Water heater with flammable vapor and co sensors

Abstract

A water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber, a flue gas collector located to receive flue gases generated in the combustion chamber, a CO sensor having at least an operative portion proximate the flue gas collector, a flammable vapor sensor having at least an operative portion positioned proximate a location where combustion air enters the combustion chamber, and a controller operatively connected to the CO and flammable vapor sensors and adapted to receive signals generated by the CO and flammable vapor sensors and responsively shut off combustion in the combustion chamber.

Description

RELATED APPLICATION

This patent application claims the benefit of U.S. Provisional Application No. 60/784,144, filed Mar. 20, 2006. This earlier provisional application is hereby incorporated by reference.

TECHNICAL FIELD

The technology in this disclosure relates to water heaters, particularly to water heaters that have a flammable vapor sensor and a CO sensor.

BACKGROUND

A number of water heaters have been developed that are flammable vapor ignition resistant (FVIR). Such water heaters are sold and available on the market today. However, under certain circumstances with certain types of FVIR water heaters, lint, dirt or other particles may collect over the course of time, thereby reducing the amount of combustion air available to the water heater. This has the potential of causing a number of disadvantages, including possible production of more than optimal amounts of CO. This is a result of incomplete combustion that is brought about by the insufficiency of combustion air. Insufficient combustion air may also occur in view of insufficient openings into the enclosed space in which the water heater is located, incorrect venting, other air-consuming appliances located within close proximity, vacuum conditions in the area near the water heater due to the tightness of the structure in which the water heater is located and the like.

Some attempted solutions to those problems include utilizing temperature sensors or switches in and around the combustion chamber to indirectly determine incomplete combustion.

SUMMARY

I provide a water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber, a flue gas collector located to receive flue gases generated in the combustion chamber, a CO sensor having at least an operative portion proximate the flue gas collector, a flammable vapor sensor having at least an operative portion positioned proximate a location where combustion air enters the combustion chamber, and a controller operatively connected to the CO and flammable vapor sensors and adapted to receive signals generated by the CO and flammable vapor sensors and responsively shut off combustion in the combustion chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a water heater, partially taken in section.

FIG. 2 is a schematic of a gas control valve and selected connected water heater components associated with the water heater of FIG. 1.

FIG. 3 is a partial sectional view of another water heater, partially taken in section.

FIG. 4 is a schematic of a gas control valve and selected connected water heater components associated with the water heater of FIG. 3.

DETAILED DESCRIPTION

It will be appreciated that the following description is intended to refer to specific aspects of the structure selected for illustration in the drawings and is not intended to define or limit this disclosure, other than in the appended claims.

Water heaters described herein can assist in reducing the likelihood that flammable vapors outside a water heater will be ignited by the water heater itself. This may be achieved with a CO sensor having an operative portion proximate to the water heater draft hood and a flammable vapor sensor having at least its operative portion positioned proximate the location where combustion air enters the combustion chamber. Both the CO sensor and flammable vapor sensor are connected to a controller which receives information generated by the CO and flammable vapor sensors and responsively shuts off combustion in the combustion chamber, depending on the received information.

Turning now to the drawings generally and FIGS. 1 and 2 in particular, a water heater 10 including a water tank/container 12 having a water inlet 14 and a water outlet 16 is shown. A flue 18 extends upwardly through the tank and outwardly from the top of water heater 10. Tank 12 is surrounded by insulation 20 and a jacket 21. Such insulation may be made from any number of foam type insulations well known in the art and/or fiberglass insulation such as around the lower portion of the water heater. Various substitutions may be made without varying from the fundamental spirit of the disclosure.

A combustion chamber 22 is located below tank 12 and formed by tank bottom 24, skirt 26 and bottom pan 28. Bottom pan 28 sits on legs 30. A burner 32 formed from a plenum 68 is positioned in combustion chamber 22. Burner 32 is also positioned to receive fuel from fuel line 34, which connects to gas control valve 36, which connects to a fuel supply line 38 connected to a fuel supply that is not shown.

Burner 32 is positioned within combustion chamber 22 and is a so-called “low NO_x” burner in this instance. It is, however, possible to utilize other types of burners that combust gas (either natural gas, propane or the like) or oil or other fuel. Many other types of burners are known and need not be discussed herein.

Fuel line 34 connects to and extends through door 44 such that the end of fuel line 34, which is nozzle 46, is proximate open end 58 of a venturi 50. Fuel exits nozzle 46 and flows directly into the exterior end. Although FIG. 1 shows a venturi 50, any number of fuel/air supply lines may be utilized such as tubes, pipes, pathways, conduits and other structures capable of channeling fuel and/or air to burner 32. Burner 32 may be held above pan 28 by support 53. Pilot fuel line 35 extends between gas valve 36 and pilot burner 86 (partially shown in FIG. 1).

A cover 45 also connects to door 44 and in this case serves several purposes. Cover 45 holds fuel line 34 in a desired position with respect to the open end 58 of venturi 50 so that fuel is directed in a desired location through open end 58 and within venturi 50. Cover 45 provides the desired nozzle to venturi alignment. Other structures may be used as alternatives. The top of cover 45 may be solid to prevent dust and other airborne particulate from entering burner 32. The sides and bottom may be perforated, enclosed in screen, or louvered to prevent rodents and large insets from entering and clogging venturi 50. Also, interchangeable nozzles 46 can be mounted in the front part of cover 45.

In operation, burner 32 operates under the fundamental condition that fuel is supplied to venturi 50 and combustion air is mixed at the end 58 of venturi 50 and the mixed fuel flows into plenum 68 and may further be mixed and distributed by some type of diffuser as desired. The air and fuel mixture is then combusted along the surface of a screen 33 located on top of plenum 68 in the usual manner.

FIGS. 1 and 2 show a pilot burner 86 connected to pilot fuel supply 35. Pilot burner 86 is mounted on a pilot mounting bracket (not shown) near screen 33 of burner 32. A power plug 31 connects to gas control valve 36 to supply power from, for example, a typical household electrical outlet. A transformer (not shown) can also be used to convert power supplied from outside to an appropriate power type/level for gas control valve 36 and/or other remotely located controllers.

Gas control valve 36 also connects to a flammable vapor sensor 80 by way of connection line 82. Flammable vapor sensor 80 is positioned in the vicinity of or proximate to the location where combustion air enters combustion chamber 22. Although this location is shown proximate cover 45 and door 44 of water heater 10 in FIG. 1, the location of entry of combustion air into combustion chamber 22 may be altered in accordance with selected design features and burners utilized. In the case that an additional passageway is provided to supply combustion air to combustion chamber 22, such as a conduit having an opening at an upper portion of the water heater, the flammable vapor sensor 80 may be located outside the opening (albeit near the upper portion of the water heater), just inside the opening, anywhere along the conduit or just outside of the combustion chamber and still be considered in the vicinity of or “proximate a location where combustion air enters the combustion chamber.”

Also, combustion chamber 22 may have more than one opening. For example, an opening covered by a flame trap/flame arrestor (not shown) such as an air inlet/flame trap of the type as disclosed in any of U.S. Pat. Nos. 5,797,355; 6,142,106; 6,085,699 and the like may be used. In such cases, more than one flammable vapor sensor may be used.

Thus, the position of sensor(s) 80 is not particularly limited so long as it is sufficiently close to the opening(s) in the combustion chamber 22 through which combustion air is drawn to be effective in accurately measuring/sensing flammable vapors. A number of flammable vapor sensors are known and may be used in accordance with water heaters disclosed herein. One particular example is manufactured by Therm-O-Disc of Mansfield, Ohio.

A CO detector 94 also connects to gas control valve 36 by way of a connection line 96. CO sensor 94 may be any type of known CO sensor. One example is a CO sensor manufactured by Applied Sensor, Inc. CO sensor 94 in FIG. 1 is located proximate the location where flue gases exit flue 18 and proceed into draft hood 88. In this particular instance, CO sensor 94 is located exteriorly of draft hood 88 with at least a portion extending interiorly of draft hood 88 to be in contact with flue gases exiting the flue 18. Other locations may be employed so long as CO sensor 84 is located to effectively detect/sense a selected amount of CO exiting from flue 18.

Sensors 80 and 94 have been shown as connected to gas control valve 36 by way of connection lines 82 and 96, respectively, which are typically wire connections. However, this is merely one example of a means for operatively connecting those sensors to gas control valve 36. Other means may be used such as optical fiber or wireless transmission, for example. Gas control valve 36 may also connect to thermister 90 by way of connection line 92. Thermister 90 senses the temperature within water tank 12 and transmits temperature information to gas control valve 36.

Referring to FIGS. 3 and 4, an alternate water heater 10 is shown. Water heater 10 in FIG. 3 contains a different type of burner 32 than the burner of FIG. 1. It, too, is a conventional well known burner and its fundamental operation need not be discussed further herein. Water heater 10 of FIG. 3 also includes a pilot burner 86 that connects to gas control valve 36 by way of pilot fuel supply line 35. Thermopile 84 connects to gas control valve 36 by way of connection line 85.

The gas control valve 36 shown in FIG. 4 generates power by means of thermopile 84. Pilot burner 86 supplies heat to thermopile 84, which generates an electrical current such as about 100-about 750 millivolts. This amount of power is sufficient to enable gas control valve 36 to perform all of its designated tasks. Also, this arrangement can produce enough power to supply any controller located in a position remote from gas control valve 36.

In operation, both water heaters 10 of FIGS. 1 and 3 draw combustion air into combustion chamber 22 through selected openings. In so doing, combustion air is drawn past flammable vapor sensor 80. In the unlikely event that flammable vapors are present at a concentration or in an amount selected by the manufacturer to detect such flammable vapors, sensor 80 sends corresponding information/a signal to gas control valve 36. In response, gas control valve 36 can typically shut off the supply of fuel 32 (and pilot burner 86 when present) to assist in avoiding ignition of flammable vapors outside of water heater 10.

Similarly, CO sensor 94, located proximate draft hood 88, can sense the presence of a selected quantity of CO that is indicative of incomplete combustion associated with water heater 10 for any reason. Thus, CO sensor 94 generates information/a signal that is transmitted to gas control valve 36. In response, gas control valve 36 can typically shut off the supply of fuel to burner 32 (and pilot burner 86 when present) to assist in avoiding ignition of flammable vapors outside of water heater 10.

Gas control valve 36 can include a microcontroller that is capable of collecting the sensor information and taking appropriate action, including shutting off fuel or engaging other water heater components (not shown) to shut off the air supply to combustion chamber 22 or other types of components, for example. The microcontroller may be integral with gas control valve 36 or located at an alternative location so long as it is operatively connected to gas control valve 36. The microcontroller can be programmable if desired.

Although this disclosure has been described selected, with specific forms of a water heater and associated components, it will be appreciated that a wide variety of equivalents may be substituted for the specified elements described herein without departing from the spirit and scope of this disclosure as described in the appended claims.

Claims

1. A water heater comprising:

a water container;

a combustion chamber adjacent the water container;

a burner associated with the combustion chamber;

a flue gas collector located to receive flue gases generated in the combustion chamber;

a CO sensor having at least an operative portion proximate the flue gas collector;

a flammable vapor sensor having at least an operative portion positioned proximate a location where combustion air enters the combustion chamber; and

a controller operatively connected to the CO sensor and the flammable vapor sensor and adapted to receive signals generated by the CO and flammable vapor sensors and responsively shut off combustion in the combustion chamber.

2. The water heater of claim 1, wherein the flue gas collector is a draft hood.

3. The water heater of claim 1, wherein the CO sensor is inside the flue gas collector.

4. The water heater of claim 1, wherein the controller is a gas control valve.

5. The water heater of claim 4, wherein the gas control valve contains a microcontroller.

6. The water heater of claim 5, wherein the microcontroller is programmable.

7. The water heater of claim 5, wherein the microcontroller is powered by a grid electrical supply.

8. The water heater of claim 5, wherein the microcontroller is powered by a thermopile.

9. The water heater of claim 8, wherein the thermopile receives heat from a pilot burner.

10. The water heater of claim 1, wherein the controller is located proximate to where the combustion air enters the combustion chamber.

11. The water heater of claim 1, wherein the flammable vapor sensor is located on the controller.

12. The water heater of claim 1, wherein the controller shuts off fuel to the burner.