Water heater for recreational vehicles having forced air/direct vent combustion

Abstract

A water heater for a recreational vehicle includes an enclosure assembly, a water tank for holding water to be heated, a combustion system for heating water within the water tank, and a control system for operating the combustion system. The combustion assembly includes a burner assembly located within a sealed combustion chamber, an inlet duct communicating an external environment with the combustion chamber, an outlet duct communicating the combustion chamber with the external environment, and an electric fan positioned to draw combustion air through the inlet duct and force flue gas into the outlet duct. A portion of the outlet duct extends within the inlet duct so that both ducts extend through a single opening in an exterior wall of the recreational vehicle. The enclosure assembly is provided with a plurality of knockouts facing in different directions for forming an opening for the inlet and outlet ducts.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable

REFERENCE TO MICROFICHE APPENDIX

Not Applicable

FIELD OF THE INVENTION

The present invention generally relates to water heaters and, more particularly, to gas-fired water heaters for recreational vehicles and the like.

BACKGROUND OF THE INVENTION

Compact water heaters of the type for use with recreational vehicles typically have a relatively small water tank in combination with a heating unit. The heating unit is typically of the gas-fired burner type. The burner can be fueled by propane gas which is usually carried on recreational vehicles. The water heater is mounted on the recreational vehicle in a convenient position connected to cold water supply and hot water outlet pipes respectively receiving cold water from a suitable water supply source and for directing heated water for use in cooking, bathing, and the like.

These gas-fired burners must be vented to the exterior of the vehicle. Typically, the water heater is located near an exterior wall of the recreational vehicle so that a door in the exterior wall can be used for gravity combustion, venting, and service. These doors, however, are considered aesthetic problems in the industry for color matching, their “postage stamp” appearance, and their contribution to cluttered exterior appearances of recreational vehicles.

As a result some water heaters have been located inward of the exterior walls and are provided with an inlet duct in the floor and an outlet duct in the ceiling for gravity combustion and venting. While these water heaters may improve the outward appearance of the exterior walls, they impose other design constraints such as the water heater must be located where ducts can be provided through the floor and ceiling. In either case, these prior water heaters place considerable constraints on the design of the recreational vehicles. Much of the interior design must often be designed around the locations of appliances such as the water heater. Additionally, different water heaters must be used in different recreational vehicle designs which prevents the cost advantages of a “universal” design. Accordingly, there is a need in the art for an improved water heater for recreational vehicles.

SUMMARY OF THE INVENTION

The present invention provides a water heater for a recreational vehicle which overcomes at least some of the above-noted problems of the related art. According to the present invention, a water heater for a recreational vehicle comprises, in combination, an enclosure assembly, a water tank for holding water to be heated located within the enclosure assembly, a combustion system for heating water within the water tank, and a control system for operating the combustion system. The combustion assembly includes a gas-fired burner assembly located within a sealed combustion chamber, a combustion air inlet duct communicating an external environment with the combustion chamber, a flue gas outlet duct communicating the combustion chamber with the external environment and extending near the water tank to transfer heat to water within the water tank, and an electric fan positioned to draw combustion air through the inlet duct and into the combustion chamber and force flue gas into the outlet duct and out of the combustion chamber. The control system includes a thermostat and is operably connected to the burner assembly, the fan, and the thermostat to generally maintain water in the water tank at a desired temperature.

According to another aspect of the present invention, a water heater for a recreational vehicle comprises, in combination, an enclosure assembly, a water tank for holding water to be heated located within the enclosure assembly, a combustion system for heating water within the water tank, and a control system for operating the combustion system. The combustion system includes a gas-fired burner assembly located within a sealed combustion chamber, a combustion air inlet duct communicating an external environment with the combustion chamber, and a flue gas outlet duct communicating the combustion chamber with the external environment and extending near the water tank to transfer heat to water within the water tank. The control system includes a thermostat and is operably connected to the burner assembly and the thermostat to generally maintain water in the water tank at a desired temperature. A portion of the flue gas outlet duct extends within the combustion air inlet duct.

According to yet another aspect of the present invention, a water heater for a recreational vehicle comprises, in combination, an enclosure assembly, a water tank for holding water to be heated located within the enclosure assembly, a combustion system for heating water within the water tank, and a control system for operating the combustion system. The combustion assembly includes a gas-fired burner assembly located within a sealed combustion chamber, a combustion air inlet duct communicating an external environment with the combustion chamber, and a flue gas outlet duct communicating the combustion chamber with the external environment and extending near the water tank to transfer heat to water within the water tank. The control system for operating the combustion system includes a thermostat and is operably connected to the burner assembly and the thermostat to generally maintain water in the water tank at a desired temperature. The enclosure assembly is provided with a plurality of knockouts facing in different directions for forming an opening for the inlet and outlet ducts.

From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of water heaters for recreational vehicles. Particularly significant in this regard is the potential the invention affords for providing a high quality, reliable, efficient, and low cost assembly that can be used in a wide variety of locations and in more than one location. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and further features of the present invention will be apparent with reference to the following description and drawings, wherein:

FIG. 1 is a top plan view of a water heater for a recreational vehicle according to the present invention;

FIG. 2 is a side elevational view of the water heater of FIG. 1;

FIG. 3 is a rear end elevational view of the water heater of FIGS. 1 and 2;

FIG. 4 is a front end elevational view of the water heater of FIGS. 1 to 3;

FIG. 5 is a bottom plan view of the water heater of FIGS. 1 to 4;

FIG. 6 is a perspective view of the water heater of FIGS. 1 to 5, wherein an exterior housing is removed for clarity;

FIG. 7 is another perspective view of the water heater of FIGS. 1 to 6, wherein a rear end cover is removed for clarity;

FIG. 8 is a schematic view of the forced air/direct vent combustion system of the water heater of FIGS. 1 to 7; and

FIG. 9 is a schematic view of a control system of the water heater of FIGS. 1 to 8.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of a water heater for a recreational vehicle as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration. All references to direction and position, unless otherwise indicated, refer to the orientation of the powered adjustable seat assembly illustrated in the drawings. In general, up or upward refers to an upward direction within the plane of the paper in FIG. 2 and down or downward refers to a downward direction within the plane of the paper in FIG. 2. Also in general, fore or forward refers to a direction toward the left within the plane of the paper in FIG. 2 and aft or rearward refers to a direction toward the right within the plane of the paper in FIG. 2.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

It will be apparent to those skilled in the art, that is, to those who have knowledge or experience in this area of technology, that many uses and design variations are possible for the improved water heaters disclosed herein. The following detailed discussion of various alternative and preferred embodiments will illustrate the general principles of the invention with reference to a preferred embodiment of a water heater for a recreational vehicle. The term “recreational vehicle” as use in the specification and claims is intended to include all vehicles which are generally permanently installed at a site but are transported along a roadway a subsequent site such as mobile homes as well as vehicles that are readily moved along roadways among sites such as recreational vehicles (RVs), travel trailers, campers, and the like. Other embodiments suitable for other applications will be apparent to those skilled in the art given the benefit of this disclosure.

Referring now to the drawings, FIGS. 1 to 7 show a water heater 10 for a recreational vehicle 12 according to a preferred embodiment of the present invention. The illustrated water heater 10 includes an enclosure assembly 14, a water tank 16 within the enclosure assembly 14, forced air/direct vent combustion system 18 for heating water within the water tank 16, and a control system 20 for operating the combustion system 18.

The illustrated enclosure assembly 14 includes a base 22, a forward end wall or bulkhead 24, a rear end wall or bulkhead 26, and a main cover 28. The illustrated base 22 is generally rectangular-shaped, having a length greater than its width, and planar and is provided with mounting brackets 30 at forward and rearward ends. The mounting brackets 30 are provided with opening for mechanical fasteners for securing the water heater 10 to a support structure of the recreational vehicle such as a floor. The illustrated forward end wall 24 is generally square shaped and planar. The forward end wall 24 perpendicularly extends in an upward direction from the forward end of the base 22. The illustrated rearward end wall 26 is generally square shaped and planar. The rearward end wall 26 perpendicular extends in an upward direction from the rearward end of the base 22. The illustrated rearward end wall 26 forms a sealed interior combustion chamber or cavity 32 therein. The illustrated rearward end wall 26 is provided with a removable end cover 34 that partially forms the combustion chamber 32 and selectively provides access to components located within the combustion chamber 32 as described in more detail hereinafter.

The illustrated water tank 16 is generally cylindrically shaped having a horizontally disposed central axis extending between the end walls 24, 26. The water tank 16 is preferably provided with flanges to secure the water tank to the base 22. The water tank 16 forms a hollow interior cavity for holding water to be heated. The water tank 16 is provided with a cold inlet pipe 36 for connection to a source of water to be heated and a hot outlet pipe 38 for directing hot water to a sink, shower etc. The illustrated inlet and outlet pipes 36, 38 forwardly extend from the water tank 16 through openings in the forward end wall 24. The illustrated water tank 16 is also provided with a drain pipe 40 that forwardly extends from the water tank 16 through an opening in the forward end wall 24. The illustrated water tank 16 is further provided with a pressure/temperature (P/T) relief valve 42 that forwardly extends from the water tank 16 through an opening in the forward end wall 24. The illustrated water tank 16 is moreover provided with motor assist inlet and outlet pipes 44, 46 of an engine assisted heat exchanger. The inlet and outlet pipes 44, 46 forwardly extend from the water tank 16 through openings in the forward end wall 24.

The illustrated combustion system 18 includes a burner assembly 48, a gas inlet line 50, a combustion air inlet duct 52, an electric fan 54, and a flue gas outlet duct 56. The illustrated burner assembly 48 is located within the combustion chamber 32 and laterally extends across the lower end of the combustion chamber 32. The illustrated burner assembly 48 generally extends between the gas inlet line 50 and an inlet opening of the flue gas outlet duct 56. The burner assembly 48 can be of any suitable type for burning a desired gas to generate heat. The illustrated burner assembly 48 includes an electric igniter 58. The illustrated gas inlet line 50 extends through a side of the rearward end wall 26 and into the sealed combustion chamber 32 to the burner assembly 48. The illustrated enclosure assembly 13 is provided with a sight glass 60 located above the burner assembly 48 for viewing the burner assembly 48 when the combustion chamber 32 is completely enclosed by the enclosure assembly 14.

A baffle 62 within the rearward end wall 26 forms an inlet air chamber 64. The illustrated combustion air inlet duct 52 is connected to a duct opening 66 in the side of the rearward end wall 26 that communicates a second or outlet end of the combustion air inlet duct 52 with the inlet air chamber 64. The illustrated combustion air inlet duct 52 is generally tubular shaped and extends from the inlet air chamber 64 through an exterior wall 68 of the recreational vehicle 12 to ambient air located at the exterior of the recreational vehicle 12. Configured in this manner the combustion air inlet duct 52 communicates ambient air at the exterior of the recreational vehicle 12 to the inlet air chamber 64 within the water heater 10 located within the interior of the recreational vehicle 12.

The illustrated electric fan 54 is located with the baffle 62 to communicate the inlet air chamber 64 with the sealed combustion chamber 32. The electric fan 54 can be of any suitable type and is sized to draw a suitable amount of air from the air inlet chamber 64 to the sealed combustion chamber 32 to provide a desired pressure level within the sealed pressure chamber 32.

The illustrated flue gas outlet duct 56 is connected to an opening in the forward side of the rearward end wall 26 that communicates a first or inlet end of the outlet duct 56 with the sealed combustion chamber 32 near the burner assembly 48. The flue gas outlet duct 56 extends adjacent the water tank 16 and then through an opening in the forward side of the rearward end wall 26 and into the air chamber 64. The flue gas outlet duct 56 then extends through air chamber 64 into the combustion air inlet duct 52 where it extends to the exterior of the recreational vehicle 12. Thus, the portion of the flue gas outlet duct 56 outside of the water heater enclosure assembly 14 is located within the combustion air inlet duct 52 and is coaxial with the combustion air inlet duct 52. The flue gas outlet duct 56 forms a closed loop heat exchanger for the water tank 16. It is noted that both ducts 52, 56 extends through a single opening 72 within the exterior wall 68 of the recreational vehicle 12. In this configuration, the flue gas may also preheat the incoming combustion air to some degree.

The illustrated rearward end wall 26 is provided with three knockouts 74 for forming the duct opening 66 in one of three different locations facing different directions. The first knockout was located on a side of the rearward end wall 26 adjacent the inlet air chamber 64 and has been removed so that the attached ducts 52, 56 extend laterally from the enclosure assembly 14. The second knockout 74 is located at a top of the rear end wall 26 adjacent the inlet air chamber 64 so that the ducts 52, 56 can alternatively extend upwardly from the enclosure assembly 14. The third knockout 74 is located at a rear side of the rearward end wall 26 adjacent the inlet air chamber 64 so that the ducts 52, 56 can extend longitudinally in a rearward direction from the enclosure assembly 14. The knockouts 74 remain in place in the enclosure assembly 14 until installation when it is determined which direction the ducts 52, 54 are to extend. The installer then “knocks-out” or removes the knockout 74 that provides the duct opening 66 facing the desired direction. The ducts 52, 56 are then installed to extend in the desired direction. Thus the same water heater 10 can be utilized in a number of different locations and orientations within recreational vehicles 12.

The illustrated control system 20 includes an ignition control or controller 76, an electromechanical valve 78, a pressure switch 80, a thermostat 82, and an emergency cut-off switch 84. The ignition control 76 is provided with suitable electronics to control operation of the burner assembly 48, the valve 78, and the fan 54 in the desired manner. The ignition control 76 operably connects the ignition components to vehicle power. The illustrated ignition control 76 is operably connected to a 12 volt source but any other suitable type of source can alternatively be utilized. The illustrated burner igniter 58 is operably connected to a 110 volt source. The illustrated water heater 10 includes a 110 volt element 86 mounted to the front side of the forward end wall 24 but any other suitable power can alternatively be utilized. The illustrated electromechanical valve 78 connects the burner assembly 48 with the gas inlet line 50 to selectively supply gas to the burner assembly 48. The ignition control 76 is operably connected to the fan 54, the burner igniter 58, and to the valve 78. The pressure switch 80 detects pressure within the inlet air chamber 64 and the combustion chamber 32 to determine whether pressure within the combustion chamber 32 is at a predetermined desired pressure. When the draft inducing fan 54 creates the desired pressure within the combustion chamber 32, the ignition control 76 passes voltage to the valve 78 to open the valve 78 and pass gas to the burner assembly 48 and to a relay 88 which passes voltage to the burner igniter 58 to start combustion of the gas at the burner assembly 48. The ignition control 76 is regulated by the thermostat 82 and the emergency cut-off (ECO) switch 84 to obtain a desired temperature of the water within the water tank 16.

To heat water, water is supplied to the water tank 16 through the inlet 36. If an operating switch 90 of the ignition control 76 is closed, the ignition control 76 determines if the water temperature is at a desired temperature via the thermostat 82. If it is determined that the water in the water tank 16 needs to be heated, the igniter control 76 passes voltage to the draft inducing fan 54. Operation of the fan 54 pulls ambient air from the environment at the exterior of the recreational vehicle 12 through the combustion air inlet duct 52 and into the inlet air chamber 64 where it passes through the fan 54 and into the combustion chamber 32. When the pressure switch 80 senses that the pressure within the combustion chamber 32 is at a desired level compared to ambient pressure, the igniter control 76 passes voltage to the valve 78 to open the valve 78 so that gas enters the gas inlet line 50 and passes to the burner assembly 48. The igniter control 76 also passes voltage to the relay 88 which in turn passes voltage to the burner igniter 58. The burner igniter 58 ignites the gas to create a combustion flame which burns the gas and the combustion air within the combustion chamber 32. The draft inducing fan 54 forces the hot combustion gases out of the combustion chamber 32 and into the flue gas outlet duct 56. The hot flue gas travels though the outlet duct 56 adjacent the water tank 16 and heats the water tank 16 which in turn convectively dissipates the heat to the water in the interior of the tank 16. The flue gas continues though the outlet duct 56 until it exits the outlet duct 56 to the ambient environment at the exterior of the recreational vehicle 12. The igniter control 76 stops and starts the burner assembly 48 to generally maintain the water in the water tank 16 at the desired temperature. The fan 54 thus creates forced air flow through the closed heat exchanger system so that the flue gas can be directly vented to the environment as desired. Thus the system is not limited by the constraints of gravity flow.

It is apparent from the forgoing that the present invention provides an improved water heater 10 that can be utilized in any position having access to an exterior wall such as a side wall, end wall, or ceiling wall and can be oriented either parallel or perpendicular to the exterior wall or the like. It is noted that the same water heater 10 can be utilized in recreational vehicles requiring different orientations or positions and requires only a single outlet opening.

From the foregoing disclosure and detailed description of certain preferred embodiments, it is also apparent that various modifications, additions and other alternative embodiments are possible without departing from the true scope and spirit of the present invention. The embodiments discussed were chosen and described to provide the best illustration of the principles of the present invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted in accordance with the benefit to which they are fairly, legally, and equitably entitled.

Claims

1. A water heater for a recreational vehicle comprising, in combination:

an enclosure assembly;

a water tank for holding water to be heated located within the enclosure assembly;

a combustion system for heating water within the water tank and including a gas-fired burner assembly located within a sealed combustion chamber, a combustion air inlet duct communicating an external environment with the combustion chamber, a flue gas outlet duct communicating the combustion chamber with the external environment and extending near the water tank to transfer heat to water within the water tank, and an electric fan positioned to draw combustion air through the inlet duct and into the combustion chamber and force flue gas into the outlet duct and out of the combustion chamber; and

a control system for operating the combustion system including a thermostat and operably connected to the burner assembly, the fan, and the thermostat to generally maintain water in the water tank at a desired temperature.

2. The water heater for a recreational vehicle according to claim 1, wherein the fan is located at an inlet of the combustion chamber.

3. The water heater for a recreational vehicle according to claim 1, wherein the control system further includes a pressure switch so that the burner assembly is ignited when the fan is operating and the combustion chamber is at a desired pressure.

4. The water heater for a recreational vehicle according to claim 1, wherein a portion of the flue gas outlet duct extends within the combustion air inlet duct.

5. The water heater for a recreational vehicle according to claim 4, wherein the portion of the flue gas outlet duct extending within the combustion air inlet duct is coaxial with the combustion air inlet duct.

6. The water heater for a recreational vehicle according to claim 4, wherein the flue gas outlet duct and the combustion air inlet duct are adapted to extend through a single opening with an exterior wall of the recreational vehicle.

7. The water heater for a recreational vehicle according to claim 1, wherein the enclosure assembly is provided with a plurality of knockouts facing in different directions for forming an opening for the inlet and outlet ducts.

8. A water heater for a recreational vehicle comprising, in combination:

an enclosure assembly;

a water tank for holding water to be heated located within the enclosure assembly;

a combustion system for heating water within the water tank and including a gas-fired burner assembly located within a sealed combustion chamber, a combustion air inlet duct communicating an external environment with the combustion chamber, and a flue gas outlet duct communicating the combustion chamber with the external environment and extending near the water tank to transfer heat to water within the water tank;

a control system for operating the combustion system including a thermostat and operably connected to the burner assembly and the thermostat to generally maintain water in the water tank at a desired temperature; and

wherein a portion of the flue gas outlet duct extends within the combustion air inlet duct.

9. The water heater for a recreational vehicle according to claim 8, wherein the combustion system further includes an electric fan positioned to draw combustion air through the inlet duct and into the combustion chamber and force flue gas into the outlet duct and out of the combustion chamber.

10. The water heater for a recreational vehicle according to claim 9, wherein the fan is located at an inlet of the combustion chamber.

11. The water heater for a recreational vehicle according to claim 8, wherein the portion of the flue gas outlet duct extending within the combustion air inlet duct is coaxial with the combustion air inlet duct.

12. The water heater for a recreational vehicle according to claim 8, wherein the flue gas outlet duct and the combustion air inlet duct are adapted to extend through a single opening with an exterior wall of the recreational vehicle.

13. The water heater for a recreational vehicle according to claim 8, wherein the enclosure assembly is provided with a plurality of knockouts facing in different directions for forming an opening for the inlet and outlet ducts.

14. A water heater for a recreational vehicle comprising, in combination:

an enclosure assembly;

a water tank for holding water to be heated located within the enclosure assembly;

a combustion system for heating water within the water tank and including a gas-fired burner assembly located within a sealed combustion chamber, a combustion air inlet duct communicating an external environment with the combustion chamber, and a flue gas outlet duct communicating the combustion chamber with the external environment and extending near the water tank to transfer heat to water within the water tank;

a control system for operating the combustion system including a thermostat and operably connected to the burner assembly and the thermostat to generally maintain water in the water tank at a desired temperature; and

wherein the enclosure assembly is provided with a plurality of knockouts facing in different directions for forming an opening for the inlet and outlet ducts.

15. The water heater for a recreational vehicle according to claim 14, wherein the combustion system further includes an electric fan positioned to draw combustion air through the inlet duct and into the combustion chamber and force flue gas into the outlet duct and out of the combustion chamber.

16. The water heater for a recreational vehicle according to claim 15, wherein the fan is located at an inlet of the combustion chamber.

17. The water heater for a recreational vehicle according to claim 14, wherein the portion of the flue gas outlet duct extending within the combustion air inlet duct is coaxial with the combustion air inlet duct.

18. The water heater for a recreational vehicle according to claim 14, wherein the flue gas outlet duct and the combustion air inlet duct are adapted to extend through a single opening with an exterior wall of the recreational vehicle.

19. The water heater for a recreational vehicle according to claim 14, wherein a portion of the flue gas outlet duct extends within the combustion air inlet duct.

20. The water heater for a recreational vehicle according to claim 14, wherein the plurality of knockouts face in at least three different directions substantially perpendicular to one another.