Method and apparatus for optically detecting and locating a fire in an enclosed space

A combination including an apparatus for detecting a fire in an enclosed space, and an aircraft having a cargo or freight compartment bounding said enclosed space, with cargo load units selected from the group consisting of containers and pallets arranged in said enclosed space,

• wherein said apparatus comprises:
• at least one thermally reactive element respectively arranged in said enclosed space and comprising a thermally intumescent material that undergoes an expansion in volume when heated above a trigger temperature, and
• an optical sensor arrangement arranged in said enclosed space and having an optical field of view encompassing said at least one thermally reactive element within said enclosed space, such that said expansion of said thermally intumescent material when said material is heated above said trigger temperature can be optically sensed by said optical sensor arrangement;
• and
• wherein:
• said apparatus is for detecting a fire in said enclosed space in said cargo or freight compartment,
• said at least one thermally reactive element includes a plurality of said thermally reactive elements arranged in a prescribed pattern above said cargo load units in said cargo or freight compartment, and
• said optical sensor arrangement comprises at least one camera selected from the group consisting of visual light video cameras and infrared cameras arranged in said cargo or freight compartment and having said field of view directed to encompass said thermally reactive elements such that said expansion of said thermally intumescent material of at least one of said thermally reactive elements when said material is heated above said trigger temperature is optically sensed by said at least one camera and is represented in an image signal output by said at least one camera.

A method of using an apparatus for detecting a fire in an enclosed space in an aircraft,

• said apparatus comprising:
• at least one thermally reactive element respectively arranged in said enclosed space and comprising a thermally intumescent material that undergoes an expansion in volume a when heated above a trigger temperature, and
• an optical sensor arrangement arranged in said enclosed space and having an optical field of view encompassing said at least one thermally reactive element within said enclosed space, such that said expansion of said thermally intumescent material when said material is heated above said trigger temperature can be optically sensed by said optical sensor arrangement;
• said method comprising the steps:
• a) arranging said at least one thermally reactive element in said enclosed space;
• b) upon the occurrence of a fire, heating said thermally intumescent material above said trigger temperature with heat from said fire, thereby expanding said thermally intumescent material;
• c) optically monitoring said at least one thermally reactive element in said enclosed space using an optical monitoring system including said optical sensor arrangement, and thereby optically sensing said expanding of said thermally intumescent material;
• and
• d) in response to said sensing of said expanding of said thermally intumescent material, concluding that said fire exists in said enclosed space;
• further comprising arranging a light source or an optical target behind a respective one said thermally reactive element along a line of sight of said optical sensor arrangement, wherein said step c) comprises sensing a change in a sensed image of said light source or said optical target along said line of sight before and after said expanding of said thermally intumescent material of said respective thermally reactive element.

An apparatus for detecting a fire in an enclosed space, comprising:

• at least one thermally reactive element respectively arranged in said enclosed space and comprising a thermally intumescent material that undergoes an expansion in volume when heated above a trigger temperature;
• and
• an optical sensor arrangement arranged in said a enclosed space and having an optical field of view encompassing said at least one thermally reactive element within said enclosed space, such that said expansion of said thermally intumescent material when said material is heated above said trigger temperature can be optically sensed by said optical sensor arrangement;
• wherein said optical sensor arrangement includes a light sensor that has said field of view encompassing only a single said thermally reactive element and that is adapted to provide an analog or digital output signal indicating merely whether or not said thermally intumescent material of said single thermally reactive element has undergone said expansion.