U.S. patent application number 11/021972 was filed with the patent office on 2006-06-22 for hvac lateral condensate drain channel.
This patent application is currently assigned to Valeo Climate Control Corp.. Invention is credited to Steven B. Marshall, Brian R. Williams.
Application Number | 20060130509 11/021972 |
Document ID | / |
Family ID | 36593996 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060130509 |
Kind Code |
A1 |
Williams; Brian R. ; et
al. |
June 22, 2006 |
HVAC lateral condensate drain channel
Abstract
The present invention relates to HVAC units with condensate
drainage systems, for use in motorized vehicles. The present
invention provides for at least two or dual condensate drain paths
with no extra parts required pre-distribution of the treated air
from the HVAC unit, the drainage means or channel situated to allow
condensate to `fall back` or, to run upstream back from the
evaporator in the opposite direction to the air in the main airflow
or stream which continues to run downstream from the drainage area
to be conditioned by the heat exchanger.
Inventors: |
Williams; Brian R.; (Troy,
MI) ; Marshall; Steven B.; (Oxford, MI) |
Correspondence
Address: |
Valeo Climate Control Corp.;Intellectual Property Department
4100 North Atlantic Boulevard
Auburn Hills
MI
48326
US
|
Assignee: |
Valeo Climate Control Corp.
Auburn Hills
MI
48326
|
Family ID: |
36593996 |
Appl. No.: |
11/021972 |
Filed: |
December 22, 2004 |
Current U.S.
Class: |
62/290 ;
62/285 |
Current CPC
Class: |
F24F 13/222 20130101;
B60H 1/3233 20130101 |
Class at
Publication: |
062/290 ;
062/285 |
International
Class: |
F25D 21/14 20060101
F25D021/14 |
Claims
1. An HVAC unit with a condensate draining system comprising: a
housing; a air propulsion means; an air flow provided by the
propulsion means; a heat exchanger downstream of the air propulsion
means; a channel or drain means downstream of the air propulsion
means and upstream of the heat exchanger; wherein the channel or
drain drains condensate from the air flow upstream up to the area
of the channel or drain means and upstream from the heat exchanger
in two separate or dual paths.
2. An HVAC unit as in claim 1, wherein the drain means is a U
shaped channel or drain.
3. An HVAC unit as in claim 2, wherein the U shaped channel or
drain has a step.
4. An HVAC unit as in claim 3, wherein of the side of the step
downstream of the air propulsion means that contacts the air flow
upstream up to the area of the channel or drain is higher than the
side of the step downstream of the channel or drain.
5. An HVAC unit as in claim 1, further comprising a step, wherein
the drainage means is a channel or drain and wherein side of the
step downstream of the air propulsion means that contacts the air
flow upstream up to the area of the channel or drain is higher than
the side of the step downstream of the channel or drain.
6. An HVAC unit, as in claim 3, wherein the HVAC unit is a lateral
HVAC unit, and the HVAC unit has a second drain with or without
drain pan, through which condensate drains from the air outflow
side of the heat exchanger prior to exiting the U shaped drain and
leaving the HVAC unit.
7. An HVAC unit as in claim 4, wherein the heat exchanger is an
evaporator.
8. An HVAC unit, as in claim 4, wherein the U shaped channel or
drain has a gap at its center, and the air from the air flow jumps,
clears or misses the gap such that a slightly lower pressure exists
in the area of the drain due to the movement of the air.
9. An HVAC unit, as in claim 4, wherein the condensate is drawn
down into a slope of the U shaped drain or channel due partly to
the lower pressure at the area of the U shaped drain or
channel.
10. An HVAC unit, as in claim 7, wherein the lower edge of the
blower and the lower edge of the evaporator are at approximately
the same height.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of HVAC units
that form condensate during normal operations, and, particularly,
HVAC units with condensate drainage systems, for use in motorized
vehicles.
BACKGROUND OF THE INVENTION
[0002] In HVAC units, heat exchangers, due to changing temperature
and other conditions within an essentially closed environment, end
up forming condensate from the air inputted into the HVAC unit. It
is undesirable for excess humidity or condensate to remain in the
HVAC unit, or to be distributed downstream of the heat exchangers
after the air is conditioned in the unit to the outside areas, such
as the passenger and other motor vehicle compartments.
[0003] In prior art HVAC unit, this undesirable condensate has
often been drained from the area of the heat exchanger, such as an
evaporator, by exhausting and/or evacuating the condensate from
areas beneath the evaporator via a separate or `segregated` channel
which is found away from the main airflow path through the HVAC
unit, and, particularly, the airflow path coming from the air
propulsion device or blower. The air in this airflow path,
therefore, flows, after blower, into an expansion zone and possible
turning housing downstream of the blower expansion zone. In most
cases, the condensate channel or drain is found underneath the
blower or blower expansion region in a separate or segregated
fashion or downstream of the evaporator. The drain is separate from
the main air flow function of the HVAC. Prior art HVAC's, therfore
allow the water to drain unhindered by the main airflow in the HVAC
and, the drain air path is never exposed to the blown airflow
upstream of the evaporator. Because of this HVAC architecture,
prior art HVAC units are often designed so that condensate in the
drain or channel does not interact with the blown air of the HVAC
itself in any appreciable way. Hence the condensate drains away
freely, unhindered or disturbed by the airflow from the blower in
the HVAC.
[0004] The present architectures mean that if a drain were open up
to an area at or just downstream of the blower, a negative impact
would result due to the fact that there would be a direct open air
path allowing drainage wall to be entrained into the airflow path
to HVAC unit from the blower expansion zone through the drain to
the exterior of the HVAC unit. An open drain anywhere between the
area of the blower expansion zone up to the evaporator intake
region, (possibly a turning area), would normally be thought of as
a detriment to the airflow quantity requirement of the unit if, an
excessive quantity of air escaped.
SUMMARY OF THE INVENTION
[0005] The present invention, therefore, allows for drainage of
condensate (such as water or other fluids in the incoming
airstream, that normally enter the HVAC outside of the HVAC unit
itself, to be exhausted. The present invention provides for at
least two condensate drain paths with no extra parts required pre
distribution of the treated air from the HVAC unit. In preferred
embodiments of the present invention, the drainage means or channel
is situated to allow condensate to `fall back` or, to run upstream
back from the evaporator in the opposite direction to the air in
the main airflow or stream which continues to run downstream from
the drainage area to be conditioned by the heat exchanger, and,
more preferably, from the evaporator. This provides for air in the
outflow region directly downstream from the evaporator to be
shedded of its condensate should the need arise, and still allow
drainage of the condensate, without entrainment of the condensate
back into the airflow so that it would eventually get to the
distribution system downstream of the HVAC unit itself.
Advantageously, the present invention allows for both the air
propulsion means (e.g. blower) and the heat exchanger, and,
preferable, the evaporator, to be positioned at approximately the
same level vertically in space, i.e. at approximately the same
height at the base of each, so that, if one is slightly higher,
(for example, a 10% difference in level or on the same plane
horizontal to the ground in normal operating position of the
vehicle), it will still operate, while preventing any backflow of
condensate or water, under nearly all vehicle parking orientations,
in the air that might otherwise be in or downstream of the drainage
area, to reach upstream areas like the blower or the area
immediately downstream from the blower.
[0006] In prior art HVAC units, water is often blown back under the
evaporator pan or drainage area during normal operations. Separate
or segregated paths or `dual paths`, one for the condensate drain
and one for the air flow, has meant increased tooling complexity
and other manufacturing difficulties. In addition to cost issues,
problems with quality and tool maintenance are intensified due to
this dual path system. The dual path systems have also led to
addition problems, particularly since in areas at or near the base
of the evaporator, where the airflow means that moving air directly
contacts that portion of the evaporator, either slots or slopes are
required to allow water to pass through with the drain airstream
into a drain pan under the evaporator itself. Such an architecture
has been required to prevent water from `pooling` or otherwise
being formed and remaining upstream of the evaporator, allowing
such pooled water to stagnate or remain and cause additional
problems such as development of odor or microbial growth in the
unit. An additional problem from the commercial standpoint rests in
the fact that `pooled` or `stagnant` condensate upstream of the
evaporator can later flow backward into the area of the blower at
blower speeds and/or during vehicle maneuveuring or parking below a
certain level, causing eventual electro-mechanical warranty
problems for such units.
[0007] In particularly preferred embodiments of the present
invention, tooling is simplified due to its dual path drainage.
Condensate, since it does not stagnate or collect in unwanted
areas, does not create unwanted odor formation or other related
undesirable effects related to condensate retention. In more
preferred embodiments, condensate for the airstream drains not only
from directly under the evaporator, but also before evaporator,
through the same mechanism. In even more particularly preferred
embodiments, condensation that forms or collects at all locations
prior to reaching the heat exchanger, and, in particular, the
evaporator region, flows to the same area and, preferably, through
the same drainage channel, even more preferably, a U shaped
drainage channel. The impact on noise is minimal to non-existent in
preferred embodiments of the present invention. By preventing
condensate from `flowing back` into the blower area once it has
passed the region of the upstream edge of the U drain, even during
heavy accelerations, the present invention allows for the maximum
of condensate free air to reach the distribution area for delivery
outside of the HVAC unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective internal view of an HVAC unit, in
according with an aspect of the present invention;
[0009] FIG. 2 is a schematic view of an HVAC unit in accordance
with an aspect of the present invention, showing airflow and
condensate pathways and an area of low pressure or suction region
of at the drainage region and condensate ingress from an area
outside of the normal HVAC airflow and drainage area, in accordance
with an aspect of the present invention;
[0010] FIG. 3 is a perspective view of an HVAC unit showing the
drain channel with upstream and downstream faces or sides, in
accordance with an aspect of the present invention;
[0011] FIG. 4 is a schematic view of an HVAC unit with condensate
flow from upstream and downstream of the drainage area with step,
in accordance with an aspect of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0012] As seen above, the current architecture of many prior art
HVAC units, particularly those units in a semi-lateral orientation,
have lead to a number of problems for which no adequate solution
has been found. The present invention solves a number of the prior
art problems, while providing for increased simplicity and lower
production costs related to the method of removing condensate from
HVAC units. In preferred embodiments of the present invention, the
present invention relates to an HVAC unit, and, preferably, an HVAC
unit for an automotive vehicle, wherein a condensate drain or `dual
path` system is provided. In addition, the present invention leads
to much simpler tooling and tooling design due to the multi path
system over previous one-path systems. Such improved tooling of the
HVAC drainage area provides the heretofore unachievable advantage
of simpler maintenance and quality improvements due to the
decreased complexity of the HVAC water removal components as a
whole. Since condensate leaves the air inflow and air outflow faces
of the evaporator and passes to the same. Drainage area and
channel, a much simpler and more effective design can be made.
[0013] In prior art HVAC units, it is often necessary to have
`covers` or `cap or plate`, such as plastic covers, over one or
more of the drain channel(s) In more preferred embodiments of the
present invention, the one or open path system provides for an HVAC
unit without additional covers, such as plastic covers.
[0014] In preferred embodiments of the present invention, an HVAC
unit, and, more preferably a laterally oriented or lateral HVAC
unit with a condensate draining system comprises: a housing; a air
propulsion means or blower; an air flow provided by the propulsion
means; a heat exchanger downstream of the air propulsion means; and
a channel or drain means downstream of the air propulsion means and
upstream of the heat exchanger. The channel or drain preferably
drains condensate from the air flow upstream up to the area of the
channel or drain means and upstream from the heat exchanger in two
separate or dual paths. More preferably, the drain means is a U
shaped channel or drain. Also more preferably, the U shaped channel
or drain has a step.
[0015] In preferred embodiments of the present invention, a step is
provided. In more preferred embodiments, the side of the step
downstream of the air propulsion means that contacts the air flow
upstream up to the area of the channel or drain is higher than the
side of the step downstream of the channel or drain. Also in more
preferred embodiments, comprising a step, wherein the drainage
means is a channel or drain and wherein side of the step downstream
of the air propulsion means that contacts the air flow upstream up
to the area of the channel or drain is higher than the side of the
step downstream of the channel or drain.
[0016] As described above, preferred HVAC units in accordance with
the present invention are lateral HVAC units. Also preferred are
HVAC units that have a second or secondary drain with or without
drain pan, through which condensate drains from the air outflow
side of the heat exchanger prior to exiting the drain, and,
preferably, a U shaped drain, and leaving the HVAC unit.
[0017] In preferred embodiments of the present invention, the HVAC
unit has a heat exchanger and/or an evaporator. In most preferred
embodiments, the heat exchanger has an evaporator. In preferred
embodiments, and especially where the heat exchanger is an
evaporator, the U shaped channel or drain has a gap at its center,
and the air from the air flow jumps, clears or misses the gap such
that a slightly lower pressure exists in the area of the drain due
to the movement of the air. In such embodiments, the condensate is
drawn down into a slope of the U shaped drain or channel due partly
to the lower pressure at the area of the U shaped drain or channel.
Also preferred are HVAC units wherein the lower edge of the blower
and the lower edge of the evaporator are at approximately the same
height.
[0018] Also, in more preferred embodiments of the present
invention, the dual path nature allows for more efficient molding,
particular for plastic and plastic like parts of the HVAC unit
including parts such as the evaporator housing, and condensate
drain. The plastic parts of the present invention can be molded,
and, preferably injection molded. The present invention, therefore,
provides, in even more preferred embodiments, for HVAC units to be
essentially composed of a resin, or resin like or resin based HVAC
unit, with only a one piece molding of the drain area. The resin,
resin like or resin based HVAC unit, and, particularly, the
drainage means comprised of drainage members or apparatuses,
provides for dual path for water condensate to flow through a
drain, while further ensuring that no condensate flows back or
backs up upstream of the drain area due to the lateral or
semi-lateral position of the HVAC unit. Therefore, the airflow in
the HVAC unit is airflow that is of reduced water content
downstream of the drain area, with no increase or re-entrainment of
water upstream of the drain area.
[0019] In preferred embodiments of the present invention, unlike
the prior art molding to segregate the water condensate flow to the
drain, from, the air-flow in the HVAC, the condensate drain is
formed in a U shape. In preferred methods of the present invention,
the U shaped drain is shaped such that it forms a step down from
downstream of the blower to the upstream of the evaporator. In
other words, the drain is constructed by shaping the upstream
(blower side) side of the main U drain such that the flow in the
expansion area after the blower causes a `suction` or lower
pressure region as the airflow passes the `backward facing step` or
step, cliff, precipice, wall, and continues onward towards the
downstream end of the drainage area.
[0020] In more preferred embodiments of the present invention, the
condensate drainage channel or, more preferably, the U shaped
drain, passes as an open type channel (i.e. a hole or opening from
the interior of the U shaped drain to the interior of the HVAC unit
where the main flow is). As described above, the condensate
drainage channel preferred in the present invention is of typically
of a U like shape or any shape that allows no air flow spitting, no
condensate return upstream, provides for water drainage from both
water paths, water check valve to prevent incoming airstream water
to be drained from the blower. The step has two faces, (the
upstream one) is typically taller than the other limb (the
downstream one). This creates the `backward facing step` geometry
allowing the two streams to pass over (the air) and under (the
condensate water) one another.
[0021] By step in the present application, it is meant an abrupt or
marked change in height of a surface allowing easy motion from the
higher to lower, but not from the lower to higher, side of
surface.
[0022] In the preferred embodiments of the present invention, water
in the form of condensate, drains towards the drainage area. Water
still present in the airflow downstream of the drainage area can
still eventually drain as condensate when precipitated after
passage of the air downstream of the drain area, due to the
negative pressure condition present in the drainage area. In
preferred embodiments, therefore, air, after arriving to and
passing by the dual path drain from downstream of the blower and
drainage area, allows water in the air to precipitate as condensate
and to `drain back` towards the drainage area from the air inflow
face/region of the evaporator downstream of the drainage area,
thereby allowing better evaporator cooling performance to be
attained. By providing for a drain that is upstream of the
evaporator, such improved evaporator cooling performance is
obtained to a large extent due to the fact that condensate that
forms from the air immediately upstream of the evaporator can drain
without the need for a bypass under the lower front edge of the
evaporator or other mechanism pre-evaporator. In the preferred
embodiments of the present invention, condensate drains back from
the air inflow face at a opposing current to the airflow leading to
the evaporator in spite of the fact that the vehicle may be
experiences heavy G forces from cornering, breaking or
accelerating. In prior art HVAC units, when vehicles face such
heavy G forces from cornering, braking and/or accelerating, the
fact that there is no mechanism for condensate removal for
condensate `back flow` means that water, in the form of condensate,
would normally run back upstream towards and/or into the blower or
blower area.
[0023] As described hereinabove, in prior art designs the lower
edge of the HVAC blower can be located at the same level vertically
in normal vehicle operating position at the lower edge of the HVAC
heat exchanger, and, especially, the evaporator of the HVAC. In
these prior art designs, problems in this positioning can occur,
particularly during periods of normal operation of the vehicle,
when acceleration needs are most required (heavy acceleration) e.g.
cornering. As described above, when as heavy acceleration occurs in
such units, water in the airflow can form condensate that may flow
back towards or into the blower, causing warranty issues. This
present invention, by providing for a drainage system, and, in
particular a drainage system with a negative pressure drop feature,
provides for a high resistance to condensate backflow and /or
drainage prior to reaching the area upstream of the drainage area
near or at the blower level and provides for a step, facing the
returning water or condensate stream, the step stopping the water
or condensate.
[0024] Referring to FIGS. 1 and 2, is shown a general layout of the
one of the embodiments of the present invention, with Axis V, W and
X denoting the section cuts provided in FIGS. 2, 3, and 4
respectively having a blower 10 within a scroll 11, an expansion
area 37, a turning area 24, the evaporator having an air inflow
(upstream) 15, 24 and air outflow (downstream) 18 face or area. U
channel or drain 13 crosses perpendicularly under the expansion
area 37 with air-flow 12 provided over the upstream or taller limb
and the downstream lower limb of the U shaped channel. This main U
channel 13 is connected to the evaporator drain/pan channel
preferably via a channel 16 generally parallel to but offset from
the main airflow 15, 12.
[0025] Referring to FIG. 2, an HVAC unit with ingressed condensate
39 is shown. Once the ingressed water has passed over the drain
region, the aforementioned process happens.
[0026] In more preferred embodiments of the present invention,
drainage channel 13, 14, 16 is constructed to have a backward
facing step 25, 26 in the drain region 13, 14 where the airflow 12
jumps or crosses over the drain 13. The airflow 12 crosses over the
drainage area 13, 14, 25, 26 without jetting down into the drain
13, 14, and hence, not causing noise or losing inordinate amounts
of airflow through the drain 14. Furthermore the drainage pan 29
from the evaporator underside, allows water or condensate to drain
back down to the said U shaped drainage channel 14, 13.
[0027] In preferred embodiments of the present invention, as shown
in FIGS. 1, 2 and 3, condensate from both the air inflow upstream
17 plus air outflow downstream 18 side of the evaporator 19 exits
easily to the drain 29, 16, 14, 13. The lower edge 35 on the inlet
side (upstream side) 17 of the evaporator 19 can be better sealed
without worry of trapping stagnant water that cannot be drained.
The water (condensate 30) from the evaporator air flow region 36
cannot drain back towards the blower area 11, 12 or the blower 10
due to the step 25, 26 in the expansion 37 or area after the blower
connecting to the corner housing. The blower 10 to evaporator 19
relative positioning is efficient and more favorable with the use
of this invention. Wall or rib 35 holds or maintains the bottom of
the evaporator, as well as prevents condensate from passing
directly under the evaporator from the air inflow side.
[0028] Referring to FIG. 4, condensate 30 from the evaporator 19
falls into a pan or collection area 29, which leads via a channel
16, cut through, but preferably integral with, the air-flow
expansion region 37 of the HVAC 10. The condensate 30 is drawn back
towards the drain 13, from the pan or collection area 29 of the
underside of the evaporator 19 due to the suction or dynamic
pressure 14 of the flow in the expansion region 12 via the drainage
channel. 13. Condensate 30 movement upstream of the evaporator
(flow) vis a vis the evaporator 19 and upstream flow 38 towards the
evaporator does not occur, because of the shape of the limbs 25, 26
of the upstream (taller) 25 and downstream (lower) 26 sides of the
U drainage channel 13, 14 cut in the air-flow expansion region 37
to ensure that adequate drainage of condensate to outside of the
HVAC unit 1 occurs. The backward facing step or difference in
height variation of 25 relative to 26 allows an area of relatively
negative or suction pressure 14 to form in the drain 13 rather than
allowing relatively positive pressure to form. From this pressure
stand point the drain functions as normal, assisting the drainage
of condensate from both sides 17, 36, 12, 29 of the evaporator,
rather than stagnate or collect in unwanted areas 10 of the HVAC
unit.
[0029] The present invention can also very easily handle the
evacuation of liquid such as rain, water moisture, windshield wiper
and other automotive and cleaning fluids, etc., ingression into the
HVAC unit from/via other means. Such as ingress from the dry or wet
plenums of the car water separation apparatus during rain, car
washing, windshield washing means water from the blower region of
the HVAC will be cast or thrown or projected along through,
preferably, the expansion part of the HVAC. A part or some of the
liquid or condensate can fall directly into the drainage channel 13
or drain area 14, while a second part of the liquid or condensate
passes through/underneath the evaporator to the drainage means
described. The drainage means or structure, and, in particular, the
channel's U shape causes the black flow of the condensation to be
impeded, therefore, stopping any ingressed liquid or condensate to
find its way back to the blower area or blower.
[0030] The present invention also allows for the lower edge of the
blower to be located at a level approximately level with the
evaporator. This positioning of blower and evaporator allows to an
overall advantage with respect to HVAC packaging environment,
allowing for large recirculation fresh air inlet possible,
containing an air filter. The U shaped drain allows for a larger
space for filter.
[0031] In preferred embodiment of the present invention, the drain
means or structure is a preferred sloping U shaped channel from the
underside of the evaporator preferably traveling firstly parallel
and then counter to the airflow. Then secondly the U shaped channel
then turns to be generally/preferably perpendicular to the airflow,
but stepped in such a way as to allow the airflow to jump over the
U or water drainage channel. The jumping action causes an
aerodynamic lower pressure in the U channel, indicating that the
airflow has no intention of directly entering the said channel, or
having any intention to return airflow back up into the underside
of the evaporator area. Hence the drain drains correctly.
[0032] The preferred embodiment of the present invention has been
disclosed. A person of ordinary skill in the art would realize,
however, that certain modifications would come within the teachings
of this invention. Therefore, the following claims should be
studied to determine the true scope and content of the
invention.
* * * * *