U.S. patent application number 11/741686 was filed with the patent office on 2008-05-15 for direct contact liquid air contaminant control system.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. Invention is credited to ALLEN K. MacKNIGHT.
Application Number | 20080112869 11/741686 |
Document ID | / |
Family ID | 33541328 |
Filed Date | 2008-05-15 |
United States Patent
Application |
20080112869 |
Kind Code |
A1 |
MacKNIGHT; ALLEN K. |
May 15, 2008 |
DIRECT CONTACT LIQUID AIR CONTAMINANT CONTROL SYSTEM
Abstract
An integrated environmental control system for cabin air of an
aircraft or spacecraft. Humidity and temperature of cabin air are
controlled with a direct contact liquid air contaminant control
system that revitalizes cabin air by removal of carbon dioxide and
other trace gas contaminants through use of a direct contact air,
liquid scrubber element and stripper element. The scrubber element
has two rotor elements rotatably mounted in a housing first for
centrifugal separation of an air flow and liquid absorbent mixture
which liquid absorbent has absorbed carbon dioxide and trace gas
contaminants. Then second for centrifugal separation of an air flow
and acid water wash mixture which acid water wash has liquid
absorbent and other contaminants. The processed air is then passed
through a charcoal bed filter for further removal of contaminants.
A rotary contact processor may also be used to reprocess
contaminated liquid absorbent for reuse.
Inventors: |
MacKNIGHT; ALLEN K.; (SIGNAL
HILL, CA) |
Correspondence
Address: |
HONEYWELL INTERNATIONAL INC.
101 COLUMBIA ROAD, P O BOX 2245
MORRISTOWN
NJ
07962-2245
US
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
MORRISTOWN
NJ
|
Family ID: |
33541328 |
Appl. No.: |
11/741686 |
Filed: |
April 27, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10611490 |
Jun 30, 2003 |
7252703 |
|
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11741686 |
|
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Current U.S.
Class: |
423/228 ; 95/159;
95/218 |
Current CPC
Class: |
B01D 2259/4575 20130101;
Y02C 20/40 20200801; Y02A 50/20 20180101; B01D 53/75 20130101; Y02C
10/08 20130101; B01D 53/1475 20130101; B01D 2257/504 20130101; B63G
8/36 20130101; B01D 53/78 20130101; Y02A 50/2342 20180101; B01D
53/0454 20130101; Y02C 10/06 20130101; B01D 2253/102 20130101; B64D
13/00 20130101; Y02C 10/04 20130101; B01D 53/18 20130101; B64D
2013/0651 20130101; B01D 53/1412 20130101; B01D 2259/4566 20130101;
Y02T 50/50 20130101; Y02T 50/56 20130101 |
Class at
Publication: |
423/228 ; 95/159;
95/218 |
International
Class: |
B01D 53/62 20060101
B01D053/62; B01D 53/14 20060101 B01D053/14 |
Claims
1. A method for providing environmental control for cabin air of a
vehicle comprising the steps of: introducing a portion of the cabin
air as air flow into a carbon dioxide scrubber; and spraying a
liquid mist into the air flow thereby modifying humidity,
temperature and carbon dioxide concentration of the cabin air.
2. The method of claim 1 wherein the liquid mist is an acid
wash.
3. The method of claim 1 comprising the further steps of: rotating
a carbon dioxide scrubber rotor to separate liquid absorbent
containing absorbed carbon dioxide and trace contaminants from the
air flow; accumulating the liquid absorbent on a first heat and
mass transfer surface for extraction from the carbon dioxide
scrubber rotor; passing the air flow downstream of the carbon
dioxide scrubber rotor through a plurality of first air passages
and a plurality of first mist separators to a liquid absorbent
scrubber rotor.
4. The method of claim 3 comprising the further steps of; rotating
the liquid absorbent scrubber rotor to separate the liquid
absorbent containing carbon dioxide and trace contaminants from the
air flow; accumulating the acid wash on a second heat and mass
transfer surface for extraction from the liquid absorbent scrubber
rotor; and passing air flow downstream of the liquid absorbent
scrubber rotor through a fan to an air exhaust.
5. The method of claim 3 wherein extracted liquid absorbent is
processed in a stripper element for reuse.
6. The method of claim 3 wherein contaminated liquid absorbents are
reconditioned by performing the steps of: heating a liquid
absorbent containing a carbonate to a decomposition temperature in
a liquid absorbent heater whereby carbon dioxide is separated from
the liquid absorbent.
7. The method of claim 6 wherein the liquid absorbent is processed
through a subsequent scrubber.
8. The method of claim 6 further comprising the steps of:
communicating the carbon dioxide which is separated from the liquid
absorbent into a second scrubber; washing the carbon dioxide using
a spray of cold liquid absorbent; accumulating the cold liquid
absorbent for extraction from the second scrubber; and passing the
carbon dioxide through a plurality of mist separators for output
from the second scrubber.
9. An environmental control apparatus for cabin air of a vehicle
comprising: a contaminant scrubber wherein a contamination-control
liquid is introduced as a mist into an air flow of a portion of the
cabin air through the contaminant scrubber; the
contamination-control liquid having a temperature lower than a
temperature of the cabin air; and wherein temperature of the cabin
air is reduced and humidity of the cabin air is modified.
10. The environmental control apparatus as in claim 9 wherein the
contaminant scrubber is comprised of at least one carbon dioxide
scrubber in fluid communication with a liquid absorbent
scrubber.
11. The environmental control apparatus as in claim 10 wherein the
at least one carbon dioxide scrubber comprises a rotary contact
processor.
12. The environmental control apparatus as in claim 11 further
comprising a stripper element which comprises a rotary contact
processor.
13. The environmental control apparatus as in claim 9 wherein: a
carbon dioxide scrubber rotor is connected to a liquid absorbent
scrubber rotor by a rotor shaft; the carbon dioxide scrubber rotor
is in communication with an air inlet and a liquid absorbent inlet
wherein a liquid absorbent is introduced as a mist into an air flow
through the air inlet, the air flow introduced into a carbon
dioxide scrubber chamber having a first heat and mass transfer
surface therein of the carbon dioxide scrubber rotor; the air flow
passes through the carbon dioxide scrubber rotor through a
plurality of first air passage tubes and a plurality of first mist
separators to be introduced downstream into an acid wash scrubber
chamber having a second heat and mass transfer surface therein; the
acid wash scrubber is separated from the carbon dioxide scrubber
rotor with a baffle; the baffle has an acid water wash inlet for
introduction of a liquid acid water wash as a mist in the air flow;
and the air flow passes through the liquid absorbent scrubber rotor
through a plurality of second air passage tubes and a plurality of
second mist separators to a fan causing the air flow to exit
through an air exhaust.
14. Apparatus for controlling humidity and temperature of cabin air
in a vehicle comprising: a rotary contact processor for direct
contact liquid absorbent and gas contaminant processing.
15. The apparatus of claim 14 wherein the rotary contact processor
comprises: a first scrubber rotor in communication with a gas inlet
and a liquid absorbent inlet, wherein a liquid absorbent is
introduced as a mist into a gas flow through the gas inlet.
16. The apparatus of claim 15 wherein the liquid absorbent inlet
and a liquid absorbent outlet are in communication with a liquid
absorbent tank, a liquid absorbent heater and a stripper
element.
17. The apparatus of claim 16 wherein an acid water wash inlet and
an acid water wash outlet are in communication with an acid water
tank and an acid water cooler.
18. The apparatus of claim 14 wherein: a first scrubber rotor is in
serial communication with a second scrubber rotor each assembled on
a rotor shaft rotatably mounted on a plurality of bearings in a
housing; and gas flow passes through the first scrubber rotor
through a plurality of first gas passage tubes and a plurality of
first mist separators to be introduced downstream into a second
scrubber chamber in fluid communication therewith and having a
second heat and mass transfer surface therein.
19. The apparatus of claim 18 wherein: the second scrubber chamber
has a liquid absorbent wash inlet for introduction of a liquid
absorbent wash as a mist in the gas flow; and the gas flow passes
through the liquid absorbent scrubber rotor through a plurality of
second gas passage tubes and a plurality of second mist separators
to a fan causing the gas flow to exit the rotary contact processor
through a gas exhaust.
20. The apparatus of claim 19 further comprising a first pitot pump
in a first scrubber chamber for liquid absorbent wash circulation
and exit through a liquid absorbent outlet.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of Ser. No.
10/611,490 filed Jun. 30, 2003.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to an air
environment control system (ECS) that revitalizes air and more
specifically to the apparatus and methods that control humidity and
temperature of cabin air of aircraft and spacecraft while removing
carbon dioxide and other trace gas contaminates.
[0003] Liquid amine (methanol amine water solutions) based carbon
dioxide and trace gas contaminant removal apparatus and processes
for regeneration of air have been used in nuclear submarines for
over forty years. Such systems are used to remove carbon dioxide
for the breathing air and depend on gravity to process the liquid
carbon amine or other liquids and air mixture.
[0004] An example of a combustion gas carbon dioxide process and
apparatus is disclosed in U.S. Pat. No. 5,318,758. This type of gas
process involves towers and other structures that depend on
gravity, blowers and pumps to process the gas. Such systems are not
simple or compact and do not work in reduced gravity environments
such as on aircraft and spacecraft.
[0005] The use of alternative absorbent solutions has been
disclosed in U.S. Pat. Nos. 4,285,918 and 3,632,519. These patents
teach that water solutions of 3-amino-1,2-propanediol and
.omega.-aminomethyl alkyl sulfone have improved performance for
carbon dioxide removal in closed environments such as submarines.
They address only the removal of carbon dioxide whereas there are a
number of other contaminants that must be removed in these closed
environments.
[0006] Centrifugal liquid and gas processors have been explored as
described in the article "The Centrifugal Mass Exchange Apparatus
in Air-Conditioning System of Isolated, Inhabited Object and Its
Work Control", by P. A. Barabash, et al, in Proceedings of the
4.sup.th European Symposium on Space Environmental and Control
Systems, Oct. 21-24, 1991. The article postulates use of a
centrifugal apparatus to work with an air-conditioning system in a
closed habitat system such as an orbital space station. A single
stage system is proposed that keeps air temperature and humidity
parameters within limits. The single stage rotor does not
anticipate a more staged air process system using contaminant
absorbent fluids and acid wash to provide carbon dioxide and other
contaminant removal from a cabin air environment. Indeed, present
spacecraft and space stations typically employ apparatus dedicated
exclusively to contaminant extraction from cabin air. Another
apparatus is used for maintaining humidity and temperature of the
cabin air. Each of these independent systems adds undesirable
weight and consumes valuable space and power in a spacecraft.
[0007] As can be seen, there is a need for a simple, compact ECS in
which humidity and temperature control are integrated with air
regeneration functions for use in aircraft and spacecraft.
SUMMARY OF THE INVENTION
[0008] An improved environmental control system and method
according to the present invention may comprise a carbon dioxide
scrubber, a liquid absorbent stripper, a charcoal filter, and
supporting containers, pumps and other elements.
[0009] In one aspect of the present invention, method for providing
environmental control for cabin air of a vehicle comprises the
steps of introducing a portion of the cabin air as air flow into a
carbon dioxide scrubber and spraying a liquid mist into the air
flow thereby modifying humidity, temperature and carbon dioxide
concentration of the cabin air.
[0010] In another aspect of the present invention, an environmental
control apparatus for cabin air of a vehicle comprises a
contaminant scrubber wherein a contamination-control liquid is
introduced as a mist into an air flow of a portion of the cabin air
through the contaminant scrubber. The contamination-control liquid
has a temperature lower than a temperature of the cabin air.
Temperature of the cabin air is reduced and humidity of the cabin
air is modified.
[0011] In another aspect of the present invention, an apparatus for
controlling humidity and temperature of cabin air in a vehicle
comprises a rotary contact processor for direct contact liquid
absorbent and gas contaminant processing.
[0012] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates a functional block diagram of the
invention;
[0014] FIG. 2 illustrates a functional block diagram of the major
elements according to an embodiment of the invention;
[0015] FIG. 3 illustrates a functional cross-sectional view of a
rotary liquid contact processor apparatus according to an
embodiment of the invention; and
[0016] FIG. 4 is a flow chart of a method for providing
environmental control for cabin air of a vehicle according to an
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The following detailed description is of the best currently
contemplated modes of carrying out the invention. The description
is not to be taken in a limiting sense, but is made merely for the
purpose of illustrating the general principles of the invention,
since the scope of the invention is best defined by the appended
claims.
[0018] Referring to FIGS. 1 and 2, an environmental control system
(ECS) 10 has an absorber element 20 and a stripper element 80 in
fluid communication and in control/data communication. Support
elements such as a control and data processor and an electric power
source, not shown, are provided by existing platform equipment as
is found on spacecraft and aircraft. The ECS 10 may be connected to
the cabin air system of a vehicle to process the return air from
use in a vehicle human environment, to decontaminate, cool and
dehumidify the air, and to return cold clean air for use in a
continuing cycle.
[0019] The current system absorber element 20 uses a rotary process
scrubber 30 and charcoal bed filter 26 to remove contaminants. Both
liquid absorbent (such as an amine) and acid water are used in the
scrubber 30 for direct contact liquid/vapor phase separation of
contaminants. The stripper 80 may also use a rotary processor for
liquid/vapor phase separation of liquid absorbent and carbon
dioxide. The use of rotary processors allows operation in variable
gravity environments such as experienced in aircraft and spacecraft
and provides compact, light weight and reliable apparatus as
compared to current art bulky, inefficient apparatus. In addition,
the use of direct contact liquid/vapor processing allows more
efficient heat transfer as compared to current technology, which
relies on use of condensing heat exchangers, slurpers, and rotating
centrifugal phase separators. A cold contamination-control liquid
such as an acid water spray may be used in the air contaminant
control system to remove absorbent vapor from the air and for
temperature and humidity control. As cabin air is introduced into
the ECS 10, and passes through the cold spray the air temperature
may be reduced. The air may become saturated as it is cooled toward
the temperature of the acid water and some of the moisture conveyed
in the air may condense and mix with the acid water. Thus moisture
content of the air may diminish. If the air does not become
saturated with water as it is cooled to the temperature of the acid
water spray, water may evaporate from the cold acid water spray and
add the water content of the air. Additionally, cabin air may be
cooled as it passes through the cold water spray. These humidity
adjustment and cooling functions may be an integral part of the
direct liquid contact system and not a separate system. For the
present inventive ECS 10 control of humidity may be the design
limiting function of the system. The ECS 10 may be sized to process
enough air to control the humidity. By doing so, the other
functions, such as temperature control and contamination control,
may be easily satisfied.
[0020] Cabin air may be drawn through the scrubber 30 by a fan that
may be used to aid vehicle cabin ventilation air flow. In the
scrubber 30 carbon dioxide and other contaminates may be removed
from the air through direct contact with a cool liquid absorbent.
The liquid absorbent removes carbon dioxide to form a carbonate
complex. The term liquid absorbent as commonly understood in the
art relates to carbon dioxide liquid absorbents, as for example,
water solutions of methanol amine, ethanol amine, isopropyl amine,
cesium carbonate, magnesium carbonate and similar solutions. The
choice of liquid absorbent may be based on system operational
factors such as carbon dioxide pressure, temperature, humidity,
regeneration temperature and energy sources.
[0021] The amines have a low vapor pressure at absorption
conditions; however, without treatment some amine vapor may remain
in the processed air to be introduced into the vehicle cabin as a
contaminant. To inhibit this event an acid water scrubber 60 may be
included in the scrubber 30 to maintain amine pressure at
acceptable levels, for example, about 1 ppm. The same process may
absorb other basic trace gases such as ammonia. A mild acid, such
as, citric, acetic, or hypo-phosphoric acid, may reduce the amine
vapor pressure to the desired levels. Additionally, the acid water
may serve as an anti-microbial with the potential for reducing
bacterial contamination or spread of pathogens. The acid water
solution may become very diluted, but the pH should be maintained
relatively low, i.e., less than about 2 value. Additional acid may
be added to the acid water scrubber 60 to maintain a low pH. For a
fully closed system acetic acid, vinegar, may be produced onboard a
vehicle using well known biological processes.
[0022] The carbon dioxide scrubber 40 may act to absorb acidic
trace gases. The combination of the carbon dioxide scrubber 40 and
acid water scrubber 60 results in substantial removal of water
soluble trace gases. There may also be hydrocarbon trace gasses in
the air that may not be absorbed in the scrubber 30. These gases
may be removed by a charcoal bed filter 26 downstream of the
scrubber 30. The charcoal bed filter 26 may be a single use or
regenerable device depending on the mission requirements. Generally
large portions of the trace contaminants are removed in the
scrubber 30 thereby reducing the contaminant load to be processed
by the charcoal bed filter 26. Such action may allow for a
relatively small charcoal bed filter 26.
[0023] The acid water wash sprayed into the acid water scrubber 60
may act to control temperature and humidity by the use of a cold
acid water wash in the temperature range of about 40 to 60.degree.
F. The cooling occurs due to direct thermal contact when cool acid
water is sprayed into the air flow. The large surface area of the
spray that may be effective for mass transfer may also be effective
for heat transfer. Water vapor in the air may condense in the cold
acid water spray and then be separated by the centrifugal action of
the acid water scrubber 60 to adjust the humidity.
[0024] The resultant dilute acid water may then be accumulated in
acid water tank 62. As part of the process water may be removed
from the acid water tank and acid may be added to maintain proper
pH for reuse in the acid water scrubber 60. The removed dilute acid
water may have salts and dissolved trace gasses. It may be
processed in a water recovery system in the host vehicle for reuse
in the water cycle. Processed acid water may be cooled at acid
water cooler 64 and introduced to the acid water scrubber 60.
[0025] The carbon dioxide rich liquid absorbent solution may also
be processed for reuse in the carbon dioxide scrubber 40. The
liquid absorbent solution may be heated and processed through the
stripper element 80 to separate carbon dioxide from the liquid
absorbent solution. The carbonate complexes formed in the scrubber
during the absorption of carbon dioxide are thermally unstable, for
example, methanol amine carbonate decomposes at 270.degree. F.
Approximately five percent of the flow of liquid absorbent used to
treat the air in the scrubber 30 may be heated in liquid absorbent
heater 44 and introduced into the stripper 80. The stripper 80 may
be a rotary contact processor similar to the rotary contact
processor 32.
[0026] The stripper 80 permits evolution of the carbon dioxide and
the separation of the liquid phase. The method for the process
using a rotary contact processor comprises the steps of heating the
carbonate rich liquid absorbent to its decomposition temperature in
a flow through liquid absorbent heater, communicating the heated
liquid absorbent into a first stage scrubber and spraying the
heated liquid absorbent onto a rotating heat and mass transfer
surface thereby separating the liquid absorbent from the evolved
carbon dioxide gas through centrifugal action, accumulating the
carbonate lean liquid absorbent and removing it from the transfer
surface using pitot pumps, and passing the carbon dioxide gas
through a plurality of mist separators for removal of droplets
prior to being output.
[0027] The carbon dioxide gas may be further processed by
introduction into a second stage scrubber to remove water and
absorbent vapors. The carbon dioxide gas may be washed by a spray
of a cold liquid absorbent that may then be sprayed onto a rotating
mass and heat transfer surface, the liquid absorbent separation
from the carbon dioxide may be caused by centrifugal action, the
liquid absorbent may then be accumulated and then removed by pitot
pumps, and the carbon dioxide may be passed through a plurality of
mist separators for removal of droplets prior to being output.
[0028] In each case of the liquid absorbent and the carbon dioxide
processing, more process stages may be used to obtain desired
absorbent regeneration and product carbon dioxide purity.
[0029] The liquid absorbent may be first processed by a stripper
element 80 to remove carbonate complexes present in the solution.
The heated liquid absorbent may be sprayed into the stripper
element 80, which may be a rotary contact processor wherein the
small droplets formed provide a large surface area permitting
efficient carbon dioxide transfer. The pressure of the carbon
dioxide may be controlled as for example by using a back-pressure
regulating valve. Depending on the liquid absorbent used, the
pressure can be set in the range of 40 to 70 psi. The rotary
stripper element 80 centrifugal action functions to separate the
liquid and gas phases similar to the scrubber 30.
[0030] The resultant carbon dioxide vapor may be hot and contain
water vapor and absorbent vapor. The vapors are removed in a
stripper element 80 by cooling the carbon dioxide and condensing
the liquid. The cool liquid absorbent solution may be returned to
the liquid absorbent tank 42 and the carbon dioxide may be
compressed, dried and stored for further use or disposal.
[0031] Referring to FIGS. 2 and 3, the scrubber 30 rotary contact
processor 32 functions to provide direct liquid contact between air
and two separate liquids, to separate the liquids and air, and to
pump the liquids. The rotary contact processor 32 may be a dual
rotor ambient pressure air scrubber that washes the air in the
carbon dioxide scrubber rotor 104 with a carbon dioxide absorbent
and washes the air with mild acid in the liquid absorbent scrubber
rotor 107 as air flows through the device. It is supplied with a
liquid absorbent solution, cooled acid wash water, atmospheric air,
and electrical power. Electrical power is used for a drive motor,
not shown. The advantage of this device is that it operates at
atmospheric pressure, it is gravity independent and it provides a
simple, rugged device.
[0032] The contact processor 32 consists of a rotor assembly
comprised of carbon dioxide scrubber rotor 104 and liquid absorbent
scrubber rotor 107 mounted in a housing 116 on bearings 120.
Scrubbing and separation occur within the rotor. Liquid absorbent
solution may be circulated through connections 102, 118 in the
stationary hub 122 at one end and cooled acid wash water may be
circulated through connections 105, 114 in a stationary baffle 115
located in the middle of the housing.
[0033] The two rotors 104, 107 are mounted on shaft 110 and are
separated by stationary baffle 115. The first rotor 104 is in the
carbon dioxide scrubber chamber 124 and may be used to remove
carbon dioxide from the air stream. The second rotor 107 is in the
acid wash scrubber chamber 126 and may be used to wash the air and
to condense water from the air stream. Mist separators 111 and
baffles 115 are used to isolate the two fluids. The air may be
moved through the rotary contact processor 32 by a built-in fan
112. An external blower, not shown, may also be used.
[0034] The rotary contact processor 32 operates in the following
manner: atmospheric air flows in the inlet 101 past the carbon
dioxide scrubber rotor 104, through air passage tubes 109 and mist
separators 111, past the liquid absorbent scrubber rotor 107,
through second air passage tubes 109 and second mist separators
111, and through the fan 112, to the air exhaust 108. The fan 112
moves the air through the rotary contact processor 32 and the drive
motor, not shown, keeps the rotors and fan moving at constant
speed.
[0035] Carbon dioxide is removed from the air stream in the carbon
dioxide scrubber chamber 124. Liquid absorbent enters at connection
118 and is sprayed into the air stream near the axis of rotation
128. It forms droplets and a thin layer on the carbon dioxide
scrubber rotor 104 heat and mass transfer surface 117. The liquid
flows by centrifugal action to the outside of the carbon dioxide
scrubber chamber 124. This direct contact promotes the rapid
absorption of carbon dioxide by the liquid absorbent. A mist
separator 111 keeps liquid absorbent from entering the next
chamber. The liquid absorbent forms a layer on the periphery of the
chamber 124 and is pumped by the liquid absorbent pitot pump 103
through the liquid absorbent outlet 102 to an external liquid
absorbent tank 42. The return liquid absorbent enters through
liquid absorbent inlet 118.
[0036] The air is washed, cooled and humidity condensed in the acid
wash scrubber chamber 126. Cold acid wash enters through the acid
water wash inlet 114 and is sprayed into the air stream near the
axis of rotation 128. It forms droplets and a thin layer on the
liquid absorbent scrubber rotor 107 transfer surface 117. The
liquid flows by centrifugal action to the outside of the acid wash
scrubber chamber 126 and a portion of the humidity in the air
stream condenses. The air stream is cooled below the dew point by
the cold acid water wash. A mist separator 111 keeps water droplets
from entering the exhaust stream at air exhaust 108. The condensate
liquid forms a layer on the periphery of the chamber 126 and is
pumped by the acid water pitot pump 106 through the acid water wash
outlet 105 to the external circuit. The return cold acid water wash
enters through the acid water wash inlet 114.
[0037] While one embodiment is described in terms of a two stage
scrubber 30 having a carbon dioxide scrubber 40 and a liquid
absorbent scrubber 60 having a common rotor shaft and housing,
these two elements may also be contained in separate housings with
fluid communication therebetween. In such an instance, the baffle
115 would be separated in structure such that the carbon dioxide
scrubber 40 would have an outlet enclosed side and the liquid
absorbent scrubber 60 would have an inlet enclosed side. Also, more
than two stages may be used depending on the purity of the output
desired by the user.
[0038] An inventive method 200 is illustrated in a flow chart of
FIG. 4. In a step 202, a flow of cabin air is introduced into a
carbon dioxide scrubber. In a step 204, a liquid mist is sprayed
into the introduced air in order to modify its temperature,
humidity and carbon dioxide concentration.
[0039] It should be understood, of course, that the foregoing
relates to preferred embodiments of the invention and that
modifications may be made without departing from the spirit and
scope of the invention as set forth in the following claims.
* * * * *