ADDRESSING OPTICAL FIRING CARTRIDGE USING CHROMATIC ABERRATION

A fire protection system includes two or more fire extinguishers. Each fire extinguisher includes a housing, the housing including an extinguisher outlet and a burst disk. The burst disk is configured to retain a volume of fire suppressant material in the housing. A firing cartridge is operably connected to the housing and includes an output charge, and an ignition charge that, when detonated, causes release of the output charge to rupture the burst disk and release the volume of fire suppressant material through the extinguisher outlet. An optical fiber is configured to transmit a light signal toward the ignition charge to heat and detonate the ignition charge. A light source is operably connected to the optical fiber to selectably transmit a first light signal to selectably activate a first fire extinguisher or a second fire extinguisher of the two or more fire extinguishers.

BACKGROUND

Exemplary embodiments pertain to the art of fire protection systems, and in particular to firing mechanisms for fire extinguishers of fire protection systems.

In fire protection systems, such as those used in aircraft, fire extinguishers utilize electrical firing cartridges to puncture a burst disk in the fire extinguisher, resulting in the release of extinguishing agent from the fire extinguisher. In such systems, an electrical pulse is generated and transmitted to the firing cartridge to activate the fire extinguisher. On detection of a fire, an electrical pulse is transmitted to each fire extinguisher separately for activation of the firing cartridge.

In such systems, there is no addressing or differentiation mechanism for the selective activation of each fire extinguisher, and individual wires must be run for connection to each of the fire extinguishers. Electrical cable losses must be accounted for in such configurations, and a high current firing circuit must be designed and installed in a remote location, with high current cable wire run to each fire extinguisher.

BRIEF DESCRIPTION

In one embodiment, a fire protection system includes two or more fire extinguishers. Each fire extinguisher of the two or more fire extinguishers includes a housing, the housing including an extinguisher outlet and a burst disk. The burst disk is configured to retain a volume of fire suppressant material in the housing. A firing cartridge is operably connected to the housing. The firing cartridge includes an output charge, and an ignition charge that, when detonated, causes release of the output charge to rupture the burst disk and release the volume of fire suppressant material through the extinguisher outlet. An optical fiber is configured to transmit a light signal toward the ignition charge to heat and detonate the ignition charge, and a light source is operably connected the optical fiber. The light source is configured to selectably transmit a first light signal to activate a first fire extinguisher of the two or more fire extinguishers, or transmit a second light signal to activate a second fire extinguisher of the two or more fire extinguishers.

Additionally or alternatively, in this or other embodiments the first light signal is a first wavelength and the second light signal is a second wavelength different from the first wavelength.

Additionally or alternatively, in this or other embodiments a hub is located between the light source and the optical fiber of each fire extinguisher of the two or more fire extinguishers.

Additionally or alternatively, in this or other embodiments each fire extinguisher of the two or more fire extinguishers further includes a bridge wire located between the optical fiber and the ignition charge, the light signal configured to heat the bridge wire to detonate the ignition charge.

Additionally or alternatively, in this or other embodiments each fire extinguisher of the two or more fire extinguishers includes a lens located between the optical fiber and the bridge wire, the lens configured to converge the light signal at the bridge wire to heat the bridge wire.

Additionally or alternatively, in this or other embodiments the lens of the first fire extinguisher is positioned to converge the first light signal at the bridge wire of the first fire extinguisher, and the lens of the second fire extinguisher is positioned to converge the second light signal at the bridge wire of the second fire extinguisher.

Additionally or alternatively, in this or other embodiments the light source is a laser.

Additionally or alternatively, in this or other embodiments a sensor is operably connected to the light source. The sensor is configured to detect a fire or smoke condition to initiate operation of the light source.

Additionally or alternatively, in this or other embodiments the first light signal is configured to activate the first fire extinguisher but not activate the second fire extinguisher.

Additionally or alternatively, in this or other embodiments the first light signal is an IR wavelength and the second light signal is a blue light wavelength.

In another embodiment, a method of operating a fire protection system includes providing two or more fire extinguishers. Each fire extinguisher of the two or more fire extinguishers includes a housing, the housing including an extinguisher outlet, and a burst disk. The burst disk is configured to retain a volume of fire suppressant material in the housing. A firing cartridge is operably connected to the housing. The firing cartridge includes an output charge and an ignition charge that, when detonated, causes release of the output charge to rupture the burst disk and release the volume of fire suppressant material through the extinguisher outlet. A first light signal or a second light signal is selectably transmitted from a light source along an optical fiber toward the ignition charge of a corresponding first fire extinguisher or second fire extinguisher of the two or more fire extinguishers. The ignition charge is heated via the corresponding light signal, thereby detonating the ignition charge of the corresponding first or second fire extinguisher.

Additionally or alternatively, in this or other embodiments the first light signal is a first wavelength and the second light signal is a second wavelength different from the first wavelength.

Additionally or alternatively, in this or other embodiments the first light signal and the second light signal are transmitted to each of the two or more first extinguishers via a hub located between the light source and the optical fiber of each fire extinguisher of the two or more fire extinguishers.

Additionally or alternatively, in this or other embodiments each fire extinguisher of the two or more fire extinguishers further includes a bridge wire located between the optical fiber and the ignition charge. The light signal is configured to heat the bridge wire to detonate the ignition charge.

Additionally or alternatively, in this or other embodiments each fire extinguisher of the two or more fire extinguishers includes a lens located between the optical fiber and the bridge wire. The lens is configured to converge the light signal at the bridge wire to heat the bridge wire.

Additionally or alternatively, in this or other embodiments the lens of the first fire extinguisher is positioned to converge the first light signal at the bridge wire of the first fire extinguisher, and the lens of the second fire extinguisher is positioned to converge the second light signal at the bridge wire of the second fire extinguisher.

In yet another embodiment, an aircraft includes an aircraft structure, and a fire protection system located in the aircraft structure. The fire protection system includes two or more fire extinguishers. Each fire extinguisher of the two or more fire extinguishers includes a housing, the housing including an extinguisher outlet and a burst disk. The burst disk is configured to retain a volume of fire suppressant material in the housing. A firing cartridge is operably connected to the housing. The firing cartridge includes an output charge and an ignition charge that, when detonated, causes release of the output charge to rupture the burst disk and release the volume of fire suppressant material through the extinguisher outlet. An optical fiber is configured to transmit a light signal toward the ignition charge to heat and detonate the ignition charge. A light source is operably connected to each fire extinguisher of the two or more fire extinguishers. The light source is configured to selectably transmit a first light signal to activate a first fire extinguisher of the two or more fire extinguishers, or transmit a second light signal to activate a second fire extinguisher of the two or more fire extinguishers.

Additionally or alternatively, in this or other embodiments the first light signal is a first wavelength and the second light signal is a second wavelength different from the first wavelength.

Additionally or alternatively, in this or other embodiments each fire extinguisher of the two or more fire extinguishers further includes a bridge wire located between the optical fiber and the ignition charge. The light signal is configured to heat the bridge wire to detonate the ignition charge.

DETAILED DESCRIPTION

FIG.1is a schematic illustration of an aircraft10. The aircraft10includes a fire protection system12including one or more fire extinguishers14. The fire extinguishers14may be arrayed around the aircraft10at selected locations. Further, while described herein in the context of an aircraft10, one skilled in the art will readily appreciate that the fire protection system12described herein may be utilized in other applications, such as buildings, trucks, trains, or the like. The fire extinguishers14are operably connected to a controller16located in the aircraft10.

Referring now toFIG.2, illustrated is an embodiment of a fire extinguisher14. The fire extinguisher14includes an extinguisher housing18or tank containing a volume of fire suppressant material20. The fire extinguisher14includes a nozzle portion22having an extinguisher outlet24through which the fire suppressant material20is expelled from the fire extinguisher14. A burst disk26or diaphragm is located in the extinguisher housing18and retains the fire suppressant material20until operation of the fire extinguisher14is initiated by rupturing of the burst disk26.

A firing cartridge28is operably connected to the fire extinguisher14such that when the firing cartridge28is activated the burst disk26is ruptured, and the fire suppressant material20flows from the extinguisher housing18and through the extinguisher outlet24.

Referring now toFIG.3, the firing cartridge28including an ignition charge30and an output charge32. When the ignition charge30is activated, the ignition charge30ignites the output charge32, which when activated ruptures the burst disk26.

In the present disclosure, a light signal34is utilized to activate the ignition charge30The firing cartridge28includes a connector housing36connected to a cartridge housing38, and includes an optical fiber40along which the light signal34is transmitted. The light signal34is transmitted through a lens42located between the optical fiber40and a bridge wire44extending across the ignition charge30. The lens42is configured and positioned such that a lens focal point46is located at the bridge wire44, such that the light signal34converges at the bridge wire44to heat the bridge wire44to the ignition temperature of the ignition charge30. The ignition charge30is thus detonated initiating output charge32to puncture the burst disk26and release the fire suppressant material20. While in the embodiment ofFIG.3a bridge wire44is utilized to ignite the ignition charge30, in other embodiments the light signal34may be converged on other elements to heat the ignition charge30, or the bridge wire44may be omitted and the light signal34may be converged directly onto the ignition charge30to heat and detonate the ignition charge30.

Referring again toFIG.1, the light signal32is emitted from a light source48, which in some embodiments is a laser, which is operably connected to the controller16, which controls operation of the light source48. The light signal32is transmitted from the light source48along a main optical fiber50to a hub52. From the hub52, the light signal32is transmitted along each optical fiber40to each fire extinguisher14. The light source48is tunable to selectable activate one or more of the fire extinguishers14, while not activating the remaining fire extinguishers14, based on a wavelength of the light signal32emitted from the light source48.

For example, and referring now toFIGS.4and5, a first fire extinguisher14ais configured to be activated by a first light signal32aat a first wavelength, for example, an IR wavelength. Configuring of the fire extinguisher14ais achieved by placement of a first lens42aat a first focal length54afrom the bridge wire44so that a first focal point46ais located at the bridge wire44so that the first light signal32aconverges at the bridge wire to sufficiently heat the bridge wire44to detonate the ignition charge30of the first fire extinguisher14a.

Similarly, a second fire extinguisher14bis configured to be activated by a second light signal32bat a second wavelength, for example, a blue light wavelength. Configuring of the second extinguisher14bis achieved by placement of a second lens42bat a second focal length54bfrom the bridge wire44so that a second focal point46bis located at the bridge wire44so that the second light signal32bconverges at the bridge wire to sufficiently heat the bridge wire44to detonate the ignition charge30of the second fire extinguisher14b. It is to be appreciated that the IR wavelength and blue light wavelength are merely exemplary, and that other light signal wavelengths may be utilized.

Referring now toFIG.6, if it is desired to activate the first fire extinguisher14a, for example, the light source48emits the first light signal32aalong the main optical fiber50to the hub52, and from the hub52along the optical fibers40to each of the fire extinguishers14a,14b,14c. Because fire extinguisher14ais configured to receive and be activated by the first light signal32ahaving the first wavelength, first fire extinguisher14ais activated. The remaining fire extinguishers14b,14c, however, are not activated because they are not configured to be activated by the first light signal32a.

Selection of the particular fire extinguisher14a,14b,14cfor activation may be made manually by, for example, an operator, or alternatively as a response to detection of a fire or smoke condition by a sensor56(shown inFIG.1) of one or more sensors56operably connected to the controller16and/or to the light source48. When the sensor56detects a fire or smoke condition, the light source48is activated to initiate operation of one or more fire extinguishers14. In some embodiments, all of the fire extinguishers14may be activated, or fire extinguishers14may be selectively activated based on a location of the sensor56detecting a fire or smoke condition. While the system12is described herein as having three fire extinguishers14, one skilled in the art will readily appreciate that in other embodiments other quantities of fire extinguishers14may be utilized.

Fiber optic activation of the fire extinguishers14is immune to electrostatic discharge and lightning disruption, and also immune to electromagnetic interference and are unaffected by moisture or gas ingress. Further, optical fibers40have a low loss relative to the fiber length, and small size and weight. Further, optical fibers40may be utilized safely in environments characterized by hazardous materials and have high sensitivity and have a high degree of long term reliability.