Fluid heater system with tiltable heater assembly

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to fluid heaters and more particularly pertains to a new fluid heater system with a heater assembly that is tiltable for facilitating the performance of maintenance on the heater assembly and has relatively cooler exterior surfaces for safer operation.

2. Description of the Prior Art

Devices for pressurizing and heating fluid are known in the art. One type of fluid heating device uses combustion of a fuel in a combustion chamber to heat fluid moving through a length of tubing located in the combustion chamber. Typically, a burner is located at one end of the combustion chamber, and one or more coils of the tubing are typically located in the chamber toward the other end of the chamber. The burner directs a flame toward and over the coils of tubing. Some types of fluid heaters position the burner below the combustion chamber, and the burner fires upward toward a coil positioned above the burner. This arrangement is highly preferable for a variety of operational reasons but places a significant maintenance hardship on user of the devices.

Significantly, positioning of the burner on the bottom of the chamber places the burner beneath the combustion chamber in a difficult orientation for performing periodic maintenance on the burner. Support framing for the combustion chamber typically extends below the burner and thus further restricts access to the burner. In order to avoid having to crawl under the fluid heating device for servicing the burner, one approach has been to periodically invert the entire fluid heating device during the servicing. Because of the presence of fuels, cleaning solutions, and engine lubricating fluids often held in tanks on the fluid heating device, tipping of the device is disfavored because the possibility of spilling the liquids requires that all of the fluids be removed prior to each servicing, and often requires awkward propping of the device in the inverted position. As these devices typically weigh between 350 and 800 pounds, any attempt to tip them is both difficult and dangerous.

Another approach for facilitating servicing of the burner has been to permanently orient the combustion chamber of the device with the burner and the coil of tubing at substantially the same vertical level, so that the burner directs the flame in a generally horizontal direction toward the coils. Since the burner is essentially located beside of the combustion chamber, the burner is generally more accessible for periodic maintenance. However, with the tubing coiled about a horizontal axis, the tubing is difficult, if not impossible, to completely drain of fluid when necessary, such as for preparing the fluid heater device for maintenance on the coil of tubing or exposure to freezing temperatures, or to prevent corrosion during a period of extended non-use.

A further challenge presented by conventional fluid heaters employing a combustion chamber is the danger of burning or injuring the personnel working closely to the surfaces of the heater assembly, especially those exterior housing surfaces shrouding the combustion chamber in which the fuel is burned. Typically, insulation is positioned inside of the exterior housing surfaces in an attempt to resist heat transfer to the housing surfaces for keeping the exterior surfaces cooler than the hot surfaces of the combustion chamber. However, the use of insulation often fails to keep the housing surfaces cool enough to be safe to touch without injuring the skin of the operating personnel. Furthermore, simply adding enough additional layers of insulation to be effective produces a device that is excessively bulky, and the heat dissipated through the insulation is wasted.

These problems presented by conventional fluid heater designs have significantly impaired the safe use and regular maintenance of known fluid heaters.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the known types of fluid heaters now present in the prior art, the present invention provides a new fluid heater system with a heater assembly design that facilitates the performance of maintenance on the heater assembly and permits safer operation of the heater assembly.

To attain this purpose, the present invention generally comprises a support frame and a heater assembly mounted on the support frame. The heater assembly comprises a combustion chamber and a burner apparatus for burning fuel in the combustion chamber. The heater assembly is pivotally mounted on the support frame for permitting pivoting of the heater assembly in a substantially vertical plane with respect to the support frame such that the heater assembly is pivotable between an operational position and a maintenance position. The operational position is characterized by a central axis of the combustion chamber being oriented in a substantially vertical direction and the maintenance position is characterized by the central axis being rotated from the substantially vertical direction toward a generally horizontal direction. A locking structure may be provided for selectively locking the heater assembly with respect to the support frame in the operational position and in the maintenance position. The combustion chamber has a chamber perimeter wall defining a chamber interior, and the chamber perimeter wall has an outer surface. A heating conduit for carrying fluid for heating by the combustion chamber is provided, and the heating conduit has an inlet and an outlet. The heating conduit has a preheating portion adjacent to the inlet, and the preheating portion extends about the outer surface of the chamber perimeter wall of the combustion chamber for absorbing heat from the chamber perimeter wall of the combustion chamber.

There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1

is a schematic side view of a new fluid heater system with the improved heater assembly according to the present invention.

FIG. 2

is a schematic end view of the present invention particularly illustrating the heater assembly in the operational position.

FIG. 3

is a schematic end view of the present invention particularly illustrating the heater assembly in the maintenance position.

FIG. 4

is a schematic side view of the heater assembly of the present invention.

FIG. 5

is a schematic end view of the combustion chamber and heating conduit of the present invention.

FIG. 6

is a schematic sectional view of the heater assembly of the present invention taken along line

6

—

6

of FIG.

4

.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference now to the drawings, and in particular to

FIGS. 1 through 6

thereof, a new fluid heater system with improved heater assembly embodying the principles and concepts of the present invention and generally designated by the reference numeral

10

will be described:

As best illustrated in

FIGS. 1 through 6

, the fluid heating apparatus of the invention generally comprises a support frame

12

, and a heater assembly

38

including a heater housing

40

, a combustion chamber

42

, a burner apparatus

44

, and a heating conduit

46

for capturing (in a flow of fluid) heat from the combustion chamber.

The support frame

12

of the invention preferably includes a pair of upstanding heater support members

14

,

15

that are generally spaced from each other. Each of the heater support members

14

,

15

may comprise a pair of substantially vertically oriented support posts and a cross member

11

extending between the support posts. One of the heater support members may have a second cross member

13

for a purpose to be described below. Each of the upstanding heater support members

14

,

15

preferably has a pivot mount

16

,

17

formed thereon. One of the pivot mounts is preferably formed on the cross member

11

of each of the heater support members. Illustratively, each of the pivot mounts

16

,

17

may comprise a U-shaped bolt

18

,

19

having arms extending through the cross member

11

. Optionally, the structure of the pivot mount may take other forms, such as, for example, a hole or channel formed in the cross member. Preferably, the pivot mount

16

of a first one

14

of the heater support members is axially aligned with the pivot mount

17

of a second one

15

of the heater support members.

The support frame

12

may include an upstanding handle member

20

. The upstanding handle member preferably includes an upper portion

22

and a lower portion

23

. The upper portion

22

may lie in a plane angled from a plane in which the lower portion

23

lies in order to extend the upper portion away from the bulk of the support frame for facilitating gripping by user walking behind the frame when the frame is being pushed. The angle between the planes of the upper

22

and lower

23

portions is preferably an obtuse angle, with the obtuse angle illustratively measuring approximately 160 degrees. Ideally, the lower portion

23

is substantially vertically oriented, and is oriented substantially parallel to the first

14

and second

15

heater support members. The handle member may comprise a pair of upstanding handle posts

24

and a handle cross member

26

extending between the handle posts.

The support frame

12

also includes a base member

28

. The heater support members

14

,

15

,and the handle member

20

have lower portions that are mounted on the base member

28

, and the support

14

,

15

and handle

20

members extend upwardly from the base member.

The support frame

12

may also include a plurality of wheels for permitting rolling transport of the support frame across a surface. The plurality of wheels is mounted on the base member

28

. Preferably, a first pair

30

of the plurality of wheels is mounted on the base member in a manner permitting rotation of the wheels in a single plane, and illustratively the first pair

30

is mounted adjacent one of the support members

14

,

15

. Preferably, a second pair

32

of the plurality of wheels is mounted on the base member in a manner permitting rotation of the wheels in a plurality of planes, such as, for example, a swivel caster structure. The second pair

32

of wheels may be mounted on the base member adjacent the handle member

20

. Optionally, at least one of the second pair

32

of wheels has a locking means for selectively locking each wheel against rotation, and the locking means may be actuated by a rocker lever mounted on the axle of the wheel.

A control panel

34

may be provided on the support frame

12

for supporting controls for the fluid heater apparatus. Illustratively, the control panel

34

may be mounted on the handle member

20

and the first heater support member

14

.

A pump

36

may optionally be provided for moving the fluid to be heated through the fluid heater apparatus, and the pump is mounted on the support frame

12

.

The heater assembly

38

of the invention is provided for heating fluid, such as water, that is moved through the heater assembly by means such as, for example, the pump

36

. The heater assembly

38

is mounted on the support frame

12

in a manner supporting the heater assembly above a ground surface, and preferably above the base member of the frame

12

.

The heater assembly generally comprises the heater housing

40

, the combustion chamber

42

located in the heater housing, the burner apparatus

44

mounted on the heater housing, and the heating conduit

46

for moving fluid through the heater housing.

The heater housing

40

includes an outer peripheral wall

48

. The outer peripheral wall defines an interior of the heater housing, and the outer peripheral wall has an upper opening

50

and a lower opening

51

into the interior. The preferred outer peripheral wall has a substantially cylindrical shape, with the upper

50

and lower

51

openings being substantially circular.

The heater housing

40

may also include an inner peripheral wall

52

. The inner peripheral wall

52

is positioned in the interior defined by the outer peripheral wall

48

. The inner peripheral wall may have a substantially cylindrical shape, and preferably, the cylindrical inner peripheral wall is oriented coaxially with the cylindrical outer peripheral wall.

The heater housing

40

may also include a bottom wall

54

that extends across the lower opening of the outer peripheral wall. The bottom wall may have a central burner opening

56

for accommodating the burner assembly. In one embodiment of the invention, the bottom wall has a shallow frustaconical shape that has a generally concave outward surface.

The heater housing

40

may also include a skirt

58

that extends from the outer peripheral wall at the lower opening for at least partially protecting the burner assembly from, for example, spray from a pressurized spray gun. Preferably, the skirt has a substantially cylindrical shape and extends from the outer peripheral wall in a downward direction from the lower opening. The skirt may comprise a resiliently flexible material that facilitates manual movement of the skirt for access to the burner assembly mounted on the bottom wall area of the heater housing.

The heater housing

40

may also include a top wall

60

covering the upper opening

50

of the outer peripheral wall. The top wall may be removably mounted on the outer peripheral wall adjacent to the upper opening. The top wall may have a circular shape for mounting on a cylindrically-shaped outer peripheral wall. Preferably, the top wall has a central vent opening

62

for permitting exhaust of combustion gases from the combustion chamber. The top wall thus has an annular shape. In one illustrative embodiment of the invention, the top wall has a diameter more than twice a diameter of the central vent opening. A retaining lip

64

may depend from an outer edge of the top wall, and may be removably secured to the outer peripheral wall. Optionally, an insulative material

66

may be positioned adjacent to an inward surface of the top wall for reducing the temperature of the top wall of the heater housing.

Optionally, a vent wall

68

may be provided surrounding the central vent opening in the top wall. The vent wall extends generally upwardly in a substantially perpendicular orientation to the top wall.

A pair of mounting members

70

,

71

are provided for supporting the heater housing on the heater support members

14

,

15

of the support frame

12

. Each of the mounting members may be located adjacent an inner surface of the outer peripheral wall

48

. The mounting members

70

,

71

are located adjacent to substantially diametrically opposite locations of the outer peripheral wall. In one embodiment of the invention having the inner peripheral wall

52

, the mounting members are positioned between the outer and inner peripheral walls.

A pair of pivot shafts

72

,

73

are provided for mounting the heater housing to the support frame. Each of the pivot shafts extend outwardly from the outer peripheral wall, and each of the pivot shafts are rotatably received in one of the pivot mounts

16

,

17

of the heater support members of the support frame. A first one

72

of the pivot shafts is axially aligned with and is substantially coaxial with a second one

73

of the pivot shafts. The first one

72

of the pivot shafts extends in a diametrically opposite direction from the heater housing with respect to the second one

73

of the pivot shafts. Each of the pivot shafts is pivotally mounted on one of the mounting members. In the embodiment of the invention having pivot mounts employing U-shaped bolts

18

,

19

, the U-shaped bolt

19

clamps a portion of one

17

of the pivot shafts against the cross member

11

. Preferably, one

71

of the mounting members has a first locking aperture

74

formed in the mounting member at a location that is separated from the location of the pivot shaft mounted on the mounting member.

The combustion chamber

42

of the heater assembly includes a chamber perimeter wall

76

that defines a chamber interior. The chamber perimeter wall has an upper end

78

and a lower end

79

, and the upper end of the chamber perimeter wall is preferably substantially open into the chamber interior. The chamber perimeter wall of the combustion chamber may be substantially cylindrical, and is preferably substantially coaxial with the outer peripheral wall of the heater housing such that a perimeter chamber

80

is formed between the chamber perimeter wall of the combustion chamber and the outer peripheral wall of the heater housing. In the embodiment of the invention employing an inner peripheral wall

52

, the chamber perimeter wall has an outer surface oriented adjacent to an inner surface of the inner peripheral wall. Preferably, the chamber perimeter wall

76

comprises a material that reflects the heat from combustion back into the interior of the combustion chamber. Ideally, the material of the chamber perimeter wall comprises a refractive material for reflecting much of the combustion heat, and retaining a significant portion of the heat that is not reflected.

A heat reflective chamber floor wall

82

may be provided that extends across the chamber interior adjacent to the lower end of the chamber perimeter wall. The chamber floor wall may have a central opening

84

therein for receiving a portion of the burner assembly. The chamber floor wall preferably comprises a heat reflective material similar to the material forming the chamber perimeter wall, such as a refractive material.

The burner apparatus

44

is provided for burning fuel in the interior of the combustion chamber. The burner apparatus expels heat into the chamber interior of the combustion chamber. The burner apparatus is mounted on the bottom wall

54

of the heater housing and directs heat upwardly into the chamber interior of the combustion chamber toward the upper end of the perimeter wall. The burner apparatus may extend through the central opening

84

in the chamber floor wall

82

of the combustion chamber, with a serviceable portion of the burner apparatus being located below the floor wall.

The heating conduit

46

for moving fluid through the heater housing has an inlet

86

and an outlet

87

. Preferably, the inlet

86

is fluidly connected to the pump

36

and the outlet

87

is fluidly connected, for example, to a dispensing hose (not shown) and a spray gun (not shown). The heating conduit has a preheating portion

88

that is located adjacent in the fluid flow to the inlet of the heating conduit, and a heating portion

90

that is located adjacent in the fluid flow to the outlet of the heating conduit.

Significantly, the preheating portion

88

of the heating conduit extends about the chamber perimeter wall

76

in the perimeter chamber

80

for absorbing heat passing through the chamber perimeter wall. The movement of unheated, relatively cool fluid (from, for example, the pump) through the perimeter chamber

80

of the heater housing permits the fluid to be initially heated prior to entry of the heating conduit into the combustion chamber. More importantly, the preheating portion serves a portion of the heat passing through the chamber perimeter wall

76

from the combustion chamber which would otherwise pass through the perimeter chamber and heat the outer peripheral wall of the housing and create a burning injury hazard to exposed skin touching the outer surface of the outer peripheral wall.

The preheating portion

88

of the heating conduit comprises a substantially helical coil

92

extending around the chamber perimeter wall. If an inner peripheral wall is included in the heater housing, the preheating portion of the heating conduit may contact an outer surface

94

of the inner peripheral wall for maximizing the heat transfer from the chamber perimeter wall and the inner peripheral wall to the preheating portion of the heating conduit.

The helical coil

92

comprises a plurality of loops

96

, and preferably, all of the loops have substantially equal diameter. The helical coil generally extends from a location adjacent to the lower end

79

of the chamber perimeter wall to a location adjacent to the upper end

78

of the chamber perimeter wall. Preferably, each of the loops

96

may be spaced from an adjacent one of the loops, and optionally the spacing between centers of adjacent loops is substantially uniform. Illustratively, the spacing between adjacent loops may be approximately two inches. Optionally, the spacing between adjacent loops may be reduced (or even eliminated) toward the upper region of the heater housing, especially at a vertical level above the upper end of the chamber perimeter wall.

In one embodiment of the invention, the helical coil

92

of the preheating portion of the heating conduit may include approximately eight loops. Preferably, each of the mounting members

70

,

71

is mounted on at least two of the loops of the helical coil of the preheating portion for supporting the heating assembly. The pivot shafts

72

,

73

extend outwardly through the outer peripheral wall

48

and engage the pivot mounts

16

,

17

.

The helical coil

92

has a lowermost loop

98

and an uppermost loop

100

. The preheating portion is adapted such that fluid enters the lowermost loop

98

of the helical coil and exits the uppermost coil

100

of the helical coil. Optionally, the helical coil

92

is spaced from an inner surface

102

of the outer peripheral wall of the heater housing to produce an air space between the helical coil and the outer peripheral wall for reducing any heat transfer between the preheating portion

88

and the outer peripheral wall

48

. Illustratively, the space between an outermost surface of the helical coil and the inner surface of the outer peripheral wall may be approximately one inch.

The heating portion

90

of the heating conduit is positioned adjacent to the upper end

78

of the chamber perimeter wall of the combustion chamber in a location permitting heat rising in the chamber interior to pass over the heating portion of the heating conduit before being vented from the interior of the heater housing.

In the preferred heater assembly, the preheating portion

88

is located below the heating portion

90

. In one illustrative embodiment, a length of the preheating portion of the heating conduit is substantially equal to a length of the heating portion of the heating conduit, although the length of the heating portion is preferably at least as long, and may be relatively longer, than the preheating portion.

Significantly, the heating portion

90

comprises at least one tier, and most preferably includes an upper tier

104

oriented above a lower tier

106

. Each tier

104

,

106

comprises a spiral coil comprising a plurality of spirals

108

. Any number of tiers may be welded together to increase the heat-transfer surface area as needed to reach the desired fluid temperature. The spirals

108

of each tier lie substantially in a common or single plane. The plane of each tier is preferably substantially horizontally oriented. Each tier of the heating portion has an outermost spiral

110

and an innermost spiral

112

, with spirals nested therebetween. The outermost spiral

110

of the spiral coil of the heating portion is fluidly connected to the uppermost loop

100

of the helical coil of the preheating portion

88

. The outermost loop of the heating portion preferably has a diameter approximately equal to the loops of the preheating portion. Illustratively, each of the tiers

104

,

106

includes approximately seven spirals.

The innermost spiral of the lower tier is fluidly connected to the innermost spiral of the upper tier. The upper and lower tiers are preferably oriented substantially parallel to each other. Illustratively, the distance between adjacent spirals of the upper and lower tiers is approximately 2 inches. The tiers may be adapted such that fluid is moved from the outermost spiral of the lower tier to the innermost spiral of the lower tier to the innermost spiral of the upper tier to the outermost spiral of the upper tier.

Optionally, an insulative annular wall

114

may be positioned laterally outward from the heating portion

90

of the heating conduit for holding heat in the area of the combustion chamber. The insulative annular wall

114

is positioned inside of the outer peripheral wall

48

of the heater housing.

Significantly, the heater assembly

38

is pivotally mounted on the support frame

12

in a manner that permits selective pivoting of the heater assembly with respect to the support frame. An operational position (see

FIG. 2

) of the heater assembly is characterized by a central axis of the combustion chamber being oriented in a substantially vertical direction. A maintenance position, (see

FIG. 3

) of the heater assembly is characterized by the central axis being shifted or rotated from the substantially vertical direction toward a generally horizontal direction. Thus, pivoting of the heater assembly from the operational position to the maintenance position raises the burner assembly relative to the combustion chamber. The maintenance position permits the burner assembly

44

mounted at the base of the combustion chamber to be worked upon without having to reach under the heater assembly, especially when the burner assembly is located in close proximity to the base member of the support frame at a height of only about 12 inches from the ground surface.

A locking means or mechanism

116

may be provided for selectively locking the heater assembly

38

with respect to the support frame in the operational position and the maintenance position. The locking mechanism

116

may include the first locking aperture

74

formed on the heater housing at a distance from one

73

of the pivot shafts of the heater housing and extending through the outer peripheral wall. A second locking aperture

120

is provided for securing the heater assembly in the operational position. The second locking aperture may be formed on one

15

of the heater support members, such as on an upper one

11

of the cross members. The second locking aperture is alignable with the first locking aperture

74

when the heater housing

40

is in the operational position for permitting a fastener to be removably extended through the second locking aperture and into the first locking aperture, which may be threaded for removably holding the fastener in the first and second locking apertures. The second locking aperture

120

is located below the pivot mount

17

in the heater support member

15

. A third locking aperture

122

is provided for securing the heater assembly in the maintenance position. The third locking aperture may be formed on the heater support member

15

, such as on a lower one

13

of the cross members. The third locking aperture is alignable with the first locking aperture when the heater housing is in the maintenance position for permitting a fastener to be removably extended through the third locking aperture and into the first locking aperture. The third locking aperture

122

is preferably located in a substantially horizontal direction from the pivot mount in the first heater support member.

With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.