Electric water heater with electronic control

Details Electric water heater with electronic control Electric water heater with electronic control

1998-06-04

2001-10-23

Walberg, Teresa (Department: 3742)

Electric resistance heating devices

Heating devices

Tank or container type liquid heater

C392S463000

Reexamination Certificate

active

06308009

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to an electric water heater, particularly to an electric water heater having an electronic control system that greatly improves manufacturing costs, reduces warranty expense and operating efficiencies.
BACKGROUND OF THE INVENTION
Typical electric water heaters are constructed with one or two electric-powered heating elements to heat water in the water tank, depending on the size and utilization of the water heater. Each element utilizes an electromechanical thermostat mounted onto the side of the tank at the point where the screw cap of the element connects to the side of the water tank. There are a number of disadvantages associated with such constructions.
Current electromechanical thermostats use bimetal technology for actuation of a set of contacts that either energize or deenergize the heating element. Such bimetal technology is comparatively imprecise and the response time to temperature changes in the water tank are relatively slow, thereby reducing water heater efficiency.
Another significant problem with present construction is the difficulty of protecting against “dry fired” elements. “Dry fire” occurs when power is applied to a heating element without water surrounding the element. Such dry firing rapidly causes damage to the heating element, thereby sharply reducing its useful life span. In most instances, dry firing can cause immediate failure of the element.
Current electromechanical thermostats also utilize a comparatively large and bulky thermostat bracket and occupy a comparatively large amount of surface area on the side of the water tank. This reduces energy efficiency since polyurethane foam insulation that surrounds the remainder of the tank is not used in this space. This occurs because the chemicals that form the polyurethane foam can interfere with the electromechanical thermostat controls during assembly and field service. Current methods for preventing such interference include foaming aprons, fiberglass batts or EPS foam dams, all of which have lower thermal efficiency (K-factors) than the polyurethane foam surrounding the remainder of the tank.
All of the above constructions result in a large number of manufacturing parts and steps, all of which add to the final cost of the product.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a water heater that increases energy efficiency.
It is another object of the invention to provide a water heater that eliminates comparatively large electromechanical thermostats and reduces the number of component parts required to produce a water heater.
It is yet another object of the invention to provide a water heater that protects against dry firing of heating elements.
Other objects and advantages of the invention will become apparent to those skilled in the art from the drawings, the detailed description of the invention and the appended claims.
SUMMARY OF THE INVENTION
In one aspect, the water heater of the invention includes a water container; an element located to heat water in the water container; a sensor located to sense temperature proximate the element; and a controller connected to the element and the sensor, the controller being capable of disengaging the element in the event that a sensed temperature over a predetermined time interval is greater than a predetermined temperature difference, wherein there is substantially no degradation of the element within the predetermined time interval.
In another aspect of the invention, there is a water heater that includes a water container; an element located to heat water in the water container; a sensor located to sense temperature of water in the water container; and a controller connected to the element and the sensor, the controller being capable of comparing temperature information received from the sensor with a predetermined temperature and energizing the element based on the comparison.


REFERENCES:
patent: 3781839 (1973-12-01), Clifford
patent: 3909588 (1975-09-01), Walker et al.
patent: 3952182 (1976-04-01), Flanders
patent: 4535931 (1985-08-01), Bartok et al.
patent: 4638147 (1987-01-01), Dytch et al.
patent: 5103078 (1992-04-01), Boykin et al.
patent: 5168546 (1992-12-01), Laperriere et al.
patent: 5377299 (1994-12-01), Anson et al.
patent: 5442157 (1995-08-01), Jackson et al.
patent: 5504306 (1996-04-01), Russell et al.
patent: 5586214 (1996-12-01), Eckman
patent: 5692096 (1997-11-01), Massey et al.
patent: 5706390 (1998-01-01), O'Neil
patent: 5797358 (1998-08-01), Brandt et al.
patent: 5808277 (1998-09-01), Dosani et al.

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