Method and Apparatus for Detecting a Threshold Deviation from Clean Combustion in a Residential Gas Heater Assembly

Abstract

A residential gas heater assembly that comprises a gas heater, a blower assembly, a flue, and a combustion sensor assembly. The gas heater assembly comprises a burner chamber. The blower assembly comprises a housing. The blower assembly is adapted and configured to move air into the burner chamber and move combustion gases through the flue along a combustion gases flow path. The combustion sensor assembly is in fluid communication with a first location and a second location. The first location is within the combustion gases flow path. The gas heater assembly is adapted and configured such that operating the gas heater and the blower assembly induces a pressure differential between the first location and the second location to thereby cause a portion of the combustion gases to be drawn from the first location and flow to the combustion sensor assembly.

Claims

1. A method for detecting a threshold deviation from clean combustion in a residential gas heater assembly, the gas heater assembly comprising a gas heater, a blower assembly, a flue, and a combustion sensor assembly, the gas heater comprising a burner chamber, the blower assembly comprising a housing and being adapted and configured to move air into the burner chamber and move combustion gases out of the gas heater and through the flue along a combustion gases flow path, the method comprising: bringing the combustion sensor assembly into fluid communication with a first location and a second location, the first location being within the combustion gases flow path; operating the gas heater and the blower assembly in a manner which causes a pressure differential, the pressure differential being between the first location and the second location such that the first location has a first pressure and the second location has a second pressure with the first pressure being greater than the second pressure, the pressure differential caused by operating the gas heater and the blower assembly causing a portion of the combustion gases to move from the first location and flow to the combustion sensor assembly.

2. The method of claim 1 further comprising detecting, via the combustion sensor assembly when a threshold deviation from clean combustion occurs, at least one of: carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and sulfur oxide.

3. The method of claim 2 further comprising powering down the residential gas heater assembly, upon detecting at least a preselected level of at least one of: carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and sulfur oxide.

4. A residential gas heater assembly comprising a gas heater, a blower assembly, a flue, and a combustion sensor assembly, the gas heater comprising a burner chamber, the blower assembly comprising a housing and being adapted and configured to move air into the burner chamber and move combustion gases through the flue along a combustion gases flow path, the combustion sensor assembly being in fluid communication with a first location and a second location, the first location being within the combustion gases flow path, wherein the gas heater assembly is adapted and configured such that operating the gas heater and the blower assembly causes a pressure differential between the first location and the second location to thereby cause a portion of the combustion gases to move from the first location and flow to the combustion sensor assembly.

5. The residential gas heater assembly of claim 4 wherein at least some of said portion of the combustion gases drawn from the first location flow to the second location.

6. The residential gas heater assembly of claim 4 wherein the second location is in the combustion gases flow path.

7. The residential gas heater assembly of claim 4 wherein the second location is not in the combustion gases flow path.

8. The residential gas heater assembly of claim 4 wherein the first location has a first pressure and the second location has a second pressure, the first pressure being a positive pressure relative to ambient pressure and the second pressure being a positive pressure relative to ambient pressure, the first pressure being greater than the second pressure.

9. The residential gas heater assembly of claim 4 wherein the first location has a first pressure and the second location has a second pressure, the first pressure being a positive pressure relative to ambient pressure and the second pressure being equal to ambient pressure.

10. The residential gas heater assembly of claim 4 wherein the first location has a first pressure and the second location has a second pressure, the first pressure being a positive pressure relative to ambient pressure and the second pressure being a negative pressure relative to ambient pressure.

11. The residential gas heater assembly of claim 4 wherein the first location has a first pressure and the second location has a second pressure, the first pressure being a negative pressure relative to ambient pressure and the second pressure being a negative pressure relative to ambient pressure, the first pressure being greater than the second pressure.

12. The residential gas heater assembly of claim 4, wherein the flue comprises a flue outlet connection forming a portion of the combustion gases flow path and the first location is at one of the housing and the flue outlet connection.

13. The residential gas heater assembly of claim 12, wherein the gas heater assembly further comprises a collector box, and wherein the first location is at one of the housing or the flue outlet connection and the second location is on the collector box.

14. The residential gas heater assembly of claim 4, wherein the combustion sensor assembly is adapted and configured to sense at least one of: carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and sulfur oxide.

15. The method of claim 4 wherein the gas heater comprises a water heater, a furnace, or a boiler.

16. An inducer blower assembly for a residential gas heater, the inducer blower assembly comprising a housing and a combustion sensor assembly, the housing having an intake opening and a discharge opening, the blower assembly being adapted to draw combustion gases generated by the gas heater and discharge such combustion gases out the discharge opening, the combustion sensor assembly being in fluid communication with a first location and a second location, the first and second locations being located on the housing of the blower assembly, wherein the inducer blower assembly is adapted and configured such that operating the inducer blower assembly and the gas heater causes a pressure differential between the first location and the second location to thereby cause a portion of the combustion gases to move from the first location and flow to the combustion sensor assembly.

17. The residential gas heater assembly of claim 16 wherein at least a portion of the combustion gases drawn from the first location flow to the second location.

18. The residential gas heater assembly of claim 16, wherein the combustion sensor assembly is adapted and configured to sense at least one of: carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, or sulfur oxides.

19. The residential gas heater assembly of claim 16 wherein the first location has a first pressure, the first pressure being a positive pressure relative to ambient pressure.

20. The residential gas heater assembly of claim 16 wherein the first location has a first pressure, the first pressure being a negative pressure relative to ambient pressure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a schematic view of an apparatus for detecting a threshold deviation from clean combustion in a residential gas heater assembly, the apparatus comprising a gas heater, collector box, blower assembly, flue having a flue outlet connection, and a combustion sensor assembly.

[0010] FIG. 2 is a schematic view of an embodiment of the apparatus of FIG. 1, showing the combustion sensor assembly being in fluid communication with the blower.

[0011] FIG. 3 is a schematic view of a method for detecting a threshold deviation from clean combustion in a residential gas heater assembly.

[0012] Reference numerals in the written specification and in the figures indicate corresponding items.

DETAILED DESCRIPTION

[0013] An embodiment of a residential gas heater assembly, generally indicated by reference number 20, is shown in FIGS. 1-2. The residential gas heater assembly comprises a gas heater 22, a blower assembly 24, a flue 26, and a combustion sensor assembly 28. The gas heater 22 may comprise a water heater, a furnace, or a boiler. The gas heater 22 comprises a burner chamber (not shown), where a fuel (e.g., propane, natural gas, fuel oil, or other combustible hydrocarbons) is combusted in the presence of air or oxygen, thereby forming combustion gasses.

[0014] The blower assembly 24 comprises a housing 32. The blower assembly 24 is adapted and configured to move air into the burner chamber and move combustion gases through the flue 26 along a combustion gases flow path. The blower assembly may be configured and oriented to either push air into the combustion chamber or draw air into the combustion chamber. The housing 32 of the blower assembly 24 may have an intake opening (not shown) and a discharge opening 34. If the blower assembly 24 is positioned downstream of the combustion chamber, then the blower assembly 24 is to adapted to draw combustion gases generated by the gas heater 22 and discharge such combustion gases out the discharge opening 32b. The blower assembly 24 may be a forced air blower or a draft inducer blow.

[0015] The combustion sensor assembly 28 is in fluid communication with a first location 40 and a second location 42. The first location 40 is within the combustion gases flow path. The second location 42 may be in the combustion gases flow path or may outside the combustion gases flow path, e.g., open to ambient. Both the first location 40 and the second location 42 may be fluidly connected with the combustion sensor assembly 28 via pressure taps or the like.

[0016] The gas heater assembly 20 is adapted and configured such that operating the gas heater 22 and the blower assembly 24 creates a pressure differential between the first location 40 and the second location 42 to thereby cause a portion of the combustion gases to move from the first location and flow to the combustion sensor assembly 28. At least a fraction of the portion of the combustion gases moved from the first location 40 may flow to the second location 42.

[0017] The first location 40 may be located on the housing 32 or may be located elsewhere on the blower assembly in the combustion gases flow path. The second location 42 may be located on the housing 32 or may be located elsewhere, and need not be located in the combustion gases flow path.

[0018] When the pressure differential is created, the first location 40 has a first pressure and the second location 42 has a second pressure. The first pressure may be a positive pressure relative to ambient pressure and the second pressure may be a positive pressure relative to ambient pressure, with the first pressure being greater than the second pressure. Alternatively, the first pressure may be a positive pressure relative to ambient pressure and the second pressure may be equal to ambient pressure. As another alternative, the first pressure may be a positive pressure relative to ambient pressure and the second pressure may be a negative pressure relative to ambient pressure. As yet another alternative, the first pressure may be a negative pressure relative to ambient pressure and the second pressure may be a negative pressure relative to ambient pressure, with the first pressure being greater than the second pressure.

[0019] The flue 26 may comprise a flue outlet connection 44. The flue outlet connection 44 may form a portion of the combustion gases flow path. The gas heater assembly 20 may further comprise a collector box 46. The combustion gases flow path extends from at least the burner chamber to the flue 26, but could also include the flow of combustion gases through the collector box 46. As an alternative to being located on the housing 32, the first location 40 may be located on the flue outlet connection 44, or on the collector box 46, or at some other suitable location along the combustion gasses flow path. The second location 42 may be located at some other location along the combustion gasses flow path or outside the combustion gasses flow path. But regardless of the location of the second location 42, a pressure differential is created between the first and second locations 40, 42 during operation of the gas heater 22 and the blower assembly 24.

[0020] The combustion sensor assembly is adapted and configured to sense at least one of: carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and sulfur oxide. When clean combustion of combustion gases occurs, carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and/or sulfur oxide will be generated, if at all, below a threshold level. But, when combustion is not clean, carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and/or sulfur oxide may be generated in excess of a threshold level.

[0021] More specifically, complete combustion of hydrocarbon fuels, such as natural gas or liquefied petroleum gas (LP-gas or propane), requires a proper mixture of air and fuel, as well as an adequate amount of heat to ignite the combustion air-fuel mixture. Incomplete combustion of the fuel supplied to gas appliances can lead to production of hazardous levels of CO. Incomplete combustion can occur when there is inadequate combustion of air (for instance when air openings to the appliance combustion chamber or burner assembly, or the exhaust outlet from the appliance is blocked); too much fuel is supplied to the appliance burner (i.e., over-firing) ; or the burner flame temperature falls below the ignition temperature of the combustion air-fuel mixture (i.e., flame quenching) . Depending on the severity and duration, all these conditions can result in incomplete combustion of the fuel; which, in turn, can result in the gas furnace or boiler producing dangerous levels of CO or other combustion products.

[0022] The combustion sensor assembly may be configured to turn off the gas heater assembly if a threshold level is exceeded. For example, the combustion sensor assembly may be configured to turn off the gas heater assembly if the amount of carbon monoxide detected by the sensor exceeds a threshold level, e.g., 400 parts per million of carbon monoxide.

[0023] FIG. 3 is a flow diagram of an embodiment of a method for detecting a threshold deviation from clean combustion in the residential gas heater assembly 20. As used herein, clean combustion refers to a combustion process in which a fuel (e.g., propane, natural gas, fuel oil, or other combustible hydrocarbons) reacts completely with oxygen during a combustion process. In other words, there is at least a sufficient amount of oxygen or an overabundance of oxygen for the combustion process.

[0024] The method first comprises bringing the combustion sensor assembly 28 into fluid communication with the first location 40 and the second location 42. This step is shown at step 200 in FIG. 3. The first location 42 is within the combustion gases flow path.

[0025] The method then comprises operating the gas heater 22 and the blower assembly 24 in a manner which induces a pressure differential. This step is shown at step 210 in FIG. 3. The pressure differential is between the first location 40 and the second location 42 such that the first location has a first pressure and the second location has a second pressure. The first pressure is greater than the second pressure. The pressure differential induced by operating the gas heater and the blower assembly causes a portion of the combustion gases to be drawn from the first location 40 and flow to the combustion sensor assembly 28.

[0026] The method may further comprise detecting, via the combustion sensor assembly 28 when a threshold deviation from clean combustion occurs, at least one of: carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and sulfur oxide. This step is shown at step 220 in FIG. 3. As used herein, a threshold deviation refers to a deviation from clean combustion sufficient to transform clean combustion to unclean combustion.

[0027] Additionally, the method may further comprise powering down the residential gas heater assembly 20, upon detecting at least a preselected level of at least one of: carbon monoxide, carbon dioxide, nitrogen oxides, natural gas, propane, and sulfur oxide. This step is shown at step 230 in FIG. 3.

[0028] In view of the foregoing, it should be appreciated that the invention has several advantages over the prior art.

[0029] It should also be understood that when introducing elements of the present invention in the claims or in the above description of exemplary embodiments of the invention, the terms comprising, including, and having are intended to be open-ended and mean that there may be additional elements other than the listed elements. Additionally, the term portion should be construed as meaning some or all of the item or element that it qualifies. Moreover, use of identifiers such as first, second, and third should not be construed in a manner imposing any relative position or time sequence between limitations.

[0030] As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.