Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02610330 2007-11-13
COMBINED SUPPLY AND EXHAUST APPARATUS
FIELD OF THE INVENTION
[00011 This invention generally relates to clothes dryers and, more
particularly, to air
supply and air exhaust apparatuses for use with clothes dryers.
BACKGROUND OF THE INVENTION
[0002] With increasing energy costs, consumers are becoming more and more
energy
conscious. As such, consumers are demanding more energy efficiency from their
appliances and the homes in which they live. Many appliance manufacturers have
responded by attempting to increase their products' energy efficiency.
However, no matter
how efficient some appliances are made, the use of the appliance may be
inefficient by
causing other less efficient devices to also activate.
[0003] One such example is the use of a dryer for drying moist articles or
goods,
commonly referred to as a clothes dryer. Common practice with clothes dryers
is to intake
air from the room in which the clothes dryer is operating, heat it, pass it
through the moist
goods housed in a drying chamber, also referred to as a drum, and then exhaust
it from the
clothes dryer through an exhaust duct to the exterior of the building. During
this process, it
is common for as much as 150 cubic feet of air to be exhausted from the
interior of the
building to the exterior of the building per minute of operation. With typical
drying cycles
lasting approximately 45 minutes in length, the average clothes dryer can
consume, on
average, 6,750 cubic feet of air during a single cycle. This is the equivalent
volume of air in
seven rooms having eight foot ceilings and ten foot by twelve foot dimensions.
As the air
from the interior of the building is exhausted to the exterior of the
building, the air that
previously occupied the building is replaced by unconditioned air from the
exterior of the
building. Typically, this replacement air enters the building through doors,
windows, cracks
and other air passages fluidly communicating the interior of the building with
the exterior.
[00041 This replacement of such a substantial volume of conditioned air from
within the
building with unconditioned air from the exterior of the building typically
causes the
condition of the air within the building to change. This, in turn, causes the
heating,
ventilating, and air conditioning system (HVAC system) of the building to
activate to return
the interior of the building to a pleasing condition. Unfortunately, the HVAC
system is the
most costly system in most buildings to operate. Thus, even if the individual
operation of
CA 02610330 2007-11-13
the clothes dryer can be made more efficient, the use of the clothes dryer
causes the HVAC
system to activate, reducing the overall efficiency of the clothes drying
process.
[0005] Other problems exist with current clothes dryers. For example, the
exhaust duct
that vents the exhaust air from the clothes dryer to the exterior of the
building can become
plugged with lint or other particulate and catch fire causing structural
damage to the
building. Further, the exhaust pipes themselves can become extremely hot as a
result of the
hot exhaust air flowing through the pipes which can damage walls, wires, and
other
structure of the building that are positioned proximate the exhaust ducts. In
addition, as the
clothes dryer expels the humid warmed air from the building, the humid warm
air takes with
it a large quantity of heat energy that has been produced by the dryer to dry
the clothes.
This heat energy stored in the exhausted humid warm air is merely dumped into
the exterior
environment and wasted further reducing the overall operating efficiency.
[0006] Thus, there is a need in the art for an air supply and exhaust system
that reduces
the amount of conditioned air that is expelled from the interior of the
building during
operation of the dryer, increases safety, and more efficiently conserves the
heat energy that
is produced to dry the moist goods.
BRIEF SUMMARY OF THE INVENTION
[0007] In view of the above, a new and improved supply and exhaust apparatus
for
supplying and exhausting air to an air using appliance is provided. An
embodiment of the
apparatus provides improved safety by insulating an exhaust air passage of the
apparatus
with an supply air passage by having the exhaust air passage passing through
the supply air
passage. The air gap between the outer passage and the inner passage reduces
the potential
for a fire when objects come into contact with the supply and exhaust
apparatus. Further, if
a fire should occur in the air exhaust passage from lint or other byproducts
of the drying
process, the concentric configuration reduces the hazard of the fire on walls
of the building.
100081 Further, in an embodiment, the exhaust air passage and supply air
passage are
separated by thermally conductive material allowing heat transfer between the
two
passages. As such, incoming air may be preheated by hot exhaust air. To
improve the heat
transfer capability, heat transfer fins are employed in embodiments to improve
extraction
and transfer of waste heat energy of the exhausted air stream. This
configuration allows
heat energy that is normally lost during standard drying cycles to be
recaptured, increasing
the energy efficiency of the drying system incorporating the supply and
exhaust apparatus.
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[0009] In a further embodiment, the supply and exhaust system reduces the
amount of
indoor conditioned air used during the drying process increasing the overall
energy
efficiency of the drying process.
[0010] In one embodiment, the invention provides a combined supply and exhaust
apparatus for an air using appliance including an air flow duct including two
air flow
passages. The air flow passages extend between two inlets and two outlets,
respectively.
Preferably, the inlets and outlets are concentrically located to one another
so that only a
single hole is needed to communicate with the exterior of the building. A
common wall
separates the first air flow passage from the second air flow passage. One air
flow passage
is configured as an air supply passage to supply air to the appliance. The
other air flow
passage is configured as an air exhaust passage to exhaust air from the
appliance.
[0011] In another embodiment of a combined supply and exhaust apparatus for an
air
using appliance, the apparatus includes an air flow duct having two air flow
passages being
separated by a common wall. A first supply and exhaust manifold is mounted to
a first end
of the air flow duct. The first supply and exhaust manifold forms a first
outlet of the first
flow passage and a second inlet of the second flow passage. A second intake
and exhaust
manifold is mounted to an opposite end of the air flow duct. The second intake
and exhaust
manifold forms a first inlet of the first flow passage and a second outlet of
the second flow
passage. The first flow passage is configured as an air supply passage for
supplying air to
the appliance therethrough and the second flow passage is configured as an air
exhaust
passage for exhausting air from the appliance therethrough.
[0012] In an embodiment, existing dryer ducts can be retrofit to take
advantage of the
features of the combined supply and exhaust apparatus. In such an embodiment,
a separate
smaller air supply means can be installed within the existing duct.
Alternatively, the
combined supply and exhaust apparatus can be retrofit to work with standard
dryers. The
combined supply and exhaust apparatus can be used to provide a fresh air
induction path
directly to the room or environment in which the dryer is located to prevent
conditioned air
from being drawn from the rest of the building. Such a configuration includes
dampers to
eliminate free air flow through the apparatus reducing the loss of conditioned
air to the
exterior of the building when the drying process is inactive.
[0013] Other aspects, objectives and advantages of the invention will become
more
apparent from the following detailed description when taken in conjunction
with the
accompanying drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings incorporated in and forming a part of the
specification illustrate several aspects of the present invention and,
together with the
description, serve to explain the principles of the invention. In the
drawings:
[0015] FIG. 1 is a simplified side view illustration of a dryer positioned
within a
building and including an supply and exhaust system according to the teachings
of the
present invention;
[0016] FIG. 2 is a simplified end view of an embodiment of a dual flow duct
for a dryer
according to the teachings of an embodiment present invention.
[0017] FIG. 3 is a simplified cross-sectional illustration of the dryer of
FIG. 1;
[0018] FIGs. 4 and 5 are simplified side views of additional embodiments of
dyers and
drying systems according to the teachings of the present invention;
[0019] FIGs. 6 and 7 are a simplified end views of additional embodiments of
dual flow
ducts according to the teachings of the present invention; and
[0020] FIG. 8 is a simplified cross-sectional illustration of the connection
between the
dual flow duct and a dryer according to the teachings of the present
invention.
[0021] While the invention will be described in connection with certain
preferred
embodiments, there is no intent to limit it to those embodiments. On the
contrary, the intent
is to cover all alternatives, modifications and equivalents as included within
the spirit and
scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Turning now to the figures, FIG. 1 illustrates a dryer 10 and a dual
flow duct 14
according to the teachings of one embodiment of the present invention. The
dryer 10
advantageously draws air from the exterior 16 of the building 17 rather than
conditioned air
from the interior 18 of the building 17 to dry moist goods 19 within the dryer
10. This
configuration significantly reduces the amount of conditioned air within the
building 17 that
is needlessly exhausted from the building 17 during a drying cycle and lost to
the exterior
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16 of the building 17. Advantageously, by reducing the amount of conditioned
air that is
exhausted from the building 17, the same amount of exterior, unconditioned
air, is
prevented from entering the building 17. By reducing the amount of
unconditioned air that
is added to the building 17, the internal conditions of the building 17 are
not significantly
altered during the drying process, thereby reducing the work load, and energy
use, of the
HVAC system of the building (not shown).
100231 According to the teachings of one embodiment, the dryer 10 functions to
dry
moist goods 19 such as clothing, towels, rags, and the like placed within the
dryer 10 by
passing air through and/or across the material of the moist goods 19. As such,
the dryer 10
includes a blower 22, shown schematically, that forces air through the dryer
10 and in
contact with the moist goods 19. More particularly, in an embodiment, the
blower 22 draws
air through an air flow passage ducted through the dryer 10 that directs air
through the moist
goods 19 to be dried.
[00241 One portion of the air flow passage includes a drying chamber 26 in
which the
moist goods 19 are placed during the drying cycle. In the illustrated
embodiment, the
drying chamber, indicated generally by reference numeral 26, is provided by a
drum 28 that
is rotatably supported within the outer housing 30 of the dryer 10. The drum
28 rotates
during the drying cycle causing the moist goods 19 that are located therein to
tumble while
drying. The tumbling action beneficially allows individual pieces of the moist
goods 19 to
separate facilitating the passage of drying air through and across the moist
goods 19 to
increase the evaporating action of the drying air, thereby increasing the rate
of moisture
removal from the moist goods 19. The drum 28 is typically rotatably supported
by a
plurality of rollers 31 and is rotatably driven by a belt 32 connected to and
powered by an
electric motor (not shown). In an embodiment, the electric motor that drives
the drum 28
also drives the blower 22.
[0025] In an embodiment, the dryer 10 includes a heater, shown in a simplified
manner
at reference number 34. The heater 34 is positioned within the air flow
passage passing
through the dryer 10 upstream from the drum 28. The heater 34 heats the air
prior to the air
passing through the drum 28 and, consequently, prior to the air passing
through the moist
goods 19. Warm air can retain and absorb more moisture from the moist goods 19
and
thereby reduce the amount of air and the length of time required to dry the
moist goods 19.
The heater 34 may be any practicable heater and may include such heaters as
electrically
resistive heaters, gas fired heaters, and the like.
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100261 In an embodiment, the blower 22 draws the "drying" air, indicated by
arrows 40,
into the dryer 10 directly from the exterior 16 of the building 17. The drying
air 40 is then
heated and passed through the moist good 19 to dry the moist goods 19. This
configuration
of using exterior air as the drying air 40 rather than conditioned air from
within the interior
18 of the building 17 reduces the amount of energy used thereby increasing the
overall
energy efficiency of the process. Particularly, this configuration reduces the
amount of
conditioned air that is consumed by the dryer and expelled from the building
17. This, in
turn, reduces the amount of non-conditioned air that enters the building from
the outside,
which, in turn, reduces the load on the HVAC system (not shown) to maintain
the desired
temperature and humidity levels of the building 17. As such, a method of
drying moist
goods 19 using a dryer 10 and dual flow duct 14 disclosed herein by drawing
air from the
exterior 16 of the building 17 through the dual flow duct 14 rather than
drawing air from the
interior of the building is highly beneficial.
[0027] Further, this configuration reduces the amount of energy that is wasted
during
warm periods by exhausting air that previously had been conditioned which
required energy
to cool the air. As noted previously, the HVAC system of a building is one of
the most
costly systems in a building to operate. Any reduction in unnecessary
operation of the
HVAC system will beneficially increase overall efficiency and energy
consumption of the
building as a whole.
[0028] As the drying air 40 passes through the drying chamber 26 and the moist
goods
19, the previous lower humidity drying air 40 absorbs moisture from the moist
goods 19 and
becomes humid stale exhaust air, indicated by arrows 44 and proceeds to be
exhausted from
the dryer 10. The exhaust air 44 passes through an exhaust air portion of the
air passage of
the dryer 10 downstream from the drying chamber 26 to the dual flow duct 14.
The dual
flow duct 14, in part, fluidly communicates the exhaust portion of air passage
with the
exterior 16 of the building 17 and as such allows the exhaust air 44 to be
exhausted from the
dryer 10 to the exterior 16 of the building 17.
[0029] More particularly, in an embodiment, a first end 50 of the dual flow
duct 14
connects to an air intake and exhaust manifold 52 of the dryer 10, and the
second, opposite,
end 54 of the dual flow duct is positioned in and in fluid communication with
the exterior
16 of the building 17. In an embodiment, the second end 54 of the dual flow
duct 14 is
connected to a second air intake and exhaust manifold 43 positioned outside of
the building
17. As is illustrated, the second air intake and exhaust manifold 43 is
configured to prevent
rain or other debris from entering the dual flow duct 14. This can be
accomplished by
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including canted roughs, tops or covers over the openings through which drying
air 40 and
exhaust air 44 enter and exit, respectively, the second air intake and exhaust
manifold 43.
Additionally, the openings in the second air intake and exhaust manifold may
include
grates, grills, mesh and the like to prevent debris from entering the
openings.
[0030] The dual flow duct 14 includes two air flow passages including an air
supply
passage 60 for drawing in the drying air 40 and an air exhaust passage 62 for
exhausting the
exhaust air 44. In an embodiment, the air supply passage 60 and air exhaust
passage 62 are
positioned proximate one another such that the two air flow passages are
separated by a
common wall 66. As such, the air supply passage 60 and the air exhaust passage
62 are
formed in a common structure, namely dual flow duct 14. As such, the air that
is drawn in
through the air supply passage 60 and the air exhausted through the air
exhaust passage 62
flow in the common air flow structure, dual flow duct 14.
[0031] In an embodiment, as illustrated in FIGS. 1 and 2, the air supply
passage 60 and
air exhaust passage 62 are concentric with one another. In such an embodiment,
the dual
flow duct 14 is provided by an outer annular wall 68 and the common wall 66
that forms an
inner annular wall, with the outer wall 68 and common wall 66 concentrically
aligned. In
this configuration, the space between an inner surface 69 of the outer annular
wall 68 and an
outer surface 70 of the common wall 66 provides the air supply passage 60. The
inner
surface 71 of the common wall 66 entirely defines the air exhaust passage 62.
When drying
moist article 19 using a method of the present invention, drying air 40 and
exhaust air 44 are
drawn in and exhausted through the dual flow duct 14 in a concentric manner,
such that the
drying air 40 flows in an opposite direction as the exhaust air 44 and through
the radially
outer passage.
[0032] In an embodiment, the common wall 66 is made from a thermally
conductive
material such as metal. Using a common wall 66 of a thermally conductive
material
beneficially increases the efficiency of the dryer 10. In such a
configuration, some of the
heat energy stored by the exhaust air 44 passing through the air exhaust
passage 62 is
dissipated to the drying air 40 drawn in through the air supply passage 60
through the
thermally conductive common wall 66. The transfer of heat energy from the
exhaust air 40
to the drying air 44 reduces the amount of heat energy required to be added to
the drying air
44 by the heater 34.
[0033] As it is beneficial to have as much heat energy transferred from the
exhaust air
44 to the drying air 40 as possible, an embodiment of the present invention
includes heat
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transfer structures, such as heat pipes and/or, as illustrated, heat transfer
fins 74 that extend
from the outer and inner surface 70, 71 of the common wall 66 of the dual flow
duct 14.
The heat transfer fins 74 increase the amount of surface area for the air
flowing through the
air intake and air exhaust passages 60, 62 to contact and impinge further
increasing the
amount of heat that will be dissipated from the exhausted air 44 and will be
absorbed by the
drying air 40. Further, the heat transfer fins 74 may be used to mount,
position and/or
support the common wall 66 within the outer annular wall 68. In such an
embodiment, the
heat transfer fins 74 extend entirely from the outer surface 70 of the common
wall 66 to the
inner surface 69 of the outer annular wall 68.
[0034] Condensation may occur as the warm humid exhaust air 44 reduces in
temperature as it dissipates heat energy to the drying air 44. Therefore, in
an embodiment,
the outer annular wall 68 and inner common wall 66 are preferably made from a
stainless or
corrosion resistant material to prevent any condensation that forms thereon
from damaging
the walls 66, 68, which may include metal or plastic.
[0035] The concentric configuration, having the air exhaust passage 62 passing
through
the air supply passage 60, has several beneficial features. First, as noted
previously, the
dual flow duct 14 functions as a dual flow heat exchanger. With the air
exhaust passage 62
positioned within the air supply passage 60, the entire surface area of the
common wall 66
that surrounds the air exhaust passage 62 is in thermal communication with the
exhaust air
44 and drying air 40 on opposite sides of the common wall 66. Thus, any heat
energy that is
dissipated from the exhaust air 44 will be transferred to the drying air 40.
It should be noted
that the illustrated embodiment uses walls 66, 68 having round cross-sections,
one of skill in
the art will recognize that the walls 66, 68 are not so limited in shape and
can be any shape
such as square, rectangular, oval, and the like. Furthermore, as the outer
annular wall 68 and
common wall 66 are both have the same shape, it is not required that both
walls have the
same shape. For example and as illustrated in an alternative embodiment of a
dual flow
duct 414 in FIG. 7, the outer wal1451 is rectangular while the inner common
wall 466 is
round having the air supply passage 460 and air exhaust passage 462 defined
between the
outer wall 451 and within the common wall 466, respectively.
[0036] As the wall forming the air exhaust passage can become very hot, it is
a benefit
of the configuration illustrated in FIG. 1 that the air supply passage 60
performs the further
function of insulating the common wall 66, which defines the air exhaust
passage 62 from
its surroundings. This increases safety by preventing the air exhaust passage
from
damaging any infrastructural components of the building that are proximate to
the dual flow
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duct 14. Similarly, the dual wall configuration prevents individuals from
getting injured
upon accidentally contacting the outer surface of the exhaust duct because the
individual
does not touch the outer surface of the exhaust air passage. Additionally, if
a fire should
occur in the exhaust air passage 62 because of excess lint or by products of
the drying
process, the double wall configuration may reduce the hazard of the fire
spreading to
interior walls or other structure of the building 17.
[0037] As indicated previously, the dryer 10 includes an air intake and
exhaust manifold
52 for connecting the dual flow duct 14 to the dryer 10. As best illustrated
with reference to
FIGS. 1 and 3, the air intake and exhaust manifold 52 forms the inlet 78 and
the outlet 80
for the air passage passing through the dryer 10. The inlet 78 and outlet 80
are formed in a
duct connection end 81 of the air intake and exhaust manifold 52 that is
configured to be
connected to a dual flow duct 14, as shown in FIG. 1. Additionally, the air
intake and
exhaust manifold 52 functions to separate the air supply passage 60 from the
air exhaust
passage 62. Furthermore, the air intake and exhaust manifold 52 communicates
the air
supply passage 60 with the portion of the air flow passage within the dryer
upstream from
the drying chamber 26 and the air exhaust passage 62 to the portion of the air
flow passage
within the dryer 10 downstream of the drying chamber 26. As illustrated, in an
embodiment, this is accomplished by a first duct 84 interconnecting the air
supply passage
60 portion of the air intake and exhaust manifold 52 to the heater 34. A
second duct 86
interconnects the air exhaust passage 62 of the air intake and exhaust
manifold 52 to the
blower 22 such that the exhaust air 44 exiting the blower 22 is directed to
the air intake and
exhaust manifold 52 such that the exhaust air 40 is exhausted to the air
exhaust passage 62.
The ducts 84, 86 may be connected to the air intake and exhaust manifold 52 by
standard
duct connections.
[0038] In an embodiment, the duct connection end 81 of the air intake and
exhaust
manifold 52 is configured of easy attachment to the dual flow duct 14. In an
embodiment
and as illustrated in FIG. 3, the air intake and exhaust manifold 52 has an
inner flange 87
that extends outward beyond an end of an outer flange 89. Altetnatively, the
dual flow duct
14 could have the ends of the common and outer walls 66, 68 offset.
[0039] Preferably, the flanges are configured to minimize resistance on the
fresh air 40
flowing through the air supply passage 60 as it passes from the dual flow duct
14 to the air
intake and exhaust manifold 52 as well as the exhaust air 44 flowing from the
air intake and
exhaust manifold 52 to the dual flow duct 14 through the air exhaust passage
62. To
minimize the air resistance and as illustrated in FIG. 8, the inner flange 87
can be
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configured to slide into the common wall 66 of the dual flow duct 14 and the
outer flange
89 can be configured to slide around and receive the outer wall 68. This can
be
accomplished by having the flanges 87, 89 of the air intake and exhaust
manifold 52
tapered, or by having the ends of the walls 66, 68 of the dual flow duct 14
tapered, or any
combination thereof. Tapering can include having a larger continuous diameter
sized to
receive the corresponding portion of the other component for easy mating
between the dual
flow duct 14 and the air intake and exhaust manifold 52 as well as
continuously varying
radii such as in a chamfer. The second air intake and exhaust manifold may be
similarly
configured to mount to an end of the dual flow duct 14.
100401 The dryer 10 may further include sensors 90 for sensing characteristics
of the
drying air 40 and exhaust air 44 flowing through the dryer 10 as well as the
air supply and
air exhaust passages 60, 62. These sensors 90 can sense characteristics such
as air
temperature, flow rate, presence of hazardous gases, humidity and the like.
The sensors 90
can operably communicate with a controller 92 or other logic device for
operably
controlling the dryer 10 in response to the sensed characteristics.
Particularly, the sensed
condition of the air can be compared with predetermined or user determined
values. Air
temperature and flow rate sensors can be beneficial in helping determine if
any portions of
the air flow passages are plugged or if the dryer 10 is functioning properly.
In such a case,
the dryer 10 and its controller 92 may be configured to activate an alarm (not
shown) or
cease operation until the dryer 10 or dual flow duct 14 has been inspected and
cleared.
100411 With reference to FIG. 4, in another embodiment, the drying air portion
of the air
intake and exhaust manifold 152 includes a damper 198 that may be opened if a
sensor 190
senses the presence of harmful gases proximate the dryer 110, such as carbon
monoxide.
Upon sensing the presence of harmful gas, the controller 192 actuates the
damper 198 to an
open position. The dryer draws the air 135, which includes the hazardous
gasses, from the
localized environment of the dryer 110, i.e. from the interior 18 of the
building 17 and
exhausts the hazardous gasses out of the building 17 as exhaust air through
the air exhaust
passage 62. Additionally, if hazardous gas is sensed, the controller 192 of
the dryer 110
may be programmed to lock out operation or activation of the dryer 110 until
the controller
192 is reset and/or the presence of hazardous gas is eliminated.
100421 Although existing ductwork in buildings does not have dual passages for
providing an air supply passage and an air exhaust passage, existing structure
can be retro
fit to form embodiments of dual flow duct work. Rather than removing the
existing
ductwork and replacing it with new dual flow ducts, existing ducts can be used
along with a
CA 02610330 2007-11-13
second duct pipe that is installed in the structure in addition to the
existing ductwork. After
the new duct pipe is installed in the dwelling, the combination of old and new
ducts can
function as explained previously, i.e. the old duct will continue to be used
to exhaust the
dryer, while the new duct will supply outside air to the dryer.
[0043] In a further embodiment of the present invention, illustrated in FIG.
5, the
embodiment incorporates a standard dryer 210 that draws drying air 240
directly from the
room of the building 17 housing the dryer 210. This embodiment may be used by
retrofitting existing ductwork with a second passage as explained previously
or with newly
installed dual flow duct previously described prior to acquiring a dryer
configured to
communicate with the dual flow duct 14.
100441 As explained previously, standard dryers draw drying air directly from
the
ambient air within the room housing the dryer and then exhaust it to the
exterior of the
building. The ambient air directly surrounding the dryer is then replenished
with other
conditioned air from within the building. Typically, this air enters through
the door or gaps
around the door leading to the room. The exhaust air exiting the building is
replaced by
other air from within the building that enters the building through doors or
windows. As
such, conditioned air is used and exhausted from the building during the
drying cycle.
However, with the present embodiment, the dryer 210 draws drying air from the
room in
which it is located, but the air is not replaced by conditioned air from the
interior 18 of the
building 17, but the ambient air surrounding the dryer is replaced by
unconditioned air from
the exterior 16 of the building 17.
[0045] In this embodiment, the dual flow duct 14 includes both an air supply
passage 60
and an air exhaust passage 62 and an air intake and exhaust manifold 252
connected to the
dual flow duct 14 external to the dryer 210. The air intake and exhaust
manifold 252
includes an exhaust air inlet 263 that is interconnected to dryer's exhaust
air outlet 164. As
such, exhaust air 244 exhausted from the dryer 210 is exhausted through the
air intake and
exhaust manifold 252 and then the air exhaust passage 62 of the dual flow duct
14, similar
to the process as explained previously.
[0046] However, the dryer 210 draws the drying air, indicated generally by
arrows 240
directly from the ambient air within the interior 18 of the building 17, and
more particularly,
the room housing the dryer 210. However, the ambient air within the room is
not primarily
replenished by conditioned air from the rest of the building 17. In this
embodiment, the air
intake and exhaust manifold 252 includes a drying air outlet 265 that is in
fluid
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communication with the exterior 16 of the building 17 through the air supply
passage 60.
As such, when the dryer 210 draws drying air 240 from the room for drying the
moist goods
19, the air is replaced by air, indicated generally by arrows 241, that is
drawn into the
building 17 through the duct 14 via a vacuum created by the exhaust air 244
exiting the
building 17.
[0047] This embodiment can be extremely beneficial as the conditioned air from
the rest
of the building is not used to continue the drying process. Instead,
unconditioned air 241
from the exterior 16 of the building 17 is used. To prevent conditioned air
from escaping
the building 17 when the dryer 210 is inoperative, the air intake and exhaust
manifold 252
includes a damper 267 that can close the drying air outlet 265 of the air
intake and exhaust
manifold 252 and prevent fluid communication between the interior 18 and
exterior 16 of
the building 17 via the air supply passage 60 of the dual flow duct 14. The
damper 267
may be configured for manual or automatic opening or closing. As such, the
damper 267
may be configured to be opened or closed directly by the user or configured to
open or close
automatically upon activation or deactivation of the dryer 210.
[0048] In another embodiment, illustrated in FIG. 6, the air supply passage
360 and the
air exhaust passage 362 are configured such that the two passages 360, 362 are
side-by-side
rather than concentric. In this configuration, a common outer wa11368 provides
an outer
periphery for the dual flow duct 314 but rather than forming the entire outer
periphery of a
single passage, like the previously described concentric embodiment, the outer
wall 368
forms a portion of both of the air intake and air exhaust passages 360, 362.
The dual flow
duct 314 further includes a common wall 366 that separates the two passages
360, 362 from
one another. Preferably, the common wal1366 is formed from a thermally
conductive
material such that heat energy can be transferred from the air exhausted
through the air
exhaust passage to the air being brought into the dryer through the air supply
passage. This
common wall 366 may further include heat transfer fins 374 to increase the
heat transfer
between the two passages 360, 362.
[0049] It will be recognized by one of ordinary skill in the art that the
embodiments of
the ducts disclosed previously could be practiced using plastic or other non-
thermally
conductive material rather than thermally conductive material. However, such
configurations will not have the additional benefits of functioning as a heat
exchanger. The
use of plastic duct could be extremely beneficial when retrofitting existing
duct with a
second passage by using flexible plastic duct that can be more easily inserted
through the
existing ductwork. Fig. 7 illustrates an embodiment where the dual flow duct
414 is formed
12
CA 02610330 2007-11-13
by an existing duct 451 that is rectangular and the inner duct 466 is formed
by circular
plastic flexible duct. As discussed previously, the dual flow duct 414
includes an air supply
passage 460 and an air exhaust passage 462.
[0050] All references, including publications, patent applications, and
patents cited
herein are hereby incorporated by reference to the same extent as if each
reference were
individually and specifically indicated to be incorporated by reference and
were set forth in
its entirety herein.
[0051] The use of the terms "a" and "an" and "the" and similar referents in
the context
of describing the invention (especially in the context of the following
claims) is to be
construed to cover both the singular and the plural, unless otherwise
indicated herein or
clearly contradicted by context. The terms "comprising," "having,"
"including," and
"containing" are to be construed as open-ended terms (i.e., meaning
"including, but not
limited to,") unless otherwise noted. Recitation of ranges of values herein
are merely
intended to serve as a shorthand method of referring individually to each
separate value
falling within the range, unless otherwise indicated herein, and each separate
value is
incorporated into the specification as if it were individually recited herein.
All methods
described herein can be performed in any suitable order unless otherwise
indicated herein or
otherwise clearly contradicted by context. The use of any and all examples, or
exemplary
language (e.g., "such as") provided herein, is intended merely to better
illuminate the
invention and does not pose a limitation on the scope of the invention unless
otherwise
claimed. No language in the specification should be construed as indicating
any non-
claimed element as essential to the practice of the invention.
[0052] Preferred embodiments of this invention are described herein, including
the best
mode known to the inventors for carrying out the invention. Variations of
those prefened
embodiments may become apparent to those of ordinary skill in the art upon
reading the
foregoing description. The inventors expect skilled artisans to employ such
variations as
appropriate, and the inventors intend for the invention to be practiced
otherwise than as
specifically described herein. Accordingly, this invention includes all
modifications and
equivalents of the subject matter recited in the claims appended hereto as
permitted by
applicable law. Moreover, any combination of the above-described elements in
all possible
variations thereof is encompassed by the invention unless otherwise indicated
herein or
otherwise clearly contradicted by context.
13
