Abstract:
An aircraft trash management system including a, trash bag, a trash compactor, a modified bilge drain valve and an improved control valve assembly. The trash bag has a porous bottom and non-porous sides. The bottom of the trash bag is impregnated with a non-leaching antibacterial and a leaching enzyme. The trash compactor has two chambers separated by a movable wall. One chamber is the compacting chamber and is sealable from ambient cabin pressure and the other chamber is always open to cabin pressure. The bottom of the compacting chamber is provided with an upper drain and a lower drain. The modified bilge valve provides a fluid path to the atmosphere outside the aircraft. The inventor also relates to a central valve assembly for simultaneous compacting and draining.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a trash collection receptacle and a trash compactor particularly adapted for use in an aircraft. 
   2. Brief Description of the Prior Art 
   Capacity of passenger aircraft has increased dramatically over the past thirty years. It is not unusual for some airlines to be equipped to carry a passenger load in excess of five hundred persons, whereas loads in excess of one hundred passengers are a common occurrence, with perhaps as many as thousands of flights a day throughout this country and the rest of the world. 
   While many flights are short in duration, three or four hours or less, in which only snacks may be served, many flights are of sufficient duration as to require the service of at least one meal to each of the passengers. On other flights, for example, coast-to-coast, and international flights, two or more meals and/or snacks may be served. Much of the equipment used in meal service is made from paper or plastic material designed to be discarded as part of the trash, together with left over food stuffs. 
   On some flights, this trash is generally collected in plastic bags and stored aboard the aircraft until the flight terminates at which time the bags are removed for disposal. These bags are bulky and at the very least they represent an inconvenience to the crew and passengers as they become filled and their numbers accumulate during the course of the flight. 
   On lengthy flights, with large passenger loads, especially when there are multiple servings of food, the problem does become acute, so much so that it is not unusual for one or more of the multiple lavatories aboard to be used as rooms for the storage of the bags. This results in further inconvenience for those aboard the aircraft. 
   One solution to the trash storage problem which has been gaining in acceptance, is that of the installation of a trash compactor onboard the aircraft. To be used onboard an aircraft, however, the trash compactor must be small in size and relatively light in weight, and must meet stringent Federal Aviation Administration (FAA) safety and airworthiness regulations, as well as airframe manufacturer and airline industry requirements. Exemplary of trash compactors specifically designed and intended for use on aircraft are those disclosed in U.S. Pat. Nos. 3,835,767, 3,835,769, 3,899,967, 4,070,962, 4,183,295, 4,444,099, 4,620,479, 4,680,808, 4,700,623, 4,719,852, 4,729,303, and 5,465,660. Some of the prior art compactors use water pressure to effect compacting, others use springs, air pressure, hydraulic fluid, or other means. 
   My prior U.S. Pat. No. 4,444,099 discloses an airborne refuse compactor in which the pressure difference between cabin pressure and outside atmospheric pressure is utilized to energize the device and to withdraw, during compaction, the liquid content of the refuse through a self-closing valve which is part of and penetrates the wall of the refuse receptacle. The liquid is discharged into the rarefied atmosphere during flight, where it evaporates. The receptacle employed in the compactor is of generally rigid construction in order to conform to the cavity within the compactor and to accommodate the piston and the one-way valve. Thus the receptacles must occupy valuable space aboard the aircraft prior to use in the compactor or be made collapsible at a significant cost. 
   In addition, the compactor employs a piston or platen filling the entire cross section of the receptacle to compress the refuse within. After a series of cycles, when the receptacle is filled the latter is removed. A single piston is not capable of adjusting readily to different kinds or densities of the trash over its area with the result that there is sometimes a tendency for the piston to become cocked. Moreover, the single piston along with its actuating structure is complicated and heavy and contributes significantly to the weight of the compactor. 
   My prior U.S. Pat. No. 4,680,808 discloses a compactor receptacle which improves the performance and usefulness of airborne refuse compactors. The receptacle is far less expensive to manufacture, lacks the need for a valve for the withdrawal of the liquid from the refuse, and can be collapsed completely prior to use, thus occupying very little valuable space. 
   According to a preferred embodiment the receptacle consists of a bag made from a porous fabric of a hydrophobic or non-wetting material such as nylon and is provided with means to suspend it with the open end up in the compactor. Extended metal arms are provided adjacent the open end of the bag to facilitate insertion and removal of the bag and to guide the sides of the opening during compaction. 
   The bag resists leakage of the liquid in the trash as the bag is being filled due to the non-wetting characteristics of the fibers, while during compaction the liquid will leak out of the bag and collect in the bottom of the compactor where it can be carried away so that when the bag is full and ready to be removed and discarded the trash is largely free of liquid thereby reducing the effort required in disposing of the trash. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the invention to improve upon the trash bag and trash compactor of my previous patents. 
   Accordingly, the present invention provides an improved trash bag for use in an aircraft trash compactor, an improved compactor and a new valve for powering the compactor. 
   The trash bag has a four piece construction which is assembled, folded and heat sealed. The two major pieces are made of non-porous polyethylene and define the sides of the bag. The third piece which forms the bottom of the polyethylene bag is perforated and covered with the fourth piece. The fourth piece is made of high strength, controlled porosity, non-woven polypropylene which is treated with two agents prior to heat sealing it, preferably heat sealing its peripheral border or rim to the inner surface of the bottom of the bag. The agents include a non-leaching antimicrobial and a leaching enzyme. The purpose of the antimicrobial agent is to provide a barrier to disease causing bacteria which might otherwise exit the bag with the liquid trash as the liquid is removed during compaction. The purpose of the enzyme is to react with and break-down plaque which often builds up in the grey water line of an aircraft. The grey water line is the vacuum drain system which drains water from sinks throughout the aircraft. Grey water is released into the atmosphere during flight and evaporates.) 
   The upper portion of the bag is fabricated with tails and flaps such that a handle is formed for lifting the bag when it is removed from the compactor. Tunnels are formed by two heat seals and are used to hang the bag on support arms inside the compactor. Flaps are provided at either end of the top of the bag to close the bag when full of compacted trash prior to removal from the compactor. Tails are tied in a knot over the flaps and form a handle to lift the bag from the compactor and carry it off the aircraft. According to the presently preferred embodiment, the top of the bag beneath the handle is provided with a ZIPLOCK closure. 
   Since the upper portion of the bag is non-porous and only the bottom is porous, all of the liquid exits the bag through the bottom which, when used with the compactor of the invention, is adjacent the liquid exit port of the compactor. 
   According to the presently preferred embodiment, the bottom of the bag is heat sealed approximately one half inch from the bottom folds. This increases the strength of the bag. 
   The compactor according to the invention is a low pressure pneumatic device which compacts solids and extracts and discharges liquid from the trash. It requires no electricity, electronics or hydraulics. Two simple plumbing connections to existing on-board systems are all that is required to operate the compactor. A single three position control valve is used to select off, compact, and drain modes of operation. The trash compactor cabinet is dimensionally similar to a conventional aircraft waste cart. However, since compaction is produced by the action of differential pressure over the cross-sectional area of an internally mounted bellows, the construction is designed to withstand both the reduced internal pressure as well as large compaction forces. 
   The bellows is held in a non-compacted position by four coil springs and the interior and exterior of the bellows exposed to cabin pressure. One end of the bellows is attached and sealed to the compactor crusher plate. The other end of the bellows is attached and sealed to the compactor side wall which has a central opening in it. This allows cabin pressure to act on both the inner and outer bellows working areas when the compactor control valve is in the off position. When the compactor control valve is in the compact or drain positions, cabin pressure acts on the inner working area while outside atmospheric pressure acts on the outer working area of the bellows. There is one valved outlet at the bottom of the compacting chamber and another above the bottom of the chamber. The lower outlet is selectively coupled to the grey water disposal system of the aircraft and the upper outlet is selectively coupled to a modified bilge drain valve in the belly of the aircraft. 
   According to the invention, the modified bilge drain valve supplies power to the compactor via differential pressure. The valve assembly includes a sleeve containing a plunger which is held in an open position by a spring. Differential pressure acting across an annular area overcomes the spring and moves the plunger to the closed position when altitude increases to approximately 5,000 feet, at which there is approximately two psi difference between cabin and outside pressure. According to the invention, the plunger is hollow. The interior of the plunger is exposed to the outside atmosphere and selectively coupled to the upper outlet of the compacting chamber. 
   The compactor is operated with a three position valve. When the valve is moved from the first (off) position to the second (compact) position, the upper outlet of the compacting chamber is coupled to the interior of the plunger of the modified bilge drain valve. At altitude, this causes the air inside the compacting chamber to exit the chamber to the outside atmosphere. Due to the pressure differential between atmospheric pressure and cabin pressure, the compactor crusher plate is moved against the springs and compacts the trash in the bag in the compacting chamber against the opposite wall of the compactor cabinet. When the valve is moved back to the off position the upper outlet is coupled to cabin pressure, the springs pull the plate back and the compacted trash falls to the bottom of the bag. When the valve is moved to the third (drain) position, the bottom of the compacting chamber is coupled to the aircraft grey water system and the liquid at the bottom of the chamber is drained from the compactor. 
   INCORPORATION BY REFERENCE 
   The complete disclosures of all of the above listed patents are hereby incorporated by reference herein. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view of one of the two major pieces of the trash receptacle; 
       FIG. 2  is a transparent plan view of the bottom of the trash receptacle; 
       FIG. 3  is a side view of the bottom of the trash receptacle, illustrating two layers; 
       FIG. 4  is a plan view of the four pieces partially assembled; 
       FIG. 5  is a side view of the four pieces partially assembled; 
       FIG. 6  is an upside down view of the trash receptacle fully assembled; 
       FIG. 7  is a section taken along the line  7 — 7  in  FIG. 6 ; 
       FIG. 8  is a perspective view of the receptacle fully assembled; 
       FIG. 9  is a view similar to  FIG. 8  with the flaps closed and tied; 
       FIG. 10  is a perspective view of an embodiment of the receptacle illustrating draw strings and ZIPLOCK closure; 
       FIG. 11  is a broken cross sectional view of the receptacle illustrating the double layered bottom; 
       FIG. 12  is an end view of the front of the compactor of the invention; 
       FIG. 13  is a top view of the compactor; 
       FIG. 14  is a side view of the compactor; 
       FIGS. 15   a  and  15   b  illustrate the section taken along line  15 — 15  in  FIG. 14 ; 
       FIG. 16  is a broken section taken along the line  16 — 16  in  FIG. 12 ; 
       FIG. 17  is a broken section taken along line  17 — 17  in  FIG. 12 ; 
       FIG. 18  is a side elevation view of a modified bilge drain valve according to the invention; 
       FIG. 19  is a section taken along line  19 — 19  in  FIG. 18  and showing as portion of aircraft fuselage; 
       FIG. 20  is a schematic diagram illustrating all of the components of the invention; and 
       FIG. 21  is a schematic diagram similar to  FIG. 20  illustrating an alternate embodiment of the control valve assembly. 
   

   DETAILED DESCRIPTION 
   Turning now to  FIGS. 1–11 , a trash bag  10  according to the invention includes three sheets of non-porous polyethylene which is folded and heat sealed to form six sides  12 ,  14 ,  16 ,  18 ,  20 ,  22 , and a bottom  24 . The bottom  24  is perforated so that liquid may drain from the bag. 
   According to the preferred embodiment, the perforated bottom  24  is covered with the second piece  32  made of high strength, controlled porosity, non-woven polypropylene which is treated with two agents prior to heat sealing it to the inner surface  24  of the bag  10 . Second piece  32  is preferably provided with a heat-sealable border  33  by which it is heat-sealed to the minor surface  24  of bag  10 . The agents include a non-leaching antimicrobial and a leaching enzyme. The purpose of the antimicrobial agent is to provide a barrier to disease causing bacteria which might otherwise exit the bag with the liquid trash as the liquid is removed during compaction. The purpose of the enzyme is to react with and break down plaque which often builds up in the aircraft grey water line through which the liquid trash is expelled. 
   The upper portion of the bag  10  is fabricated with tails and flaps such that a handle is formed for lifting the bag when it is removed from the compactor. Tunnels  12   a ,  14   a  are formed by two heat seals and are used to hang the bag on support arms inside the compactor described below with reference to  FIGS. 12–17 . Flaps ( 16   a ,  18   a ,  20   a ,  22   a ) are provided at opposite ends of the top of the bag to close the bag when full of compacted trash prior to removal from the compactor. Tails (at the top of panels  14  and  20 ) are tied in a knot over the flaps as shown in  FIG. 9  and form a handle to lift the bag from the compactor and carry it off the aircraft. 
   According to one embodiment, as shown in  FIG. 10 , the top of the bag beneath the handle is provided with a ZIPLOCK closure  28 ,  30 . 
   Since the upper portion of the bag is non-porous and only the bottom is porous, all of the liquid exits the bag through the bottom which, when used with the compactor of the invention, is adjacent the liquid exit port of the compactor described in detail below with reference to  FIGS. 12–17 . According to the presently preferred embodiment, the bottom of the bag is heat sealed approximately one-half inch from the bottom folds. This increases the strength of the bag. 
   Turning now to  FIGS. 12–17  and  20  the compactor  100  according to the invention is a rectangular box which is substantially the same size as a standard food service cart. The box defines two compartments  102 ,  104  separated from each other by a movable wall (crusher plate)  106  (seen best in  FIGS. 15   a ,  15   b ). The compartment  104  contains a bellows  108  the interior of which is open to cabin atmosphere via the large opening  110  on one side of the compactor and is attached to the movable wall (crusher plate)  106 . A door  112  with a locking handle  114  allows access to the compartment  102 . The opening  110  is a peripheral slot 1/32 inch wide to prevent mice or other pests associated with food service from entering the compartment  104 . 
   As seen best in  FIGS. 15   a  and  15   b , springs  116 ,  118  are attached to the movable wall (crusher plate)  106  and to the side wall  120  of the compactor. The springs hold the movable wall (crusher plate)  106  in the position shown in the figures defining the compartment  102  dimensioned to receive the trash bags described above. 
   As seen best in  FIGS. 16 and 20 , two ports  122 ,  124  are located at the bottom of the compactor and in fluid communication with compartment  102 . These ports are selectively coupled to the aircraft drain mast (grey water line) and modified bilge drain valve, respectively, via a control valve assembly  126  which is coupled by a vertical shaft (tube)  128  to a knob  130  which has a locking pin  132 . 
   As seen best in  FIG. 17 , the door  112  cooperates with a sealing gasket  134  which surrounds the opening to compartment  102 . The door handle  114  engages a latching pin  136  which is movable into and out of the latch socket  138 . The pin  136  is tapered so that as it is moved into the socket  138  the door  112  is pressed firm against the gasket  134   
   Prior to discussing the operation of the compactor, the valve  200  shown in  FIGS. 18 and 19  should be understood. The valve  200  has in inner annular flange  202  and an outer flange  204  which embrace the fuselage  2  of an aircraft. The outer flange  204  has a throughbore  208  which is in fluid communication with the annular space  206  thereby providing a fluid path from the inside of the aircraft to the outside atmosphere. A spring biased plunger  210  is movable against the spring  212  from the position shown in the figures to a position which blocks the fluid connection between the bore  208  and the annular space  206 . In a state of the art bilge drain (not shown) the plunger is solid and is moved against the spring when the difference between cabin pressure and atmospheric pressure is increased as the aircraft gains altitude. When the aircraft descends prior to landing, the valve opens and allows water which condensed inside the aircraft to drain. In medium sized aircraft there are fifty to one hundred bilge drain valves on the bottom of the fuselage. 
   According to the invention, the plunger  210  is hollow and forms a fluid path through an elbow joint  214 . Thus, when the aircraft reaches altitude, the bilge valve closes but the fluid path through the elbow  214  remains in fluid communication with the outside atmosphere. According to the presently preferred embodiment, a threaded sleeve  216  is provided and the moving parts of the valve are supplied as a replaceable cartridge accessible via the threaded sleeve. 
   Referring now to  FIG. 20 , the compactor  100  of the invention is illustrated containing a trash filled bag  10  in the compartment  102  and a schematic illustration of value assembly  126  coupled to the ports  122 ,  124 , the modified bilge valve  200  and the grey water drain mast  4 . 
   The valve assembly  126  has three positions. In the first “off” position, the upper port  122  is coupled to ambient cabin pressure and the lower port  124  is closed. When the valve is moved from the first (off) position to the second (compact) position, the upper port  122  of the compacting chamber is coupled to the elbow  214  of the modified bilge valve  200 . At altitude, this causes the air inside the compacting chamber  102  to exit the chamber to the outside atmosphere. Due to the pressure differential between atmospheric pressure and cabin pressure, the crusher plate  106  is moved against the springs  116 ,  118  and compacts the trash in the bag  10  in the compacting chamber. As this is happening, liquid trash will accumulate in the bottom of the chamber  102 . The position of the port  122  above the bottom of the chamber  102  assures that no liquid trash is allowed to exit through the bilge valve. When the valve assembly is moved back to the off position the upper port  122  is coupled to cabin pressure, the springs pull the crusher plate back and the compacted trash falls to the bottom of the bag  10 . When the valve assembly is moved to the third (drain) position, the bottom of the compacting chamber  102  is coupled via the lower port  124  to the aircraft grey water system  4  and the liquid at the bottom of the chamber is drained from the compactor. 
   Those skilled in the art will appreciate that in order for the compactor to function properly, the door  112  must seal the chamber  102  from cabin pressure. This is effected by the gasket  134  shown in  FIG. 17 . The nature of the gasket  134  is such that if any article of clothing or even the hair of the operator is between the door and the gasket, a proper seal will not be made and the compactor will not operate. 
   An alternate control valve assembly is a rotary, four port, two position direction control valve. Its functions can more easily be seen and understood by viewing  FIG. 21  which is a schematic diagram of a comparable linear four port, two position direction control valve. The two valve positions and the internal porting passages are shown. The four ports are “cab hi”, “cab lo”, “amb”, and “dm”, as shown. The valve is detented in position  1  (off), “cab hi” is connected to “amb”, and “cab lo” and “dm” blocked. By pushing on the “manual” button the valve advances from position  1  to position  2  and the detent changes its point of application from detent point  1  to point  2 . In position  2  (compact and drain), “cab hi” and “cab lo” are connected to “dm” and “amb” is blocked. 
   With the control valve assembly in position  1  (off) as shown above ambient cabin pressure is present inside the compactor and acts on both the inner and outer surfaces of the compactor bellows  108 . The net effect is zero and the return springs  116 ,  118  hold the bellows and crusher plate assembly  106  in the retracted (off) position. It is in this position that the mouth of the trash bag  10  is open and is filled with trash. Once the bag is filled the compactor door is closed and bolted. The control valve  226  is moved to Position  2  (compact and drain). This internally blocks “amb” and opens “cab hi” and “cab lo” to “dm”. The “dm” port of the control valve assembly  226  is connected to the drain mast plumbing of the aircraft and allows outside atmospheric pressure into the compactor cabinet. The volume between the inside of the compactor cabinet  100  and the outer surface of the compactor bellows  108  is exposed to this outside atmospheric pressure. The differential pressure (cabin pressure minus outside atmospheric pressure) acting over the working area of the bellows causes the bellows to extend. The bellows, which is attached to the crusher plate  106  drives the crusher plate which compacts the trash in the trash bag  10  against the compactor cabinet wall. As part of the compacting process, and by gravity, liquid in the trash falls to the bottom of the trash bag. The outside atmospheric pressure present inside the compactor cabinet sucks the liquid through the porous trash bag bottom and discharges it thru the existing aircraft gray water line to the drain mast where it is vaporized when leaving the aircraft. 
   After “compact and drain” functions have been completed valve position  1  (off) is selected. This allows “dm” to be blocked and allows the pressure acting over the bellows outer surface to rise and become equal to the cabin pressure acting over the bellows outer surface. As the differential pressure acting over the working area of the bellows approaches zero the return springs  116 ,  118  retract the bellows and the attached crusher plate  106 . The dry compacted trash in the trash bag falls to the bottom of the bag. 
   Since the differential pressure has dropped to zero the force keeping the door sealed becomes zero and the compactor door can be opened, the entire process can be repeated as many times as necessary to fill the trash bag with compacted, dry trash. 
   The alternate embodiment of the control valve assembly is simpler in design and construction. It is smaller, weighs less and is less expensive to manufacture. It is more reliable and is easier to install. It involves fewer plumbing connections and can be installed and removed quickly. 
   There have been described and illustrated herein an aircraft trash management system including a trash bag, a trash compactor, and a modified bilge drain valve. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.