Portable system for heating water

FIELD OF THE INVENTION

The present invention relates to an apparatus for heating water. More particularly, the present invention relates to a portable apparatus for heating water that may also be self-contained. In certain embodiments, the present invention may used to provide heated water for showers, cleaning, food preparation, and the like.

BACKGROUND OF THE INVENTION

Heated water is expected by many to be readily available under circumstances that may range from simple convenience to practical necessity. With usage varying from bathing to hot food, there is a demand for heated water over a broad range of temperatures and volumes. Consequently, water heaters and piping are installed as permanent fixtures for water delivery in homes, offices, and industrial settings. Faucets supplying heated water may be installed in fixed locations at anticipated points of use.

For some applications, a portable system for heating water may be required. Soldiers in the field may establish remote, temporary camps needing a portable water supply with heating capability. Requirements for military readiness and mobility may dictate that equipment should not be bulky, cumbersome, or difficult to unpack and setup. Similarly, campers may plan extended outdoor events in areas with water but limited or no access to heated water. Pet owners may wish to bathe an animal outside of the home but may not have an outdoor faucet supplying heated water.

Furthermore, permanent fixtures for the delivery of heated water remain unavailable in parts of the world. The infrastructure necessary for water delivery from a central location to individual homes and businesses may not be available. Elsewhere, a readily available water supply may exist but without fixtures for heating or an energy source to provide the heat.

Thus, an apparatus capable of heating water that is portable and that may be self-contained is desirable. Self-contained, as used with the present invention, means an apparatus capable of heating the water without requiring connection to an external or remote power source or remote fuel source. An apparatus that can also rapidly heat water without requiring storage in insulated tanks or containers would be an added benefit for portability.

Various devices for heating water exist. As the following examples demonstrate, the portability and degree of self-containment varies. U.S. Pat. No. 5,524,820, issued to Regan, discloses a device described as a portable water heater unit for field use. The device includes a housing containing a water heater and uses a heated water storage tank. An external supply of a flammable liquid fuel provides an energy source for heating. A pump and various controls are powered by an external power supply—i.e. the device must be plugged into a generator, external battery, or receptacle for operation. Accordingly, the portability of this device is delimited by the requirement that external equipment must be used in the disclosed embodiments.

U.S. Pat. No. 4,947,025, issued to Alston et al., discloses a portable electric water heater. The device contains a coiled water conducting tube and a rheostat for varying the amount of current supplied to the electric heating element. The power supply for the electric heating element is external to the device and serves to limit its portability.

U.S. Pat. No. 4,552,125 issued to Borodulin et al, discloses a portable solar water heater. The device includes a table containing solar collector panels for heating water when exposed to solar radiation. By definition, this device is limited to use during time periods when solar energy is available.

Numerous references disclose outdoor showering equipment, but each assumes either a separate device for supplying heated water, or an external power source for heating the water. U.S. Pat. No. 5,774,908, issued to Hall, discloses an outdoor shower with a chamber for holding water to be heated by solar energy. U.S. Pat. No. 5,920,927, issued to Thomas, discloses a combined portable shower and toilet assembly without a means for heating the water within the device. U.S. Pat. No. 5,911,520, issued to Kenney, discloses a portable shower apparatus with a vessel for storing water that can also be pressurized. Water of the desired temperature is placed into the vessel without an internal means for heating the water. U.S. Pat. No. 5,852,836, issued to Montrose, discloses a portable shower with water that is dispensed from a container within the apparatus. Water is placed into the container at the desired temperature without an internal means for heating.

Accordingly, a need exists for a portable apparatus that can provide for heating water. An apparatus that is portable and also self-contained is also needed. Specifically, there is a need for an apparatus that can heat water over a wide range of volumes and temperatures while minimizing the weight and space of the apparatus. The apparatus should also have an embodiment that can provide heated water without requiring connection to an external fuel supply or power source that is not equipped with the apparatus.

SUMMARY OF THE INVENTION

The present invention is directed to water heater that is portable and has a minimum of weight and requires minimal space. In specific embodiments, the present invention is also self-contained in that connection to an external power or fuel source is not required for heating water. The storage of heated water within tanks that add weight and consume space is also not required. The present invention also provides an apparatus that may be used to heat water for showering, cleaning, food preparation, and other applications where heated water is desired. The apparatus is not limited to heating water, and may be used by those skilled in the art with the teachings disclosed herein to heat other aqueous fluids that are non-flammable and that are not otherwise sensitive to the application of heat.

Specific embodiments of the present invention may be used in applications where a minimum of space is available. Accordingly, embodiments of the present invention may be installed into boats, campers, or other transportation vessels to provide heated water for showers, sinks, and the like. These embodiments may connect to an existing fuel source or power supply at the point of installation.

Furthermore, certain embodiments of the present invention may also be self-contained and of a size that can be easily transported by a single person. Thus, embodiments of the present invention may be used by soldiers, campers, sportsmen, or others desiring a portable and self-contained apparatus for heating water. For these embodiments, a fuel source or energy source may be provided with the apparatus so that connection to an external fuel supply or electrical power source is not necessary. A handle may also be provided in these embodiments for transporting the apparatus.

In one particular embodiment, the present invention includes a housing with a water inlet conduit, through which water to be heated may enter the housing. A pump is located within the housing. The pump has a supply section and a discharge section. The supply section of the pump is in fluid communication with the water inlet conduit. A battery is also located within the housing for providing power to operate the pump.

A heat exchanger is located within the housing that has an inlet section and an outlet section. The inlet section is in fluid communication with the discharge section of the pump. The heat exchanger preferably includes a conically-shaped interior coil. The conically-shaped interior coil is constructed of conduit and has a first end and a second end. The diameter of the conically-shaped interior coil decreases along the coil axis from the first end to the second end of the coil. The heat exchanger also includes a cap that is located proximate to the second end of the conically-shaped interior coil. The heat exchanger has an exterior coil constructed of conduit that is in fluid communication with the conically-shaped interior coil and the outlet section of the heat exchanger. A water outlet conduit is provided that is in fluid communication with the outlet section of the heat exchanger. Heated water may exit the housing of the water heater through the water outlet conduit.

The water heater includes a fuel inlet section, releasably connectable to a fuel source, through which fuel may be supplied to the water heater. A gaseous fuel control system is provided for controlling the flow of fuel from the fuel inlet section. A burner section, located in the housing, is provided for generating heat from fuel supplied to the water heater. The gaseous fuel control system connects the fuel inlet section to the burner section.

The gaseous fuel control system includes a valve that is located subsequent in flow to the fuel inlet section. An orifice, having an effective diameter in the range of about 0.010 to about 0.030 inch, is in communication with the valve. A port, also having an effective diameter in the range of about 0.010 to about 0.030 inch, is also in communication with the valve. During operation, fuel flows from the fuel inlet section and through the valve, then through the first orifice, and then through the port.

Accordingly, by way of example only and using the embodiment above described, to provide heated water from the portable water heater, the fuel inlet section is connected to a fuel supply through the resealable connection. The water inlet conduit is connected to or immersed into a water supply. If the water is not already pressurized, the pump is powered by connecting it to the battery. After obtaining flow of the water from the water outlet conduit, the burner section is ignited and begins to create heat through combustion of the fuel.

Unheated water enters the housing through the water inlet conduit and then flows to the supply section of the pump. When the pump is powered, the pump causes water to flow through the discharge section of the pump and into the inlet section of the heat exchanger. As the water travels through the coils of the heat exchanger, the temperature of the water increases from heat generated by the burner section. Heated water flows through the outlet section of the heat exchanger and is then released from the housing through the water outlet conduit. The valve may be adjusted to vary temperature of the water to enable one to obtain heated water at a desired temperature.

This description of an embodiment of the present invention is provided by way of example only. Various other embodiments exist and may be practiced using the teachings disclosed herein. By way of example only, the water outlet conduit may be connected to a shower head so that the apparatus may be used to heat water for bathing. Alternatively, in another embodiment, the present invention may include only a burner section, gaseous fuel control system, and fuel inlet section. Such an embodiment might be installed within the heated water system of a boat or camper to provide a heat source requiring only a minimum of space. In addition, the pump, switch, battery and fuel source may also be included, but without the housing, so as to provide a water heater that is self-contained but occupying a minimum of space.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a perspective view of an embodiment of the present invention.

FIG. 2

is a perspective and partial cross-sectional view of the embodiment of the present invention depicted in FIG.

1

.

FIG. 3

is a perspective view of a preferred embodiment of a burner section and heat exchanger according to the present invention.

FIG. 4

is a schematic representation of an embodiment of the present invention.

FIG. 5

is a side elevational view of the preferred embodiment of the burner section depicted in FIG.

3

.

FIG. 6

is a top view of the preferred embodiment of the burner section depicted in FIG.

3

.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference now will be made in detail to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.

Generally, the present invention relates to an apparatus for heating water. In particular embodiments, the present invention relates to a portable apparatus that may also be self-contained in that connection to an external fuel or electrical power source is not necessary to heat water. Alternatively, embodiments of the present invention may be connected to the fuel source or power source of an existing system to provide a portable and space saving water heater. Embodiments of the present invention may be used for providing heated water for bathing, cleaning, food preparation, and the like. In addition to water, the invention may also be used for heating other aqueous nonflammable solutions that are not otherwise adversely sensitive to the application of heat.

Referring now to

FIG. 1

, an embodiment of the water heater generally

10

is depicted with a housing

12

and a handle

14

for carrying the apparatus. Housing

12

may be constructed of any material that is suitable for protecting the internal components of the heater

10

and that is compatible with the intended use. For example, materials of construction may include various metals, plastics, composites, and the like. The shape of housing

12

is not limited to that depicted in FIG.

1

. Various shapes and sizes may be envisioned that protect the apparatus, provide stability during use, and that may also facilitate transport, storage, and use. A base

16

may also be included to further stabilize the apparatus and may be modified to shapes that facilitate use or installation of heater

10

in specific applications. Base

16

may include an aperture (not shown) for draining condensate away from the housing during operation of the water heater

10

. Similarly, handle

14

may be variously shaped and constructed of materials that are suitable for the lifting and handling of heater

10

. These materials include various metals, plastics, and the like.

A vent cap

18

is included to dissipate heat and gas created by the combustion of fuel. Preferably, vent cap

18

is shaped and constructed such that its surface temperature is minimized during operation of heater

10

. Accordingly, vent cap

18

may be any number of shapes and configurations in addition to that depicted in FIG.

1

. Alternatively, vent cap

18

may be replaced with a pipe or conduit for transporting released heat and gas away from the water heater

10

. This may be desirable or required for applications where the water heater

10

is being used in semi-enclosed locations.

Referring now to

FIG. 1

,

FIG. 2

, and

FIG. 4

, a fuel inlet section

20

is provided that is resealably connectable to a fuel source

22

. Fuel source

22

may be selected from any flammable fuels that will safely operate in the apparatus. For example, propane fuel may be used with the embodiment depicted in FIG.

1

and

FIG. 2. A

gaseous fuel control system is used to control the flow of fuel and includes a valve

25

, located subsequent in flow to fuel inlet section

20

, and activated through an actuator

26

. Valve

25

and the fuel inlet section

20

may be formed together as one piece as depicted in FIG.

1

and

FIG. 2

, or may be two separate pieces. The fuel inlet section

20

is resealably connectable to a fuel source

22

. Accordingly, fuel inlet section

20

may be a connectable conduit, a threaded conduit, an O-ring connector, a threaded base with an aperture, and the like for connecting to the fuel source

22

using a connection that is resealable and that will not allow a fuel leak.

Fuel source

22

may be positioned on the housing

12

as shown or may be contained within the housing

12

. In order to facilitate replacement and transport of the fuel source

22

, fuel source

22

is shown attached to the surface of the housing

12

by a suitable bracket

28

. When mounting the fuel source

22

outside of the housing

12

, the bracket

28

and fuel source

22

may be located anywhere upon the housing.

FIG. 1

shows a location that facilitates access to fuel source

22

while minimizing the volume and footprint occupied by water heater

10

.

Water to be heated may enter the housing

12

through a water inlet conduit

30

, and preferably is constructed from a flexible material. By way of example, inlet conduit

30

may be constructed from a polymer such as polyvinyl chloride tubing or polyvinyl chloride pipe, from copper tubing, or the like. A threaded connector

32

may be attached to one end of water inlet conduit

30

to allow connection to conventional fittings such as a faucet. Alternatively, for those embodiments that include a pump, threaded connector

32

may not be necessary since conduit

30

may simply be immersed into the water to be heated, such as a river, stream, lake, container of water, or the like. A strainer (not shown) may be located within water inlet conduit

30

or connector

32

to remove particulate matter from the unheated water supply.

A flow restrictor

34

may be used to regulate the flow of water into the water inlet conduit

30

. As shown in

FIG. 1

, a restrictor

34

may be connected to a pressurized water supply using threaded connector

32

.

The pressure of the water supply may be adequate to operate the water heater

10

without using a pump

42

within the housing

12

. However, a high pressure supply may cause a flow rate through the housing

12

that does not allow enough residence time within the housing

12

for heating the water to the desired temperature. Accordingly, flow restrictor

34

may be used to restrict the rate of flow to a level where the water may be heated to the desired temperature in a single pass through the heat exchanger. The flow restrictor

34

may be connected to conduit

30

as shown in

FIG. 1

, or otherwise located.

Heated water exits housing

12

through a water outlet conduit

36

. As with water inlet conduit

30

, the water outlet conduit

36

may be constructed from any material suitable and compatible with the water to be heated. The embodiment depicted in

FIG. 1

shows water outlet conduit

36

constructed from flexible tubing, and with a threaded connector

38

attached to the end thereof for connection to a shower head

40

or other water dispenser. Shower head

40

may be equipped with a variable flow valve for controlling the flow, and therefore also the temperature, of the heated water. A variety of shower heads may be utilized to produce differently shaped streams of heated water exiting the water heater

10

through the water outlet conduit

36

. Accordingly, the water heater

10

may be used for bathing, showering, washing, food preparation, and the like.

A control switch

60

may also be included with the water heater

10

for operating or controlling the pump. While a conventional off/on switch is illustrated in the figures, a push-button switch, toggle switch, dial, or the like may be employed. Furthermore, control switch

60

may include a rheostat or other variable control by which the speed of the pump

42

and therefore the temperature of the water may be varied.

Referring now to FIG.

2

and

FIG. 4

, water inlet conduit

30

is shown in fluid communication with a supply section

44

of the pump

42

. Pump

42

may be provided for applications where the unheated water is not adequately pressurized. For example, water heater

10

may be used by simply immersing water inlet conduit

30

into a container of water. Pump

42

may draw the water from the container, through the water inlet conduit

30

and into the supply section

44

of the pump

42

. The pump

42

then discharges the water through a discharge section

46

of the pump

42

.

Pump

42

may be constructed such that water heater

10

may be used with both a supply of water that is pressurized, or a supply of water that is not pressurized. For example, pump

42

may be structured such that when it is powered, water will be drawn from its source through water inlet conduit

30

. Alternatively, when water inlet conduit

30

is connected to a pressurized water supply, such as a water faucet, pump

42

will allow water to pass even when pump

42

is not powered. A preferred pump for use according to the present invention is a manual demand pump that will allow flow through even when the pump

42

is not powered, such as a Flojet, Model LF122002C manufactured by Flojet Corporation.

As depicted in

FIG. 4

, pump

42

may be powered by a battery

66

or any other sufficient power source. A solar panel recharger

68

may be included to recharge the battery

66

. A solar panel (not shown) may also be connected to power the pump without requiring power from the battery

66

.

Referring now to

FIGS. 2-4

, the discharge section

46

of pump

42

is in fluid communication with an inlet section

48

of a heat exchanger

50

. As depicted in

FIG. 3

, heat exchanger

50

preferably includes a conically-shaped interior coil

54

having a first end generally

56

and a second end generally

58

and being constructed of conduit. Conically-shaped coil

54

decreases in diameter along the coil axis

62

from the first end

56

to the second end

58

. A cap

64

is located proximate to the second end

58

of coil

54

, and generally plugs the space within coil

54

. An exterior coil

66

, preferably a continuation of coil

54

, is located exterior to conically-shaped interior coil

54

and is in fluid communication therewith. Exterior coil

66

is also in fluid communication with an outlet section

52

of heat exchanger

50

. From the outlet section

52

, heated water flows into the water outlet conduit

36

, and exits heater

10

.

Accordingly, as indicated by the arrows in

FIG. 3

showing flow through the conduit, water to be heated enters heat exchanger

50

through inlet section

48

, travels through conically-shaped interior coil

54

and exterior coil

66

, and exits heat exchanger

50

through outlet section

52

.

Heat exchanger

50

and cap

64

may be constructed of any material that will withstand the heat generated by combustion of the fuel and that will efficiently transfer heat to the water. This material should also be capable of manufacture into the described coil shapes. Suitable materials include steel, copper, and the like. Overall dimensions of heat exchanger

50

may be varied while adhering to the description herein provided. Cap

64

may be shaped as depicted in

FIG. 3

or may take any form that provides a restriction to the flow of heated gas from the second end

58

of interior coil

54

.

As shown in

FIG. 2

, heat exchanger

50

may be enclosed by a vent pipe

84

located within the housing

12

. Vent pipe

84

serves to insulate heat exchanger

50

and to direct combustion gases towards the vent cap

18

. Preferably, vent pipe

84

is double-walled as at

85

,

86

to provide additional insulation. Materials such as steel, aluminum, or other materials that will withstand the heat of combustion may be used for the vent pipe

84

.

Referring to

FIGS. 2-4

, the heat exchanger

50

may be heated through the combustion of fuel in a burner section

72

. Burner section generally

72

is located within the housing

12

and proximate to inlet section

48

of heat exchanger

50

. Fuel is supplied to burner section

72

from fuel source

22

via a gaseous fuel control system that also serves to control the flow of fuel. The gaseous fuel control system includes valve

25

, and conduits which contain an orifice

74

, and a port

76

. Valve

25

is located subsequent in flow to fuel inlet section

20

. From fuel inlet section

20

, fuel flows through valve

25

, then through orifice

74

in conduit

71

, and then through port

76

in conduit

71

. Orifice

74

has an effective diameter in the range of about 0.010 inch to about 0.030 inch, and preferably about 0.013 inch. Port

76

has an effective diameter in a range of from about 0.010 inch to about 0.030 inch, preferably about 0.018 inch.

Port

76

is in communication with a burner section

72

whereby fuel flows through port

76

into burner section

72

where the fuel is mixed with air and ignited. Combustion of the fuel releases heat for raising the temperature of water within the conduit of the heat exchanger

50

.

Referring to

FIGS. 2

,

5

, and

6

, burner section

72

may be circular as depicted or may take any shape capable of allowing the air to be mixed with fuel for proper combustion. Burner section

72

may also include one or more apertures

73

, located on side walls of same, with apertures

73

having effective diameters of about 0.25 to about 0.5 inch. Preferably, burner section

72

includes two such opposing apertures

73

.

Burner section

72

may have any height and diameter combination that provides for efficient combustion of the fuel. Preferably, burner section

72

has an effective diameter of about 0.5 inch to about 3 inches and an effective length of no less than about 0.5 inch. Still more preferably, burner section

72

has an effective diameter of about 1 inch and an effective length of about 2.5 inches, with two apertures

73

each having an effective diameter of about {fraction (5/16)} inch.

Burner section

72

may be constructed of any material capable of withstanding the heat generated by combustion of the fuel, such as copper, steel, ceramic materials, or the like. Conduit

71

is preferably positioned with respect to burner section

72

so as to locate port

76

within the burner section

72

as depicted in

FIGS. 2-6

, or may be located proximate to the burner section

72

for the release of fuel into the burner section

72

. Additionally, burner section

72

may be closed by a bottom

75

as depicted in

FIG. 5

, or may be left open. If burner section

72

is closed by bottom

75

, an opening may be made to allow the release of condensate.

Referring to FIG.

2

and

FIG. 4

, the gaseous fuel control system may also include a thermocouple

78

, a pilot switch

80

, and a shut-off valve

82

. During operation, thermocouple

78

detects the presence of heat from the burner section

72

whereby a shut-off valve

82

controlled thereby remains open allowing fuel to continue flow from fuel source

22

through conduit

71

to burner

72

. In the event the thermocouple

78

fails to detect adequate heat from the burner section

72

, shut-off valve

82

is closed and prevents the flow of fuel from fuel source

22

, shutting off heater

10

. Initial ignition is accomplished by activating a pilot switch

80

which overrides the action of the thermocouple

78

and the shut-off valve

82

until the fuel can be ignited and combustion is sufficient enough for thermocouple

78

to permit continued operation.

Operation of water heater

10

, as shown in

FIGS. 1 through 4

, will now be described. Water inlet conduit

30

is immersed into an unheated water source or may be connected to pressurized unheated water using threaded connector

32

. If the unheated water is not already pressurized, the pump

42

is then activated through control switch

60

.

Unheated water then flows into the housing

12

through the water inlet conduit

30

. From the water inlet conduit

30

, unheated water enters supply section

44

of pump

42

, exits pump

42

through discharge section

46

and passes through heat exchanger

50

, exiting through conduit

36

and shower head

40

.

Actuator

26

opens valve

25

permitting fuel to flow through inlet section

20

, through valve

25

, and orifice

74

and port

26

in conduit

71

to burner section

72

.

Pilot switch

80

is depressed to override the thermocouple

78

, and an ignition source or flame is placed at burner section

72

. Upon obtaining the production of heat from combustion of the fuel, the water is heated while passing through heat exchanger

50

. Valve

25

may be adjusted to regulate the temperature as desired.

The present invention may include other embodiments in addition to those already described. By way of example only, a further embodiment may include the fuel inlet section

20

, the gaseous fuel control system, and the burner section

72

connectable to a heat exchanger in, by way of example, a boat, camper, motor home or the like for heating water with an apparatus that occupies a minimum of space. Alternatively, an embodiment may include all of the components described as herein with the exception of the pump

42

. This particular embodiment may be acceptable where the water to be heated will always be supplied to the water inlet conduit

30

or the inlet section

48

of the heat exchanger

50

at a pressure sufficient to operate the water heater

10

without the pump

42

. In another example, a further embodiment may include all of the components described herein with the exception of the housing

12

for a permanent or semipermanent installation in a boat, motor home, or the like.

Although preferred embodiments of the invention have been described using specific terms, devices, and methods, such description is for illustrative purposes only. The words used are words of description rather than of limitation. It is to be understood that changes and variations may be made by those of ordinary skill in the art without departing from the spirit or the scope of the present invention, which is set forth in the following claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained therein.