Patent ID: 12222136

DETAILED DESCRIPTION

Schematically illustrated inFIG.1is a dual element electric water heater10embodying principles of the present invention. Water heater10includes a vertically oriented cylindrical metal water storage tank12which has, at its top end, suitable water inlet and outlet piping connections14and16. Vertically spaced apart elongated upper and lower electric resistance type water heating elements18and20longitudinally extend horizontally into the interior of the tank12from a vertical sidewall portion thereof. The tank12is surrounded by an insulation jacket structure22including an outer metal skin portion24and a foamed-in insulation material26interposed between the metal skin portion24and the tank12.

Extending along a vertical side portion12aof the tank through which the upper and lower heating elements18and20inwardly extend is an insulating structure28, such as a bag or another type of construction, which is designed to incorporate the insulating material26and provides a vertically spaced pair of peripherally sealed access openings30and32extending therethrough and respectively positioned somewhat above the outer ends of the upper and lower heating elements18and20. Openings30,32are respectively aligned with sidewall access openings formed in the jacket metal skin portion24and covered by removable access plates34and36. Upper and lower electric thermostats38and40are respectively received in the access openings30and32and may be accessed by removing the plates34and36.

The upper and lower thermostats38and40are respectively and controllingly coupled to the upper and lower heating elements18and20and are electrically interconnected to one another by a subsequently described wiring harness42which is disposed between the insulation28and a vertical sidewall portion of the tank12. During shipment of the water heater10, upper end portions of various individual conductors which make up the harness42are placed in a top end well area44in the water heater10for subsequent operative connection to a terminal block portion46of a junction box48. The term “conductor” as used in this patent application refers to electrical conductors and can include, as non-limiting examples, a wire, a lead, a cable, or a busbar. Representatively, the junction box48is shipped loose with the water heater and is subsequently attached to a top end portion thereof as schematically depicted inFIG.1. In other embodiments, the well area44and the junction box48may also be attached or placed in an enclosure at the front of the water heater.

Turning now toFIG.2, in the illustrated preferred embodiment of the dual element electric water heater10, the upper thermostat38is of a single pole double throw configuration and has an ECO (energy cut-off) high limit control portion38aoperatively associated with a switch portion38b, and the lower thermostat40is of a single pole single throw configuration and has an ECO high limit control portion40aoperatively associated with a switch portion40b.

The upper thermostat ECO portion38ahas power supply terminals50,52,54, and56, and the upper thermostat switch portion38bhas a switch power terminal58and switch contacts60and62. The lower thermostat ECO portion40ahas power supply terminals64,66,68, and70, and the lower thermostat switch portion40bhas a switch power terminal72and a switch contact74.

Wiring harness42includes a conductor76interconnected between the power supply terminal54and the switch power terminal58; a conductor78interconnected between the switch contact60and the upper heating element18; a conductor80interconnected between the power supply terminal56and the upper heating element18; a conductor82interconnected between the power supply terminal68and the switch power terminal72; a conductor84interconnected between the switch contact74and the lower heating element20; and a conductor86interconnected between the power supply terminal70and the lower heating element20.

The wiring harness42also includes five water heater power connection conductors WHi, WH2, WH3, WH4, and WH5which are connected to the terminal block portion46of the junction box48. As subsequently described, selectively variable connections or using jumpers or other connectors in the terminal block46provide the upper and lower heating elements with a variety of control modes without the necessity of removing and replacing either of the thermostats38and40, altering any of the wiring that interconnects the thermostats38and40, or altering the wiring that interconnects the five water heater power connection conductors WHi, WH2, WH3, WH4, and WH5to the terminal block46. The power connection conductors WHi, WH2, WH3, WH4, and WH5extend upwardly from the thermostats38and40behind the insulation structure28(seeFIG.1), with upper end portions of the conductors WHi, WH2, WH3, WH4, and WH5being received in the well area44prior to connection of such upper conductor end portions to the terminal block46as subsequently described herein.

As schematically depicted inFIG.2, the lower end of conductor WHiis connected to the lower thermostat power supply terminal64; the lower end of conductor WH2is connected to the upper thermostat power supply terminal50; the lower end of conductor WH3is connected to the upper thermostat power supply terminal52; the lower end of conductor WH4is connected to the upper thermostat switch contact62; and the lower end of conductor WH5is connected to the lower thermostat power supply terminal66.

Turning now toFIG.3, the terminal block portion46of the junction box48has a line side46awith terminals LA, LB, Lc, LD, and LE, and a water heater side46bwith terminals HA, HB, Hc, HD, and HEelectrically coupled to the line side terminals LA, LB, Lc, LD, and LEas indicated by the dashed lines. With the junction box48either operatively mounted on the top end of the water heater10as schematically shown inFIG.1or attached or placed in an enclosure at the front of the water heater, the control mode of the water heater's upper and lower heating elements18and20may be selectively varied simply by adding or reconfiguring various wiring connections in the terminal block46as will now be described.

In a preferred embodiment, on the water heater side46bof the terminal block46wiring harness conductor WHiis connected to terminal HB, wiring harness conductor WH2is connected to terminal Elc, wiring harness conductor WH3is connected to terminal HD, wiring harness conductor WH4is connected to terminal HA, and wiring harness conductor WH5is connected to terminal HE. Representatively, there are seven different dual heating element operational control modes available for the water heater10simply by adding wiring connections to the terminal block46, and without changing the wiring interconnection between the thermostats38and40, replacing either thermostat with another type of thermostat, or changing the wiring interconnection from the thermostats38and40to the terminal block46. The seven heating element operational control modes, and the terminal block wiring configurations that yield them, are as follows:

Dual Independent Branch Circuit Installation Mode

As schematically depicted inFIG.4, to provide the water heater10with a dual independent branch circuit installation for its upper and lower electric resistance type upper and lower heating elements18and20, first power supply conductors88and90are respectively connected to the terminal block line side terminals Lc and LD, and second power supply conductors92and94are respectively connected to the terminal block line side terminals LBand LE.

Single Phase Simultaneous Dual Element Control Mode

As schematically depicted inFIG.5, to provide the water heater10with a single phase, simultaneous operation of its upper and lower electric resistance type upper and lower heating elements18and20, single phase power supply conductors96and98are respectively connected to the terminal block line side terminals Lc and LD. On the water heater side46bof the terminal block46, terminals HBand Heare connected such as with additional wiring or a jumper, and terminals HDand HEare connected such as with additional wiring or a jumper.

Single Phase Non-Simultaneous Dual Element Control Mode

As schematically depicted inFIG.6, to provide the water heater10with a single phase, non-simultaneous operation of its upper and lower electric resistance type upper and lower heating elements18and20, single phase power supply conductors100and102are respectively connected to the terminal block line side terminals Lc and LD. On the water heater side46bof the terminal block46, terminals HAand HBare connected such as with additional wiring or a jumper, and terminals HDand HEare connected such as with additional wiring or a jumper.

Single Phase Non-Simultaneous Dual Element Control Mode with 4 Wire Outlet Operation

As schematically depicted inFIG.7, to provide this dual element operational control mode, single phase power supply conductors104and106are respectively connected to the terminal block line side terminals Lc and LD. On the water heater side46bof the terminal block46, terminals HDand HEare connected such as with additional wiring or a jumper. Additionally, if off peak metering is desired, an off peak meter or timer is connected to terminals LAand LBon the line side46aof the terminal block.

Single Phase Non-Simultaneous Dual Element Control Mode with 3 Wire Outlet Operation

As schematically depicted inFIG.8, to provide this dual element operational control mode, single phase power supply conductors110and112are respectively connected to the terminal block line side terminals Lc and LD. On the water heater side46bof the terminal block46, terminals HAand HBare connected such as with additional wiring or a jumper. If off peak metering is desired, an off peak meter or timer is connected to terminal LE.

Three Phase Simultaneous Dual Element Control Mode

As schematically depicted inFIG.9, to provide this dual element operational control mode, three phase power supply conductors116,118, and120are respectively connected to the terminal block line side terminals Lc, LD, and LE. On the water heater side46bof the terminal block46, terminals HBand Heare connected such as with additional wiring or a jumper.

Three Phase Non-Simultaneous Dual Element Control Mode

As schematically depicted inFIG.10, to provide this dual element operational control mode, three phase power supply conductors122,124, and126are respectively connected to the terminal block line side terminals Lc, LD, and LE. On the water heater side46bof the terminal block46, terminals HAand HBare connected such as with additional wiring or a jumper.

As can readily be seen from the foregoing, the water heater10may uniquely be field-converted selectively among its seven representative dual heating element operational control modes simply by appropriately altering the electrical connections in the terminal block46. In contrast to conventionally constructed dual element electric water heaters, there is simply no need to either (1) replace either of the upper and lower thermostats38and40with another type of thermostat, or (2) change the wiring connections to the two thermostats or from the thermostats to the terminal block. This advantageously makes the representatively listed seven dual heating element operational control modes available with the single illustrated variant of the dual element electric water heater10. In addition, as can readily be seen from the foregoing preferred embodiments, the connections of terminals in the terminal block46are to adjacent terminals and can be made using connections such as additional wiring or a jumper of a uniform size. While the present invention has been illustratively incorporated in an electric water heater, it will be readily appreciated that principles of the invention could also be incorporated in dual element liquid heating devices of other types if desired. It will additionally be appreciated that while the terminals HA, HB, Hc, HD, and HEare representatively connectable in selectively variable manners using jumpers or other similar connectors to a terminal block portion of a junction box, the outer ends of the wiring harness conductors WHi, WH2, WH3, WH4, and WH5could alternatively be variably connected to an external electrical power source in a variety of other manners, including, for example, the use of connections between LA, LB, Lc, LD, and LE, if desired.

The foregoing detailed description is to be clearly understood as being given by way of illustration and example, the spirit and scope of the present invention being limited solely by the appended claims.