Electric heating – Heating devices – With power supply and voltage or current regulation or...
Reexamination Certificate
2000-02-16
2001-08-07
Walberg, Teresa (Department: 3742)
Electric heating
Heating devices
With power supply and voltage or current regulation or...
C219S486000, C219S488000, C392S454000
Reexamination Certificate
active
06271505
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to electric heating apparatus and, in a preferred embodiment thereof, more particularly relates to a specially designed dual element electric water heater which is easily field convertible among various heating element control modes without the previous necessity of changing either of the heating element control thermostats or altering the wiring interconnections therebetween.
In a common construction thereof a vertically oriented dual element electric water heater has spaced apart upper and lower resistance type electric heating elements which horizontally extend into the interior of the water storage tank portion of the heater. The operation of these upper and lower heating elements is controlled by upper and lower electric thermostats which are respectively associated with the upper and lower heating elements.
Various modes of operating the upper and lower heating elements, with either single or three phase electric power supply to the water heater, are typically available. Representatively, these heating element operational modes include (1) single phase simultaneous element operation, in which the two heating elements are simultaneously cycled by their associated thermostats; (2) single phase simultaneous element operation with 4 wire outlet operation, (3) single phase non-simultaneous element operation, in which the two heating elements are independently cycled by their associated thermostats, (4) single phase non-simultaneous element operation with 4 wire outlet operation; (5) single phase non-simultaneous element operation with 3 wire outlet operation; (6) three phase simultaneous element operation; and (7) three phase non-simultaneous element operation. The two heating element-controlling thermostats are typically disposed in openings formed in the jacket insulation structure of the water heater that surrounds its storage tank portion. The electrical wiring that operatively interconnects the thermostats is, for the most part, disposed between the tank and the insulation structure.
In the past, in order to provide these seven representative element control modes seven separate embodiments or “variants” of the water heater needed to be built, with each water heater variant having different thermostat wiring configurations and/or combinations of thermostat types. The need to build separate variants to provide all of the representative types of heating element control listed above carries with it several problems, limitations and disadvantages.
For example, the construction of the water heater is made more complex since, in essence, it needs to be constructed in seven different ways—each having a different thermostat type combination and/or thermostat wiring interconnection configuration. Additionally, and quite importantly, once the water heater is constructed to provide a predetermined element: control mode, it is not practical or economical to alter this selected control mode. This is due to the fact that to alter the originally built-in element control mode, changes must be made to the thermostat wiring and/or the types of thermostats used must be altered. Because the thermostat interconnection wiring is disposed between the jacket insulation structure and the water heater storage tank portion such wiring is, as a practical matter, inaccessible for such conversion.
Accordingly, if a dual element water heater constructed in this conventional manner does not provide the desired heating element control mode, it has to be replaced with another manufactured variant of the water heater that has the desired heating element control mode incorporated therein during its original manufacture. In view of this it can be readily seen that a need exists for a dual element electric water heater which eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages typically associated with conventionally constructed dual element electric water heaters. It is to this need that the present invention is directed.
SUMMARY OF THE INVENTION
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, a liquid heating apparatus having first and second spaced apart liquid heating elements is provided. The apparatus is representatively in the form of an electric water heater having vertically spaced apart upper and lower electric resistance type heating elements that horizontally extend into the interior of a water storage tank portion of the water heater. First and second electric thermostats are respectively and controllingly associated with the upper and lower heating elements, and wiring, representatively in the form of a wiring harness, is operatively connected to the first and second thermostats and has lead end portions variably connectable to a source of electrical power. The water heater also preferably includes a junction box having a terminal block portion with line side terminals to which electrical power supply leads may be variably connected, and water heater side terminals to which the aforementioned wiring harness lead end portions may be variably connected.
Preferably, the first electric thermostat, which controls the upper heating element, is of a single pole double throw configuration, and the second electric thermostat, which controls the lower heating element, is of a single pole single throw configuration. The wiring harness is connected to the first and second thermostats in a manner such that, without replacing either of the first and second thermostats and/or altering the wiring connections to either thermostat, a plurality of heating element control modes may be provided simply by changing the wiring connections to the terminal block.
Representatively, these element control modes include (1) a single phase simultaneous dual element control mode, (2) a single phase simultaneous dual element control mode with four wire outlet operation, (3) a single phase non-simultaneous dual element control mode, (4) a single phase non-simultaneous dual element control mode with four wire outlet operation, (5) a single phase non-simultaneous dual element control mode with three wire outlet operation, (6) a three phase simultaneous dual element control mode, and (7) a three phase non-simultaneous dual element control mode.
In an illustrated preferred embodiment of the electric water heater, the first electric thermostat has an ECO portion with first, second, third and fourth power supply terminals, and a switch portion with a switch power terminal and first and second switch contacts. The second electric thermostat has an ECO portion with first, second, third and fourth power supply terminals, a switch power terminal and a switch contact.
Additionally, the wiring harness includes (1) a first wire interconnected between the first power supply terminal of said first thermostat ECO portion and the switch power terminal of the first thermostat switch portion, (2) a second wire interconnected between the first switch contact of the first thermostat switch portion and the upper heating element, (3) a third wire interconnected between the fourth power supply terminal of the first thermostat ECO portion and the upper heating element, (4) a fourth wire interconnected between the first power supply terminal of the second thermostat ECO portion and the switch power terminal of the second thermostat, (5) a fifth wire interconnected between the switch contact of the second thermostat switch portion and the lower heating element, (6) a sixth wire interconnected between the fourth power supply terminal of the second thermostat ECO portion and said lower heating element, and (7) a series Of electrical leads each having a first end portion operatively connected to one of the first and second thermostats, and a second end variably connectable to the water heater side of the terminal block.
The series of wiring harness leads variably connectable to the water heater side of the terminal block preferably include (1) a first lead connected at one end to the
Campbell Thor
Konneker & Smith P.C.
Rheem Manufacturing Company
Walberg Teresa
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