Abstract:
Embodiments of the present invention relate generally to systems and methods for preventing mineral scale deposits in an aircraft water system, and more specifically, within devices and water transport systems, such as coffeemakers and other galley equipment, as well as the water lines themselves.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/671,911, filed Jul. 16, 2013, titled “Scale Prevention for Aircraft Water System,” the entire contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention relate generally to systems and methods for preventing mineral scale deposits in an aircraft water system, and more specifically, within devices and water transport systems, such as coffeemakers and other galley equipment, as well as the water lines themselves. 
       BACKGROUND 
       [0003]    Potable water to be loaded onto aircraft contains various minerals, including calcium and magnesium, and some regions have especially hard water with high mineral levels. These minerals have the potential to combine with carbonate ions in water to form hard scale on surfaces in contact with the water. Scale particles&#39; solubility decreases with increasing temperature, causing it to precipitate at elevated temperatures, especially onto heating elements. Frequently used heating elements, such those used in coffeemakers, experience the most damage from scale. Layers of scale create resistance to heat transfer, placing excessive load on heating components and elevating energy usage. Device lifetime is shortened due to severely reduced performance or failure. In addition to causing physical damage, scale is also conducive to bacteria growth, which creates a health hazard. 
         [0004]    Coffeemakers, water heaters, steam ovens, and other devices receive frequent usage on commercial airline flights and therefore accumulate scale rapidly, limiting their useful lifetime. The financial resources and time spent on repairs and replacements are costly for airlines. It is therefore beneficial to eliminate this problem by preventing scale from depositing on any device or pipe surfaces. 
         [0005]    Scale prevention devices are used for residential and commercial uses, for example, in homes, restaurants, and any other locations where there are scale problems associated with hard water. Embodiments of the invention will be described throughout the remainder of this document for use in connection with aircraft, but it should be understood that uses in other locations and for other purposes are possible as well. Although the embodiments described are particularly designed to be lightweight, small, and efficient as required for a passenger transport vehicle, it is envisioned that uses in other environments are possible. 
         [0006]    Airlines have great need for products with high reliability, low acquisition and maintenance costs, minimized weight and size, and demonstrated functionality. The scale prevention devices described herein are intended to meet all of these needs within its compact design, as well as improve these attributes for other devices, such as coffeemakers and other heating elements. Simply reconfiguring a currently-available scale prevention device or plumbing it in-line with an aircraft water line system is not a feasible way to prevent scale on an aircraft or other transportation vehicle due to the nature of the water lines associated with vehicles and various space, weight, and other aircraft requirements. The system should be compact, it should have an inlet and an outlet so that it can be plumbed in-line with a water line, it should have enhanced drainage, it should work under various orientations, and should also be easy to disassemble for service. 
       BRIEF SUMMARY 
       [0007]    Embodiments of the invention described herein thus provide a granular fluidization cartridge useful in an aircraft plumbing system. The system provides improved flow through the media bed, improved drainage features, a stand-alone cartridge, and other advantages that allow the devices to be used on-board aircraft and other passenger transport vehicles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows a side perspective view of one embodiment of a scale prevention system. 
           [0009]      FIG. 2  shows a side perspective view of another embodiment of a scale prevention system. 
           [0010]      FIG. 3A  shows a side perspective view of an alternate embodiment of a scale prevention system.  FIG. 3B  shows contoured or angled walls for water drainage. 
           [0011]      FIG. 4  shows one example of a potential housing. 
           [0012]      FIG. 5  shows one example of a potential location for a device to be positioned in an aircraft galley. 
           [0013]      FIG. 6  shows the device of  FIG. 5  in position. 
           [0014]      FIG. 7  shows one embodiment of a permanent housing with replaceable cartridge insert. 
           [0015]      FIG. 8  shows a schematic of a potential water system. 
           [0016]      FIG. 9  shows spinning nozzle embodiments. 
           [0017]      FIG. 10  shows a water inlet located at a top of a cartridge. 
           [0018]      FIG. 11  shows how multiple chambers may be used. 
           [0019]      FIG. 12  illustrates a water line pipe with scale deposits formed therein. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Embodiments of the present invention provide a scale prevention device for use on board passenger transport vehicles, such as aircraft, that treats water to minimize the amount of scale deposited on surfaces within the water system after water treatment. Embodiments may also be designed to gradually remove scale deposits already in place. The technology for scale prevention is generally a salt-free method that uses a polymer-based media to control the type and/or size of calcium carbonate crystals that are formed, so that the crystals will not deposit onto heating elements and pipes. The granular media prevents minerals from depositing on the inside of water pipes, which can cause damage and slow the flow of water therein. One example of a water pipe that has been blocked with scale is shown in  FIG. 12 . Potential examples of such granular/filter media are manufactured and sold by companies such as Watts Water Technologies and Watch Water Technology, among others. However, water scale prevention systems designed for land-based use, for example in residential and business environments, do not need to meet aerospace standards and are designed such that they are not feasible for use on-board an aircraft, due to either weight considerations, drainage requirements, and so forth. 
         [0021]    Accordingly, the present inventors have designed a way to provide a water scale prevention device  10  for use on-board a passenger transport vehicle. In one embodiment, the media used is held in a cartridge  12  that fits within a housing  14 . The cartridge  12  may be replaceable, and the housing  14  may be a permanently positioned housing. One example of a potential housing is shown in  FIG. 4 . An alternate embodiment of a housing that uses a replaceable cartridge  12  is shown in  FIG. 7 . Modifications to conventional water media housings may include using appropriate water connections and airworthy materials, and designing for the spatial envelope in which the cartridge will be installed. 
         [0022]    The housing  14  is generally located in-line with the water system and may be installed immediately upstream of targeted areas, e.g. coffeemaker, as shown in  FIGS. 5 and 6 . Bypass plumbing options are described below; it is relevant to note here that the first installation may need to interrupt water, but periodic replacements generally will not. Alternatively, the housing  14  may be installed at the water system point of entry. 
         [0023]    This system provides a lightweight, cost-effective design that allows materials to be used in an economic disposable cartridge. This style would utilize an interface that allows water to continue to flow through the lines even when the filter has been removed, in case of the need for a water system disinfection procedure or to facilitate faster drainage. 
         [0024]    In one embodiment, as shown in  FIG. 8 , there may be an upstream diverter valve  42  located at the housing water inlet  44  and a downstream diverter valve  46  at the housing water outlet  48 . The two valves  42 ,  46  can be manually operated valves, such that when the valves are oriented in line with the cartridge  12 , water flows only through the cartridge and not through the bypass line  50 . With the valves in this position, the cartridge  12  is locked in place and is not able to be removed. When the valves are turned to their alternate or diverting position, water will then flow through the bypass line  50  and the cartridge  12  will be released and can be replaced. Alternatively, the valves may be automatic in such a way that the position of the cartridge will control the orientation of the valves. When the cartridge is in place and rotated to lock the inlet  44  and outlet  48  connections, the valves  42 ,  46  will open to allow water flow into the cartridge  12 . When the cartridge  12  is rotated to unlock from its position, the valves will allow water to flow only through the bypass line  50 . 
         [0025]    In all embodiments, no power or chemicals are needed for operation. The device is designed to be generally maintenance-free for the lifetime of the media. The quantity of the media and therefore the size of housing to be used are determined by the location in which the system is to be installed, as well as the hardness and flow rate of the entering water. 
         [0026]    The device  10  may be cylindrical or any other appropriate cross section. The device may be installed as a single replaceable part, complete with media and shell structure as one piece. An alternative design would involve a permanent housing  14  or shell, while the media is contained in a separate cartridge  12 . This cartridge  12 , inserted in the permanent housing, would be the replacement part in this configuration. Water ports allow water to enter and exit the cartridge. For example, there is provided an inlet  44  and an outlet  48  to the cartridge. Although shown at the top and bottom of the cartridge, these ports/inlets/outlets may be located anywhere along the cartridge, such as along the side or elsewhere. 
         [0027]    A drainage system is also provided. The drainage system is generally provided by the combination of various drainage features. Examples of potential drainage systems include but are not limited to sloped interior contours, and screen/mesh to allow water to flow through but retain filter media. The drainage systems generally use gravity to drain the device  10 . A drainage feature is particularly important for a scale prevention device  10  to be used in connection with aircraft because water should be drained from the scale prevention device  10  at the end of every use. Water remaining in any water lines or water systems in the aircraft can freeze, creating water line bursts, and stagnant water can foster bacteria growth and create health problems. Accordingly, the system provides alternate drainage options. 
         [0028]    As shown in  FIGS. 3A and 3B , it is possible to provide an angled and sloped container  32  geometry to avoid stagnant areas. Such angled or sloped walls  34  may be provided in any of the embodiments shown in  FIGS. 1-3A , if desired. By providing angled cartridge walls  34  in the cartridge area, water can better flow by gravity away from the filtering area  36 , as shown by the arrows in  FIG. 3A . Curved walls  33  are an alternate drainage option, as shown in  FIG. 3B . It is also possible to provide one or more media barriers  38 , such as slots  16  or screens  30 , and/or other orifices that allow water passage down through cartridge  12 , but that do not allow passage of any filter media. For example, a mesh screen  52  at the lowest point in the cartridge interior may be provided in order to allow water to drain back through the system, avoiding any accumulation of water at these low points. A combination of these options may also be used if desired. 
         [0029]    Such media barriers  38  create a negligible interruption to the flow path during normal operation. The mesh screens that aid in water drainage out of the cartridge after use, described above, also retain media within the cartridge. The size of these screens is designed based on media type used within the filter. 
         [0030]    Regarding improved flow and performance, the fluidized bed may span the substantial interior of cartridge, which results in uniform aging of the media. Encouraging full fluidization of the media bed and usage of the entire cartridge volume can help extend the life of the device. For example, in one embodiment, as shown in  FIGS. 1 and 2 , a domed umbrella feature  22  redirects fluid flow, especially in the case of incoming flow at the bottom of the cartridge. This facilitates water passage through all of the media rather than forcing a path through a small percentage of media. 
         [0031]    In another embodiment of the invention, the incoming flow of water is directed through a freely spinning nozzle  54  protruding into the media cavity  56 , as shown in  FIG. 9 . In the resting state, the nozzle  54  sits motionless within the unexpanded media bed. A flow of liquid, having been introduced into the inlet  44 , flows through the nozzle  54  to propel the armatures forward via Newton&#39;s third law. The nozzle  54  spins clockwise or counterclockwise about the vertical axis of the cartridge  12 . Momentum of the liquid quickly expands the media bed into the media cavity  56  by imparting kinetic energy and a liquid matrix into which the media can expand. Internal geometry of the cartridge is designed to direct the fluid&#39;s axial momentum upward against gravity to support the expansion of the media bed. The spinning action of the nozzle further imparts kinetic energy and turbulence to the expanded media bed in order to increase liquid contact time with media. It is also possible to use a porous panel or mesh screen  52  to divert flow laterally before allowing upflow and fluidization of media for treatment of the water. 
         [0032]    The umbrella feature or the rotating nozzle feature generally provide a system to provide uniform fluidization system of the water that flows through the cartridge. These features are provided in order to control the direction of the incoming flow of water to guide the flow path to cover the full cartridge cross-section. In doing this, the entirety of the media bed is contacted and fluidized, creating a well-mixed reaction chamber. These unique features of the cartridge design ensure that the media bed is completely and evenly fluidized. Because the full amount of media is in contact with the water during treatment, additional head space is not necessary to achieve the desired contact time. This results in a more compact design package, a critical feature due to the limited space and weight allowances on aircraft and other passenger transport vehicles. 
         [0033]    As shown in  FIG. 10 , if a water inlet  44  is provided at the top of the cartridge  12 , a tube  28  may be provided that directs flow to bottom of the cartridge  12  and forces turn-around to allow upflow of water through the media. Additionally or alternatively, spherical and/or flat screens or porous panels  30  may be used to distribute water flow and to hold media within the cartridge  12 . The choice as to which water flow design to use is generally based upon space available within cartridge, pressure drop restrictions, and any other water flow considerations to be addressed by the design. 
         [0034]    It is also possible to use multiple chambers to house multiple media types, separated by an additional screen or panel (e.g. granular activated carbon and scale prevention media), as shown in  FIG. 11 . Multiple chambers  58  for multiple media types may be provided. For example, a screen  30  and/or slots  16  may be provided at the bottom chamber  60  of the unit for drainage and holding media in, and a large screen  62  may separate the two different chambers. 
         [0035]    Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the invention and the following claims.