Abstract:
A fire suppression system adapted for use in a lavatory of an aircraft. The system includes a water supply coupled to one or more fluid discharge nozzles via one or more fluid flow lines. A pressure source in communication with the fluid flow lines provides pressure to assist in supplying a pressurized flow of fluid through the flow line(s) to the nozzles(s). The fire suppression system creates a spray of water capable of suppressing fires within a waste container area or within the entire lavatory area. Heat sensitive valves enable the system to automatically detect the start of a fire. Furthermore, the system is capable of using the potable water supply of the aircraft or it can be self-contained with its own water supply reservoir. If self-contained, the system includes a pressurized fluid source to assist in supplying water to the discharge nozzle(s).

Description:
FIELD OF THE INVENTION 
   The present invention relates to fire suppression systems. More particularly, the present invention relates to water based fire suppression systems on aircraft. 
   BACKGROUND OF THE INVENTION 
   It is generally known to include a fire suppression system in certain portions of aircraft, in particular lavatories and the waste containers within the lavatories. One fire suppression system includes a canister filled with pressurized Halon. Such Halon systems, however, are no longer desirable for fire suppression. Also, any chemical fire suppressant which is pressurized within a canister includes these similar disadvantages. 
   One disadvantage of the pressurized chemical systems is that the only way to determine when such a system has been discharged or is leaking is to dismantle it and weigh the bottle holding the pressurized chemical to determine if the amount present is within acceptable ranges. This requires that the system is substantially dismantled and parts of it are removed from the aircraft itself. Thus, a large amount of labor and time is required to ensure that such systems remain within acceptable operating ranges. 
   Another disadvantage is when the pressurized chemical fire suppression system has been discharged, the bottle holding the pressurized chemical must be replaced. These systems do not allow easy recharging of the pressurized chemical to reuse the system since they must be sent to the manufacturer for recharge. Furthermore, other portions of the system, including the nozzles and lines, may also need to be replaced after only one discharge of the fire suppression system. 
   Yet a further disadvantage of the pressurized chemical systems includes the chemical itself. It has become undesirable to emit such chemicals into the atmosphere and some have been banned due to ozone depletion. Therefore, it has become desirable to use a fire suppression system that does not employ a pressurized chemical such as Halon. 
   It would therefore be highly desirable to provide a fire suppression system that operates without introducing undesirable chemicals into the environment. 
   It would also be desirable to provide a fire suppression system which enables easy identification of whether the fire suppression system has been activated. Furthermore, it would be helpful if the system allowed a maintenance person to easily identify whether the system must be recharged or serviced. 
   It would be a further advantage to provide a fire suppression system which could be installed on an aircraft without requiring significant structural modifications to the aircraft 
   Still further, it would be desirable to provide a fire suppression system for any aircraft lavatory or waste container used in the lavatory, which does not require extensive machining and creation of new parts for the fire suppression system. 
   It is also desirable to provide a system that may be easily installed in the aircraft, and which forms a small modular apparatus that may be used with its own water supply or with the main water supply of the aircraft. 
   SUMMARY OF THE INVENTION 
   The present invention includes a fire suppression system especially well suited for waste containers used in lavatories and other limited access spaces of commercial and private aircraft. The present invention may also be readily adapted for fire suppression of the entire lavatory or fire suppression of the entire aircraft including cargo areas. In a preferred embodiment, the present invention includes one or more spray nozzles that respond to heat, thereby releasing water from a reservoir or from the aircraft&#39;s water system. In a second alternative embodiment, the present invention includes sensors that sense heat, flame, or smoke, and which activate the system releasing water from a reservoir or the plane&#39;s water system through one or more spray nozzles. In a third alternative embodiment, the present invention forms a self-contained system wherein either sensors or heat or flame detecting nozzles release water from a pressurized canister. 
   Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
       FIG. 1  is an environmental view of a first preferred embodiment of the present invention installed in a lavatory of an aircraft; 
       FIG. 2  is a schematic diagram of the first preferred embodiment of the present invention including eutectic valves; 
       FIG. 3  is a schematic diagram of a second alternative preferred embodiment of the present invention including sensors; 
       FIG. 4  is a schematic diagram of a third alternative preferred embodiment of the present invention including sensors and electronically controlled solenoid valves; and 
       FIG. 5  is a schematic diagram of a fourth alternative preferred embodiment of the present invention including a modular system. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
   With reference to  FIG. 1 , modern day commercial and private aircraft typically include a lavatory  10 . The lavatory  10  generally includes at least a toilet  12 , a sink  14 , and a waste container  16 . Water is generally supplied to the lavatory  10  through one or more water lines  18  that supply water to the toilet  12  and the sink  14 . In accordance with a preferred embodiment of the present invention, a fire suppression system  20  is disclosed which makes use of a portion of the water flow diverted from the water lines  18  to suppress fires in the waste container  16  or within the area of the entire lavatory  10 . 
   The system  20  includes a main valve  22  that controls the water supply to one or more fire suppression lines or conduits  24  of the fire suppression system  20 . In particular, at least one nozzle  26  in flow communication with the conduits  24  is installed above the waste container  16  to direct water into the waste container  16 . The nozzle  26  can be of several types including those that are automatic or actuated by external mechanisms. Pressurized water in the conduit  24   a  is released through the nozzle  26  when the fire suppression system  20  is activated. In this way, fires which might occur in the waste container  16  are suppressed by the release of water. Additional nozzles  26   a  coupled to conduit  24   b  may be placed throughout the lavatory area  10  itself to suppress any fires that may occur within the lavatory  10 , as a whole, as opposed to being localized to the waste container  16 . 
   With reference to  FIG. 2 , a schematic representation of the system  20  is shown. The fire suppression system  20  is tied into the total airplane potable water reservoir  28 . The main valve  22  that controls the supply of water to the water suppression system  20  is used to turn off the system  20 . A pressure source  29  is connected to the total airplane potable water reservoir  28  to ensure pressure within the total airplane potable water supply  28  and to the water lines  18 . The pressure source  29  is preferably a powered compressor or an air-bleed form the aircraft&#39;s engines. As an alternative, a pump  19  may be installed in circuit with the water lines  18  to provide down stream pressure to the water in the water lines  18  while not requiring the pressure source  29 . An optional water reservoir  30  provides additional water for immediate release onto a fire before depleting the airplane potable water reservoir  28  through the fire suppression system  20 . Though the water reservoir  30  is optional, when present it is the primary water supply for the system  20 . That is, when the water reservoir is present  30 , water is first drained from the water reservoir  30  and only secondarily drained from the total airplane potable water reservoir  28  after the reservoir  30  becomes empty. A second valve  32  provides control of water from the water reservoir  30 . The fire suppression water line  24  connects the water reservoir  30  and the water lines  18  of the aircraft to the spray nozzles  26 . Fire suppression is optionally provided to the entire lavatory area  10  by adding the additional fire suppression water lines  24   b  and additional fire suppression nozzles  26   a.    
   The fire suppression nozzles  26 , in one preferred form, include a eutectic valve which will activate the fire suppression system  20  when a fire is present. Eutectic valves melt at a particular temperature thereby opening the valve through the nozzle  26 . The eutectic valve is formed, as is well known in the art, by placing a substance which melts over at least a portion of an opening of the nozzle  26 . The eutectic substance melts at a temperature low enough so that the fire suppression system  20  is actuated before any fire within the waste container  16 , or in the lavatory overall  10 , can spread. Once the euteutic valves of the nozzle  26  melt, water can flow through the fire suppression water line  24  out through the nozzle  26 . In this way, no additional or active sensors or valves are necessary to release water from the fire suppression system  20  through the nozzles  26 . 
   During operation of the system  20 , water is first evacuated from the water reservoir  30 , with additional water coming from the total airplane potable water reservoir  28 , if needed, until the fire is extinguished. In this embodiment, the system  20  supplies water until shut off by a cabin attendant. A pressure sensor  34  is placed in the fire suppression water line  24  or a heat or smoke detector  35  is provided to send a signal to a cabin attendant alert system  36  to apprise the cabin attendants that the fire suppression system  10  has been evacuated or is activated. In this way, a cabin attendant may go to the lavatory  10  and turn off the fire suppression system  20  or otherwise evaluate the need for further assistance or fire suppression. 
   The nozzles  26   a  of the lavatory area would also be activated in the event of a fire. Again, the sensor  34  in the fire suppression water line  24  sends a signal to the cabin attendant alert system  36  thereby alerting the cabin attendant that the fire suppression system  20  has been activated. 
   With reference to  FIG. 3 , a second alternative preferred embodiment  120  of a fire suppression system according to the present invention is illustrated. Like elements corresponding to those of  FIG. 2  have been given like numerals increased by  100 . In the fire suppression system  120 , a primary water reservoir  138  provides a primary source of water to the fire suppression system  120  which is fed through water line  124  when the fire suppression system  120  is activated. A primary valve  122  allows for manual shut-off of the fire suppression system  120  by an individual to stop the fire suppression system  120  or for maintenance. A first nozzle  140  is placed adjacent or above the waste container  16 . Additionally, a first sensor  142  is placed above or adjacent the waste container  16 . The sensor  142  is able to sense heat or smoke which comes from the waste container  16  when a fire occurs in the waste container. An electronic control unit  144  is connected to the sensor  142  to receive a signal from the sensor  142 . A pressurized fluid source  146  is connected to a primary water reservoir  138  through a pressurized fluid source line  148 . The pressurized fluid source  146  comprises any suitable device having a compressible fluid to provide a rapid increase of pressure to the primary water reservoir  138  or to the fire suppression water line  124  to provide pressure to fluid traveling through the fire suppression system  120 . In one preferred embodiment, the pressurized fluid source  146  comprises a canister pressurized with liquid carbon dioxide. When opened, the carbon dioxide from the pressurized fluid source  146  quickly expands to a gas, thereby pressurizing the suppression system  120 . 
   When the sensor  142  senses heat or smoke that is produced by a fire, a signal is sent to the electronic control unit (ECU)  144 . Once the ECU  144  receives the signal, it then sends a signal to the pressurized fluid source  146  that activates the pressurized fluid source  146 . When the pressurized fluid source  146  is activated, pressure is transmitted to the water reservoir  138  through the pressurized fluid source line  148 . Once the water reservoir  138  is pressurized, water is evacuated through the water line  124  and out the nozzle  140 . Before the water from the reservoir  138  is evacuated, the fire suppression water lines  124   a  are dry. Alternatively, a check valve  150  may be installed in the water lines  124   a  which is held closed until water pressurized by the pressurized fluid source  146  is applied. Once the primary water reservoir  138  is emptied, if additional water is needed, water from a potable water reservoir  128  runs through a valve  122 , which is normally open, through the airplane water lines  118  and through the fire suppression water line  124 . Pressure is provided to the airplane water lines  118  through the pressure source  129 . Furthermore, when the electronic control unit  144  receives a signal from the sensor  142 , it also in turn sends a signal to the cabin attendant system  136  to apprise a cabin attendant that the fire suppression system  120  has been activated. 
   In addition, water may be applied to the entire lavatory area  10  through additional nozzles  126   a  which receives water from a water line  124   a  in communication with water line  124 , and an additional sensor  142   a  installed to sense a fire that may occur within the lavatory area as a whole. The additional sensor  142   a  acts in a similar way as the sensor  142  to send a signal to the electronic control unit  144  to activate the pressurized fluid source  146 . Also, the fire suppression water lines  124   b  are dry before the pressurized fluid source  146  is activated or a check valve  150   a  holds the lines  124   b  closed until the water is pressurized by the pressurized fluid source  146 . Additionally, the electronic control unit  144  sends a signal to the cabin attendant system  136  to apprise a cabin attendant that the fire suppression system  120  has been activated. Water which is released from the primary water reservoir  138 , travels through the nozzle  140  to extinguish any fire that has occurred in the waste container  16 . The nozzles  140  include a valve which is pressure sensitive and which opens when pressurized. Water from the airplane potable water reservoir  128  continues to run through the fire suppression water line  124  and feed the nozzles  140  until the system  120  is turned off by the cabin attendant. 
   With reference to  FIG. 4 , a third alternative preferred embodiment  220  of a fire suppression system according to the present invention is illustrated. Again, elements in common with those of the embodiment of  FIGS. 1 and 2  are given like numerals increased by  200 . Water for the fire suppression system  220  is provided from an airplane potable water reservoir  228  through airplane water lines  218  and from a water reservoir  230 . Pressure is provided to water used by the fire suppression system  220  through an external pressure source  229 . Sensor  244 , which is sensitive to either smoke or heat, or both, is placed near the waste container  16 . An electronic control unit  246  receives signals from the sensor  244 . Solenoid valves  248  are placed in the conduit water lines  224  which are opened and closed by the electronic control unit  246 . The electronic control unit  246  is also able to send a signal to a cabin attendant alert system  236 . Water flows from the reservoir  230  through the conduit water lines  224  and through a nozzle  250  which allows water to be applied to the waste container  16 . 
   The sensor  244  sends a signal to the electronic control unit  246  to indicate that a fire is occurring within the waste container  16 . Upon receiving this signal, the electronic control unit  246  sends a signal to a solenoid valve  248  to open the valve  248  to allow water to flow through the fire suppression water line  224  to the nozzle  250 . Furthermore, the electronic control unit  246  preferably sends a signal to a cabin attendant alert system  236  to indicate that the system  220  has been activated. The electronic control unit  246  may be programmed to allow water to flow through the system  220  continuously until shut off by an attendant. Alternatively, the electronic control unit  246  may be programmed to shut off the solenoid valve  248  when the sensor  244  no longer senses heat or smoke. Again, additional nozzles  250   a  allow water from the fire suppression system  220  to be introduced into the entire lavatory area  10  via a water line  244   a  in communication with water line  224 . A sensor  244   a  sends a signal to the electronic control unit  246  that heat or smoke has been detected from the lavatory area  10 . The electronic control unit  246  then opens the solenoid valve  248   a  to allow water to be supplied through the additional fire suppression water lines  224   a  to the nozzles  250   a . Again, a signal is sent to the cabin attendant alert system  236  to ensure that the cabin attendants know that the fire suppression system  220  has been activated and to alert them that further attention may be needed. 
   With reference to  FIG. 5 , a fourth alternative preferred embodiment  320  of a fire suppression system according to the present invention is illustrated. The fire suppression system  320  comprises a modular system that acts independently of the airplane water supply. A pressurized fluid source  352  provides pressure to force water from a water reservoir  354  through one or more of the fire suppression water lines  356  to a nozzle  358 . The fire suppression to system  320  may include nozzles, sensors, and control units as described in the previous embodiments. In particular, a sensor  360  is included to sense heat or smoke from the waste container  16  which signals the cabin alert system  336  to indicate a fire is occurring. The nozzle  358  may include a eutectic valve as described in the first preferred embodiment  20 . Therefore, when a fire occurs within the waste container  16 , the eutectic substance would melt opening the nozzle  358  to allow water to be discharged from the reservoir  354 . The pressure provided by the pressurized fluid source  352  automatically forces water through the fire suppression water lines  356  when the eutectic valve of the nozzle  358  is opened. A pressure gauge  360  provides a visual indication that a suitable pressure exists within the pressurized fluid source  352 . A valve  362  allows easy refilling of the pressurized fluid source  352  when necessary. It is to be understood that the system  320  may also include sensors and solenoid valves to actuate the pressurized fluid source  352  as described in the previous embodiments. Furthermore, the water reservoir  354  may be formed of a clear material so that a flight attendant or technician may easily determine whether any water needs to be added to the water reservoir  354 . 
   It is to be understood that any of the preferred embodiments described herein may be used with little or no modification to provide fire suppression to the entire fuselage of an aircraft. To this end, additional fire suppression water lines and nozzles may be installed throughout the aircraft to provide water to suitably positioned discharge nozzles which can spray water over a desired interior area of the aircraft. In this way, the presently disclosed invention may be expanded to suppress fires throughout an aircraft or may be installed simply to suppress fires with an area as small as a waste container in the lavatory. In particular, nozzles may be installed to create an optimal spray of water depending upon the application. Furthermore, the sensors of the present invention may detect particles from smoke or include infra-red sensors to detect a heat source such as a flame. 
   The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.