Patent Application
20080066308
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The water heater 10 includes two heating elements 28. In some embodiments, the water heater 10 can include one, three, or more heating elements 28. In the illustrated embodiment, the heating elements 28 are U-shaped tubes that conduct electricity to heat water in the tank 14. The heating elements 28 include a threaded portion at one end that permit the heating elements 28 to thread into spuds (not shown) which are connected to the wall of the tank 14. In the illustrated embodiment, a thermostat 34 is positioned on the wall of the tank 14 over each spud and communicates with the heating elements 28. In some embodiments, a single thermostat 34 can be used to communicate with both heating elements. The thermostats 34 monitor the temperature of the water in the tank 14, and turn the corresponding heating elements 28 on and off to maintain a desired water temperature in the tank 14. In the illustrated embodiment, the thermostats 34 permit an operator to adjust the desired water temperature. The thermostats 34 are accessible to an operator through apertures 36 defined by the jacket 26. In the illustrated embodiment, the apertures 36 are oval-shaped. In some embodiments, the apertures 36 can be round, square, rectangular, or any other desired shape.
In the illustrated embodiment, the insulation material 24 is injected between the tank 14 and the jacket 26, and expands to fill the volume between the tank 14 and the jacket 26. A dam assembly 12 is inserted into each of the apertures 36 prior to injecting the insulation material 24 to help prevent the foam from potentially damaging the thermostats 34 and escaping through the apertures 36.
As best shown in
In the illustrated embodiment the outer portion 38, the inner portion 40, and the web 48 are constructed from expanded polystyrene foam, and are molded together as a single piece in a single operation. Unassembled dam assemblies 12 constructed in this manner can nest together, and are stackable for convenient storage. In some embodiments, either or both of the outer portion 38 and the inner portion 40 can be constructed from other materials such as, for example, polyethylene, polypropylene, or polyurethane, and are not necessarily molded as a single piece. In the illustrated embodiment, the seal 45 is constructed from open-cell polyurethane. In some embodiments, the seal 45 can be formed from other materials such as, for example, a hot melt adhesive that is flexible enough to form a seal around wires. In the illustrated embodiment, the seal 45 is applied to the bottom of the outer portion 38 with adhesive after the outer portion 38 and inner portion 40 are molded. As shown in
To install the dam assembly 12, an operator inserts the outer portion 38 in the aperture 36 and applies force to the inner portion 40. The force is transferred to the outer portion 38 through the web 48. As best shown in
The web 48 can withstand sufficient force applied to the inner portion 40 to seat the dam assembly 12 in the aperture 36. Application of additional force causes the web 48 to rupture and the inner portion 40 to be pressed inside the wall 42 of the outer portion 38. The inner portion 40 forms an interference fit with the wall 42 of the outer portion 38, and forces the wall 42 into tighter interference with the jacket 26, thereby improving the seal between the wall 42 and the jacket 26. After the web 48 breaks, the outer portion 38 remains installed in the aperture 36 in the jacket 26. The inner portion 40 is removable from the outer portion 38, but the inner portion 40 should remain inside the wall 42 of the outer portion 38 during injection and expansion of the insulation material 24 to ensure the best seal between the outer portion 38 and the jacket 26. An operator can grasp the handle 50 near the recesses 52 to remove of the inner portion 40 from the outer portion 38 and provide access to the thermostat 34.
A lid 60 is installed over the dam assembly 12 to further increase the seal between the wall 42 and the jacket 26 and between the seal 45 and the tank 14 during injection of the insulation material 24. The lid 60 improves the seal by engaging the handle 50 of the inner portion 40 and pressing and holding the inner portion 40 within the outer portion 38. The lid 60 also helps prevent unwanted access to the dam assembly 12 without tools by substantially covering the dam assembly 12. As best shown in
One of the tabs 46 on the outer portion 38 extends to the locking aperture 66 when the dam assembly 12 is installed in the aperture 36. The lid 60 compresses the tab 46 when the locking tab 62 of the lid 60 engages the locking aperture 66 and the lid 60 is installed as described above. The compressed tab 46 forms a seal between the lid 60 and the jacket 26 adjacent the locking aperture 66 to help prevent injected insulation material 24 from leaking through the locking aperture 66. The outer portion 38 includes tabs 46 at opposite ends so that the dam assembly 12 cannot be inserted in an incorrect orientation in the aperture 36.
