Note: Descriptions are shown in the official language in which they were submitted.
CA 02460623 2004-03-25
AIR TO ATR HEAT AND MOISTURE RECOVERY VENTILATOR
This is a divisional of application serial number
2,270,881 filed November 4, 1997.
BACKGROUND OF THE INVENTION
The present invention relates to air to air heat and
moisture recovery ventilators and their use to obtain
thermally efficient ventilation of buildings and
dwellings. Specifically, the present invention relates to
an improved rotary wheel heat exchanger mounting
arrangement which enables convenient removal of the
rotary wheel and/or the exchange media supported by the
rotary wheel.
Heat exchangers are used in ventilation systems
installed in residential, commercial, and industrial
buildings to extract and remove heat and/or moisture from
one air stream and transfer the heat and/or moisture to a
second air stream. In particular, rotary wheel heat
exchangers are known wherein a wheel rotates in a housing
through countervailing streams of exhaust and fresh air.
In the winter, the heat exchanger extracts heat and
moisture from the exhaust stream and transfers the heat
and moisture to the fresh air stream while, in the
summer, the heat exchanger extracts heat and moisture
from the fresh air stream and transfers it to the exhaust
stream, preserving building heatingfair conditioning
while providing desired ventilation.
Conventional commercial, industrial, and residential
ventilation systems, such as those illustrated in U.S.
Pat. Nos. 5,069,272, 5,183,098, and 5,285,842, utilize
rotary heat exchanger wheels having diameters ranging
from 25 cm to greater than 100 cm. As heat exchanger
wheel size increases, conventional wheel bearings and
wheel drive mechanisms are subject to mechanical and
operational failure. Accordingly, there is a need for a
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rotary wheel heat exchanger ventilation system employing
an improved heat exchange wheel mounting assembly.
As heat exchanger wheel size increases it is also
more difficult and costly to preserve wheel circularity.
As wheel circularity degrades, conventional wheel drive
mechanisms are less likely to operate properly and
ventilation system sealing members are more likely to
fail. For example, where a wheel drive roller contacts
the outer periphery of a rim body, as is the case with
the wheel drive mechanism disclosed in U.S. Pat. No.
5,069,272, it is difficult to maintain roller-to-rim
contact if the rim is out of round. Similarly, where a
sealing member is provided in contact with the outer
periphery of the rim body, it is also difficult to
1S maintain seal-to-rim contact if the rim is out of round.
Accordingly, there is a need for a rotary wheel heat
exchanger ventilation system employing an improved wheel
drive mechanism and mounting assembly. Further, there is
a need for a rotary wheel heat exchanger ventilation
system wherein wheel drive integrity and ventilation
system efficiency are preserved where wheel circularity
degrades.
Conventional commercial, industrial, and residential
ventilation systems utilizing rotary heat exchanger
ZS wheels operate most efficiently if the heat exchange
media is cleaned or replaced regularly. The mechanical
arrangements of some of the conventional systems make
removal and/or cleaning of the heat exchange media
difficult and time consuming. Accordingly, there is also
a need for a ventilation system which provides for
convenient and efficient heat exchange media removal for
replacement or cleaning.
Although some of the conventional ventilation
systems discussed above transfer moisture as well as heat
~S from an exhaust stream to a fresh air stream, e.g., see
U.S. Pat. Nos. 5,069,272 and 5,285,842, these
conventional systems rely upon the heat exchange media
alone to effect transfer of the moisture. Accordingly,
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there is a need for a ventilation system which includes a
supplemental moisture transfer mechanism.
SUMMARY OF THE INVENTION
This need is met by the present invention wherein a
ventilator is provided which incorporates an improved
rotary wheel mounting assembly reducing the stress borne
by the hub of the rotary wheel, is less susceptible to
drive failure where the rotary wheel is out of round,
enables convenient and efficient removal and replacement
of the heat exchange media, and which incorporates a
supplemental moisture transfer mechanism.
One embodiment of the invention provides a
ventilator comprising: a rotary wheel including a
substantially circular rim having a first rim edge
portion defining a first side of said rotary wheel, a
second rim edge portion defining a second side of said
rotary wheel, and a circumferential rim body extending
between said first and second rim edge portions; an
exchange media supported by said rotary wheel; a rotary
wheel mounting assembly; a circulation fan mounting plate
positioned adjacent said second side of said rotary wheel
and defining an exhaust air inlet and a fresh air outlet;
an exhaust air circulation fan and a fresh air
circulation fan mounted to said circulation fan mounting
plate; a ventilator housing supporting said rotary wheel
mounting assembly and said circulation fan mounting
plate; a partition assembly is positioned so as to
isolate an exhaust air flow section of said ventilator
housing from a fresh air flow section of said ventilator
housing; and a moisture transfer wick positioned adjacent
said second side of said rotary wheel and extending
through said partition assembly between said exhaust air
flow section and said fresh air flow section.
Another embodiment of the invention provides a
ventilator comprising: a ventilator housing defining an
exhaust air flow section and a fresh air flow section,
said exhaust air flow section having an exhaust air inlet
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and an exhaust air outlet, and said fresh air flow
section having a fresh air inlet and a fresh air outlet;a
rotary wheel including a substantially circular rim
having a first rim edge portion defining a first side of
said rotary wheel, a second rim edge portion defining a
second side of said rotary wheel, and a circumferential
rim body extending between said first and second rim edge
portions; an exchange media supported by said rotary
wheel, said exchange media intersecting said exhaust air
flow section and said fresh air flow section; a rotary
wheel mounting assembly coupled to said ventilator
housing; a rotary wheel driving assembly; and a rotary
wheel seal positioned between said circumferential rim
body and said ventilator housing and comprising a first
sealing member having a first sealing member end and a
second sealing member end, wherein said first sealing
member end of said first sealing member is pivotally
mounted to said ventilator housing at a first pivot mount
and said second sealing member end of said first sealing
member is spring mounted to said ventilator housing at a
first spring mount.
A further embodiment of the invention provides an
exchange media wheel comprising: a rim having a first rim
edge portion defining a first side of said rotary wheel,
a second rim edge portion defining a second side of said
rotary wheel, and a rim body extending between said first
and second rim edge portions; a hub; a set of ribs
including at least one pair of adjacent ribs wherein each
rib extends from said hub to said rim body; and an
exchange media comprising a plurality of divided media
portions positioned between adjacent ribs, wherein each
of said divided media portions are secured to at least
one of said adjacent ribs.
A still further embodiment provides a rotary
exchange media assembly comprising: a rotary wheel
including (i) a rim having a first rim edge portion
defining a first side of said rotary wheel, a second rim
edge portion defining a second side of said rotary wheel,
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and a rim body extending between said first and second
rim edge portions, (ii) a hub, and (iii) at least one
support member extending from said hub to said rim; a
rotary wheel mounting assembly; an exchange media secured
to said rotary wheel assembly; and a bearing assembly
coupled to said hub and defining a bearing assembly axis,
said bearing assembly being designed to permit said
rotary wheel to tilt relative to said bearing assembly
axis.
In order that the invention may be more readily
understood, reference will now be made by way of example
to the accompanying drawings, in which:
FIG. 1 is an exploded perspective view of a
ventilator according to the present invention;
FIG. 2 is a side elevational view, partially is
cross section, of a ventilator according to the present
invention;
FIG. 3 is an illustration, partially broken away, of
a portion of a rotary wheel mounting assembly in the
ventilator of the present invention;
FIGS. 4A and 4B are side and top plan views,
respectively, illustrating the rotary wheel, a guide
roller, and the drive roller in the ventilator of the
present invention;
FIG. 4C is a partial cross sectional view of the
rotary wheel, guide roller, and drive roller taken along
line 4C-4C of FIG. 4A;
FIG. 4D is a partial cross sectional view of an
alternative rotary wheel arrangement to that illustrated
in FIG. 4C;
FIGS. 5A and 5B illustrate another embodiment of the
rotary wheel and the positioning of the ffirst and second
rotary wheel sealing members relative to the rotary wheel
in the ventilator of the present invention;
3j FIG. 5C is a cross sectional view of a portion of
the rotary wheel in FIG. 5A;
FIGS. 6A and 6B are perspective views, broken and
unbroken respectively, of a sealing block in the
ventilator of the present invention;
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FIGS. 7A and 7B are perspective views, broken and
unbroken respectively, illustrating the positioning of
the sealing block and first and second sealing members in
the ventilator of the present invention;
FIG. 8 is an exploded perspective view of a bearing
and hub assembly according to the present invention; and
FIG. 9 is a side view, partially in cross-section,
of the bearing and hub assembly of FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 and 2, a ventilator 10 is shown
comprising a ventilator housing 12 defining an exhaust
air flow section 14 and a fresh air flow section 16 and
comprising a frame assembly 13, an inner frame assembly
IS 15, an inner frame assembly shell 19 shown partially
broken away in FIG. 1, and a housing body 17 enclosing
the frame assembly 13 and the inner frame assembly 15.
The housing body 17, shown partially broken away in FIG.
1, comprises a rigid shell Lined with a thermally
insulating material, e.g., a foam or fiber lined sheet
metal shell. It is contemplated by the present invention,
however, that a rigid thermally insulating material alone
may be utilized in place of the lined sheet metal shell
throughout all or part of the ventilator housing 12
depending upon the strength of the rigid insulating
material. It is further contemplated that a variety of
materials and structural framing arrangements may be
utilized to form the supportive housing of the present
invention.
The exhaust air flow section 14 includes and extends
between an exhaust air inlet 18 and an exhaust air outlet
20, while the fresh air flow section 16 includes and
extends between a fresh air inlet 22 and a fresh air
outlet 24. A motor driven exhaust air circulation fan 26
is positioned in communication with the exhaust air flow
section 14 and a motor driven fresh air circulation fan
28 is positioned in communication with the fresh air flow
section 16. The motor driven exhaust fan 26 is connected
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to a conventional power source (not shown) via
conventional electrical connections (not shown) and is
oriented so as to enable production of an exhaust air
flow stream (indicated by arrows 30) through the exhaust
air flow section 14. The motor driven fresh air fan 28 is
connected to a conventional power source (not shown) via
conventional electrical connections (not shown) and is
oriented so as to enable production of a fresh air flow
stream (indicated by arrows 32) through the fresh air
f low section 16 .
A rotary wheel 34 includes a substantially circular
rim 36, a hub and bearing assembly 39, a first rim edge
portion 38 defining a first side 40 of the rotary wheel
34, a second rim edge portion 42 defining a second side
44 of the rotary wheel 34, and a circumferential rim body
46 extending between the first and second rim edge
portions 38, 42. Although the hub and bearing assembly 39
may comprise any one of a variety of commercially
available designs, a specific embodiment of the hub and
bearing assembly 39 is described below with reference to
FIGS. 8 and 9.
A rotary wheel seal 47, a particular embodiment of
which is described in detail below with respect to FIGS .
5A-7B, is positioned between the circumferential rim body
46 and the housing body 17 to prevent the passage of air
between the housing body 17 and the rotary wheel 34.
A heat and moisture exchange media 48 intersecting
the exhaust air flow section 14 and the fresh air flow
section 16 is supported by the rotary wheel 34. The first
and second rim edge portions 38, 42 extend in the
direction of a central rotational axis of the rotary
wheel 34 so as to enclose a portion of the exchange media
48, see FIG. 4C. However, as is illustrated in FIG. 4D,
the first and second rim edge portions 38, 42 may extend
away from a central rotational axis of the rotary wheel
34 or, as a further alternative, may terminate at the
circumference of the rim 36, i.e., not extend in either
direction.
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The heat and moisture exchange media 48 is a random
matrix media consisting of a plurality of interrelated
small diameter, heat-retentive, fibrous material. Such
materials may be randomly interrelated by mechanical,
thermal, or chemical means for interrelating. Mechanical
means for interrelating may be, for example, needle-
punching. Thermal means for interrelating may, for
example, comprise radiant heat or ultrasonic methods for
bonding adjacent fibers or filaments. Chemical means for
interrelating may, for example, involve known methods for
bonding adjacent, randomly interrelated filaments with
adhesives.
Whether entirely random, or superficially
maintaining some semblance of a pattern comprising a
randomly interrelated assemblage of materials having
somewhat more ordered patterns, the fibrous material of
the exchange media 48, preferably, forms a mat of
material which is easy to work with, handle, and cut to
shape. The exchange media 48 may be made from one or more
of many commercially available filaments, fibers,
staples, wires, or yarn materials, natural (such as metal
wire) or man-made (such as polyester and nylon). Filament
diameters from substantially about 25 microns to
substantially about 150 microns may be used. Below
substantially about 25 microns, the small size of the
filaments creates excessive resistance to air flow, and
above about 150 microns, inefficient heat transfer
results due to decreased surface area of the larger
filaments. Single strand filaments from substantially
about 25 microns to substantially about 80 microns in
diameter are preferred, for example a 60 denier polyester
needle-punched felt having filament diameters of about 75
to 80 microns.
The mat of material which forms the random matrix
media should have a porosity (i.e., percentage of open
space in total volume) of between substantially about 830
and substantially about 960. Below substantially about
83%, resistance to air flow becomes too great, and above
substantially about 96o heat transfer becomes ineffective
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due to the free flow of air. Preferably the mat thickness
should be less than 6" to prevent excessive resistance to
air flow. Porosity is preferable from substantially about
90a to substantially about 940, as for example, with 60
denier polyester needle-punched felt, having a porosity
of about 92.5x. Representative of random matrix materials
which may be used in exchange media 48, 60 denier
polyester needle-punch felt has a specific gravity of
approximately 1.38, thermal conductivity of approximately
0.16 watts/m°K and specific heat of approximately 1340
J/Kg°K.
The exchange media 48 functions as a filter for
particles as small as 5 microns. For example, pollen in
the fresh air flow stream (indicated by arrows 32) driven
to the surface of the exchange media 48 does not
substantially penetrate the exchange media 48 and may be
removed by the exhaust air flow stream (indicated by
arrows 30). Pre-filters (not shown) may be positioned in
the exhaust air inlet 18, the fresh air inlet 22, the
fresh air outlet 24, or elsewhere to supplement the
filtering achieved by the exchange media 48 or to prevent
the exchange media 48 from becoming clogged with
particles.
Although according to the embodiments of the present
invention disclosed herein the exchange media 48
comprises a pair of exchange media layers 48a, 48b, see
FIG. 4C, secured about the spokes 35 of the rotary wheel
34 by passing thread 37 through the exchange media 48 and
around individual spokes 35 at multiple points, the
exchange media 48 may be supported by the rotary wheel 34
in any conventional manner, e.g., wire, clips, hook and
loop fasteners, etc. The spokes 35 provide a means by
which the circularity of the rotary wheel 34 can be
conveniently maintained through adjustment of individual
spoke length, i.e. the length of the spoke extending
between the hub and the rim is adjustable. The spokes 35,
which comprise rigid metal wires connected between the
circumferential rim body 46 and to the hub and bearing
assembly 39 and lying substantially in a common plane,
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also provide a means by which an exchange media 48 having
an un-partitioned continuous surface bounded by the
circular rim 36 may be secured to the rotary wheel 34. In
this manner, the fresh air flow stream (indicated by
arrows 32) and the exhaust air flow stream (indicated by
arrows 30) are forced to pass through the exchange media
48, as opposed to spaces between partitions of the
exchange media 48. Preferably, the common plane defined
by the spokes 35 bisects the rim body 46 around the
entire circumference of the rotary wheel 34.
Referring now to FIGS. 5A and 5C, according to
another embodiment of the present invention, a rotary
wheel 34' comprises integrally formed plastic ribs 35'
and a substantially circular rim 36'. The integral
construction is typically achieved through an injection
molding process but may also be formed in another
suitable manner. Heat and moisture exchange media 48, a
portion of which is illustrated in FIG. 5A, is secured
the ribs 35' extending from the hub 39 of the rotary
wheel to the substantially circular rim. For illustrative
purposes, only a portion of the exchange media 48 is
shown in FIG. 5A although it should be understood that,
according to the present invention, substantially the
entire circle defined by the rotary wheel 34' is occupied
by the exchange media 48.
The exchange media 48 comprises divided media
portions 48' positioned between adjacent ribs 35'. FIG.
5A illustrates the positioning of one of the divided
media portions 48'. Rigid channels 33 are secured, via
conventional securing means, e.g., an adhesive, to the
ribs 35' and the rim 36' so as to receive and secure
peripheral portions of the divided media portions 48'.
The rigid channels are preferably constructed of a rigid
plastic material but may also be constructed of other
materials suitable for supporting the weight of the
exchange media 48 and the force of fresh and exhaust air
flow streams 30, 32 moving through the exchange media 48.
In this manner, it is not necessary to provide screens
enclosing and supporting the exchange media. Further,
CA 02460623 2004-03-25
removal of the exchange media for cleaning or replacement
is enabled because each divided media portion 48' may be
separately removed from the rotary wheel 34'. It is
contemplated by the present invention that structure
other than rigid channels 33 may be provided to secure
the exchange media between the ribs 35', e.g., tape, hook
and loop fasteners, etc.
The exchange media 48 may comprise a single unitary
mass of material or a plurality of distinct layers of
material. Where a plurality of distinct layers of
exchange media are utilized, individual layers may be
specifically treated to encourage moisture removal,
particulate removal, odor removal, fire retardation,
anti-microbial activity, and other improvements related
to indoor air quality. For example, an individual layer
of the exchange media may be treated with silica,
activated alumina, and/or a zeolite to improve moisture
transfer or activated carbon to remove odors and
particulate matter. Further, the exchange media may be
enclosed on one or both sides by a screen 45.
A rotary wheel mounting assembly 50, which is
illustrated with reference to FIGS. 3 and 4A-4C in
addition to FIG. 1, is coupled to the ventilator housing
12 and comprises an upper mounting assembly frame 50a, a
lower mounting assembly frame 50b, a first set of guide
rollers 52 in contact with the first rim edge portion 38,
and a second set of guide rollers 54 in contact with the
second rim edge portion 42. Similarly, a rotary wheel
driving assembly 56 is coupled to the rotary wheel
mounting assembly 50 and comprises a motor driven drive
roller 58 in contact with the second rim edge portion 42.
It is contemplated by the present invention that the
drive roller 58 may alternatively be arranged so as to
contact the first rim edge portion 38 and that the rotary
wheel driving assembly 56 may be coupled to the
ventilator housing 12 as opposed to the rotary wheel
mounting assembly 50. The drive roller and guide rollers
are preferably formed of 50-110 durometer hardness
plastic.
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Referring to FIG. 3 in addition to FIGS. 1 and 2,
each guide roller 53 within the f first and second sets of
guide rollers 52, 54 is coupled to a positional
adjustment assembly 55 which is operative to move the
guide roller 53 towards and away from the rotary wheel 34
or a rotary wheel plane in which the rotary wheel 34 is
to be positioned. The positional adjustment assembly 55
comprises a pivot bolt 57 and an adjustment bolt 59. To
position the guide roller 53, the pivot bolt 57 is
loosened to permit a guide roller arm 51 to pivot about
the pivot bolt 57 when the adjustment bolt 59 is rotated
clockwise and counterclockwise. In this manner, each
guide roller 53 may be positioned to forcibly engage one
of the rim edge portions 38, 42 such that the rotary
wheel 34 is secured between the first and second set of
guide rollers 52, 54. It is contemplated by the present
invention that any number of guide rollers 53 may be
utilized within each set of guide rollers 52, 54
depending upon the size and weight of the rotary wheel 34
and exchange media 48 supported therein. Further, it is
contemplated by the present invention that other
mechanical arrangements by be employed to adjustably
secure the rim edge portions 38, 42 between the first and
second set of guide rollers, e.g., a spring loaded
mechanical assembly.
A partition assembly 60, not shown in FIG. 1 but
illustrated in FIG. 2, is positioned so as to isolate the
exhaust air flow section 14 from the fresh air flow
section 16. The partition assembly 60 comprises a first
partition 62, including the upper mounting assembly frame
50a, positioned adjacent the first side 40 of the rotary
wheel 34, a second partition 64, including the lower
mounting assembly frame 50b, positioned adjacent the
second side 44 of the rotary wheel 34, a first partition
seal 66 extending from the first partition 62 to the
exchange media 48, and a second partition seal 68
extending from the second partition 64 to the exchange
media 48. As will be appreciated by one skilled in the
art, a variety of materials, including a TEFLON~-based
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tape, as disclosed in U.S. Pat. No. 5,069,272, may be
utilized to form the first and second partition seals 66,
68.
Referring now back to FIG. 1, the circulation fan
mounting plate 70, in conjunction with the inner frame
assembly 15, the inner frame assembly shell 19, the
partition assembly 60, the housing body 17, and a rotary
wheel access plate 72, described in detail below, seal-
off or enclose respective portions of the exhaust and
fresh air flow sections 14, 16 along portions of the
exhaust and fresh air flow streams 30, 32 extending
between the exhaust and fresh air circulation fans 26, 28
and access plate ports 74. This air-tight sealing
arrangement ensures maximum operating efficiency by
containing the exhaust air flow stream 30 within the
exhaust air flow section 14 and the fresh air flow stream
32 within the fresh air flow section 16. Further, the
rotary wheel seal 47, in cooperation with the housing
body 17, ensures that a large portion of the respective
exhaust and fresh air flow streams pass through the
exchange media 48.
The circulation fan mounting plate 70 is supported
by the ventilator housing 12, and the exhaust air
circulation fan 26 and the fresh air circulation fan 28
are mounted to the circulation fan mounting plate 70. The
exhaust and fresh air circulation fans 26, 28 are
oppositely oriented so as to create the oppositely
directed exhaust and fresh air flow streams 30, 32.
Alternatively, the exhaust and fresh air circulation fans
26, 28 may be similarly oriented but oppositely rotated
so as to create the oppositely directed exhaust and fresh
air flow streams 30, 32. It is contemplated by the
present invention that the exhaust and fresh air
circulation fans 26, 28 may be positioned on opposite
sides of the rotary wheel 34.
A moisture transfer wick 69 is positioned adjacent
the second side 44 of the rotary wheel 34 and extends
across the partition assembly 60 between the exhaust air
flow section 14 and the fresh air flow section 16 to
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transfer moisture from one section to the other. A
moisture transfer wick, as utilized in the present
specification, comprises a material or device that
conveys liquid by capillary action or other means. For
example the wick 69 may comprise a length of natural or
synthetic, braided or non-braided, cloth, thread, or
other material. It is contemplated by the present
invention that a mechanism may be provided to induce a
pressure differential across the partition assembly 60
L0 between the exhaust air flow section 14 and the fresh air
flow section 16 to encourage transfer of moisture along
the wick 69.
The rotary wheel access plate 72 includes access
plate ports 74 which define the exhaust air outlet 20 and
the fresh air inlet 22. Access plate 72 is positioned
adjacent the first side of rotary wheel 40. An access
plate opening assembly 76 is coupled to access plate 72
such that access plate 72 is easily opened and closed. In
this manner, convenient maintenance of exchange media 48
and/or other components within the ventilator housing 12
is enabled. Specifically, the opening assembly comprises
a pair of pneumatic lifts 78 and a hinge assembly 80
coupling access plate 72 to ventilator housing 12 such
that access to the interior of the ventilator housing 12
is achieved by swinging open access plate 72 with the aid
of pneumatic lifts 78. It is contemplated by the present
invention that a variety of arrangements could be
substituted for the pneumatic lifts 78 and hinge assembly
80 to facilitate opening of access plate 72.
A pair of assembly frame mounting grooves 49 are
provided such that, upon opening of the access plate 72,
the upper mounting assembly frame 50a and the rotary
wheel 34 may be conveniently removed from the ventilator
housing 12 and subsequently reinstalled. In this manner,
the exchange media 48 may be cleaned, modified or
replaced to optimize the operational characteristics of
the ventilator 10. Typically, a frame assembly and rotary
wheel securing means (not shown), e.g., a bolt on the hub
and bearing assembly 39, must be removed prior to the
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removal of the upper mounting assembly frame 50a and the
rotary wheel 34.
It is contemplated by the present invention that the
ventilator housing 12 may be provided as a single unit or
cartridge not including the motor driven fans 26 and 28
and the associated air ducts 29. In this manner, the
single unit or cartridge may be positioned within an
existing air duct system to intercept respective forced
exhaust and fresh air supplies. It is further
contemplated by the present invention that the size of
the rotary wheel 34, the ventilator housing 12, and the
associated hardware can vary according to the particular
intended operating environment, e.g., residential,
industrial, etc. Specifically, the diameter of the
exchange media can vary from about 25 cm to greater than
100 cm.
Referring again to FIGS. 5A-7B, a particular
embodiment of the rotary wheel seal 47 includes a first
sealing member 82 having a first sealing member end 82a
and a second sealing member end 82b. The first sealing
member end 82a of the first sealing member 82 is
pivotally mounted to the ventilator housing 12 at a first
pivot mount 86 and the second sealing member end 82b of
the first sealing member 82 is spring mounted to the
ventilator housing 12 at a first spring mount 90.
Similarly, the rotary wheel seal includes a second
sealing member 84 having a first sealing member end 84a
and a second sealing member end 84b. The first sealing
member end 84a of the second sealing member 84 is
pivotally mounted to the ventilator housing 12 at a
second pivot mount 88, and the second sealing member end
84b of the second sealing member 84 is spring mounted to
the ventilator housing 12 at a second spring mount 92. As
will be appreciated by one skilled in the art, a variety
of materials, including a TEFLON-based material, as
disclosed in U.S. Pat. No. 5, 069, 272, may be utilized to
form the first and second sealing members 82, 84.
The first sealing member end 84a of the second
sealing member 84 overlaps the second sealing member end
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82b of the first sealing member 82 and the second sealing
member end 84b of the second sealing member 84 overlaps
the first sealing member end 82a of the first sealing
member 82, see FIGS. 7A and 7B. A first seal block
assembly 94, which is illustrated in FIGS. 6A and 7A
broken away along a cutting plane for illustrative
purposes only, defines a sealing member passageway 95 and
includes first pivot mount 86 provided therein and second
spring mount 92 attached thereto. A second seal block
assembly 96 defines a sealing member passageway 95 and
includes second pivot mount 88 provided therein and first
spring mount 90 attached thereto. The first seal block
assembly 94 and the second seal block assembly 96 are
positioned adjacent substantially circular rim 36' and
are spaced approximately 180° apart relative to the
periphery of rim 36'. The first and second pivot mounts
86, 88 each comprise a sealing member pin 100 resting in
a pin catch 102 formed in first and second seal block
assemblies 94, 96. Each sealing member pin 100 passes
through a corresponding pin slot 104 formed in one of the
first and second sealing members 82, 84. When rotary
wheel 34' rotates in a first direction 98, any contact
between substantially circular rim 36' and the first
sealing member 82 will cause the first sealing member 82
to pivot about the first pivot mount 86 and abut or urge
against the periphery of substantially circular rim 36'.
Similarly, any contact between substantially circular rim
36' and second sealing member 84 will cause second
sealing member 84 to pivot about second pivot mount 88
and abut or urge against the periphery of substantially
circular rim 36'. In this manner, a strong seal is
maintained between housing body 17 and rotary wheel 34'
while rotary wheel 34' rotates. Further, noting that the
frictional moving contact between the first and second
sealing members 82, 84 and the circular rim 36' causes
the sealing members 82, 84 to gradually wear, the strong
seal is maintained as the sealing members 82, 84 wear
because the sealing members 82, 84 continually abut or
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urge against the periphery of substantially circular rim
36'.
Referring now to FIGS. 8 and 9, a bearing assembly
110, an inner hub portion 112, and an outer hub portion
114 are fixed between opposing hub plates 116. The outer
hub portion 114 includes spoke mounting holes 115. It is
contemplated by the present invention that, where a
particular rotary exchange wheel to be fitted with the
hub and bearing assembly 39 illustrated in FIGS. 8 and 9
includes ribs or other radial support members, as opposed
to spokes, appropriate mounting hardware, holes, or slots
may be provided in the outer hub portion 114.
Four hub plate screws or bolts (not shown) are
provided in hub plate mounting holes 118 such that the
inner and outer hub portions 112, 114 are secured within
respective annular hub mounting grooves 120 formed in the
opposing hub plates 116. The bearing assembly 110
comprises an outer bearing race 122 fixed to the inner
hub portion 112 at outer bearing race mounts 126. An
inner bearing race 124 is fixed to an axle 130 at inner
bearing race mounts 128. The outer bearing race mounts
126 and the inner bearing race mounts 128 comprise snap
rings or another conventional mounting arrangement. The
axle 130 comprises axle shoulders 134 which engage a
portion of a wheel mounting assembly between the axle
shoulders 134 and a securing bolt (not shown) threaded
onto the axle 130.
The bearing assembly 110 defines a bearing assembly
axis 132 and the bearing assembly 110 permits a rotary
wheel mounted to the hub and bearing assembly 39 to tilt
relative to the bearing assembly axis 132 and relative to
a rotary wheel mounting assembly (not shown). In this
manner, slight misalignments or irregularities in the
particular mounting assembly in use will not inhibit free
rotation of the rotary wheel about the axle 130. To
facilitate the axial tilting, the bearing assembly 110
comprises a single bearing and opposing apertures 117
formed in the opposing hub plates 116 are sized so as to
provide a minimum tilting clearance 136 between the inner
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CA 02460623 2004-03-25
race 124 and the opposing hub plates 116. The single
bearing may be a conventional ball bearing arrangement or
sphere roller bearing available from McGill Precision
Bearings, Valparaiso, Indiana.
Having described the invention in detail and by
reference to preferred embodiments thereof, it will be
apparent that modifications and variations are possible
without departing from the scope of the invention defined
in the appended claims.
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