U.S. patent application number 12/816751 was filed with the patent office on 2011-12-22 for water heater blower housing.
This patent application is currently assigned to Bradford White Corporation. Invention is credited to Michael W. Gordon, Eric Truskoski.
Application Number | 20110308481 12/816751 |
Document ID | / |
Family ID | 45327284 |
Filed Date | 2011-12-22 |
United States Patent
Application |
20110308481 |
Kind Code |
A1 |
Gordon; Michael W. ; et
al. |
December 22, 2011 |
WATER HEATER BLOWER HOUSING
Abstract
A fuel-fired water heater includes a water storage tank, a flue
positioned to receive combustion gases and transfer heat from
combustion gases to water in the water storage tank, and a blower
assembly. The blower assembly includes a housing defining an inlet
positioned to receive combustion gases from the flue, an interior
defined by the housing, and an outlet positioned to exhaust
combustion gases from the interior of the housing. The blower
assembly further includes a motor/impeller assembly that is
positioned in the interior of the housing and is configured to
direct combustion gases from the inlet of the housing toward the
outlet of the housing. The housing of the blower assembly includes
an interior wall portion, an exterior wall portion, and
sound-absorbing material interposed between the interior and
exterior wall portions. The interior wall portion defines
perforations extending between the sound-absorbing material and the
interior of the housing.
Inventors: |
Gordon; Michael W.; (East
Grand Rapids, MI) ; Truskoski; Eric; (Grandville,
MI) |
Assignee: |
Bradford White Corporation
Ambler
PA
|
Family ID: |
45327284 |
Appl. No.: |
12/816751 |
Filed: |
June 16, 2010 |
Current U.S.
Class: |
122/18.1 ;
417/312 |
Current CPC
Class: |
F24H 1/205 20130101;
F23L 11/02 20130101; F23L 17/005 20130101 |
Class at
Publication: |
122/18.1 ;
417/312 |
International
Class: |
F24H 1/18 20060101
F24H001/18; F04B 39/00 20060101 F04B039/00 |
Claims
1. A fuel-fired water heater comprising: a water storage tank; a
flue positioned to receive combustion gases and transfer heat from
combustion gases to water in the water storage tank; and a blower
assembly having a housing defining an inlet positioned to receive
combustion gases from the flue, an interior defined by the housing,
and an outlet positioned to exhaust combustion gases from the
interior of the housing, the blower assembly also having a
motor/impeller assembly positioned in the interior of the housing
and configured to direct combustion gases from the inlet of the
housing toward the outlet of the housing; the housing of the blower
assembly comprising an interior wall portion, an exterior wall
portion, and sound-absorbing material interposed between the
interior and exterior wall portions, the interior wall portion
defining perforations extending between the sound-absorbing
material and the interior of the housing.
2. The fuel-fired water heater of claim 1, wherein the housing of
the blower assembly further comprises an air inlet port positioned
to deliver air into the interior of the housing.
3. The fuel-fired water heater of claim 2 further comprising a
perforated wall that is positioned to at least partially conceal
the air inlet port of the housing.
4. The fuel-fired water heater of claim 1, wherein the
sound-absorbing material comprises fiberglass or mineral wool.
5. The fuel-fired water heater of claim 1, wherein the interior
wall portion is composed of a metallic material.
6. The fuel-fired water heater of claim 1, wherein an aperture is
formed in the interior wall portion, the exterior wall portion, and
the sound-absorbing material to form the inlet of the housing.
7. The fuel-fired water heater of claim 1, wherein an aperture is
formed in the interior wall portion, the exterior wall portion, and
the sound-absorbing material to form the outlet.
8. A blower assembly for a fuel-fired water heater having a water
storage tank and a flue positioned to receive combustion gases and
transfer heat from combustion gases to water in the water storage
tank, the blower assembly comprising: a blower housing assembly
including: a perforated sheet having an interior surface that
defines a hollow interior region configured to receive combustion
gases from the flue; a sound-absorbing material positioned adjacent
an entire exterior surface of the perforated sheet that is opposite
the interior surface of the perforated sheet; and a housing
encapsulating both the sound-absorbing material and the perforated
sheet, wherein an exterior surface of the sound-absorbing material
and an interior surface of the housing together define an air gap
between the sound-absorbing material and the housing, a
motor/impeller assembly positioned within the hollow interior
region defined by the perforated sheet; wherein the arrangement of
the sound-absorbing material, the perforated sheet and the air-gap
dampens audible noise emitted by the motor/impeller assembly.
9. The blower assembly of claim 8, wherein the sound-absorbing
material comprises fiberglass or mineral wool.
10. The blower assembly of claim 8 further comprising an air intake
port and another perforated sheet mounted to the air intake
port.
11. The blower assembly of claim 8 further comprising an air intake
plenum mounted to the housing, an air intake port positioned to
deliver air into the air intake plenum, and another perforated
sheet mounted to the air intake port of the air intake plenum.
12. The blower assembly of claim 8, wherein the sound-absorbing
material is positioned adjacent an entire exterior surface of the
perforated sheet.
13. The blower assembly of claim 8, wherein the perforated sheet is
composed of a metallic material.
14. The blower assembly of claim 8 further comprising a passageway
that is positioned to receive combustion gases from the flue tube
of the water heater, said passageway being defined in the housing,
the sound-absorbing material and the perforated sheet.
15. The blower assembly of claim 8 further comprising an exhaust
passageway that is positioned to exhaust combustion products from
the housing, said passageway being defined in the housing, the
sound-absorbing material and the perforated sheet.
16. The blower assembly of claim 8 further comprising an air
passageway through which atmospheric air is delivered into the
housing of the blower assembly, said passageway being defined in
the housing, the sound-absorbing material and the perforated
sheet.
17. A housing assembly for a water heater, said housing assembly
comprising: a perforated sheet having an interior surface that
defines a hollow interior region for encapsulating a noise
producing component of the water heater; a sound-absorbing sheet,
which is composed of sound-absorbing material, positioned adjacent
an exterior surface of the perforated sheet that is opposite the
interior surface of the perforated sheet; and a housing
encapsulating the sound-absorbing sheet and the perforated sheet,
wherein the sound-absorbing sheet is separated from an interior
surface of the housing by a pre-determined distance thereby
defining an air gap between the sound-absorbing sheet and the
housing, wherein the arrangement of the sound-absorbing sheet, the
perforated sheet and the air-gap dampens audible noise emitted by
the noise producing component positioned within the hollow interior
region.
18. The housing assembly of claim 17, wherein the sound-absorbing
sheet comprises fiberglass or mineral wool.
19. The housing assembly of claim 17 further comprising an air
intake port and another perforated sheet mounted to the air intake
port.
20. The housing assembly of claim 17 further comprising an air
intake plenum mounted to the housing, an air intake port positioned
to deliver air into the air intake plenum, and another perforated
sheet mounted to the air intake port of the air intake plenum.
21. The housing assembly of claim 17, wherein the sound-absorbing
material is positioned adjacent an entire exterior surface of the
perforated sheet.
22. The housing assembly of claim 17, wherein the perforated sheet
is composed of a metallic material.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a blower housing for a
water heater and to a method of reducing the noise produced by a
blower of a water heater.
BACKGROUND OF THE INVENTION
[0002] Many water heaters commonly include a water storage tank for
storing water, a gas-fired or oil-fired burner that produces hot
combustion gases or flue gases, a flue tube that is positioned
within the water tank to transfer heat from combustion gases to
water in the water storage tank, and a blower that draws the hot
flue gases through the flue tube and out of the water heater. Such
water heaters may be installed in a residence or a commercial
building, for example.
[0003] The following patent documents describe samples of water
heater systems and are incorporated by reference herein in their
entirety: U.S. Pat. Nos. 5,199,385, 7,484,688, 7,540,354 7,559,293,
and 7,604,463 and U.S. Patent App. Pub. Nos. 2009/0205901 and
2009/0173572.
[0004] Despite past improvements to water heater systems such as
those described in the foregoing patent documents, there remains a
need for improved water heater systems and for improved blower
components for use in such water heater systems.
SUMMARY OF THE INVENTION
[0005] In one exemplary embodiment, this invention provides a
fuel-fired water heater. The fuel-fired water heater generally
comprises a water storage tank, a flue positioned to receive
combustion gases and transfer heat from combustion gases to water
in the water storage tank, and a blower assembly. The blower
assembly includes a housing defining an inlet positioned to receive
combustion gases from the flue, an interior defined by the housing,
an inlet to draw in dilution air, and an outlet positioned to
exhaust combustion gases from the interior of the housing. The
blower assembly further comprises a motor/impeller assembly that is
positioned in the interior of the housing and is configured to
direct combustion gases from the inlet of the housing toward the
outlet of the housing. The housing of the blower assembly comprises
an interior wall portion, an exterior wall portion, and
sound-absorbing material interposed between the interior and
exterior wall portions. The interior wall portion defines
perforations extending between the sound-absorbing material and the
interior of the housing.
[0006] In another exemplary embodiment, a blower assembly for a
fuel-fired water heater having a water storage tank and a flue
positioned to receive combustion gases and transfer heat from
combustion gases to water in the water storage tank is provided.
The blower assembly comprises a blower housing assembly including a
perforated sheet having an interior surface that defines a hollow
interior region configured to receive combustion gases from the
flue. A sound-absorbing material is positioned adjacent an entire
exterior surface of the perforated sheet that is opposite the
interior surface of the perforated sheet. A housing encapsulates
both the sound-absorbing material and the perforated sheet, wherein
an exterior surface of the sound-absorbing material and an interior
surface of the housing together define an air gap between the
sound-absorbing material and the housing. A motor/impeller assembly
is positioned within the hollow interior region defined by the
perforated sheet. The arrangement of the sound-absorbing material,
the perforated sheet and the air-gap dampens audible noise emitted
by the motor/impeller assembly.
[0007] In yet another exemplary embodiment, a housing assembly for
a water heater is provided. The housing assembly generally
comprises a perforated sheet having an interior surface that
defines a hollow interior region for encapsulating a noise
producing component of the water heater. A sound-absorbing sheet,
which is composed of sound-absorbing material, is positioned
adjacent an exterior surface of the perforated sheet that is
opposite the interior surface of the perforated sheet. A housing
encapsulates the sound-absorbing sheet and the perforated sheet.
The sound-absorbing sheet is separated from an interior surface of
the housing by a pre-determined distance thereby defining an air
gap between the sound-absorbing sheet and the housing. The
arrangement of the sound-absorbing sheet, the perforated sheet and
the air-gap dampens audible noise emitted by the noise producing
component positioned within the hollow interior region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The invention is best understood from the following detailed
description when read in connection with the accompanying drawings.
It is emphasized that, according to common practice, the various
features of the drawings are not to scale. On the contrary, the
dimensions of the various features are arbitrarily expanded or
reduced for clarity. Included in the drawings are the following
figures:
[0009] FIG. 1 depicts a schematic cross-sectional elevation view of
an embodiment of a water heating system, which is shown
schematically, according to aspects of this invention.
[0010] FIG. 2 depicts a schematic cross-sectional view of a blower
assembly of the water heating system of FIG. 1.
[0011] FIGS. 3A through 3D depict perspective, rear elevation, side
elevation and top plan views, respectively, of another embodiment
of a blower assembly according to aspects of this invention.
[0012] FIG. 3E depicts a detailed view of the air inlet plenum of
the blower assembly of FIG. 3C taken along the lines 3E-3E.
[0013] FIG. 4 depicts a rear elevation view of yet another
exemplary embodiment of a blower assembly according to aspects of
this invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0014] Exemplary features of selected embodiments of this invention
will now be described with reference to the figures. It will be
appreciated that the spirit and scope of the invention is not
limited to the embodiments selected for illustration. Also, it
should be noted that the drawings are not rendered to any
particular scale or proportion. It is contemplated that any of the
exemplary configurations and materials and sizes described
hereafter can be modified within the scope of this invention.
[0015] Referring generally to the figures and according to one
exemplary embodiment of the invention, this invention provides a
fuel-fired water heater 15. The fuel-fired water heater 15
generally comprises a water storage tank 22, a flue 25 positioned
to receive combustion gases and transfer heat from combustion gases
to water in the water storage tank 22, and a blower assembly 30.
The blower assembly 30 includes a housing 31 defining an inlet 38
positioned to receive combustion gases from the flue 25, an
interior defined by the housing 31, and an outlet 42 positioned to
exhaust combustion gases from the interior of the housing 31. The
blower assembly 30 further comprises a motor/impeller assembly 32
and 36 that is positioned in the interior of the housing 31 and is
configured to direct combustion gases from the inlet 38 of the
housing 31 toward the outlet 42 of the housing 31. The housing 31
of the blower assembly 30 comprises an interior wall portion 60, an
exterior wall portion 50, and sound-absorbing material 52
interposed between the interior and exterior wall portions. The
interior wall portion 60 defines perforations 70 extending between
the sound-absorbing material 52 and the interior of the housing
31.
[0016] In another exemplary embodiment, a blower assembly 30 for a
fuel-fired water heater 15 having a water storage tank 22 and a
flue 25 positioned to receive combustion gases and transfer heat
from combustion gases to water in the water storage tank 22 is
provided. The blower assembly 30 comprises a blower housing
assembly 31 including a perforated sheet 60 having an interior
surface that defines a hollow interior region configured to receive
combustion gases from the flue 25. A sound-absorbing material 52 is
positioned adjacent an entire exterior surface of the perforated
sheet 60 that is opposite the interior surface of the perforated
sheet 60. A housing 50 encapsulates both the sound-absorbing
material 52 and the perforated sheet 60, wherein an exterior
surface of the sound-absorbing material 52 and an interior surface
of the housing 50 together define an air gap 54 between the
sound-absorbing material 52 and the housing 50. A motor/impeller
assembly 32 and 36 is positioned within the hollow interior region
defined by the perforated sheet 60. The arrangement of the
sound-absorbing material 52, the perforated sheet 60 and the
air-gap 54 dampens audible noise emitted by the motor/impeller
assembly 32 and 36.
[0017] In yet another exemplary embodiment, a housing assembly 31
for a water heater 15 is provided. The housing assembly 31
generally comprises a perforated sheet 60 having an interior
surface that defines a hollow interior region for encapsulating a
noise producing component 32 and/or 36 of the water heater 15. A
sound-absorbing sheet 52, which is composed of sound-absorbing
material, is positioned adjacent an exterior surface of the
perforated sheet 60 that is opposite the interior surface of the
perforated sheet 60. A housing 50 encapsulates the sound-absorbing
sheet 52 and the perforated sheet 60. The sound-absorbing sheet 52
is separated from an interior surface of the housing 50 by a
pre-determined distance thereby defining an air gap 54 between the
sound-absorbing sheet 52 and the housing 50. The arrangement of the
sound-absorbing sheet 52, the perforated sheet 60 and the air-gap
54 dampens audible noise emitted by the noise producing component
32 and/or 36 positioned within the hollow interior region.
[0018] Referring now to FIG. 1, a fuel-fired water heating system
embodying exemplary aspects of this invention is shown
schematically and is generally designated by the numeral "10." In
the water heating system 10, a water heater 15 is attached to a
fuel supply line 17 and an exhaust vent 20. The fuel supply line 17
supplies fuel (e.g., oil or combustible gas) to a fuel burner 21 of
the water heater 15 for combustion, and the exhaust vent 20
provides a conduit for exhausting the products of combustion from
the water heater 15. The exhaust vent 20 may be integrated with a
residential structure, or integrated with the water heater 15.
[0019] The water heater 15 generally includes a water storage tank
22 for containing water, an outer shell 24 for encapsulating the
water tank 22, and a flue 25 positioned within the interior region
of the water tank 22 for distributing combustion products for heat
exchange with water in the water tank 22. The fuel burner 21
produces combustion products and is positioned within a combustion
chamber 29 beneath the water tank 22. The combustion chamber 29
directs the combustion products into an inlet end 27 of the flue
25. The flue 25 is positioned within the interior of the water tank
22 for distributing combustion products for heat exchange with
water in the water tank 22. The outlet end 23 of the flue 25
extends through apertures provided in the top surface of the water
tank 22 and the top surface of the outer shell 24.
[0020] A blower assembly 30 is mounted to the top surface of the
outer shell 24. The blower assembly 30 generally includes a housing
assembly 31, a motor 32 that is fastened to the housing assembly 31
by a plurality of brackets 34, and an impeller 36 that is coupled
to the motor 32 by a shaft 37 such that the impeller 36 is driven
by the motor 32. The impeller 36 includes veins (not shown) which
urge combustion products and air into the housing assembly 31 and
exhaust the combustion products and air into the exhaust vent
20.
[0021] Referring now to FIGS. 1 and 2, the housing assembly 31 of
the blower assembly 30 includes an inlet port 38 that is connected
to the outlet end 23 of the flue 25, an air intake plenum 41
defining an air intake port 40, and an exhaust port 42 that is
coupled to the exhaust vent 20. In operation, as indicated by the
arrows in FIG. 1, combustion products from the flue 25 are urged by
the impeller 36 into the interior of the housing assembly 31
through the inlet port 38. Atmospheric air is urged by the impeller
36 into the interior of the housing assembly 31 through the air
intake port 40. The products of combustion and the atmospheric air
are then exhausted through the exhaust port 42 into the exhaust
vent 20. Further details of the structure and operation of examples
of a blower motor and a impeller are disclosed in U.S. Pat. No.
5,199,385, which is incorporated by reference herein in its
entirety.
[0022] FIG. 2 depicts a detailed view of a cross-section of the
blower assembly 30 of the water heating system of FIG. 1. The
blower assembly 30 is shown schematically in FIGS. 1 and 2. As
described in detail hereinafter, the housing assembly 31 of the
blower assembly 30 is uniquely arranged to dampen (i.e., muffle)
audible noise that is produced by the motor 32 and/or the impeller
36 of the blower assembly 30, thereby reducing the noise emanating
from the blower assembly.
[0023] The motor 32 and the impeller 36 are almost entirely
surrounded by, i.e., encapsulated by, a perforated wall such as a
perforated sheet 60. The perforated sheet 60 includes an array of
perforations 70 (see FIG. 3E) in the form of small apertures, the
purpose of which will be described later. The number, size and
shape of the perforations 70 may vary, and the perforations are
optionally provided uniformly throughout the perforated wall or at
one or more selected locations. The perforated sheet 60 may be
composed of a metallic material, such as carbon steel, stainless
steel, aluminum, for example. Alternatively, the perforated sheet
60 may be composed of a polymer. The thickness of the perforated
sheet 60 may vary. The perforated wall may be formed by stamping,
molding, bending, or other manufacturing methods.
[0024] A sound-absorbing material such as a sheet 52 is positioned
adjacent the perforated sheet 60. In an exemplary embodiment,
sound-absorbing sheet 60 is mounted to the entire outer surface of
the perforated sheet 60 by either adhesive or mechanical fasteners,
for example. The sound-absorbing sheet 52, which may also be
referred to herein as a sound-absorbing layer or a sound-absorbing
portion, is provided to dampen audible noise emitted by the motor
32 and/or the impeller 36. The sound-absorbing sheet 52 may be
composed of fiberglass or mineral wool, for example, or any other
materials having sound dampening properties that are known in the
art, and its thickness may vary.
[0025] The sound-absorbing sheet 52 and the perforated sheet 60 are
completely encapsulated within an exterior shell 50 of the housing
assembly 31. All or substantially all of the exterior surface of
the sound-absorbing sheet 52 is separated from an interior surface
of the exterior shell 50 by an air gap 54. The depth of the air gap
54 is substantially constant, as measured from any point on the
exterior surface of the sound-absorbing sheet 52. According to one
exemplary embodiment of the invention, the depth of the air gap 54
may vary from 0.01 inches to 3.0 inches, for example. The depth of
the air gap and the size of the air gap at selected locations in
the shell 50 may vary without departing from the scope or spirit of
the invention.
[0026] The inlet port 38 is formed in the exterior shell 50, the
sound-absorbing sheet 52 and the perforated sheet 60 to accommodate
the flue tube 25. A passageway 66 is formed in the exterior shell
50, the sound-absorbing sheet 52 and the perforated sheet 60 to
permit the passage of air into the housing assembly 31. The air and
combustion products exit the housing assembly 31 through another
passageway (not shown) that is formed in the exterior shell 50, the
sound-absorbing sheet 52 and the perforated sheet 60 at a location
that is proximal to the exhaust port 42.
[0027] Although not shown, provisions such as bosses or brackets
may be provided on the interior surfaces of the exterior shell 50
for mounting the sound-absorbing sheet 52 and the perforated sheet
60 to the exterior shell 50. The exterior shell 50 may be composed
of plastic or metal, for example. The exterior shell 50 may also be
referred to herein as a housing, a blower housing or a blower
housing wall.
[0028] The arrangement of the perforated sheet 60, the air gap 54
and the sound-absorbing sheet 52 may be characterized by those
skilled in the art as a resonant sound absorber. The resonant sound
absorber of the housing assembly 31 is particularly suited to
dampen the sound waves produced by the motor 32 and the impeller
36. While simply increasing the thickness of the sound-absorbing
sheet 52 would improve the sound dampening qualities of the housing
assembly 31, such improvements in sound dampening, however, would
come at the expense of reduced space within the housing assembly 31
and added material costs. By attaching the perforated sheet 60 to
one side of the sound-absorbing sheet 52 and optionally providing
an air gap 54 on the opposite side of the sound-absorbing sheet 52,
the thickness of the sound-absorbing sheet 52 may be relatively
small to achieve superior sound dampening.
[0029] In operation of the resonant sound absorber, the
perforations 70 provide a passageway through which sound waves
pass, without being diminished or reflected, to reach the
sound-absorbing sheet 52. The air motion into and out of the
perforations 70 of the perforated sheet 60 oscillates in response
to an incident sound wave. At the frequency of oscillation, the air
moves violently in and out of the perforations 70 and, also, back
and forth in the sound-absorbing sheet 52.
[0030] The resultant friction between the air and the perforations
70 and the sound-absorbing material 50 converts the acoustic energy
of the sound wave into heat, thereby diminishing the acoustic
energy and the resultant sound emitted by the blower assembly 30.
The frequency of oscillation is influenced by the thickness of the
perforated sheet 60, the size and number of the perforations 70,
and the depth of the air gap 54. The thickness of the
sound-absorbing sheet 52 that is required to either remove or
significantly reduce the sound emitted by the blower assembly 30 is
calculated as a function of the frequency of oscillation.
[0031] FIGS. 3A through 3D depict exterior views of another
exemplary embodiment of a blower assembly. With the exception of
the shape, the blower assemblies of FIG. 1 and FIGS. 3A-3D are
substantially similar, thus, like numerals refer to like elements
of the blower assemblies 30 in those figures. FIG. 3E depicts a
detailed view of the air inlet plenum 41 of the blower assembly 30
of FIG. 3C taken along the lines 3E-3E. A rectangular shaped
perforated sheet 62 is positioned over the air intake port 40 of
the air intake plenum 41. The perforated sheet 62 dampens the noise
produced by the blower assembly 30.
[0032] FIG. 4 depicts a rear elevation view of another exemplary
embodiment of a blower housing 131 according to aspects of this
invention. The blower housing 131 is substantially similar to the
blower housing 31 of FIG. 3A-3E, with the exception that the blower
housing 131 does not include an air intake plenum, such as intake
plenum 41. The air intake port 140 of the blower housing 131 is
disposed on the rear face of the blower housing 131. The air intake
port 140 is concealed by a circular perforated sheet 162 that
includes a series of perforations 170. The purpose and function of
the perforations 170 are the same as that of the perforations 70 of
the perforated sheet 62 of FIG. 3E.
[0033] The housing assemblies described herein may be assembled
onto a new water heater in the factory, or, alternatively, the
housing assembly 31 may be retrofitted onto an existing water
heater in a residence or commercial building, for example.
[0034] It should be understood that the housing assemblies
described herein are not limited for use with the blower shown in
FIGS. 1 through 4. With only minor modifications, the housing
assembly may be utilized to muffle noise produced by other
noise-producing components of a water heater. For example, minor
modifications may be made to the housing assembly 31 to configure
it for use with a forced draft burner. A forced draft burner
delivers products of combustion directly into a flue tube. An
example of a forced draft burner is disclosed in U.S. Pat. No.
7,559,293, which is incorporated by reference herein in its
entirety. The modified housing assembly would be positioned to
encapsulate a blower of the forced draft burner to dampen the noise
produced by the blower.
[0035] Although this invention has been described with reference to
exemplary embodiments and variations thereof, it will be
appreciated that additional variations and modifications can be
made within the spirit and scope of this invention. Although this
invention may be of particular benefit in the field of residential
water heaters, it will be appreciated that this invention can be
beneficially applied in connection with commercial, industrial or
domestic water heaters and other heating systems as well.
Additionally, the invention disclosed herein is not limited to
fuel-fired water heaters. Many of the details of this invention may
also apply to any other type of heat exchanger or insulated
tank.
* * * * *