircular locking snap ring with easily manipulable handles. The locking snap ring is configured for retaining and locking an accessory such as a heating element in any desired rotational position within the port. An o-ring is sealingly compressed in a radial direction between the mount and the port assembly. A specific application includes the positioning of a non-linear electrical heating element within a non-metallic water heater.

Abstract: A thin-walled pressure vessel having an improved insert. The insert increases the thickness of a portion of a pressure vessel's sidewall to allow the sidewall to accommodate a port. The insert comprises a main body structural member defining an opening through its center. The opening through the body member communicates with openings in an inner liner and an outer shell which comprise the vessel to provide an opening through the sidewall of the vessel. A fitting disposed in pressure contact with the main body member circumjacent the opening lines the walls of the opening in the body member and engages a portion of the main body member with an annual flange to restrain expansions of the body member at increasing temperatures while defining a port which maintains a constant shape and size for receiving other fittings.

Abstract: A method is provided for constructing a thinwall pressure vessel having a thermoplastic inner liner, a filament wound outer shell and at least one localized area of increased thickness in its sidewall. The method includes providing an insert formed from thermoplastic material or other suitable material which is bondable with the material of the inner liner. The manufacturer uses this insert to form a localized area of increased thickness in the sidewall of the pressure vessel. First, the manufacturer blow molds or otherwise forms a thermoplastic inner liner and bonds the insert to the inner liner. The manufacturer then provides a means for locating or finding the port of the insert and constructs the outer shell with glass filaments impregnated with a resinous material or other suitable material. Then, after locating the insert, the maker forms an opening which extends through the entire sidewall of the pressure vessel.

Abstract: A temperature sensing device for a thin-walled pressure vessel is provided. This device comprises an insert segment which lies inside the pressure vessel in heat exchange relation with the fluids contained by the vessel, an outer segment disposed outside of the pressure vessel, a linking segment normally disposed in a port through the side wall of the pressure vessel for connecting the outer segment with the insert segment, and a temperature sensing device connected to the outer segment. The device also includes an o-ring disposed around the linking portion and forming a seal between the linking portion and the sidewalls of the port.

Abstract: A method and apparatus for selecting the quantity of salt to be used during each regeneration of a water softener system. The quantity of salt used during each regeneration is approximately equal to the quantity of salt needed to regenerate the resin bed to a preselected design capacity, which is less than the maximum capacity of the resin bed. The design exchange capacity is approximately equal to the exchange capacity of the resin bed at a particular salt dosage, wherein the exchange capacity of the bed at the particular salt dosage divided by the particular salt dosage is generally equal to or greater than 2850. The system is regenerated when at the end of any preselected time period, the percentage of the design capacity of the resin bed used since the last regeneration cycle exceeds a predetermined percentage.In determining the salt dosage used during each regeneration cycle, the exchange capacity of the resin bed is determined for various salt dosages.