Automatic fire extinguishing apparatus

Claim 1

An automatic fire extinguishing apparatus comprising: a portable tank containing pressurized fire extinguishing agent; means, mounted to said tank, for automatically releasing said fire extinguishing agent, said automatic release means including a tube extending from said tank, said automatic release means further including a closed heat fusible element extending across the distal end of said tube in direct contact with at least a portion of said fire extinguishing agent for blocking the flow of said fire extinguishing agent therethrough; said closed heat fusible element including a flat, rigid inner disc having a central aperture and a flat rigid outer disc large enough to cover said aperture but smaller in diameter than said inner disc; said inner and outer discs being held together in a sealing face-to-face fashion by a fusible material disposed at their interfacing surfaces which melts at said threshold temperature; said automatic release means yet further including a sprinkler cap, attached to said distal end of said tube, for distributing said fire extinguishing agent in a pre-determined spray pattern; said sprinkler cap including an annular shoulder for holding said closed heat fusible element in place across said distal end of said tube; said sprinkler cap further including a cavity for receiving said fusible element outer disc when it is forced away from said fusible element inner disc; whereby said outer disc will be forced away from said inner disc and into said cavity by the pressure of said fire extinguishing agent when the temperature of the contiguous environment exceeds said threshold temperature, permitting said fire extinguishing agent to flow through said aperture and out said sprinkler in said pre-determined spray pattern.