Patent Description:
For the protection of aircraft engine, auxiliary power units (APU) and cargo compartments use Halon <NUM> as the fire suppressant. Many of the currently used vaporizing liquids (FICs and FICs blends of HFCs, fluoroketone FK-<NUM>. <NUM>, fluoroolefins) may be unsuitable as they have relatively high boiling points than Halon <NUM> and may not disperse as efficiently particularly at low temperatures. A fire suppression system for an aircraft having a compound discharge nozzle is known from <CIT> for example.

The present invention provides a fire suppressant system for an aircraft as claimed in claim <NUM>.

In addition to the above disclosed aspect, the first nozzle head may be disposed on a first centerline and the second nozzle head is disposed on a second centerline, wherein the first centerline and the second centerline are skewed relative to one another.

In addition to one or more of the above disclosed aspects or as an alternate the first nozzle head and the second nozzle head may be movable to change an orientation of the first centerline and the second centerline.

In addition to one or more of the above disclosed aspects or as an alternate the third nozzle head may be disposed on a third centerline that is skewed relative to the first centerline and the second centerline.

In addition to one or more of the above disclosed aspects or as an alternate the third nozzle head may be movable to change an orientation of the third centerline.

In addition to one or more of the above disclosed aspects or as an alternate the one or more predetermined locations may include a forward cargo bay and an aft cargo bay; the discharge nozzle is a forward discharge nozzle connected to a forward end of the tubing system; the system includes an aft discharge nozzle disposed in the aft cargo bay and connected to an aft end of the tubing system for delivering the fire suppressant to the aft cargo bay; and the source of the fire suppressant includes one or more bottles connected to the tubing system intermediate the forward end and the aft end of the tubing system.

In addition to one or more of the above disclosed aspects or as an alternate the fire suppressant may be a mixture one of: HFC-<NUM> and CF3H; HFC-<NUM> and CF3CF2H; HFC-227ea and CF3CFHCF3; Novec <NUM> and CF3CF2C=OCF(CF3)<NUM>; and Solstice, HCFO-1233zd(E) and CF3CH=CClH.

Further disclosed is an aircraft comprising: a fire suppressant system that includes one or more of the above disclosed aspects.

In addition to one or more of the above disclosed aspects or as an alternate the one or more predetermined locations may include a forward cargo bay and an aft cargo bay; the discharge nozzle is a forward discharge nozzle connected to a forward end of the tubing system; the system includes an aft discharge nozzle disposed in the aft cargo bay and connected to an aft end of the tubing system for delivering the fire suppressant to the aft cargo bay; the source of the fire suppressant includes one or more bottles connected to the tubing system intermediate the forward end and the aft end of the tubing system.

The present invention also provides a method of fire suppressing a fire in one or more predetermined locations of an aircraft as claimed in claim <NUM>.

In addition to one or more of the above disclosed aspects or as an alternate distributing the fire suppressant may comprise distributing the fire suppressant from the first nozzle head along a first discharge path and from the second nozzle head along a second discharge path, wherein the first discharge path and the second discharge path are skewed relative to one another.

In addition to one or more of the above disclosed aspects or as an alternate distributing the fire suppressant may comprise distributing the fire suppressant from the third nozzle head along a third discharge path, wherein the first discharge path, the second discharge path and the third discharge path are skewed relative to one another.

Turning to <FIG>, an aircraft <NUM> is illustrated that may benefit from aspects of the disclosed embodiments. The aircraft <NUM> may include a fuselage <NUM>, with a cockpit <NUM> at the forward end <NUM> and a tail <NUM> at the aft end <NUM>. The aircraft <NUM> may include a pair of wings <NUM>. Each of the wings <NUM> may have one or more engines <NUM>. Distributed between the forward end <NUM> and aft end <NUM> may be a plurality of cargo bays <NUM> including a forward cargo bay 39A and an aft cargo bay 39B. When used in the singular, cargo bay can refer to either the forward cargo bay 39A or the aft cargo bay 39B. A fire suppression system <NUM> may be included for suppressing fires in one or more predetermined locations, which may include the cargo bay <NUM>. As illustrated, the fire suppression system <NUM> may include a monitoring system <NUM>. The monitoring system <NUM> which may include a plurality of detectors <NUM> including forward detectors 46a in the forward cargo bay 39A and aft detectors 46B in the aft cargo bay 39B. Of course, the system could be included in only one of the bays.

The monitoring system <NUM> may electronically communicate with the cockpit <NUM> for the purpose of transmitting warnings when a fire is detected.

The fire suppression system <NUM> may include a plurality of fire suppressant storing canisters, otherwise referred to as a pack of bottles <NUM> (illustrated schematically in <FIG>). The pack of bottles <NUM>, which may include one or more bottles depending on demands of the fire suppression system <NUM>. The pack of bottles <NUM> are generally stored next to one of the cargo bays <NUM>. Suppressant may be discharged into the forward cargo bay 39A or aft cargo bay 39B during a fire. The probability of a cargo fire in any one of the cargo bays <NUM> is low, and the likelihood of two simultaneous fires in both cargo bays <NUM> is lower. Because of this, it is not required to have separate packs of bottles <NUM> for each of the cargo bays <NUM>. One pack of bottles <NUM> typically provides suppression capability to the cargo bays <NUM>.

<FIG> further illustrates the pack of bottles <NUM>. The pack of bottles <NUM> are discharged through a tubing system <NUM> that distributes suppressant to a plurality of discharge nozzles <NUM>. The plurality of discharge nozzles <NUM> includes for example a forward discharge nozzle 100A in the forward cargo bay 39A and an aft discharge nozzle 100B in the aft cargo by 39B. The discharge nozzles <NUM> have a same configuration so the forward discharge nozzle 100A may be generally referred to herein as a discharge nozzle.

The tubing system <NUM> may include a plurality of flow valves <NUM>. For example a forward flow valve 56A and an aft flow valve 56B may be provided in the tubing system <NUM>. The fire suppression system <NUM> may operate to provide an initial high-rate knockdown discharge of fire suppressant during a fire, followed by a lowrate metered discharge of fire suppressant. This is intended to keep a fire suppressed for continued safe flight and landing at the nearest suitable airport. Thus, between the flow valves <NUM>, a first bottle <NUM> of the bottles <NUM> is configured as a high-rate discharge bottle and is initially discharged to knock down flames and suppresses a fire. The first bottle <NUM> of the bottles <NUM> may include, for example, a minimum of five (<NUM>) percent concentration by volume of Halon, for example Halon <NUM>.

A second discharge of fire suppressant comes from a second bottle <NUM> of the bottles <NUM>. Flow from the second bottle <NUM> of the bottles <NUM> is metered by a flow regulator <NUM>. That is, the second bottle <NUM> of the bottles <NUM> is configured as lowrate metered discharge bottle. The second discharge occurs at the same time as the initial knockdown discharge or after a predetermined time delay. The second discharge provides, for example, a steady-state suppressant flow rate. For example, when the bottles are filled with Halon, the flow rate will maintain a Halon concentrations of, for example, three (<NUM>) percent for a specified duration.

A challenge with discharging suppressant in the cargo bays <NUM> is that suppressant may not reach an entirely of an area impacted by fire. For example, a suppressant throw by the discharge nozzles <NUM> may not be far enough, or may be too far relative to a location of a fire.

Turning to <FIG> and <FIG>, in view of the identified challenges, and according to the disclosed embodiments, the discharge nozzles <NUM> are configured as compound nozzles. As indicated, the forward discharge nozzle 100A is representative of the discharge nozzles <NUM> and it includes a plurality of nozzle heads <NUM>. A first nozzle head 110A has a first flow area defined by a first diameter opening D1 (<FIG>). A second nozzle head 110B has a second flow area defined by a second diameter opening D2 (<FIG>). A third nozzle head 110C has a third flow area defined by a third diameter opening D3 (<FIG>). The first diameter opening D1 is smaller than the second diameter opening D2. The second diameter opening D2 is smaller than the third diameter opening D3. Of course the utilization of additional nozzles with additional diameter openings is within the scope of the disclosure.

The different diameters are selected to provide a predetermined throw for suppressant that is disbursed by the forward discharge nozzle 100A. A droplet size generated by D1 is <NUM> microns or less, a droplet size generated by D2 is <NUM>-<NUM> microns and a droplet size generated by D3 is <NUM> to <NUM> microns. The smaller diameter for the first nozzle head 110A compared with the other ones of the nozzle heads <NUM> will result in a more rapid atomization of fire suppressant from the first nozzle head 110A than the other ones of the nozzle heads <NUM>. Similarly, the smaller diameter for the second nozzle head 110B compared with the third nozzle head 110C will result in a more rapid atomization of fire suppressant from the second nozzle head 110B than the third nozzle head 110C. Nonatomized suppressant throws further than atomized suppressant. Therefore the configuration of the forward discharge nozzle 100A in <FIG> and <FIG> throws suppressant to a plurality of distances relative to the forward discharge nozzle 100A, i.e., near, far and intermediated distances.

The nozzle heads <NUM> are disposed along respective centerlines <NUM>. This includes a first centerline 115A for the first nozzle head 110A, a second centerline 115B for the second nozzle head 110B and a third centerline 115C for the third nozzle head 110C. As a result the fire suppressant is discharged along respective discharge paths <NUM>. This includes a first discharge path 120A for suppressant discharged from the first nozzle head 110A, a second discharge path 120B for suppressant discharged from the second nozzle head 110B and a third discharge path 120C for suppressant discharged from the third nozzle head 110C.

In the embodiment illustrated in <FIG>, the centerlines <NUM>, and as a result the discharge paths <NUM>, are parallel. As illustrated in <FIG>, the centerlines <NUM>, and as a result the discharge paths <NUM>, are skewed relative to one another. That is, the discharge paths <NUM> are non-parallel. Thus, in the embodiment illustrated in <FIG>, suppressant distributed from the nozzle heads <NUM> will be respectively distributed along mutually skewed discharge paths <NUM>.

In one embodiment the nozzle heads <NUM> are adjustable, to thereby change an orientation of the centerlines <NUM>, and, accordingly, an orientation of the discharge paths <NUM>. This configuration provides an array of fire suppressant distribution patterns. The distribution patterns may be selected based on the load distribution in the cargo bays <NUM> or any reconfiguration of the cargo bay <NUM>.

The embodiments utilize a mixture of sizings of nozzle heads <NUM> in a discharge nozzles <NUM> are that configured as a compound nozzles. The disclosed configuration may be used with pure suppressants for example or blends. Examples of blending agents include: (<NUM>) HFC-<NUM>, CF3H; (<NUM>) HFC-<NUM> CF3CF2H; (<NUM>) HFC-227ea, CF3CFHCF3; (<NUM>) Novec <NUM> CF3CF2C=OCF(CF3)<NUM>; (<NUM>) Solstice, HCFO-1233zd(E), CF3CH=CClH; and (<NUM>) Other HCFOs or HFOs. Efficient agent vaporization and distribution provides a more efficient design of the fire protection system <NUM> by optimizing agent weight and volume to generate desired agent concentrations. Thus, depending on a blend of selected sizes of the nozzle heads <NUM>, it is possible to circumvent the identified challenges associated with known systems and derive a solution that meets air-framer's needs.

Turning to <FIG>, a flow chart shows a method of distributing fire suppressant to cargo bays <NUM>, for example the forward cargo bay 39A, in an aircraft <NUM>. As shown in block <NUM>, the method includes transporting the fire suppressant in a tubing system <NUM> from a suppressant source, i.e., the pack of bottles <NUM>, to a forward discharge nozzle 100A in the forward cargo bay 39A. As shown in block <NUM> the method includes distributing the fire suppressant from the forward discharge nozzle 100A into the forward cargo bay 39A, through a first nozzle head 110A having a first diameter D1, a second nozzle head 110B having a second diameter D2 that differs from the first diameter D1, and a third nozzle head 110C having a third diameter D3 that differs from the first diameter D1 and the second diameter D2. As shown in block <NUM> the method includes distributing the fire suppressant from the first nozzle head 110A along a first discharge path 120A, from the second nozzle head 110B along a second discharge path 120B, and from the third nozzle head 110C along a third discharge path 120C. The first discharge path 120A, the second discharge path 120B and the third discharge path 120C are skewed relative to one another.

Claim 1:
A fire suppressant system (<NUM>) for an aircraft (<NUM>) comprising:
a source of a fire suppressant (<NUM>);
a tubing system (<NUM>) for delivering the fire suppressant to one or more predetermined locations; and
a discharge nozzle (<NUM>) disposed in the one or more predetermined locations, the discharge nozzle (<NUM>) connected to the tubing system (<NUM>), and being configured to distribute the fire suppressant in the one or more predetermined locations during a fire,
the discharge nozzle (<NUM>) including a first nozzle head (110A)with a first opening (D1) having a first flow area and a second nozzle head (110B) with a second opening (D2) having a second flow area that differs from the first flow area, and
a third nozzle head (110C) with a third opening (D3) having a third flow area that differs from the first flow area and the second flow area,
wherein:
the first opening (D1) is smaller than the second opening (D2), and the second opening (D2) is smaller than the third opening (D3), so that a the first opening (D1) is configured to generate a droplet size of <NUM> microns or less, the second opening (D2) is configured to generate a droplet size of <NUM>-<NUM> microns and the third opening (D3) is configured to generate a droplet size of <NUM> to <NUM> microns.