Abstract:
Water-treatment systems and techniques are addressed. These systems and techniques contemplate monitoring water-quality-related information and creating residual disinfectant in recirculating water loops. Such circulating residuals also may help control biofilm otherwise likely to be present in the conduits and other equipment through which the water passes. Heaters may be employed as parts of the systems, and pressure differentials may be exploited to control water flow. Principally for use on-board aircraft operable at substantial altitude, the systems and methods may nevertheless be utilized in other vehicles or vessels or otherwise as appropriate or desired.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to systems and techniques for treating water and more particularly, but not exclusively, to such systems and techniques implemented on-board commercial passenger or other aircraft.  
       BACKGROUND OF THE INVENTION  
       [0002]     According to the U.S. Environmental Protection Agency (“EPA” or “Agency”), more than twelve percent of passenger aircraft tested in the United States during August and September 2004 “carried water that did not meet EPA standards.” Water on-board these aircraft tested positive for total coliform bacteria, with some water also testing positive for  E. coli  bacteria. As noted by the EPA, “[b]oth total coliform and  E. coli  are indicators that other disease-causing organisms (pathogens) could be in the water and could potentially affect people&#39;s health.” See “Airline Water Supplies” at http:H/www.epa.gov/airlinewater.  
         [0003]     On Nov. 9, 2004, EPA announced commitments from numerous U.S. passenger airlines “to implement new aircraft water testing and disinfection protocols.” Administrative agreements executed with these airlines require increased monitoring of water quality on-board commercial aircraft. They also require airlines to analyze possible sources of contamination existing outside their aircraft and “to provide information related to practices of boarding water from foreign public water supplies not regulated by EPA.” See “EPA Reaches Agreement with Major Airlines to Implement New Aircraft Water Protocols” at http://yosemite.epa.gov/opa.  
         [0004]     Clear from EPA&#39;s recent public announcements is that improving water quality on-board passenger aircraft is an important objective of the Agency. Systems and techniques effecting such improvement thus may provide valuable tools to U.S. airlines as they seek to comply with the administrative agreements. They may also be useful to the EPA as it works to enhance the quality of drinking and other water made available to the public.  
         [0005]     U.S. Pat. No. 4,871,452 to Kohler, et al., entitled “On-Board Water Supply,” discloses equipment for purifying waste water from galleys, sinks, and toilets of aircraft. Waste water from these areas discharges to a tank, after which it passes through a mechanical filter, a bed of active carbon, ozone and osmotic stages, and a disinfection stage involving addition of chlorine and irradiation with ultraviolet (“UV”) light. Thereafter, the water is made available to aircraft passengers for certain uses.  
         [0006]     Discussed in U.S. Pat. No. 6,143,185 to Tracy, et al. are alternate systems for decontaminating waste water from aircraft toilets, sinks, and galleys. They too include a mechanical particulate filter, activated carbon, and a source of UV light. Alternatively, according to the Tracy patent, the waste water may be exposed to microwaves or treated with chlorine or iodine. A sensor may be used to measure “the level of clarity of the treated water as an indication of its purity” and restrict opening of a control valve until acceptable clarity levels are obtained. The entire contents of both the Kohler and Tracy patents are incorporated herein by this reference.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides different systems and techniques for treating water likely, among other things, to assist airlines in complying with their commitments to EPA. Monitoring of water-quality-related information other than clarity is contemplated as part of the present invention, as is creating residual disinfectant in recirculating water. This residual disinfectant may function not only to inhibit growth of bacteria in the water, but also to control biofilm otherwise likely to be present in the conduits and other equipment through which the water passes.  
         [0008]     Pressure differentials may be used to force quantities of recirculating water out of the main recirculation loop and into a bypass area in which disinfection principally may occur. Use of pressure differentials may also result in more uniform placement of disinfected water within multiple holding tanks and greater temperature control of water within the tanks. Heaters additionally may be included in the systems both to reduce the possibility of water freezing within the conduits (particularly when used on-board aircraft at altitude) and as part of the disinfection process.  
         [0009]     Consistent with the present invention, disinfectant may be generated on-board aircraft or other vehicles or vessels using electrolysis of salt water. By creating a system admitting residual disinfectant to be in the recirculating water, monitoring the amount of the residual in the recirculation loop may provide information relating to the quality of the water therein. Finally, the weight of any descaling device utilized as part of the innovative systems may be reduced by using magnetic alloys as shields.  
         [0010]     It thus is an optional, non-exclusive object of the present invention to provide systems and techniques for treating water.  
         [0011]     It also is an optional, non-exclusive object of the present invention to provide water-treatment systems and techniques for use on-board aircraft or other vehicles.  
         [0012]     It is a further optional, non-exclusive object of the present invention to provide systems and techniques for monitoring water-quality related information, with such information preferably (but not necessarily) being or relating to amounts of residual disinfectant present in recirculating water.  
         [0013]     It is another optional, non-exclusive object of the present invention to provide systems and techniques for controlling biofilm within recirculating water loops.  
         [0014]     It is, moreover, an optional, non-exclusive object of the present invention to provide systems and techniques in which pressure differentials are utilized to control water flow into either or both of a disinfectant area and holding tanks.  
         [0015]     It is yet another optional, non-exclusive object of the present invention to provide water-treatment systems and techniques in which heaters are used both to reduce the possibility of freezing and for disinfecting purposes.  
         [0016]     It is an additional object of the present invention to provide systems and techniques in which magnetic alloys are used as shields of descaling devices.  
         [0017]     Other objects, features, and advantages of the present invention will be apparent to those skilled in the relevant field with reference to the remaining text and the drawings of this application. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a schematic representation of an exemplary water-supply and -treatment system for an aircraft.  
         [0019]      FIG. 2  is a schematic representation of a portion of the system of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0000]     1. Structure of the System  
         [0020]     Illustrated schematically in  FIG. 1  is an exemplary water-supply and -treatment system  10  consistent with the present invention. System  10  is designed especially for a commercial passenger aircraft. It is, however, not limited to use in these aircraft, but instead may be used in other aircraft, other vehicles, or otherwise as appropriate or desired.  
         [0021]     Included in the system  10  shown in  FIG. 1  are one or more tanks  14 . Such tanks  14 , of which six are detailed in  FIG. 1 , typically contain potable water for use by humans. If present in an aircraft, for example, the water may be used for any or all of drinking, cooking, or hygienic purposes. Sensors  18  present on any or all of tanks  14  may provide indication of one or more characteristics of water contained in associated tanks, including the amount (level) of water contained in a tank  14 .  
         [0022]     Also associated with tanks  14  are valves or other mechanisms capable of selectively allowing water to exit therefrom. Water exiting tanks  14  travels through conduit of drain lines  22  to distribution line  26 . Thereafter, some of the water in distribution line  26  may travel directly to areas prepared for its use. As illustrated in  FIG. 1 , for example, water in line  26  may travel to any or all of the forward or aft main or upper decks of an aircraft for use by passengers and crew.  
         [0023]     However, at least some water in line  26  is intended to travel to water-treatment module  30  shown in  FIGS. 1-2 . Module  30  effectively forms a by-pass disinfection loop, returning disinfected water to tanks  14 . Such water does so through conduit forming circulation line  34 , following which it reenters tanks  14  through, preferably (but not necessarily), appropriate valves.  
         [0024]     Additionally schematically shown in  FIG. 1  is optional equipment  38  and  40  useful for filling tanks  14  and draining both the tanks  14  and, possibly, any storage tanks in which waste water accumulates in flight. Equipment  38 , for example, includes fill/drain switch  42  typically located on the external underside of an aircraft. Switch  42  may be manipulated by ground staff at an airport to permit tanks  14  either to be filled or emptied as appropriate. Equipment  38  also may include connectors  46 , motors  50 , and other devices adapted for creating or allowing fluid to flow. Equipment  40 , by contrast, is designed solely to drain water. As detailed in  FIG. 1 , equipment  40  may be connected to forward water-distribution system  54  of an aircraft, while equipment  38  may be connected to either or both of tanks  14  and aft water-distribution system  58  of the aircraft.  
         [0025]      FIG. 1  further illustrates ancillary equipment  62  useful in connection with the present invention. Equipment  62  may comprise any or all of such things as pressure switches  66 , relief and check valves  70 , compressors  74 , filters  78 , and controllers  82 . Pressurized air produced by equipment  62  may flow through manifold  86  to tanks  14  so as to pressurize the water therein.  
         [0026]     Illustrated in greater detail in  FIG. 2  is water-treatment module  30  of the present invention. Module  30  receives water from distribution line  26  via circulation pump  90  and returns treated water to circulation line  34  via conduit  94 . Incorporated into module  30  may be scaling-inhibition module  98  and heater  102 . Preferably, although not necessarily, all water entering module  30  passes through or by both module  98  and heater  102  before returning to circulation line  34 .  
         [0027]     Also forming part of module  30  may be sensor  106  and flow restrictor  110 . Although sensor  106 , if present, may indicate any characteristic of the water flowing through module  30 , it preferably provides information as to the amount of residual chlorine or other disinfectant contained in the water. Such information may be in the form of any or all of oxidation-reduction potential (ORP), pH, water temperature, or otherwise as desired.  
         [0028]     Flow restrictor  110  provides a pressure differential designed to force at least some water through sanitization section  114  when stop valve  118  is open. Typically including an electrolytic cell  122 , section  114  also may include resin cartridge  126 , brine cartridge  130 , and brine pump  134 . Passage through resin cartridge  126  functions to soften water. While brine pump  134  is operating, a bypass of (pure) water flows into brine cartridge  130  and brine solution flows out of cartridge  130  and is diluted with fresh water to a concentration advantageous for electrolytic cell operation before flowing into electrolytic cell  122 . Within cell  122 , the brine solution is converted into mixed oxidants via electrolysis, with the mixed oxidants thereafter injected into line  34  via conduit  94 .  
         [0029]     Control unit  138  operates to control components of module  30 . Additionally depicted in  FIG. 2  are PTC ambient sensor  142 , which functions to sense air temperature within module  30  during operation, and drain valve  146 . Drain valve  146  permits drainage of the lines and conduit of module  30  when necessary or desired.  
         [0000]     2. Selected Functions of the System  
         [0030]     System  10  performs numerous supply and treatment functions. Module  30 , for example, operates to decrease pathogens in a water supply passing through the module. However, it also may deposit residual disinfectant in the water so that disinfectant is carried by the circulating water throughout other components of system  10 . This residual disinfectant thus may both inhibit growth of bacteria in the water throughout system  10  and control biofilm otherwise likely to be present in the conduits and other equipment of the system  10 . Furthermore, monitoring one or more aspects of the residual disinfectant may be used to provide feedback as system  10  as to the quality of the water therein, with such feedback potentially used by control unit  138 , via valve  118 , to increase or decrease (as a function of time) the time during which valve  118  remains open, thereby affecting the amount of water shunted to sanitization section  114 . This change in the amount of shunted water in turn will cause corresponding change in the amount of residual disinfectant in the circulating water, with such updated information likewise ultimately being provided to control unit  138 .  
         [0031]     System  10  also utilizes heat and pressure to facilitate the disinfection process. For example, not only does heater  102  assist in preventing circulating water from freezing, by heating the flowing water it also may assist some of the chemical reactions in which sanitization occurs. Pressurization of the water likewise may assist these reactions; it also may be employed to force quantities of water into the by-pass loop including sanitization section  114 .  
         [0032]     Moreover, controls associated with system  10  may use pressurization and differential pressures to cause water to flow relatively uniformly into tanks  14 . Because tanks  14  may be connected in parallel to circulation line  34  and distribution line  26 , providing approximately equal disinfectant residual in water entering each such tank  14  may be beneficial. This is particularly true for controlling biofilm in the tanks  14  and drain lines  22 , which otherwise might not receive a desirable amount of disinfectant.  
         [0033]     Commercially-available magnetic descaling products generally are unshielded or shielded with a heavy layer of, e.g., steel. This shielding causes the units to be bulky and heavy. Module  98 , however, may comprise a shield made from a sheet of Netic S3-6 alloy (available from Magnetic Shield Corporation) or other magnetic alloys with similar characteristics to reduce the weight and size of the module  98 .  
         [0034]     The foregoing is provided for purposes of illustrating, explaining, and describing exemplary embodiments and certain benefits of the present invention. Modifications and adaptations to the illustrated and described embodiments will be apparent to those skilled in the relevant art and may be made without departing from the scope or spirit of the invention.