Liquid heaters and vaporizers – Safety devices
Reexamination Certificate
2002-05-31
2003-09-30
Wilson, Gregory (Department: 3749)
Liquid heaters and vaporizers
Safety devices
C122S013010, C122S014200, C392S441000
Reexamination Certificate
active
06626133
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to sensing devices. More particularly, the present invention relates to self-powered sensing devices used for the detection of dangerous environments that can cause an explosion or a fire around appliances such as water heaters, stoves, gas fireplaces, etc.
BACKGROUND OF THE INVENTION
Currently there are studies warning consumers of the dangers of storing flammable materials in close proximity to water heaters. In particular, there is a concern with the presence of liquids that give off flammable vapors such as gasoline. Approximately 50 million homes have gas water heaters with an additional 3.5 million new heaters sold each year. Gas-fired water heaters igniting flammable vapors are associated with nearly 2,000 fires a year, resulting in an estimated 316 injuries, 17 deaths, and $26 million in property damage for a total societal cost, which may be as high as $395 million. Typically, injuries occur when the victim is using a flammable liquid (usually gasoline) for cleaning purposes or when the liquid leaks or is accidentally spilled near a water heater. Water heaters are often installed in locations where people might normally place other things for storage including flammable liquids (e.g. garages, basements, utility areas).
Water heater manufacturers have tried to educate consumers on measures that can be taken to reduce risk of fires related to water heaters and flammable vapors including:
Making sure gas fired water heaters are installed according to code requirements.
Elevating heaters (gas vapors are heavier than air) where possible.
Avoiding the use gasoline to clean equipment or tools.
Using gasoline only as a motor fuel.
Storing gasoline only in tightly sealed red containers intended for gasoline.
Keeping all flammable materials and liquids away from gas fired heaters.
There are two types of water heaters sold in the US. The vast majority of water heaters are naturally vented appliances that typically utilize a pilot light to light the heater and to provide a continuous natural draft for the exhaust flue of the heater. These types of water heaters typically do not require external power. About 10% of gas heaters sold are power vented where a fan is activated to induce a draft in a flue to exhaust combustion fumes. Both types of units draw combustion air from the area below the water heater. The risk occurs when the open flame or igniter of the water heater is exposed to flammable vapors from liquids stored nearby.
One possible solution is to utilize a sensor that could sense the presence of combustible vapors and which would turn off the pilot light or prevent a fan powered water heater. A specification for such a device should have the following characteristics:
Ability to sense hydrocarbon fumes like gasoline vapors very quickly and efficiently.
Ability to send a control signal to interact with water heater operation.
Long lifetime.
Ability to operate in high and low humidity environments.
The sensor must not require calibration or if calibration is required the sensor must be able to send a signal to the control that it is non functional.
In addition, for the vast majority of non-vented water heaters, a source of power for a sensor may not be available.
Traditional approaches to hydrocarbon sensing including electrochemical cell, metal oxide sensors and catalytic bead are problematic for this application because of the detection speed, lifetime, calibration and humidity requirements.
Infrared sensing has some inherent advantages as a sensor, but the conventional technology does need innovation to be applied to this application which also demands low product cost.
Accordingly, a system which is easily calibrated and can operate in high and low humidity environments is desired.
In addition, a system that is self-powered and can detect multiple vapors is also desired.
SUMMARY OF THE INVENTION
It is therefore a feature and advantage of the present invention to provide a sensor that is easily calibrated and operates in high and low humidity environments. In one embodiment of the invention the sensor does not require external calibration. In another embodiment the sensor requires calibration and sends a signal indicating that the sensor is non-functional.
It is another feature and advantage of the present invention to provide a sensor that is self powered and that can detect multiple vapors.
It is also another feature and advantage of the present invention to provide a sensor that has the ability to sense hydrocarbon fumes like gasoline vapors very quickly and efficiently.
It is also another feature and advantage of the present invention to provide a sensor that has the ability to send a signal to interact with water heater operation.
It is also another feature and advantage of the present invention to provide a sensor that has a long lifetime and that is self-powering.
The above and other features and advantages are achieved through the use of a novel device for sensing a dangerous environment as herein disclosed. In accordance with one embodiment of the present invention, a device for sensing a dangerous condition includes a sensor that provides a signal when a dangerous condition is sensed by the sensor. A power source in communication with the sensor is provided. The power source supplies the sensor with power. A trigger is provided which is in communication with the sensor. The trigger is activated by the signal to prevent the dangerous condition from producing a harmful effect.
In accordance with another embodiment of the present invention, a system for sensing a dangerous condition includes a sensing means for detecting a dangerous condition and providing a signal indicating that the dangerous condition has been detected. A power source means is provided for supplying the sensing means with power. The power source means is in communication with the sensor. A trigger means is provided for preventing the dangerous condition from producing a harmful effect when activated. The trigger means is in communication with the sensor means and is activated by the signal.
In accordance with another embodiment of the present invention, a method of preventing a harmful effect of a dangerous condition includes the steps of providing a sensor with power from a power source and using the sensor to determine if there is a dangerous condition when the sensor detects a dangerous condition, the dangerous condition is prevented from producing a harmful effect.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
REFERENCES:
patent: 2815035 (1957-12-01), Eskin et al.
patent: 3581062 (1971-05-01), Aston
patent: 5749327 (1998-05-01), K
Kouznetsov Andrian I.
Schell Michael B.
Valenta Rod J.
Baker & Hostetler L.L.P.
Edwards Systems Technology, Inc
Wilson Gregory
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