Note: Descriptions are shown in the official language in which they were submitted.
CA 02525701 2005-11-07
COMBUSTION AIR INTAKE FILTER
Field of the Invention
[0001] This invention relates to water heaters and burners used in conjunction
with such
water heaters. In particular, this invention relates to air intake filters for
burners used in such
water heaters.
Background
[0002] Water heater burner air intakes/flame traps are sometimes installed in
locations
that are difficult to clean or that cannot be cleaned without removing the
water heater or
disassembling the water heater burner apparatus. For example, water heaters
for building
systems are often installed in "roughed-in" locations such as closets, utility
rooms, attics or crawl
spaces. These locations are often remote from environmental control systems.
As such, they are
prone to the build up of particulate matter and debris such as lint, dust, oil
and other
miscellaneous residue.
[0003] Like any combustion device, the efficiency of a water heater burner is
at least
partially determined by the quality of its air supply. Therefore, the build up
of particulate matter
around the air intake can lead to performance degradation. Unfortunately, due
to cost, packaging
and/or other reasons, many water heaters include burner apparatuses that are
constructed with no
more than adequate air intake filtration for the typical operating
environment.
Summary of the Invention
[0004] This invention relates to a filter for the air intake of a water heater
burner
including a frame structure incorporating an expandable screen, a plurality of
connectors and
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corresponding receivers positioned to engage the connectors to locate the
frame structure at a
selected position relative the exterior of a water heater. This invention
further relates to a filter
for the air intake of a water heater burner that can be retrofitted to an
operational water heater.
[0005] This invention also relates to an air intake filter for a water heater
including a
frame structure including a screen, a connector and a receiver positioned to
removably engage the
connector to position the fi-ame structure at or around an exterior
circumferential portion of a
water heater.
[0006] This invention further relates to an air intake filter for a water
heater including a
first frame structure including a screen, a connector and a receiver, and a
second frame structure
including a screen, a connector and a receiver, wherein the connector of the
first frame structure
is positioned to removably engage the receiver of the second frame structure
to position the first
and second frame structures at or around an exterior circumferential portion
of a water heater.
[0007] This invention still further relates to a system including a water
heater and a filter
including a frame structure including a screen, a connector and a receiver
positioned to
removably engage the connector to position the frame structure at or around an
exterior
circumferential portion of the water heater.
Brief Description of the Drawings
[0008] Fig. 1 is a schematic partial sectional view of a water heater in
accordance with
aspects of the invention which emphasizes certain features of the water heater
and omits others
for ease of understanding.
[0009] Fig. 2 is a schematic partial sectional view of another water heater in
accordance
with aspects of the invention.
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[0010] Fig. 3 is a schematic partial sectional view of a water heater with an
air filter
secured to its bottom portion in accordance with aspects of the invention.
[0011 ] Fig. 4 is a schematic partial sectional view of an air filter which
illustrates the
operation of various aspects of the invention.
[0012] Fig. 5A is a schematic front elevational view of an air filter in
accordance with
aspects of the invention.
[0013] Fig. 5B is a schematic top plan view of the air filter in Fig. 5A.
[0014] Fig. SC is a schematic side view of portions of the air filter in Fig.
5A.
[0015] Fig. SD is a schematic top plan view of portions of the air filter in
Fig. 5A.
[0016] Fig. SE is a schematic front view of an interior portion of the air
filter in Fig. 5A.
[0017] Fig. SF is a schematic front view of an end portion of the air filter
in Fig. 5A.
[0018] Fig. SG is a schematic side view of portions of the filter in Fig. 5A.
[0019] Fig. 6 is a schematic partial sectional view of a water heater fitted
with an air filter
in accordance with aspects of the invention which emphasizes certain features
of the water heater
and omits others for ease of understanding.
Detailed Description
[0020] It will be appreciated that the following description is intended to
refer to specific
embodiments of the invention selected for illustration in the drawings and is
not intended to
define or limit the invention, other than in the appended claims.
[0021] Turning now to the drawings generally and Fig. 1, in particular, an
environment
for the implementation of one aspect of the invention is shown. A basic
illustration of a water
heater 10 includes a water tanklcontainer 12. One skilled in the art will
appreciate that the water
heater tank 12 comprises several components that serve to receive cold water
and store and
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dispense heated water, as well as other components that, while essential to
the operation of the
water heater, are not pertinent to the description of this invention. The
water heater 10 includes a
combustion chamber 14 that, in one preferred embodiment is located below the
water tank 12
and is formed by the tank bottom 16, skirt 18 and bottom pan 20. The bottom
pan 20 sits on legs
22.
[0022] A burner 24 is positioned in the combustion chamber 14. The burner 24
is also
positioned to receive fuel from a fuel supply line 28, which connects to a gas
valve 30.
[0023] The burner 24 is positioned within the combustion chamber 14 and above
an
opening 34 in the bottom pan 20. The opening 34 is preferably covered with an
air inlet/flame
arrestor such as an air inlet/flame arrestor 36 of the type as disclosed in
any of US Patents
5,797,355, 6,142,106 and 6,085,699, for example. Combustion air enters the
combustion
chamber 14 via the opening 34 and the flame arrestor 36 (when present). The
fuel supply line 28
connects to and extends through a door 40 such that the end of the fuel supply
line 28 is
proximate an end of a venturi 46. Although Fig. 1 shows a venturi 46, one
skilled in the art will
recognize that other fuel/air supply methods may be utilized such as, for
example, tubes, pipes,
pathways, conduits and other structures capable of channeling fuel and air to
the burner 24. The
burner 24 may be connected directly to the door 40 by a pair of connectors and
held above the
bottom pan 20 by a support. Alternative means of securing burner 24 within
combustion
chamber 14 may be used.
[0024] As shown in Fig. 1, if the venturi 46 is encapsulated within the
combustion
chamber 14, it will draw all the air it needs to sustain complete combustion
entirely through
opening 34 located on the bottom pan 20. Typically, this structure offers
several advantages such
as flame safety protection and some protection from dust or particulate
matter. However, for
some environments in which water heaters may operate, the dust and/or
particulate matter
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protection provided by this structure may be limited. Particulate matter,
including dust, rodents
and insects may build up on the lower surface of the air intake
screen/arrestor or in the area
between the bottom pan 20 and a water heater mounting surface 26 which may
lead to
performance degradation.
[0025] Fig. 2 illustrates a water heater substantially similar to the water
heater of Fig. 1
except that it employs a different burner and, accordingly, different
apparatus through which to
receive fuel and air. Most of the other components of the water heater are the
same. Water
heater 10 of Fig. 2 also employs a fuel line 28 that extends into combustion
chamber 14 and
connects to burner 24. An opening 34 receives combustion air for mixture with
fuel from fuel
line 28.
[0026] All of Figs. 1 - 3 illustrate an air filter 60 in accordance with
aspects of the
invention. Fig. 3 illustrates an air filter 60 associated with the water
heaters 10 as described in
Figs. l and 2 according to various aspects of the invention. In one embodiment
as shown in
particular in Fig. 3, the air filter 60 includes a frame structure 62
incorporating a screen 64. In a
preferred embodiment, the frame structure 62 and the screen 64 are vertically
expandable and
constructed of plastic. In a particularly preferred embodiment, the screen 64
is integrated into the
frame structure 62 as a contiguous plastic component. Alternatively, the frame
structure 62 and
the screen 64 may be constructed of the different materials including, but not
limited to, any of
metal, plastic, a composite material or the like.
[0027] The air filter 60 may be attached to the water heater 10 to
substantially enclose the
space bounded by the bottom pan 20 and the water heater mounting surface. In
one embodiment,
the frame structure 62 and the screen 64 may be expandable to fully enclose
the space underneath
the bottom pan 20. For example, if the legs 22 are adjustable in height, frame
structure 62 and
the screen 64 can adjust to match the height of the legs 22 and thus, enclose
the area underneath
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the bottom pan 20. It should be noted that by enclosing the space between the
bottom pan 20 and
a water heater mounting surface 26, the air filter 60 effectively increases
the surface area of the
air intake 34. The preferred embodiment has a height dimension of about 25/g
inches to
accommodate standard height legs 22.
[0028) The air filter 60 is further adjustable to fit around or at the
circumference of the
bottom pan 20. As such, the air filter 60 may be fitted to any of the various
size water heaters 10
that are currently available or may at some point be available in the future
including, for
example, water heaters made to metric rather than standard specifications. The
preferred
embodiment fits to 18 and 24" diameter water heaters currently available.
[0029) Fig. 4 illustrates one aspect of an adjustable connection mechanism of
the air filter
60. The adjustable connection mechanism allows the air filter 60 to be secured
at or around an
exterior circumferential lower portion of water heater 10. The air filter 60
comprises a
contiguous frame structure 62 incorporating the screen 64, connectors 66 and
receivers 68. The
receivers 68 are positioned to receive the connectors 66. In one embodiment,
the connectors 66
are located proximal to an end portion of the frame structure 62, and the
receivers 68 are located
at the end portion of the frame structure distal from the end portion proximal
to the connectors
66. In a preferred embodiment, the frame structure 62, being adjustable to fit
various size water
heaters 10, includes additional receivers 68, distal from the receivers 68
proximal to the one end
portion of the frame structure 62, that are also positioned to receive the
connectors 66. This
provides for the preferred fit to both 18 and 24" diameter water heaters.
[0030] In one embodiment, the connectors 66 are connection posts and the
receivers 68
are receiving holes/openings. For example, the connection posts 66 may
comprise extensions
from the interior of the frame structure 62, each of which include a elongated
portion 70 and a
head portion 72. The elongated portion 70 of each connection post 66 passes
through a
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corresponding receiving opening 68 while the head portion 72 removably engages
the connection
post 66 to the receiving opening 68 (and the interior of the frame structure
62). In a preferred
embodiment, the frame structure 62 incorporates pairs of corresponding
connection posts 66 and
receiving openings 68 to achieve each connection, for a combination of frame
structural rigidity
and ease of attachment/release. However, any number of connectors 66 and
receivers 68 may be
combined to connect the frame structure 62.
[0031 ] While the frame structure 62 described herein incorporates connectors
66 that may
be removably engaged with various receivers 68, one skilled in the art will
note that the frame
structure 62 may be secured to the exterior of a water heater 10 by a variety
of different methods.
As such, the invention should not be construed to be limited to the connection
methods described
herein.
[0032] In another aspect, the frame structure 62 further includes a tab ?4.
The tab 74 is
operable to assist in the removal of the connectors 66 from engagement with
the receivers 68.
For example, in one embodiment incorporating pairs of corresponding connection
posts 66 and
receiving openings 68 for each frame structure 62 connection, the tab 74 is
located at the end
portion of the frame structure 62 distal from the connection posts 66. As
such, when the
corresponding connection posts 66 and receiving openings 68 are engaged, the
tab 74 will be
adjacent to the removable connection. In operation, the pair of connection
posts 66 may be
disengaged from the corresponding receiving openings 68 by pushing the head
portions 72 of the
pair of connection posts 66 toward each other while the tab 74 is depressed.
(0033] In a particularly preferred embodiment, the air filter 60 includes a
first frame
structure and a second frame structure, each with the features described for
the frame structure 62
above, wherein the connectors 66 of the first frame structure are positioned
to be removably
engaged with the receivers 68 of the second frame structure and the connectors
66 of the second
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frame structure are positioned to be removably engaged with the receivers 68
of the first frame
structure. The first and second frame structures may be the same length or
different lengths in
order to removably attach to circumferential portions of water heaters 10 of
various sizes. As
such, the circumference of the air filter 10 will be limited only by the
number of receivers 68
incorporated on the frame structures.
[0034] The embodiments shown in Figs. SA-SG illustrate various schematic views
of the
air filter 60 in accordance with aspects of the invention.
[0035] Fig. 6 illustrates an alternative environment for the implementation of
the
invention wherein the water heater 10 comprises a burner 24 that is open to
the combustion
chamber 14 and receives combustion air through the flame arrestor 36, which is
located at the
opening 34. The fuel is supplied to the burner 24 through the fuel supply line
28, which connects
to the gas valve 30. The opening 34 is closed tightly by the flame arrestor 36
which admits air
for combustion of the fuel gas combusted through the burner 24, regardless of
the relative
proportions of primary and secondary air used by the burner 24. For example,
the opening 34
may be air/gas sealed by a door, except for the intake of the flame arrestor
36. In another
embodiment, the combustion chamber 14 is sealed air/gas tight except for means
to supply
combustion air through the flame arrestor 36 and exhaust combustion products
though an exhaust
flue. The flame arrestor 36 is preferably made from a thin metallic perforated
sheet of stainless
steel, such as described in U.S. Pat. No. 6,085,699, for example.
[0036] However, similar to as described above, in the operating environment
illustrated
in Fig. 6, the accumulation of particulate matter on the lower surface of the
air inlet
screen/arrestor or in the area between the bottom pan 20 and a water heater
mounting surface 26
could lead to performance degradation. As such, the air filter 60 is secured
around or at the
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bottom portion of the water heater 10 to enclose the space between the bottom
portion of the
water heater 10 and the water heater mounting surface 26.
[0037] Utilization of the air filter 60 in any of the above-described
configurations may
reduce the amount of particulate matter entering the air intake of a water
heater burner for both
new and previously operated water heaters in typical operating environments
while increasing the
surface area of the air intake in most instances.
[0038] Although this invention has been described in connection with specific
forms
thereof, it will be appreciated that a wide variety of equivalents may be
substituted for the
specified elements described herein without departing from the spirit and
scope of this invention
as described in the appended claims. For example, the above description refers
to connectors 66
and receivers 68. Alternate structures may be used. Such structures include,
but are not limited
to, straps, Velcro, snaps, buttons, hooks and the like. Thus, the connectors
and receivers referred
to in the claims encompass such structures, similar structures and equivalents
thereof.
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