Abstract:
A backflow resistant stop valve for an aircraft galley plumbing system comprises a valve body defining an inlet, and inlet chamber, a transfer chamber, an outlet chamber, and an exit. The valve incorporates an anti-backflow device at the exit to prevent backflow, and flow through the body is controlled by a pivoting paddle disposed within the valve body having an upper flap, a spindle, and a lower flap, where the upper flap seals against the inlet chamber and the lower flap seals against the outlet chamber when the paddle is rotated to a first position. The valve utilizes a negative pressure at the outlet chamber that biases the valve closed until a sufficient column of water overcomes the bias.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Application No. 61/651,740, filed May 25, 2012, incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    One important system on a commercial aircraft is the galley plumbing system. Both potable and waste water must be stored, circulated, and collected on the aircraft via the plumbing system. On a commercial aircraft, potable water is used for multiple applications, including drinking water, beverages such as coffee and tea, and cooking (steam ovens, rice boilers etc.), and as a result must meet certain safety regulated requirements. That is, to ensure that it fit for human consumption, potable water available on an aircraft has to meet certain minimum health and safety standards. This is partially accomplished with aggressive filtering, which also improves the taste and smell, and removes impurities and harmful bacteria. The aircraft plumbing system encompasses all aspects of water usage on a galley, and includes its associated hardware and components as well as the other galley equipment, either consuming or producing water. 
         [0003]    To meet the requirements of potable water, galley plumbing systems must pass design requirements specified by the aircraft manufacturers and proving tests to ensure that the potable, waste and foul water systems remain separated and that no cross contamination can occur. Also, when the aircraft shuts down after completion of a flight, or for longer periods of storage or maintenance, all of the systems must be capable of draining completely to evacuate all residual water so as to eliminate all retained water that could potentially become contaminated or breed bacteria. To this end, the plumbing system must be capable of gravitational draining, i.e., receiving air into the system to cause rapid displacement and removal of any trapped water. 
         [0004]    It is common practice in the airlines for potable water that has passed through the water filter of the plumbing system to be regarded as waste water. However, recent changes in policy by aircraft manufacturers that are driven by the need to conserve water, has led to requirements that potable water only becomes waste water when it has entered the galley sink. In view of this, it is possible to reclaim potable water by draining all other water fed devices including water boilers, faucets, ovens, filters, etc. into the fresh water tanks. In addition, at the resumption of service, the potable water supply circuit must be capable of being filled automatically without manual assistance, and all sections that may potentially trap air must be capable of self-venting. When filling the potable water circuit, it is important to remember that pressures vary depending on the aircraft and design. 
         [0005]    One challenge when designing aircraft plumbing systems on an aircraft is preventing backflow of waste water, which can contaminate the system and foul the drains and venting devices. Moreover, in severe cases foul air from the waste water can rise up and make things unpleasant for the passengers. Accordingly, a reliable and effective stop valve is essential to permit flow through the system, but prevent back flow of waste water. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is an air stop valve for an aircraft galley plumbing system. the air stop valve is part of a full potable/waste water/vacuum plumbing system in a reduced footprint, wet/refrigerated galley. Drainage of waste water in the galley plumbing system is controlled by the air stop valve, which also doubles as a back flow prevention device. The air stop valve utilizes the aircrafts applied vacuum downstream of the outlet to drain water into the waste water tank, whereby the vacuum cooperates with the valve to hold the valve closed until the column of water in the hose above the inlet to the stop valve overcomes the vacuum and opens the valve automatically. The vacuum is used to ensure the waste water can be effectively drained into the waste tank. Since the valve is held closed to maintain the vacuum in the system, foul odors from the waste tank are prevented from entering the cabin. The air stop valve also operates to prevent waste water from flowing back up the waste line into the cabin sink. 
         [0007]    The valve of the present invention comprises a compact flow control body that reduces exterior dimensions substantially and allowing it to be installed in a confined space. A pivoting paddle within the valve rotates from the open to closed position, sealing the valve to prevent waste water and foul air from passing through the valve. In a preferred embodiment, the paddle has a trapezoidal shape that allows water in certain conditions to bypass the paddle and flow through the valve. 
         [0008]    Other features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments in conjunction with the accompanying drawings, which illustrate, by way of example, the operation of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic illustration of an exemplary galley utilizing the air stop valve of the present invention; 
           [0010]      FIG. 2   a  is a first cross sectional view of the air stop valve of  FIG. 1 ; 
           [0011]      FIG. 2   b  is a second cross sectional view of the air stop valve of  FIG. 1 ; 
           [0012]      FIG. 3  is a side view and front view of the paddle of the valve; 
           [0013]      FIG. 4   a  is a first cross sectional view of an alternate embodiment of the air stop valve; 
           [0014]      FIG. 4   b  is a second cross sectional view of the alternate embodiment of the air stop vavle; 
           [0015]      FIG. 5  is a side view and front view of the paddle of the alternate embodiment; 
           [0016]      FIG. 6   a  is a first cross sectional view of another alternate embodiment of the valve; 
           [0017]      FIG. 6   b  is a second cross sectional view of the alternate embodiment of  FIG. 6 ; 
           [0018]      FIG. 7  is a schematic diagram of an air stop valve with a manual release cable; and 
           [0019]      FIG. 8  is a schematic diagram of an air stop valve with a front mounted manual release cable. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    The plumbing system as shown in  FIG. 1  illustrates a schematic diagram for a compact integrated plumbing system designed for use in a reduced foot print refrigerated/wet galley. Water is provided via a bottom fed potable water delivery system where the water supply originates from the bottom of the monument, although similar systems include water fed from above. The invention works well with either system, as well as other plumbing systems. Potable water (indicated by arrow  10 ) enters the plumbing system via a “T” valve  12  incorporating a remotely operated shut off valve. The main feed  14  supplies the water distribution/filter block  16  through a two way valve  17 , where it is filtered using a selected filtration method such as, for example, a spin on type water purification cartridges that incorporate self-venting units  18 . Preferably two or more filters  18  are used to reduce back pressure in the system and to allow airlines to select different levels of filtration, a GAINS supply line water filter  18   a  and a faucet supply line water filter  18   b.  One line  20  connected to the filter  18   a  supplies the galley insert equipment (GAINS) such as coffee makers, steam ovens, etc., and the other line  22  from the filter  18   b  supplies the fresh water faucet  24 . The distribution block  16  includes a remote emergency potable water shut off valve  21  and a backflow prevention valve manual override  23  controlled by a cable  27 . 
         [0021]    The second branch of the Tee valve  12  supplies pressurized water to the compact pressure check valve  26  at a pre-defined pressure. This check valve  26  closes the valve  12  preventing drain down from the GAIN water distribution manifold  28 . The distribution manifold  28  supplies potable water via quick disconnect fittings  30 . The GAINS are connected to the manifold  28  by flexible hoses  32 . The manifold  28  also preferably incorporates self-venting devices  34  to aid the (potable water) filling process, as does the faucet  24 . Water from the faucet  24 , from GAIN drip trays  36  via condensate drainage catch pots  38 , and any condensate from galley air chiller units, is disposed of via drain line  52  to waste line  44  via Tee piece  42 . Drainage of waste water entering the sink is accomplished via a Tee piece  42  in the waste water drain line  44  and through a compact, backflow prevention device or Air Stop Valve  46 , which operates under a partial vacuum. A manual over ride is remotely connected to the distribution filter block  16 . Both the potable drain line  52  and waste water line  44  drain down into the aircraft waste water tank via line  48 . 
         [0022]    In the foregoing plumbing system, all of the waste water drains downward to the aircraft waste water tank (not shown). Filtered water is distributed from the filter  18   a  to the GAINS manifold  28  and then to the GAINS via flex hose connections  32 . The system is self-venting through various self-venting devices  34 , the water filters  18  and faucet  24 . All standing water can be quickly vented to prevent contamination of the system and comply with regulation for potable water systems. 
         [0023]      FIG. 2  illustrates multiple cross sectional views of a first embodiment of the air stop valve  46  of the present invention. The valve body  102  is divided into three main chambers, the inlet chamber  104 , transfer chamber  106 , and outlet chamber  108 . Within the body  102  is a rotary action paddle  110  that provides a water tight seal, and an anti-backflow device  112  such as a poppet valve  112  or ball valve. In normal operation, the valve  46  is held closed by a vacuum pressure on the downstream side of the system that closes the lower flap  114  of the rotary paddle  110 , which is provided by the aircraft drainage system. The rotation of the lower flap  114  against the passageway between the outlet chamber  108  and the transfer chamber  106  also closes the upper flap  116 , preventing water from passing through the valve. When the column (head) of water in the drain hose  44  reaches a sufficient pressure, the upper flap  116  of the valve  46  is forced away from its seal to open the drain and water passes through the transfer chamber  106  and out through the outlet chamber  108 . Spigots for a standard water drain waste connection are provided at the inlet  118  and outlet  120 . 
         [0024]    The upper flap  116  of the paddle  110  is preferably configured in a trapezoidal shape as shown in  FIG. 3 , which facilitates drainage by allowing water to flow past on either side in the respective chambers once the flap  116  is opened. After the water has drained through the valve  46 , the subsequent decrease in hydraulic pressure (head) will allow the vacuum below the valve to re-close the valve. In a preferred embodiment, the pivot point  122  of the paddle mechanism  110  is offset from the flap  116 , providing a weighted bias to the lower portion of the paddle that assists in closure. The upper flap  116  is preferably formed with a greater surface area than the lower flap to aid opening under pressure. Both inlet and outlet flaps  116 , 114  are preferably lined with a durable seal material  142 , although this may alternatively or additionally be fitted to the valve body  102 . 
         [0025]    In the event of a failure of the aircraft vacuum system, waste water will continue to drain through the valve  46  under the action of gravity, although the hydraulic pressure (head) required to open the valve will be greatly reduced. If a backflow surge occurs following the failure of the vacuum system (water is forced up the drain hose from the waste water tank to the valve outlet  120 ), the valve  46  is fitted with an anti-backflow prevention device in the form of a one way poppet valve  112 , shown in the open position in  FIG. 2   a  and in the closed position in  FIG. 2   b.    
         [0026]    Under normal operating conditions, the poppet valve  112  is held open by the aircraft vacuum system as shown in  FIG. 2   a . In some cases, restriction of the outflow is reduced by incorporating a bell chamber  124  around the poppet head. The valve preferably also incorporates flotation assistance in the form of a light or buoyant material or air filled cap  128  to assist in its effective closure. Oscillation of the valve during drainage also serves to counteract the possibility of seizure due to lack of use. 
         [0027]      FIG. 3  illustrates the shape and profile of the paddle  110 , including a trapezoidal upper flap  116  and a generally square bottom flap  114 . The paddle  110  pivots about a hole  130  that is sized to receive a pin. The hole  130  is offset from both the upper flap  116  and the lower flap  114 , and located closer to the upper flap  116  than the lower flap  114  in a preferred embodiment. In this configuration, the paddle  110  can be biased in the closed position which, along with the vacuum, ensures that the valve is closed under ordinary circumstances. 
         [0028]      FIGS. 4   a  and  4   b  illustrate a variation of the valve  46   a  with a secondary reverse flow poppet valve  150  fitted to the outlet flap  114  of the paddle  110 . The additional poppet  150  assists in preventing the valve from being opened by a waste water backflow in the event of a seizure or failure to seal of the primary backflow prevention device  112 . In normal operation, the poppet  150  is held closed by the aircraft vacuum system and drainage functions in the same way as detailed above. In the event of backflow, however, the secondary poppet  150  allows water to enter the outlet side of the transfer chamber  106  at a controlled rate. Due to the position of the pivot point  122  in relation to the outlet flap  114 , the waste water will not be capable of exerting the necessary pressure on the lower half of the paddle  114  in order to open valve. In addition, as the center section  152  of the paddle is not water tight, any water reaching the inlet section of the transfer chamber  106  forces the inlet flap  116  against its seal to prevent the water from reaching the inlet chamber  104 . Further, with the vacuum restored but the transfer chamber  106  full of waste water, a manual override may be required to allow the automatic drainage to be re-set.  FIG. 5  shows the paddle  110   a  with the secondary anti-backflow device  150  embedded in the lower flap  114 . Other anti-backflow devices could also be used as an alternative to the device shown. 
         [0029]      FIGS. 6   a  and  6   b  illustrate another variation of the valve  46  of the present invention with a reduced valve body  200  housing a cranked paddle  210 . The paddle  210  includes an offset upper flap, wherein the upper flap is angled with respect to a radius passing through its pivot point  225 . The paddle further comprises at least one, and preferably a plurality of fluid transfer apertures  220  on each side of the spindle  225  to allow unrestricted fluid flow through the transfer chamber  206 . The hose connections on this configuration use spigot-like connections  218  on the main body  221 , although other types of connections are available as well. The lower outlet flap  214  may also be fitted with a secondary reverse flow poppet valve  150  as shown in  FIG. 4 . However, the backflow surge will pass easily through the fluid transfer apertures  220  although it cannot progress beyond the inlet flap  216  where increased pressure will increase the sealing capability. Also, the through mounting hole  235  is shown on either side of the valve body. The primary anti-backflow protection is provided by a captive ball float anti-backflow device  250 . This variation has the advantage of simplicity and reliability, since there is a reduced opportunity for becoming jammed or seizing. The ball float device  250 , which benefits from a weight reduction, rests on a support ring  252  and seals against a wide seat  254  within a bell chamber  124  that allows flow around the sides of the ball  250 . In normal operation, the ball  250  rests on its support ring  252 , remaining static as a result of the vacuum (suction) at the waste water hose outlet connection. In the event of a loss of vacuum and a backflow surge, the ball  250  is forced against its seat  254  thereby preventing water from entering the outlet chamber  108  of the valve. As with the previously discussed examples, a secondary reverse flow poppet valve may be fitted to the outlet flap. 
         [0030]      FIG. 7  illustrates a version of a manual release mechanism attached to the paddle spindle  225  of the valve. The release mechanism comprises a cable  260 , a cable mounting  262 , an actuating lever  264 , and spindle boss  252 . In this design, the mechanism is mounted on the front face of the valve. If the valve fails to operate automatically for any reason, the manual release mechanism may be operated manually by pulling the emergency release control which is integrated into the water distribution/filter block  16  located in the service area at the top of the galley.  FIG. 8  illustrates a second version of a manual release mechanism attached to the paddle spindle  225  of the valve, mounted on the side of the valve. The side mounting reduces the physical depth that the valve needs to occupy. If the valve fails to operate automatically, it can be released as set forth above in Example 5. 
         [0031]    The present invention has many benefits over the prior art. Namely, the depth foot print of the valve of the present invention is significantly reduced as compared with traditional valves, allowing installation in confined spaces. The valve of the present invention also operates on a completely different principal to existing devices, by using a rotating paddle design, while maintaining the functional requirement required by the aircraft manufacturers. This ensures that the valve inhibits water backflow by a combination of the flaps, paddle and paddle pivot point design. Further, the valve may be fitted with primary and secondary mechanical anti-backflow devices, or a simple ball float valve, or a combination of such, as required. In a preferred embodiment, the primary poppet anti-backflow device is float assisted, with the resulting oscillation caused during drain down of waste water keeping the valve free and less prone to sticking. The valve can be made economically, with as few as two moving parts and constructed entirely from non-metallic materials. The valve of the present invention can include up to three stages of anti-backflow protection. Finally, the valve has the flexibility of alternative locations for the emergency manual release mechanism. 
         [0032]    It will become apparent from the foregoing descriptions that while particular forms of the invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.