Note: Descriptions are shown in the official language in which they were submitted.
~ ~6~39 ~
LIQUID SPRAY AIR PURIFICATION AND
CONTROLLED HUMIDIFICATION APPARATUS
BACKGROUND OF THE INVENTION
The present invention generally relates to
environmental control apparatus and, in a preferred
embodiment thereof, more particularly relates to an
improved liquid spray air purification and controlled
humidification system.
Interior spaces of homes and other buildings are
typically provided with automatically controlled
temperatures using one or more air handling units that
provide a recirculating flow of air drawn out of the
conditioned space, flowed through the air handling unit
by an air blower therein, heated or cooled as necessary
within the unit, and then flowed back into the
conditioned space. In addition to providing the
desired temperature control within the conditioned
space, air handling units of this general type are also
often provided with the capability of purifying, at
least to some extent, air flowing through the units.
A
.
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The most common device used for this air
purification task is the familiar replaceable flow-
through air filter element that is disposed within the
unit cabinet structure in the path of air being forced
therethrough on its way back to the conditioned space
served by the unit. Filters of this type are typically
formed from a matted fibrous material (such as
fiberglass) that serves to trap particulate matter,
such as dust, borne in the conditioned space return air
entering the unit. Additionally, electrostatic air
filters are often incorporated in air handling units
and provide improved particulate removal performance
due to their electrostatic attraction and trapping of
particulates substantially smaller than the ordinary
fibrous filter can effectively capture.
However, as is well known, undesirable air
pollutants are present in a variety of forms other than
the relatively easy to capture particulates that the
fibrous and electrostatic filter structures are
designed to remove from the recirculated air from the
conditioned space. Another known type of air
purification process is the use of a liquid spray,
typically a water spray, directed against filter
element through which air to be supplied to a
conditioned space is flowed. The liquid spray is
maintained in continuous contact with the flowing air
traversing the filter element, and, depending on the
type of air purification system in which it is
incorporated, serves to entrain a variety of airborne
particulates as well as other types of pollutants such
as aerosols, nitrogen oxides, sulfur oxides, carbon
dioxides and monoxides, hydrogen sulfides and
hydrocarbons, and then be drained away carrying
entrained pollutants with it. This general type of air
2 1 64039
purification system also desirably serves to humidify
the air delivered to the conditioned space.
Despite the pollution removing effectiveness of
various known types of liquid spray air purification
systems, their use has typically been limited to
industrial and commercial applications, as opposed to
residential applications, due to reasons such as
excessive humidity and lack of humidity control,
complexity, cost and increased maintenance requirements
compared to dry filtering systems. Because of the
increased awareness of air polluting materials, and the
desirability of removing them from residential
environments, it is seen as desirable to provide a
liquid spray air purification system that is suitable
for incorporation in residential as well as commercial
applications. It is accordingly an object of the
present invention to provide such a system which will
both purify the air and control the humidity of the air
delivered to a conditioned space.
SUMMARY OF THE lNv~NllON
In carrying out principles of the present
invention, in accordance with a preferred embodiment
thereof, an air handling unit is provided that includes
a housing having an inlet opening, an outlet opening,
and an internal flow path extending between the inlet
opening and the outlet opening, and blower means for
sequentially flowing air inwardly through the inlet
opening, through the internal flow path, and outwardly
through the outlet opening. The air handling unit is
representatively illustrated in both HVAC unit and air
purification and controlled humidification unit
embodiments.
Air purification means are disposed in the
internal housing flow path, and are operative to
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receive pressurized liquid from a source thereof,
create a spray from the received liquid, use the spray
to purify air traversing the internal housing flow
path, and then permit the sprayed liquid to drain
therefrom into sump means operative to hold a supply of
liquid to be operatively supplied to the air
purification means and receive liquid draining
therefrom.
The air handling unit further comprises filter
means having therein a filtering flow path through
which liquid may be forced to trap pollutants in the
filter means, and a backwashing flow path through which
liquid may be forced to cleanse the filter means of
trapped pollutants. A pump portion of the air handling
unit has an inlet communicatable with liquid in the
sump means, and an outlet. Conduit means interconnect
the pump outlet with the filtering flow path and the
backwashing flow path, and also interconnect the
filtering flow path with the air purification means.
Switching means are associated with the conduit
means and are selectively operative in a first mode to
cause sump liquid discharged from the pump to be forced
through the filtering flow path to the air purification
means, or in a second mode to cause sump liquid
discharged from the pump to be forced through the
backwashing flow path.
First monitoring means are provided for detecting
a change in an apparatus operating parameter,
indicative of a predetermined lessening in the
filtration efficiency of the filter means, and
temporarily changing the switching means from their
first mode to their second mode. The first monitoring
means representatively are capable of detecting an
increase in pumping back pressure upstream of the
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filter means as well as detecting particulate and/or
gaseous pollutants.
According to other features of the invention,
second monitoring means are operative to sense a
decrease in the normal concentration of chemical
treatment additive in the sump liquid and/or a
predetermined level of chemically treatable pollutants
in the sump liquid and responsively inject a quantity
of chemical treatment additive into the sump liquid
from a source thereof, and dehumidification means are
provided in the housing, downstream from the air
purification means, and are operative to remove
moisture from air exiting the air purification means.
In a preferred embodiment thereof, the air
handling unit further comprises humidification control
means for sensing an excess humidity condition in air
being discharged by the blower means within the housing
and responsively causing a portion of the discharged
air to be returned to and operatively flowed across the
dehumidification means before being forced outwardly
through the outlet opening by the blower means, to
thereby reduce the humidity of the air discharged from
the housing. The housing may be provided with a second
inlet opening, and the humidification control means may
be further operative, in response to sensing an excess
humidity condition in air being discharged by the
blower means within the housing, to responsively permit
the blower means to sequentially draw air inwardly
through the second inlet opening, into the interior of
the housing between the air purification means and the
dehumidification means, and across the dehumidification
means and into the fan inlet to further reduce the
humidity of the air discharged from the housing.
In a preferred embodiment thereof, the
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humidification control means include damper means
operable to controllably vary the flow of air through
the air handling unit housing, and humidistat means
positioned in the housing in the path of air discharged
from the blower means and operative to sense the
humidity in the discharged air and responsively operate
the damper means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevational view of a
representative heating, ventilation and air
conditioning unit in which an improved liquid spray air
purification system embodying principles of the present
invention is operatively incorporated;
FIG. 2 is an enlarged scale schematic cross-
sectional view through the unit and its associated air
purification system;
FIG. 3 is an enlarged scale partially cut away
schematic side elevational view of a liquid sump
portion of the air purification system;
FIG. 4 is a partial top plan view of the liquid
sump portion shown in FIG. 3;
FIGS. 5A and 5B are schematic cross-sectional
views through a free standing liquid spray air
purification and humidification unit embodiment of the
present invention, with FIG. 5A illustrating the unit
in its normal operating mode, and FIG. 5B illustrating
the unit in a recirculating/blending operating mode
thereof; and
FIG. 6 is a schematic side elevational view of an
alternative embodiment of the heating, ventilation and
air conditioning unit illustrated in FIG. 1.
DETAILED DESCRIPTION
Schematically depicted in FIG. 1 is a heating,
ventilation and air conditioning (HVAC) unit 10
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incorporating therein a specially designed liquid spray
air purification system 12 embodying principles of the
present invention. HVAC unit 10 serves an interior
space 14 disposed within a building 16 having an
exterior wall 18 and a roof 20. The conditioned
interior space 14 representatively has a vertical
interior wall 22 and a ceiling 24 spaced downwardly
apart from the roof 20. The unit 10 is supported
within the space 26 between the roof 20 the ceiling 24,
in a horizontal airflow orientation, on suitable
support members 28, such as metal hanger rods or
straps, secured to the roof structure. A conventional
thermostat 30 mounted on interior wall 22 senses the
need for heating or cooling in the interior space 14
and appropriately controls the operation of the HVAC
unit 10.
Referring now to FIGS. 1 and 2, the HVAC unit 10
includes a horizontally elongated hollow rectangular
metal cabinet structure 32 having an open inlet end 34
and an open outlet end 36. From right to left as
viewed in FIG. 2 the HVAC unit 10 has operatively
disposed within its cabinet 32 a return air damper
structure 38 adjacent the cabinet inlet end 34; a
replaceable cartridge type air filter 40; a supply air
blower 42; a heat exchanger 44; and a cooling coil 46.
Representatively, the heat exchanger 44 is a fuel-fired
heat exchanger having a burner structure 47 operatively
associated therewith, and the cooling coil is of the
direct expansion refrigerant type and is connected to
conventional air conditioning refrigerant circuitry
(not illustrated).
A return air duct 48 is interconnected between the
cabinet inlet end 34 of the HVAC unit 10 and a suitable
return air grille 50 mounted on the underside of the
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ceiling 24. At the opposite end of the unit 10 a main
supply air duct 52 is connected to the cabinet outlet
end 36 and extends horizontally through the above-
ceiling space 26 as best illustrated in FIG. 1. Spaced
apart branch supply air ducts 54 are operatively
interconnected between the bottom of the main supply
air duct 52 and a series of supply air diffusers 56
mounted on the underside of the ceiling 24 of the
conditioned space 22 as schematically illustrated in
FIG. 1.
Upon a demand for heat, or cooling as the case may
be, by the thermostat 30 the supply air blower 42 and
the heating or cooling portion of the unit 10 are
appropriately energized. Operation of the blower 42
draws return air 58 upwardly into the cabinet 32,
through the return air grille 50 and the return air
duct 48, and then forces the air through the unit 10,
across the heat exchanger 44 and the cooling coil 46,
and into the main supply air duct 52. The heated or
cooled air forced into the main supply air duct 52 is
discharged into the space 22, in the form of
conditioned air 58a, through the branch supply ducts 54
and the ceiling mounted air diffusers 56.
The HVAC unit 10 is merely representative of a
wide variety of units, which may be generically
referred to as "air handling" units, into which the air
purification system 12, which will be subsequently
described herein, may be operatively incorporated. For
example, while the unit 10 has been illustratively
described as being adapted to both heat and cool the
conditioned space 22, it could alternatively be a
heating-only unit, a cooling-only unit, or simply a
ventilating unit. Additionally, while the unit 10 has
been depicted in a horizontal interior air flow
21 6403q
orientation, it could also be alternatively oriented in
a vertical air flow orientation (of either the upflow
or downflow variety).
Referring again to FIG. 2, the air purification
system 12 includes a horizontally oriented hollow
rectangular metal housing 60 representatively disposed
in an upwardly spaced apart relationship with the
return air duct 48 and a rear end portion of the unit
cabinet 32. Housing 60 has an open inlet end 62 that
faces the exterior wall 18, and an open outlet end 64.
Operatively disposed within the housing 60 are, from
right to left as viewed in FIG. 2, upper outside air
and lower return air flow control damper sections 66
and 68 positioned at the inlet end of the housing 60; a
liquid dispersion unit 70; a liquid spray air cleaner
structure 72; a mechanical mist eliminator 74;
dehumidification cooling coils 76; and an auxiliary
supply air blower 78 disposed at the outlet end of the
housing 60. As later described herein, a liquid sump
pan structure 80 is positioned within the housing 60
beneath the air purification system components 70,72,74
and 76.
A discharge duct 82 is connected between the
outlet end 64 of the housing 60 and a top side portion
of the unit cabinet 32, generally between the filter 40
and the blower 42, and serves to communicate the
interiors of the housing 60 and the unit cabinet 32.
An auxiliary return duct 84 is operatively connected
between the ceiling mounted return air grille 50 and
the damper section 68, and an outside air intake duct
86 is operatively connected between the damper section
66 and an outside air intake louver 88 mounted on the
exterior wall 18.
During operation of the main unit 10, simultaneous
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operation of the purification system air blower 78
draws return air 58 into the housing 60 sequentially
through the a portion of the return air grille 50, the
auxiliary return air duct 84 and the damper section 68.
At the same time, outside air 90 is also drawn into the
housing 60 sequentially through the outside air intake
louver 88, the outside air duct 86 and the damper
section 66. By the operation of the blower 78, these
incoming quantities of return air and outside air are
flowed across the purification and humidification
components 70,72,74 and 76 to form a quantity of
purified air 92 that is delivered into the unit cabinet
32 between the filter 40 and the main supply air blower
42. Together with the return air 58 entering the
cabinet 32 through the damper section 38 and the filter
40 the purified air 92 forms the conditioned air 58a
discharged from the supply air diffusers 56 (see FIG.
1) .
lt should be noted that both the purified air
percentage of the conditioned air 58a delivered to the
space 22 served by the unit 10, as well as the outside
air-to-return air ratio of the purified air 92, may be
conveniently controlled by suitable adjustment of the
three damper sections 38,66 and 68 - an adjustment that
may be carried out manually or automatically depending
upon the degree and type of air proportioning control
desired in conjunction with the overall operation of
the unit 10 and its associated air purification system
12. For example, the damper sections 38 and 68 shown
in FIG. 2 are linked (as schematically indicated by the
dashed line 94) in a manner such that a movement of the
vanes of the damper section 38 toward their closed
positions correspondingly moves the vanes of the damper
section 68 toward their fully open positions, and vice
21 64039
versa. This permits the regulation of the total
percentage of the discharge air 58a which has traversed
the purification system 12.
Further, the damper sections 66 and 68 may be
linked together in a manner such that movement of the
vanes in the damper section 68 toward their fully
closed positions automatically move the vanes in the
damper section 66 toward their fully open positions,
and vice versa. This permits the selective varying of
the outside air-to-return air ratio of the purified air
92.
Still referring to FIG. 2, the water dispersion
unit 70 is basically a pad of fibrous matting material
(such as shredded plastic, fiberglass or metal) similar
to the spray pad material used in evaporative coolers
and is operative to receive a throughflow of air while
at the same time being impinged upon by a cleansing
liquid spray. The air cleaner structure 72 is
representatively a horizontally spaced series of
vertically extending tubes 96 having discharge orifices
formed along their lengths and facing the downstream
side of the water dispersion unit 70. The mist
eliminator 74 representatively comprises a plurality of
vertically spaced rows of horizontally extending angled
baffle members 98 which, in a right-to-left direction
define a zig-zag air flow path through the overall mist
eliminator structure.
The dehumidification cooling coils 76, which are
preferably included in the purification system 12,
representatively are direct expansion refrigerant
cooling coils the operation of which may be controlled
by a conventional humidistat 100 operatively disposed
in the main supply air duct 52. Other dehumidification
means, such as an electrostatic precipitator, chemical
2 1 64039
dehumidifier, centrifugal mist eliminator, mist
eliminator pad or desiccant pad or the like, may be
used in place of or in addition to the coils 76 if
desired. As will additionally be appreciated, the
5 cooling medium for the coils 76 could be one other than
refrigerant (such as chilled water) if desired.
During operation of the purification system blower
78 return air 58 and outside air 90 entering the inlet
end 62 of the system housing 60 are drawn through the
dispersion unit 70 while pressurized water 102,
supplied to the tubes 96 from a subsequently described
source, is sprayed onto the left or downstream side of
the dispersion unit 70. Particulate and chemical
pollutants in the return air/outside air mixture
15 passing through the dispersion unit 70, such as dust,
pollen, smoke, aerosols, nitrogen oxides, sulfur
oxides, carbon dioxides and carbon monoxides, hydrogen
sulfide and hydrocarbons, are absorbed into the
impinging water spray and thus are drained with the
20 spent water into the sump structure 80.
The purified, now moisture-laden return
air/outside air mixture is then drawn, via the
aforementioned zig-zag path, through the mist
eliminator 74 which functions to mechanically remove a
25 substantial portion of the moisture from the return
air/outside air mixture. Water mechanically removed
from the air in this manner is drained from the mist
eliminator 74 and falls into the sump pan 80. Further
moisture is removed from the air exiting the mist
eliminator 74 by the dehumidification of the coils 76
as automatically called for by the humidistat 100.
Accordingly, the air 92 entering the unit cabinet 32 is
both cleansed of pollutants and dehumidified before
being mixed with the return air 58 exiting the filter
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40 and delivered to the conditioned space 22.
Turning now to FIGS. 3 and 4, the sump pan 80 has
an open top side 104 and an overflow fitting 106
secured to a side wall of the sump pan, just beneath
its open top side, and connected to a suitable drain
line 108 that is tied into the building drainage
system. A quantity of water 102 is continuously
maintained in the sump pan 80, at an operating level
110, by the operation of a float-operated fill valve
112 connected to a suitable water makeup supply pipe
114. Appropriate heating and/or cooling means (not
illustrated) may be used to control the temperature of
the water if desired.
A spray pump 116 is supported in the sump pan 80
and has an open-ended inlet pipe 118 submerged in the
water 102. The outlet of the pump 116 is connected to
the inlet of a two-way switchable diverting valve 120
by a discharge pipe 122. A pipe 124 is interconnected
between the normally closed outlet port 126 of valve
120 and an end 128 of a cylindrical, backwashable
filter structure 130, and a pipe 132 is connected
between the normally open outlet port 134 of the valve
120 and the opposite end 136 of the filter structure
130.
A supply pipe 138 has a switchable, normally open
valve 140 therein and is connected at one end to the
end 128 of the filter structure 130 and at the opposite
end to the vertical pipes 96 of the liquid spray air
cleaner structure 72 (see FIG. 2). A discharge pipe
142 has a switchable, normally closed valve 144 therein
and is connected at one end to the end 136 of the
filter structure 130, and at its opposite end to a
drain line 146 extending from the bottom side of the
sump pan and connected to the building drainage system.
21 64039
14
During normal operation of the purification system
12 the pump 116 forces water 102 from the sump pan 80
to the spray pipes 96 sequentially through the pipe
122, the normally open outlet 134 of the valve 120, the
interior of the filter 130, and the pipe 138 (as
indicated by the solid line flow arrows in FIG. 4) to
thereby create the water spray that continuously
impinges on the downstream side of the water dispersion
unit 70 (see FIG. 2). Pollutant-bearing water also
continuously drains from the previously described air
purifying components of the system 12 back into the
sump pan 80 and is recycled through and cleansed by the
filter structure 130 on its way back to such air
purifying components.
Even with the pollutant cleansing action of the
filter 130, as the filter nears its fully loaded state
the levels of various contaminants in the sump water
will increase. A monitor and additive injector 148 is
disposed in the sump water 102 and is operative to
sense a decrease in the normal concentration of
chemical treatment additive in the water and/or the
buildup therein of undesirable water pollutants, such
as algae, slime, bacteria and fungi, and responsively
inject a suitable chemical additive, from an additive
container 150 connected to the monitor/injector 148,
into the sump water to control the buildup of these
water pollutants and thereby reduce their deleterious
effects on the air cleansing efficiency of the
recirculating sump water. The additive in the
container 150 may representatively contain (1) selected
non-toxic organic or inorganic chemicals which assist
in cleaning the air of difficult to remove pollutants
and/or (2) non-toxic bactericides, fungicides,
herbicides and the like to control the aforementioned
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water pollutants.
A monitor and filtering control structure 152 is
also disposed in the sump water 102 and is electrically
coupled to the valves 120,140 and 144 via the
schematically depicted dashed control lines in FIG. 3.
The monitor/control structure 152 is operative to sense
an increase in back pressure indicated by a pressure
transducer 154 located in pump discharge pipe 122
upstream of the filter 130 and/or the presence of a
predetermined maximum level of particulate and gaseous
air pollutants in the sump water 102 (which have been
withdrawn from the air flowing through the purification
system) and responsively switch the valves 120, 140 and
144 in a manner (1) opening the normally closed outlet
126 in valve 120 and closing its normally open outlet
134, (2) closing the normally open valve 140, and (3)
opening the normally closed valve 144.
The switching of these three valves causes the
water being discharged from the pump 116 to backwash
the filter 130 by forcing sump water sequentially
through the pipe 122, the opened valve outlet 126,
through the filter 130 from top to bottom as viewed in
FIG. 4, and through the pipe 142 and the opened valve
144 into the drain pipe 146 as indicated by the dashed
line flow arrows in FIG. 4. Accordingly, the trapped
particulate matter and other pollutant matter in the
filter are flushed into the building drainage system
via the drain pipe 146. In response to the resulting
drop in the sump water level, the float-operated fill
valve 112 opens to replenish the sump water supply with
clean water. When the particulate/gaseous pollutant
level in the sump water falls to an acceptable level
the monitor structure 152 responsively permits the
valves 120, 140 and 144 to return to their normal
2 1 6403~
16
operating positions to permit the pump 116 to deliver
water to the liquid spray air cleaner structure 72
through the now backwashed filter 130.
As can be seen from the foregoing, the
incorporation of the air purification system 12 into
the representative air handling unit 10 affords the
unit the ability to continuously flow highly purified
air into the conditioned interior building space 22
served by the unit. The cooperative use of the damper
structures 38,66 and 68 permits control of the overall
volumetric air cleansing rate of the purification
system 12 while at the same time permitting a
selectively variable quantity of outside ventilation
air to be introduced into the conditioned space.
Moreover, the automatic control characteristics of the
liquid spray purification system 12 substantially
reduce the amount of inspection and maintenance time
required to keep it in good working order. The unit 10
is thus quite suitable for both residential and
commercial heating, ventilating and air conditioning
applications.
The liquid spray-based air purification principles
of the present invention may also be incorporated in
other types of air handling units as illustrated by the
air purification and controlled humidification unit 160
schematically depicted in FIGS. 5A and 5B. The unit
160 is a free standing structure adapted to be
supported on a floor 162 or other horizontal support
surface, and includes a vertically elongated
rectangular housing 164 having front and rear exterior
side walls 165 and 166, a top end wall 168, opposite
left and right exterior side walls 169 extending
between the front and rear exterior side walls 165 and
166, and a vertically extending interior partition wall
- 2164039
170 that divides the interior of the housing 164 into
front and rear plenum areas 171a and 171b. A
vertically spaced pair of air inlet grilles 172,174 are
mounted on the rear housing side wall 166, with the air
inlet grille 172 being positioned adjacent the bottom
end of the housing 164, and the air inlet grille 174
being spaced upwardly apart from the air inlet grille
172 on a vertically intermediate portion of the rear
housing side wall 166.
The air inlet grille 172 is communicated with a
lower end portion of the front plenum area 171a via a
transfer duct 176 extending horizontally through the
rear plenum area 171b between the air inlet grille 172
and a suitable opening in the vertical partition wall
170. Installed in a right end portion of the transfer
duct 176 is an electrically operable, normally open
motorized air flow control damper structure 178. The
air inlet grille 174 is communicated with a vertically
intermediate portion of the front plenum area 171a via
a transfer duct 180 extending horizontally through the
rear plenum area 171b between the air inlet grille 174
and a suitable opening in the vertical partition wall
170. Installed in a right end portion of the transfer
duct 180 is an electrically operable, normally closed
motorized air flow control damper structure 182.
Positioned immediately above the control damper
structure 182 in an opening in the partition wall 170
is an electrically operable, normally closed motorized
air flow control damper structure 184 through which the
plenum areas 171a,171b are communicated.
An air discharge grille 186 is mounted on the top
end of the front side wall 165 over an electrically
operable, normally open motorized air flow control
damper structure 188 that faces and is forwardly spaced
21 64039
18
apart from an electrically operable, normally closed
motorized air flow control damper structure 190 mounted
in an opening in the top end of the vertical partition
wall 170.
Vertically arranged in the front plenum area 171a
are air purification and controlled humidification
components similar to those incorporated in the
previously described air purification system 12
schematically depicted in FIGS. 2-4. These components,
which have been given reference numerals identical to
those of their counterparts in FIGS. 2-4, include, from
top to bottom in FIGS. 5A and 5B, (1) a supply air
blower 78 and dehumidification cooling coils 76
vertically positioned between the damper structures
188,190 and the damper structure 184; (2) a mechanical
mist eliminator 74, a liquid spray air cleaner
structure 72, and a liquid dispersion unit 70
vertically positioned between the damper structures
182,178; and (3) a liquid sump pan structure 80
positioned at the bottom end of the front plenum area
171a.
Mounted within the sump pan structure 80 is a
schematically indicated pumping, filtering and
pollution monitoring system 192 whose components are
identical to those depicted in the previously described
FIGS. 3 and 4. The components of the system 192 are
connected to the liquid spray air cleaner structure 72
in the same manner as their counterpart components in
FIGS. 3 and 4 are connected to the liquid spray air
cleaner structure 72 in FIG. 2. During operation of
the air purification and controlled humidification unit
160, water draining from the components 70,72,74 and 76
falls into the liquid sump pan structure 80. An
electric humidistat 194 is mounted in an upper end
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19
portion of the front plenum area 171a and is
operatively wired to the motorized damper structures
178, 182, 184, 188 and 190 as schematically indicated
by the dotted line electrical circuitry 196.
Referring now to FIG. 5A, during normal operation
of the unit 160 the damper structures 182, 184 and 190
are fully closed, and the damper structures 178 and 188
are fully open. Operation of the supply air blower 78
draws air 198 from the conditioned space 200 served by
the unit 160 sequentially through the air inlet grille
172, the transfer duct 176, the damper structure 178,
and upwardly through the front plenum area 171a across
the vertically arranged air purification and controlled
humidification components 70-76, and then discharges
the air outwardly through the damper structure 188 and
the air discharge grille 186 into the conditioned space
200 in the form of purified air 198a with controlled
humidity.
As schematically indicated in FIG. 5B, upon
sensing that the humidity in the discharged air 198a is
above a predetermined set point humidity, the
humidistat 194, via the electrical circuitry 196,
functions to partially close the damper structure 178,
partially open the damper structures 182 and 184,
partially close the damper structure 188, and partially
open the damper structure 190. This repositioning of
the various damper structures by the humidistat 194,
during operation of the blower 78, reduces the flow
rate of room air 198 being drawn inwardly through the
air inlet grille 172 and passing upwardly through the
purification and humidification components 70-74, while
at the same time permitting a second flow of room air
198 to be drawn inwardly through the return air grille
174 and into the portion of the front plenum area 171a
2 1 64039
between the mist eliminator 74 and the coils 76,
thereby bypassing the moisture-adding portion of the
air purification and humidification system.
These two flows of room air 198 are then drawn
upwardly through the blower 78 and discharged therefrom
into an upper end portion of the front plenum area
171a. As indicated in FIG. 5B, a first portion of this
discharged air 198 is forced outwardly through the air
discharge grille 186 as purified air 198a with
controlled humidity, and a second portion of the
discharged air 198 is sequentially flowed leftwardly
through the damper structure 190, downwardly through
the rear plenum area 171b, rightwardly through the
damper structure 184 into the space between the coil 76
and the mist eliminator 74, and then upwardly across
the coils 76.
Accordingly, with the various damper structures in
their humidistat-controlled FIG. 5B positions, the
purified and controlled humidity air 198a delivered to
the conditioned space 200 by the unit 160 has a lower
moisture content than when the damper structures are in
their FIG. 5A orientation. As can be seen from FIG.
5B, this lowered moisture content in the supply air
198a is achieved by (1) causing utilization of all the
dehumidifying coils 76 to thereby remove more water
from the air, (2) causing a portion of the room air 198
entering the unit 160 to bypass the moisture-adding
components 70 and 72, and (3) causing a portion of the
air 198 discharged by the blower 78 to be cycled back
across the dehumidifying coils 76 before being
delivered to the conditioned space 200.
The damper structures 178, 182, 184, 188 and 190
may be moved by action of the humidistat 194 only
between their two indicated positions shown in FIGS. 5A
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21
and 5B. Alternatively, the damper structures may be
moved to further positions by the humidistat to
provide, as needed, for even greater moisture reduction
in the air 198a delivered to the conditioned space 200.
For example, the humidistat 194, after the damper
structures were moved to their FIG. 5B positions, could
be used to further open the damper structures 182, 184
and 190, and further close the damper structures 178
and 188 if movement of the damper structures to their
initial FIG. 5B positions did not eliminate excessive
moisture in the air 198a delivered to the conditioned
space 200. This further repositioning of the damper
structures would reduce the air flow across the
humidifying components and at the same time increase
the air flow bypassing the humidifying components and
operatively traversing the dehumidifying cooling coils
76. While the air handling unit 160 has been
representatively illustrated as being in a vertical,
free standing orientation, it will be readily
appreciated by those of skill in this particular art
that it could alternatively be arranged in a horizontal
orientation as well if desired.
Illustrated in FIG. 6 is an alternate embodiment
lOa of the HVAC unit 10 previously described in
conjunction with FIGS. 1-4. HVAC unit lOa incorporates
therein the same components as the unit 10, and
additionally incorporates a modified air purification
and controlled humidification unit 160a having therein
various indicated components of the air purification
and controlled humidification unit 160 previously
described in conjunction with FIGS. 5A and 5B. For
ease in comparing the HVAC unit lOa to the previously
described units 10 and 160, components and structures
in the modified unit lOa similar to those in the
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previously described units 10 and 160 have been given
identical reference numerals.
The HVAC unit 10a shown in FIG. 6 is provided with
a modified purification system housing 60a which,
relative to the housing 60 described in FIG. 1, is
horizontally lengthened, and is positioned closely
adjacent the top side of the cabinet 32. The modified
housing 60a has a left end wall 168 corresponding to
the top end wall 168 of the unit 160, a top side wall
170 corresponding to the partition wall 170 in the unit
160, and a bottom side wall 165 corresponding to the
side wall 165 in the unit 160. An auxiliary housing
202 is positioned over the top side 170 of the modified
housing 60a and has a top side wall 166 corresponding
to the side wall 166 in the unit 160. The interiors
171a,171b of the housings 60a,202 respectively
correspond to the plenum areas 171a,171b in the housing
portion 164 of the unit 160 shown in FIGS. 5A and 5B.
The air purification and humidification components
70,72,74,76 and 78 are positioned as shown within the
modified housing 60a, with the components 74 and 76
being horizontally separated from one another a
substantially greater distance than their counterpart
components in the HVAC unit 10. The interior 171a of
the housing 60a, downstream of the fan 78, is
communicated with the interior of the cabinet 32,
between the filter 40 and the fan 42, by the normally
open damper structure 188 which is positioned directly
beneath the normally closed damper structure 190
mounted in the housing wall 170. Damper structures
182,184 are mounted in the housing wall 170 between the
coils 76 and the mist eliminator 74, and the sump pan
structure 80 extends beneath the components 70,72,74
and 76. Operatively mounted in the sump pan structure
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is the pumping, filtering and monitoring system having
components identical to those shown in FIGS. 3 and 4.
A drain pan 81 is positioned beneath the main
cooling coil 46, to catch condensate dripping therefrom
during operation of the HVAC unit lOa, and a condensate
drain line 204 having a condensate pump 206 installed
therein is interconnected between the drain pan 81 and
the sump pan structure 80. During operation of the
HVAC unit lOa, condensate received in the drain pan 81
is transferred into the sump pan structure 80, via the
line 204, by the pump 206. The transfer duct 180
extends through the housing 202, is connected at one
end thereof to the damper structure 182, and is
connected at its other end to the auxiliary return air
duct 84 as indicated. Via the schematically depicted
control circuitry 196, the humidistat 100 is
operatively connected to the system components
indicated in FIG. 6.
During normal operation of the HVAC unit lOa, as
illustrated in FIG. 6, the damper structures 182,184
and 190 are fully closed and the damper structures
66,68 and 188 are fully open, and the HVAC unit lOa
operates in essentially the same manner as the
previously described HVAC unit 10. Specifically, the
purification system blower 78 draws return air 58 and
outside air 90 through damper structures 68 and 66,
respectively, into the plenum 171a. These two air
streams are mixed as they are drawn through the
dispersion unit 70 and pressurized water 102 from the
liquid spray air cleaner structure 72, and then through
the mist eliminator 74 and dehumidification cooling
coils 76. Excess water from components 70,72,74 and 76
flows by gravity into the sump pan structure 80
positioned below such components. As the air flows
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through the housing 60a, it is washed by water, excess
water is removed, and humidity is reduced to form
purified air 92 with controlled humidity. Then such
air 92 passes through damper structure 188 into the
unit cabinet 32 of the HVAC unit lOa where it mixes
with return air 58 which has entered cabinet 32 through
the damper structure 38 and the filter 40.
Further humidity control is provided to the air
mixture 92/58 as it flows through (1) the heat
exchanger 44 when the unit lOa is operating in the
winter and (2) the cooling coils 46 when the unit lOa
is operating in the summer. Water removed from the air
mixture 92/58 by the cooling coils 46 drips into the
drain pan 81. As previously mentioned, this water is
pumped from drain pan 81 to the liquid sump pan
structure 80. The pumping, filtering and pollution
monitoring system within the sump pan structure 80
returns the water for recycling through the liquid
spray air cleaner structure 72.
The humidity of the resulting conditioned air 58a
is measured by the humidistat 100. In the event the
humidity of the conditioned air 58a is below a
predetermined set point humidity (i.e., humidity needs
to be increased), the humidistat 100, via the
electrical circuitry 196, automatically calls for (1) a
reduction in dehumidification by coils 76 and/or (2) an
increase in return air 58 and/or outside air 90 flowing
through unit 160a by partially opening damper
structures 68 and 66 as well as a corresponding
reduction in return air 58 entering cabinet 32 by
partially closing damper structure 38.
If the humidity of the conditioned air 58a is
above a predetermined set point humidity, the
humidistat 100 automatically calls for (1) an increase
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in the dehumidification by coils 76 and/or (2) a
reduction in return air 58 and/or outside air 90
flowing through housing 60a by partially closing damper
structures 68 and 66 as well as a corresponding
increase in return air 58 entering cabinet 32 by
partially opening damper structure 38. In the event
the humidity of conditioned air 58a is still above a
predetermined set point humidity, the humidistat 100
functions to partially close damper structures 66 and
68, partially open damper structures 182 and 184,
partially close damper structure 188, and partially
open damper structure 190. Lower moisture content in
the purified air 92 with controlled humidity is
achieved by (1) causing utilization of all
dehumidifying coils 76 to thereby remove more water
from the air, (2) changing the ratio of purified 92 to
the return air 58, (3) causing a portion of the room
air 58 entering the housing 60a to bypass the moisture-
adding components 70 and 72, and (4) causing a portion
of the air 92 discharged by the blower 78 to be cycled
back across the dehumidifying coils 76 before being
delivered to the cabinet 32.
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.
