US20090084328A1

US20090084328A1 - Water heaters with combustion air inlet

Info

Publication number: US20090084328A1
Application number: US11/865,378
Authority: US
Inventors: Jeff L. Lyons; Timothy Smith; Roger A. Gillespie; John L. Dreher, III; Emadeddin Y. Tanbour
Original assignee: American Water Heater Co
Current assignee: American Water Heater Co
Priority date: 2007-10-01
Filing date: 2007-10-01
Publication date: 2009-04-02
Also published as: CA2639991A1

Abstract

A water heater includes a water container, a combustion chamber adjacent the, water container, a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, a blower assembly positioned to receive combustion gases generated by the burner, a shield positioned below at least a heating portion of the burner, a diverter that directs combustion air into the combustion chamber below the shield, and a passageway that directs at least a portion of the combustion air from the combustion air inlet, as primary combustion air, to the burner.

Description

TECHNICAL FIELD

The technology in this disclosure relates to water heaters, particularly to Water heaters that have a combustion air intake.

BACKGROUND

Both natural draft and power vented water heaters face a number of challenges with respect to providing proper air fuel mixtures for combustion, establishing and maintaining flame patterns on the burners, maintaining lower surface temperatures of the lower portion of the water heater while adhering to stringent cost requirements. Thus, it could be advantageous to provide water heaters that address these various issues.
Power vented water heaters face many of the same challenges as natural draft water heaters, but some that are different with respect to reducing the likelihood of igniting flammable vapors outside the power vented water heater. Designing a solution to that challenge and at the same time provide a reliable, safe and efficient system that supplies combustion air to the burner has been an ongoing problem.

SUMMARY

We provide a water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, a shield positioned below at least a heating portion of the burner, a diverter that directs combustion air into the combustion chamber below the shield, and a passageway that directs at least a portion of the combustion air from the combustion air inlet, as primary combustion air, to the burner.
We also provide a water heater including a water container; a combustion chamber adjacent the water container; a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container; a blower assembly positioned to receive combustion gases generated by the burner; a shield positioned below at least a heating portion of the burner that directs secondary combustion air toward at least one outer portion of the combustion chamber; a combustion air intake system that directs combustion air into the combustion chamber below the shield and comprises a combustion air supply portion, a dilution air supply portion, a connector portion extending between the blower assembly and the dilution air supply portion, and a diverter connected to the combustion air supply portion; and a passageway that directs at least a portion of the combustion air from the diverter, as primary combustion air, to the burner.
We further provide a water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber and arranged to combust fuel to heat waters in the water container, a shield positioned below at least a heating portion of the burner such that secondary combustion air is directed substantially to the side wall of the combustion chamber to thereby supply secondary combustion air to he heating portion of the burner and cause a temperature reduction effect on the side wall, a diverter that directs at least a portion of combustion air into the combustion chamber below the shield, and a passageway that directs at least a portion of the combustion air from the combustion air inlet, as primary combustion air, to the burner.
We even further provide a water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, a combustion air feed system that supplies ambient air to the combustion chamber, a primary air passageway connected between the combustion air feed system and the burner that supplies primary combustion air to the burner, and a secondary air passageway connected between the combustion air feed system and a space located below at least a heating portion of the burner that supplies secondary combustion air to the burner.
We still further provide a water heater comprising: a water container; a combustion chamber adjacent the water container; a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container; and a combustion air intake system that directs combustion air into the combustion chamber comprising a combustion air supply portion arid a supply air portion connected between the combustion air supply portion and a side wall of the combustion chamber; the supply air portion comprising a side wall connector portion fixed to the side wall and a coupling which connects to and substantially seals with the side wall connector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a water heater with a combustion air inlet.

FIG. 2 is a perspective view of a water heater showing selected interior portions with dashed lines.

FIG. 3 is a front elevational view of the water heater of FIG. 2, taken partially in section.

FIG. 4 is a perspective view of the combustion chamber bottom pan of the water heater of FIGS. 2 and 3 and selected portions of a combustion air inlet and diverter.

FIG. 5 is an exploded interior perspective view of a portion of the diverter shown in FIG. 4 connected to a combustion chamber skirt of the water heater.

FIG. 6 is an exploded interior perspective view of the structure shown in FIG. 5 with the diverter removed.

FIG. 7 is an exploded exterior perspective of a portion of the combustion air supply structure connected to a combustion chamber skirt of the water heater.

FIG. 8 is an exploded exterior perspective view of a larger portion of the combustion air supply structure from FIG. 7.

FIG. 9 is a perspective view of the end portion of the structure shown in FIG. 8.

FIG. 10 shows a partial sectional view of the end of the, combustion air supply structure shown in FIG. 8.

DETAILED DESCRIPTION

It will be appreciated that the Following description is intended to refer to specific aspects of the representative structures selected for illustration in the drawings and is not intended to define or limit the technology of this disclosure, other than in the appended claims.
Our water heaters are efficient and produce reduced emissions. This result is achieved by supplying primary and secondary combustion air to the burner in a desired fuel mix and in an improved flame pattern. This maximizes heat production and minimizes emissions production.
Our water heaters can also assist in reducing the likelihood that flammable vapors outside a water heater will reach the combustion chamber where they may be ignited by the main burner or pilot ignition device. One way that this is achieved is with a bidirectional air intake system that directs separate air intake paths to the water heater blower and vent system. One representative air intake path provides air for combustion and may be located above the dilution air intake for the blower. The intake pipe may be a large diameter pipe that allows air for dilution of the combustion exhaust products to be drawn from an upper portion of the water heater and directly into the blower assembly and exhausted to the outside. Another smaller pipe, a portion of which is inside of the large diameter air intake pipe, permits air for combustion to be drawn from the upper portion of the water heater or even above the blower assembly and travel down to a substantially sealed combustion chamber. These bidirectional air paths are separate and do not intermix.
Turning now to the drawings generally and FIGS. 1-3 in particular, a representative water heater 10 is shown. FIG. 1 shows the exterior of a water heater 10 which includes, but is not limited to, a jacket 12, a gas control valve 13 and an air intake system 38.
Another water heater 10 in FIGS. 2-3 includes, but is not limited to, a jacket 12, insulation 14, tank 16, combustion chamber 18 and burner 20. A flue 22 extends longitudinally substantially concentrically within tank 16 from an uppermost portion (tank head) to a lowermost portion (tank bottom). Combustion chamber 18 contains burner 20 which connects to a fuel supply line (not shown). Fuel supply line connects to gas control valve 24 that connects to a fuel supply (not shown).
A blower assembly 26 is positioned on the top pan 28 of water heater 10 and sealingly connects to flue 22 at its upper terminus. Accordingly, exhaust/combustion gases generated by burner 20 flow upwardly through flue 22 and into blower assembly 26. Blower assembly 26 has an electrical supply cord (not shown) that may be “plugged in” a typical electrical residential household socket (or hard wired into an electrical supply). Various electric control lines may be contained within a conduit (not shown) connected between blower assembly 26 and gas valve 24.
Water heater 10 has a bottom pan 34. Bottom pan 34 rests on legs 36 that support the entire water heater 10.
An air intake system 38 of FIG. 1 includes a substantially vertically oriented portion 40 and a substantially horizontally oriented portion 44 that penetrates through the side of jacket 12 and into the water heater combustion chamber. Substantially vertically oriented portion 40 has a distal end portion 43 that has an opening 45 covered by a louvered grate 41. Just inside louvered grate 41 is a fan 49. Fan 49 is optional.
An air intake system 38 of FIG. 2, connects between blower assembly 26 and combustion chamber 18. Air intake system 38 includes an air intake conduit and a dilution air conduit. The air intake conduit includes a substantially vertically oriented portion 40 that extends alongside or adjacent jacket 12 of water heater 10. It may also extend between jacket 12 and tank 16 if desired. The air intake conduit also comprises an angled portion 43 and a substantially horizontally oriented portion 44 that extends from the substantially vertically oriented portion 40 to opening 46 in jacket 12 and opening 47 in skirt 56. Substantially vertically oriented, portion 40 may extend upwardly beyond the top of blower assembly 26.
The dilution air conduit includes a substantially vertically oriented portion 42 that substantially extends around at least a portion of portion 40. The dilution air conduit also includes a connector portion 48 that extends between blower assembly 26 and substantially vertically oriented portion 42. Substantially vertically oriented portion 42 preferably has a perforated cap 52 at its upper portion and is positioned to allow ambient air to enter through the perforated cap, as shown by arrows “A”, and through an open end of substantially vertically oriented portion 40. Portions of substantially vertically oriented portion 40 and substantially vertically oriented portion 42 are preferably concentric.
Substantially horizontal portions 44 of the water heaters of FIGS. 1-3 connect to a diverter 54 that is located within combustion chamber 18. The connection between substantially horizontal portion 44 and diverter 54 is preferably made substantially adjacent skirt 56 that forms the side wall of combustion chamber 18. It is thus preferable that combustion air enters through the side wall (skirt 56) of combustion chamber 18. However, combustion air need not enter only through the side wall. For example, it is possible for combustion air to be introduced through combustion chamber bottom pan 34. In such a case, opening 46 would be eliminated and opening 47 would be moved to bottom pan 34. Horizontally-oriented portion 44 would extend under bottom pan 34 and connect to combustion chamber 18 through repositioned opening 47.
Diverter 54 is also connected to combustion chamber bottom pan 34 as particularly shown in FIG. 4. Diverter 54 further connects to shield 58 that in FIG. 4 is substantially hexagonally shaped and spaced above bottom pan 34. Shield 58 spreads air received from diverter 54 across the bottom portion of the combustion chamber 18 and also preferably acts as a radiation shield. The pace creates a pathway for the flow of combustion air along at least selected portions of the top surface of bottom pan 34 and below the lower surface of shield 58.
The edge portions of shield 58 are folded into side walls 60 having a substantially vertical orientation. Side walls 60.have lower edge portions that lie on the upper surface of bottom pan 34. Side walls 60 support shield 58 and act to substantially enclose the space between bottom pan 34 and shield 58. There are a plurality of openings 62 in vertical side walls 60. Clamps 64 retain shield 58 in a desired, selected position. Of course, other retention means known in the art may be substituted for clamps 64.
A set of secondary substantially vertically oriented walls 66 extend between shield 58 and bottom pan 34. Those side walls 66 also help to support shield 58 and form a channel 68 that connects to diverter 54. Channel 68 engages an opening 70 in shield 58 which leads to a burner air conduit 72 (see FIG. 2, for example) that connects to and channels primary combustion air to burner 20.
During operation as shown with respect to FIG. 1, a burner generates heat and exhaust gases which creates a draft flowing through the combustion chamber. This causes air to flow through air intake system 38 to feed combustion of the fuel at the, burner. Thus, combustion flows through grate 41, substantially vertically oriented portion 40 which acts as an air supply portion, substantially horizontally oriented portion 44 which acts as an air supply passageway portion, and into combustion chamber 18. Fan 49 may be actuated at that time to cause ambient air to flow into air intake system 38 and toward the combustion chamber. Alternatively, fan 49 can be connected to the gas control valve 13 so that its operation is initiated prior to the supplying fuel to the burner and before ignition is initiated.
The air flow, whether achieved through natural draft or by way of fan 49 causes flow of air in the space under shield 58 of FIG. 4, through diverter 54, substantially horizontal portion 44, angled horizontal portion 43 and substantially vertical portion 40. Combustion air enters air intake system 38 by way of louvered grate 41 as shown by arrows “X” in FIG. 1. Then, fresh combustion air flows downwardly through vertically oriented portion 40 as shown by arrow “Y”, into horizontally oriented portion 44 and into the combustion chamber 18 by way of diverter 54.
During operation as shown in FIGS. 2-3, burner 20 generates exhaust gases. Blower assembly 26 initiates a flow of air and exhaust gases upwardly through flue 22. This also causes an upward flow of air/exhaust gases through combustion chamber 18. This in turn causes, flow of air in the space under shield 58, through diverter 54, substantially horizontal portion 44, angled portion 43 and substantially vertical portion 40. Combustion air enters air intake and exhaust system 38 by way of perforations in cap 52 as shown by arrows “A” in FIG. 2. Then, fresh combustion air flows, downwardly through vertically oriented portion 40 as shown by arrows “B”, into horizontally oriented portion 44, upwardly through openings 46 and 47 and into combustion chamber 18 by way of diverter 54.
Substantially simultaneously, as shown by reference to FIG. 2, blower assembly 26 causes the flow of air to supply air to the blower to mix with exhaust gases entering blower assembly 26 through flue 22, which decreases the temperature of the exhaust gases and provides for a range of types of exhaust lines.(not shown), but which would extend in a direction “away” from water heater 10 in the Figures. The suction created by blower assembly 26 causes dilution air to move into and through substantially vertically oriented portion 42. With particular reference to FIG. 2, arrows “C” depict the entrance of dilution air through an opening in the lowermost portion of substantially vertically oriented portion 42. That lowermost opening is preferably at least no lower than about a mid point of the height of water heater 10. Dilution air flows upwardly through substantially vertically oriented portion 42, through connector 48 and into blower assembly 26 for combination with exhaust gases exiting from the terminus of flue 22.
It can be seen, especially as shown in FIG. 2, that simultaneous intake of combustion and dilution air can occur at locations relatively high off the floor and without intermixing. This can be achieved by the seal between combustion air pipe 40 and dilution air pipe 42. This simultaneous flow from a relatively elevated position reduces the chances of undesirable flammable ignition of vapors that might be located adjacent the water heater and provides for a means to lower the temperature of exhaust gases to increase flexibility of installation of the water heater.
Combustion air passing through combustion air pipe 40 as shown by arrows “B” flows through angled portion 43 and into substantially horizontal portion 44. Then, as particularly shown in FIG. 4, combustion air enters diverter 54 whereby the flow is divided into three different portions. Arrow “D” represents the flow of primary combustion air traveling through channel 68, through opening 70, into burner air feed channel 72 and subsequently into burner 20 to mix with fuel as primary combustion air in a desired proportion.
On the other hand, the outer portions of combustion air flowing through diverter 54 pass into the space between shield 58 and bottom pan 34 as shown by the arrows “E.” That combustion air is secondary combustion air and exits from the space between shield 58 and bottom pan 34 through openings 62 as shown by arrows “F.” That secondary combustion air flows around the outermost edges of shield 58 and passes upwardly into combustion chamber 18 and towards burner 20 as shown by arrow “G” (FIG. 3) as secondary combustion air. This helps to create and maintain an even and consistent flame pattern.
The movement of secondary combustion air as shown by arrows “F” and “G” causes that air to impinge on skirt 56 that forms the side wall of combustion chamber 18 and thereby causes a temperature reduction effect on skirt 56 which helps to retain heat within combustion chamber 18 so that it can better be directed to the water of water tank 16, as opposed to radiating outwardly towards jacket 12 in the lower portions of the water heater.
The sizes, shapes and arrangement of diverter 54 and shield 58 as shown in FIG. 4 are merely one possible arrangement. Other sizes and shapes of diverters and shields are possible. For example, shield 58 can be round or any other shape. Also, it can cover more or less surface area. Alternative means of providing side walls 60 and opening 62 may also be provided. Similarly, channel 68 can be formed in any number of alternative ways as can be diverter 54. One example may be that diverter 54 is divided into two passageways, possibly without connection to bottom pan 34, whereby one passageway flows directly to opening 70 in shield 58 and the other passageway flows to a sized and shaped air diffusion device that directs secondary combustion air toward the outer portions of combustion chamber 18.
It is also possible for the diverter and shield to be made from a variety of different heat resistant materials. Preferably, those materials should also be corrosion resistant in the presence of moisture and elevated temperatures.
FIG. 5 shows an exploded view of how diverter 54 is mounted between skirt 56 which serves as the side wall of the combustion chamber, diverter 58 and bottom pan 34. It is preferred that diverter 58 be sized and shaped to closely connect between those various portions so that air will be substantially completely channeled in the desired directions. However, it is not necessary for diverter 54 to be air tightly sealed to those respective structures. It is typically sufficient for diverter 54 to be secured to bottom pan 34 by way of a screw 101, for example, or any other means known in the art such as connectors, spot welds, heat resistant adhesives and the like. The most important part of the connection with respect to diverter 54 is that it covers an opening 106, shown in FIG. 6, in skirt connector 102 that extends from an opening 105 in skirt 56.
FIGS. 6 and 7 are further exploded views of the structure shown in FIG. 5, except that diverter 54 has been removed to substantially completely reveal skirt connector 102. Skirt connector 102 includes a proximal end portion 104 with an opening 106 that extends into combustion chamber 18. Skirt connector 102 also has a distal end portion 108 extending outwardly from skirt 56. A, pair of slots 110Q are cut into distal portion 108 at opening 112 to facilitate engagement of other portions of substantially horizontally oriented portion 44.
Skirt connector 102 is preferably substantially sealed to skirt 56 at opening 105 such that air will not flow into combustion chamber 18 or but of combustion chamber 18 except through openings 106 and 112 of skirt connector 102. Attachment of skirt connector 102 to skirt 56 can be achieved in any number of ways known in the art such as by welding, for example. Other means for mounting and sealing skirt connector 102 to skirt 156 may be employed.
FIG. 8 shows horizontally oriented portion 44 in its, entirety as connected to the water heater. In particular, skirt connector 102 is mounted and sealed to skirt 56. A tube connector 114 having a pair of protrusions 116, shown in FIG. 9, engage slots 110 to thereby attach tube connector 114 to skirt connector 102 and fix connector 114 into a substantially rigid position with respect to the balance of the water heater. Tube connector 114 is in turn connected to elbow 116 to complete substantially horizontally oriented portion 44. This arrangement causes combustion air to be supplied directly from the air intake system to combustion chamber 18.
FIG. 10 shoves a partial cross section of substantially horizontally oriented portion 44 connected to skirt 56. Also, diverter 54 is shown in a selected position relative to horizontally oriented portion 44 to receive combustion air from the combustion air supply system. By utilizing slots 110 and protrusions 116 to attach the connector 114 portion of elbow 118 to skirt connector 102, the combustion air system is easy to manufacture, assemble, disassemble and maintain.
The size and shape of the various portions can be increased or decreased to suit the application and/or size and/or shape of the water heater. The location of the various conduits relative to the water heater may also be varied depending on the size, shape and location of the water heater. Conversely, the upper portion of the water heater may be the upper half of the water heater, but may be a larger portion so long as the combustion air opening is above the dilution air intake.
It will be understood that water heater 10 may be constructed with a wide variety of materials, in a wide variety of shapes and sizes. For example, any number of types of burners 20 may be employed, along with various types of blower assemblies 26, gas control valves 24 and the like. Also, various types of insulation, water containers/tanks and jackets may be employed. Preferably, air intake system 38 is constructed of PVC, ABS or CPVC materials, although other suitable materials may be employed. Skirt connector 102 should, on the other hand, preferably be made from the same or similar material as skirt 56, which is preferably a heat and corrosion resistant metal.
Although the technology of this disclosure has been described in connection with specific representative forms thereof, 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 technology 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 and arranged to combust fuel to heat water in the water container;

a shield positioned below at least a heating portion of the burner;

a diverter that directs combustion air into the combustion chamber below the shield; and

a passageway that directs at least a portion of the combustion air from a combustion air inlet, as primary combustion air, to the burner.

2. The water heater of claim 1, wherein the combustion chamber is substantially air-tight except for an opening in the diverter.

3. The water heater of claim 1, wherein the diverter, substantially sealingly connects to a side wall of the combustion chamber.

4. The water heater of claim 1, wherein the shield directs secondary combustion air toward at least one outer portion of the combustion chamber and has an opening that permits the primary combustion air to pass to the passageway.

5. The water heater of claim 1, wherein the shield directs secondary air substantially to a side wall of the combustion chamber to thereby supply secondary combustion air to the heating portion of the burner and cause a temperature reduction effect on the side wall.

6. The water heater of claim 1, wherein the diverter directs at least a portion of the combustion air to a space between the shield, and a floor of the combustion chamber.

7. The water heater of claim 1, wherein the passageway is positioned along a portion of a floor portion of the combustion chamber.

8. The water heater of claim 1, further comprising a blower assembly positioned to receive combustion gases generated by the burner.

9. The water heater of claim 1, further comprising a blower connected to an air inlet in the combustion chamber.

10. A water heater comprising:

a water container;

a combustion chamber adjacent the water container;

burner associated wit the combustion chamber and arranged to combust fuel to heat water in the water container;

a blower assembly positioned to receive combustion gases generated by the burner;

a shield positioned below at least a heating portion of the burner that directs secondary combustion air toward at least one outer portion of the combustion chamber;

a combustion air intake system that, directs, combustion air, into the combustion chamber below the shield and comprises a combustion air supply portion, a dilution air supply portion, a connector portion connected between the blower, assembly and the dilution air supply portion, and a diverter positioned in the combustion chamber and associated with the combustion air supply portion; and

a passageway that directs at least a portion of the combustion air from the diverter, as primary combustion air, to the burner.

11. A water heater comprising: a water contained;

a combustion chamber adjacent the water container;

a burner associated with the combustion chamber and arranged to, combust fuel to heat water in the water container;

a shield positioned within the combustion chamber and below at, least a heating portion of the burner such that, secondary combustion air is directed substantially to a side wall of the combustion chamber to thereby supply secondary combustion air to the heating portion of the burner and cause a temperature reduction effect on the side wall;

a passageway that directs at least a portion of the combustion air from the combustion air inlet, as primary combustion air, to the burner.

12. The water heater of claim 11, further comprising a blower assembly positioned to receive combustion gases generated by the burner.

13. The water heater of claim 11, further comprising a blower connected to an air inlet in the combustion chamber.

14. A water heater comprising:

a water container;

a combustion chamber adjacent the water container;

a combustion air feed system that supplies ambient air to the combustion chamber;

a primary air passageway connected between the combustion air feed system and the burner that supplies primary combustion air to the burner; and

a secondary air passageway connected between the combustion air feed system and a space located below at least a heating portion of the burner that supplies secondary combustion air.

15. The water heater of claim 14, wherein the secondary air passageway directs the secondary combustion air substantially to a side wall of the combustion chamber to thereby supply secondary combustion air to a heating portion of the burner and cause a temperature reduction effect on the side wall.

16. The water heater of claim 14, further comprising a blower assembly positioned to receive combustion gases generated by the burner.

17. The water heater of claim 1, further comprising a blower connected to the combustion air inlet.

18. The water heater of claim 14, wherein the, secondary air passageway comprises a chamber positioned below at least a heating portion of the burner that has a plurality of openings to diffuse the secondary air toward a side wall of the combustion chamber.

19. A water heater comprising:

a water container;

a combustion chamber adjacent the water container;

a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container; and

a combustion air intake system that directs combustion air into the combustion chamber comprising a combustion air supply portion and an air supply passageway portion connected between the combustion air supply portion and a side wall of the combustion chamber;

the supply air portion comprising a side wall connector portion fixed to the side wall and a coupling which connects to and substantially seals with the side wall connector.

20. The water heater of claim 19, wherein a distal end portion of the side wall connector has a plurality of slots that engage a corresponding number of protrusions located on the coupling to substantially lock the side wall connector and coupling in a selected position with respect to each other.

21. The water heater of claim 19, wherein the coupling slides concentrically over the side wall connector portion.

22. The water heater of claim 19, wherein the coupling is a distal portion of an elbow in the supply air portion.

23. The water heater of claim 19, further comprising a blower assembly positioned to receive combustion gases generated by the burner.

24. The water heater of claim 19, further comprising a blower connected to an air inlet of the combustion chamber.

25. The water heater of claim 19, further comprising:

a shield positioned below at least a heating portion of the burner;