Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Docket No.: RHAC-0141
COIL DRAIN PAN APPARATUS
BACKGROUND OF THE INVENTION
The present invention generaliy relates to air conditioning apparatus
and, in representatively illustrated embodiments thereof, more
1o particularly relates to condensate drain pan structures used in conjunction
with air conditioning cooling coils.
A coil used in air conditioning apparatus such as furnaces, air
handling units, and heat pumps extracts moisture from the air which is
being flowed externally across the coil (by a blower portion of the
apparatus) and cooled by the coil for delivery to a conditioned space
served by the apparatus. This moisture extraction creates condensation
(water) on the exterior of the coil which drips from the coil into an
associated drain pan structure within the air conditioning apparatus. Coil
condensation dripping into the pan flows away therefrom by gravity via a
condensate drain line suitabiy connected to the pan. While this general
approach to coil condensate removal has long been utilized and is
generally suitable for its intended purpose, it typically presents several
well known problems, limitations and disadvantages.
For example, an air conditioning apparatus (such as a furnace, air
handling unit or heat pump) incorporating a cooling coil therein may
customarily be fabricated in either (1) a vertical configuration in which air
is to be operationally flowed upwardiy or downwardiy through the
cooling coil, or (2) a horizontal configuration in which air is to be
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operationally flowed horizontally in one of two opposite directions
through the coil. To permit a given vertical air flow coil/drain pan
subassembly to be utilized in a horizontal air flow application (in which the
associated drain pan is verticaliy oriented) it is typicaliy necessary to
attach to the re-oriented drain pan a horizontal drip shield structure to
catch the condensate falling from the coil. Attachment of the auxiliary
drip shield structure to the drain pan tends to be a fairiy tedious
procedure requiring the use of separate fasteners, and the application of
a suitable sealing material at the joint between the pan and the shield.
1o Such fabricational complexity undesirably adds to the overall cost of the
air conditioning apparatus.
Additionally, condensate drain pans of conventional constructions
often present problems associated with the coil condensate which they
receive. Such problems arise from the often unavoidable presence of
standing water within the pans for long periods of time, and include
sweating of the pans, fungus growth, and reduction in the quafity of air
delivered to the conditioned space.
AS can readily be seen from the foregoing, a need exists for a coil
drain pan structure which eliminates or at least substantially eliminates
the above-mentioned problems, limitations and disadvantages of
conventionally constructed coil drain pans. It is to this need that the
present invention is directed.
SUMMARY OF THE INVENTION
In carrying out principles of the present invention, in accordance
with representatively illustrated embodiments thereof, air conditioning
apparatus is provided which is representativeiy in the form of an air
conditioning unit having has operatively incorporated therein a cooling
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coil for lowering the temperature of supply air internally traversing the
apparatus. The air conditioning apparatus may be utilized in either a
vertical air flow or horizontal air flow orientation, and is provided with a
specially designed condensate drain pan structure for receiving and
draining away condensation dripping off the cooling coil during its
operation. While the coil is representatively a cooling coil, the present
invention is not limited to cooling coils, with the term air conditioning"
as used herein encompassing both heating and cooling applications.
According to one aspect of the invention, the coil drain pan is
lo selectively positionable in horizontal and vertical air flow orientations
and
includes a drain structure having an outlet opening therein, and a plurality
of interconnected troughs, in drainage flow communication with the
outlet opening. The drain structure includes a wall area which projects
downwardly beyond the interconnected troughs and is in fluid flow
communication herewith, the outlet opening extending through a wall
portion of the well area. The interconnected troughs representatively
border a generally rectangular air flow opening and, when the drain pan is
in its vertical air flow orientation, lie generally in a horizontal plane, are
positioned above the outlet opening, and are sloped relative to one
2o another in a manner such that essentially all condensation entering any of
the troughs flows by gravity to and outwardly through the outlet
opening, thereby substantially eliminating standing water in the drain pan
structure.
To permit the drain pan to be utilized in its horizontal air flow
orientation, with the trough portion lying generally in a vertical plane, a
drip shield structure is removably connected to the trough portion of the
drain pan to lie generally in a horizontal plane and receive condensate
from the cooling coil and drain the received condensate into one of the
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drain pan troughs for discharge therefrom through the outlet opening.
According to another feature of the invention, the drip shield structure is
connectable to the drain pan trough portion without the use of separate
fasteners, tools, or sealant material.
Illustratively, the drip shield structure is press-fittable onto a support
wall extending outwardly from one of the drain pan troughs using
resilient tabs formed on the support wall, and lanced-out locking barbs
formed on an edge portion of the drip shield structure. The drip shield
edge portion is pressed into spaces between the resilient tabs and the
1o support wall to outwardly deflect the tabs and bring the barbs into
locking engagement with inner side surface portions of the tabs.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 1A, respectively, are schematic side elevational views of
vertical flow and horizontal flow furnaces incorporating therein air
conditioning coil sections embodying principles of the present invention;
FIGS. 2 and 2A, respectively, are schematic side elevational views of
vertical flow and horizontal flow air handling units incorporating therein
similar air conditioning coil sections embodying principles of the present
invention;
FIG. 3 is an enlarged scale cut away side elevational view of one of
the vertically oriented air conditioning coil sections;
FIG. 3A is an enlarged scale cut away side elevational view of one of
the horizontally oriented air conditioning coil sections;
FIG. 4 is a front and right side perspective view of a specially
designed drain pan/drip shield subassembly used in the air conditioning
coil sections;
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FIG. 4A is a simplified cross-sectional view through a corner portion
of the drain pan/drip shield subassembly taken along line 4A-4A of FIG. 4;
FIG. 5 is an enlarged scale cross-sectional view through a portion of
the drain pan/drip shield assembly taken along line 5-5 of FIG. 4;
FIG. 6 is a front and left side perspective view of the trough portion
of the FIG. 4 drain pan/drip shield subassembly;
FIG. 7 is an exploded perspective view of the drain pan/drip shield
interface area of the drain pan/drip shield subassembiy shown in FIG. 4;
FIG. 8 is an enlarged scale detail view of the dashed circle area "8" in
FIG. 7; and
FIG. 9 is a perspective view of a corner portion of an alternate
embodiment of the trough part of the drain pan/drip shield subassembly.
DETAILED DESCRIPTION
Schematically depicted in FIGS. 1-2A are four representative types of
air conditioning apparatus embodying principles of the present invention
-(1) a vertical air flow furnace 10 shown in FIG. 1; (2) a horizontal air flow
furnace 12 shown in FIG. 1A; (3) a vertical air flow air handling unit 14
shown in FIG. 2; and (4) a horizontal air flow air handling unit 16 shown in
FIG. 2A. Each of these four illustrative units incorporates therein a
specialiy designed air conditioning coil section 18, and is operative to flow
air 20 from a conditioned space therethrough, with the air exiting the
unit as cooled air 20a, for return to the conditioned space, during
operation of the coil section 18.
AS used herein, the term "air conditioning" is intended to encompass
both cooling and heating applications. Thus, while the air conditioning
coil section 18 is illustratively a cooling coil section, it could
alternativeiy
be a heating coil section without departing from principles of the present
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invention. Also, the air flow in the units 10 and 14 could alternatively be
downwardly directed, and the air flow in the units 12 and 16 could
alternatively be rightwardly directed. Further, the coil section 18 could be
mounted in other types of air conditioning units such as in a heat pump,
or simply mounted in a duct, without departing from principles of the
present invention.
The coil section 18, shown in a vertical air flow orientation in FIG. 3
and in a horizontal air flow orientation in FIG. 3A, includes a rectangular
outer housing 22, having opposite inlet and outlet openings 24 and 26, in
lo which an air conditioning cooling coil 28 is disposed and operatively
associated with a specially designed drain pan structure 30 adapted to
receive and drain away condensate (i.e., water) dripping from the coil 28
during it operation. Representatively, the coil 28 is a direct expansion
type refrigerant coil having three alternatingly sloped sections 32, but
could be another type of cooling coil, such as a chilled water cooling coil
or a heat pump coil, and have a different configuration, without
departing from principles of the present invention.
Turning now to FIGS. 4 and 6, the drain pan structure 30 includes a
rectangular, generally frame-shaped trough portion 34 which borders an
2o air flow opening 35 and is representatively of a molded plastic
construction, and a generally rectangular drip shield structure 36 (which
has been removed from the drain pan structure 30 in FIG. 6 for illustrative
purposes) which is formed from a suitable material such as, for example,
plastic or sheet metal. With the drain pan 30 in its vertical air flow
orientation shown in FIGS. 4 and 6, the trough portion 34 is generally
horizontally oriented and includes spaced apart, parallel and facing front
and rear trough portions 38 and 40, and spaced apart parallel and facing
left and right trough portions 42 and 44 which are transverse to the
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troughs 38 and 40. For purposes later described herein, the left side of
the trough 42 has an upstanding support wall 46 formed thereon and
having four mutually spaced apart, upwardly projecting resilient tabs 48
formed on its inner side surface. While the representatively illustrated
trough portion 34 has four interconnected troughs, it will be readily
appreciated by those of ordinary skill in this particular art that it could
alternatively have a greater or lesser number of interconnected troughs,
if desired, without departing from principles of the present invention.
With the drain pan 30 in its vertical air flow orientation shown in
1o FIGS. 4 and 6, all of the troughs 38,40,42,44 are sloped in a manner such
that condensation from the cooling coil 28 (see FIG. 3) entering any of the
troughs flows downwardly by gravity to the junction of the troughs 38
and 42 (i.e., to the left corner of the overall troughs portion 34 as viewed
in FIG. 4). Specifically, as viewed in FIG. 4, the left and right troughs
42,44
slope downwardly toward trough 38 as indicated by the arrows 50 and 52,
trough 38 slopes downwardly toward the trough 42 as indicated by the
arrow 54, and an outer or right end portion of the trough 40 slopes
downwardly toward the trough 44 as indicated by the arrow 56. The
portion 40a of the trough 40 between the troughs 42 and 44 is sloped in
opposite directions from a Iongitudinally intermediate point 58, with a
left section of the trough portion 40a sloping downwardly toward the
trough 42, and a right section of the trough portion 40a a sloping
downwardly toward the trough 44.
Accordingly, with the drain pan 30 in its vertical air flow orientation
cooling coil condensation received by any of the troughs 38,40,42,44 flows
by gravity to the juncture of the troughs 38 and 42 which forms the low
point of the interconnected troughs 38,40,42 and 44. Disposed at this low
point of the interconnected troughs is a drain structure 60 comprising a
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well area 61 (see FIG. 4A) which projects downwardly beyond the juncture
of the troughs 38 and 42 and serves as a condensate disposal area which is
positioned below the troughs and their associated coil. Well 61 has an
inner wall 63 (see FIG. 4A), a main condensate outlet opening 62 (see FIGS. 3
and 6), a vertical orientation condensate overflow opening 64, and a
horizontal orientation condensate overflow opening 66. Conventional
condensate drain tubing (not shown) may be appropriately connected to
these openings during field installation of the air conditioning apparatus
in which the drain pan 30 is incorporated, and the overflow openings
1o 64,66 are adapted to receive removable plugs 68 as shown in FIGS. 3 and
3A.
With the drain pan 30 in its vertical air flow orientation, the main
outlet opening 62, which communicates with the interior of the well 61,
and the vertical overflow opening 64 is slightly higher than the main
outlet opening 62. Thus, when the drain pan 30 is in its vertical air flow
orientation, substantially all of the coil condensation entering the trough
portion 34 flows by gravity into the downwardly projecting well 61 and is
discharged by gravity through the main outlet opening 62, thereby
substantially eliminating standing drain pan water and its attendant
problems such as sweating, fungus growth and reduced indoor air quality.
Should the main outlet opening 62 be restricted or blocked, the pan-
received condensation is simply discharged through the back-up overflow
opening 64. The downwardly projecting well 61 acts as a condensate
collection area to hold only a small amount of condensate before it is
discharged through opening 62, thus preventing or minimizing the
growth of mold and mildew that can be exposed to the indoor airstream.
Referring now to FIG. 3A, with the drain pan 30 and its associated
cooling coil 28 in their horizontal air flow orientations, the trough portion
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34 lies generally in a vertical plane, and the generally flat pan-shaped drip
plate structure 36 underlies the coil 28 to receive condensation dripping
therefrom, lies generally in a horizontal plane, and is sloped slightiy
downwardiy toward the trough 42 (see FIG. 4) which now forms a lower
edge section of the verticaliy disposed trough portion 34. Coil
condensation received by the drip plate structure 36 flows therethrough
by gravity into the trough 42 for discharge through main outlet opening
62 in the drain structure 60 via the downwardly projecting well 61. In the
event that the main outlet opening 62 becomes restricted or clogged, this
1o condensation simpiy flows outwardiy through the horizontal overflow
opening 66 which is now positioned somewhat above the main outlet
opening 62.
In accordance with a feature of the present invention, the drip plate
structure 36 may be removabiy and operatively connected to the support
wall 46 of the trough portion 34, without the use of separate fasteners or
joint sealant material, by simpiy press-fitting the drip plate structure 3q
onto the support wall 46 as will now be described with reference to FIGS.
4, 5, 7 and 8.
As best illustrated in FIGS. 7 and 8, a horizontaliy spaced plurality of
lanced-out triangular locking barbs 70 are formed in a lower edge portion
36a of the drip plate structure 36 and are alignable with the tabs 48 on the
support wall 46. To quickly attach the drip plate structure 36 to the
support wall 46, the barbs 70 are aligned with the tabs 48, and the lower
drip plate edge portion 36a is pushed downwardly toward the support
wall 46, as indicated by the arrow 72 in FIG. 7, until the lower drip plate
edge portion 36a and its associated locking barbs 70 are forced
downwardiy between the support wall 46 and the resilient tabs 48, as
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cross-sectionaliy depicted in FIG. 5, to bring the drip plate structure 36 to
its installed orientation as shown in FIG. 4.
This laterally outwardiy deflects the resilient tabs 48 and causes
upper end points 70a on the barbs 70 (see FIG. 8) to engage the inner sides
of the outwardly deflected tabs 48 in a manner releasably locking the drip
plate structure 36 on the trough structure 34 without the use of any
separate fasteners or tools of any sort. Since, with the drain pan 30 in its
horizontal air flow orientation, the inner edge portion 36a of the drip
plate 36 overlies the top side of the horizontally oriented support wall 46,
1o no sealant material need be utilized at the juncture between the support
wall 46 and the drip plate structure 36. This feature of the present
invention advantageously simplifies the assembly of the coil/drain pan
subassembly and thus reduces the fabrication cost for the overall air
conditioning apparatus in which it is operatively incorporated.
A drain corner area of an alternate embodiment 34a of the
previously described drain pan trough portion 34 is perspectively
illustrated in FIG. 9. In order to facilitate a comparison of the drain
portion embodiments 34 and 34a, components in the embodiment 34a
similar to those in the embodiment 34 have been given identical
2o reference numerals with the subscripts "a". The trough structure 34a is
substantially identical to the previously described trough structure 34
with the exception that in the trough structure 34a the drain structure
60a extends outwardly from the trough structure 34a in a direction
substantially parallel to the length of the trough 42a, whereas in the
previously described trough structure 34 the drain structure 60 is
leftwardly angled as viewed in FIG. 4.
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The foregoing detailed description is to be clearly understood as
being given by way of illustration and example only, the spirit and scope
of the present invention being limited solely by the appended claims.
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