Fire suppression system with controlled secondary extinguishant discharge

Claim 1

A fire extinguishing system for aircraft cargo compartments and the like, comprising: a first bottle containing an extinguishant under substantial pressure in liquid form; a first extinguishant discharge line connected to the first bottle and extending into a compartment in which a fire is to be extinguished; rapid discharge first nozzles connected to the first line and positioned in the compartment for rapid discharge of the extinguishant from the first bottle to ensure a sufficient gas extinguishant average concentration in the compartment for an initial flame knockdown of a fire in the compartment; a second bottle containing the extinguishant under substantial pressure in liquid form; a second extinguishant discharge bleed and metering line connected to the second bottle and extending into the compartment; said second line having a small diameter relative to said first line; small liquid second discharge nozzles connected to the second line and positioned in the compartment to discharge the extinguishant from the second bottle; means between the second bottle and liquid discharge second nozzles and within the liquid discharge nozzles for maintaining the extinguishant in wholly liquid form with no phase change and avoiding significant pressure loss in the second line, to prevent freeze-up, to provide controlled rate flow accuracy maintenance to introduce the extinguishant into the compartment at a rate at least equal to the amount lost through compartment leakage, and to provide a violent boil-off when discharged from the second nozzles to provide for a thorough and rapid mix of gas within the compartment to ensure a predetermined average extinguishant concentration for a predetermined time in the compartment to adequately control or extinguish a fire in the compartment; the bottles having normally closed connections to the lines; and means associated with the bottles and lines to open the connections to the lines; said means associated with the second bottle being operable to open the connection at a predetermined time relative to the discharge from the first bottle to establish said predetermined concentration in the compartment.

Claim 21

A method of extinguishing or controlling a fire in an aircraft cargo compartment or the like, comprising: rapidly releasing and spreading a gas extinguishant into a compartment in an amount sufficient for an initial flame knockdown of a fire in the compartment; the extinguishant being under substantial pressure in a first container so as to be in liquid form before being released; at a predetermined time releasing and spreading more of the extinguishant into the compartment from a second container in which the extinguishant is under substantial pressure so as to be in liquid form; maintaining the extinguishant from the second container in wholly liquid form in a discharge bleed and metering line and nozzles, and avoiding significant pressure loss, preventing freeze-up and providing controlled rate flow accuracy maintenance in the line and nozzles, and providing violent boil-off when discharged from the nozzles to provide a thorough and rapid mix of the gas within the compartment; and releasing and spreading the liquid near the ceiling from the second container at a predetermined rate at least equal to the amount lost through compartment leakage to ensure a predetermined average gas extinguishant concentration for a predetermined time in the compartment to adequately control or extinguish a fire in the compartment.

Claim 22

A method of extinguishing or controlling a fire in an aircraft cargo compartment or the like, comprising: rapidly releasing and spreading a gas extinguishant into a compartment in an amount sufficient for an initial flame knockdown of a fire in the compartment; the extinguishant being under substantial pressure in a first container so as to be in liquid form before being released; at a predetermined time releasing and spreading more of the extinguishant into the compartment from a second container in which the extinguishant is under substantial pressure so as to be in liquid form; maintaining the extinguishant from the second container in wholly liquid form in a discharge bleed and metering line and nozzles, and avoiding significant pressure loss, preventing freeze-up and providing controlled rate flow accuracy maintenance in the line and nozzles, and providing violent boil-off when discharged from the nozzles to provide a thorough and rapid mix of the gas within the compartment; and releasing and spreading the liquid near the ceiling from the second container at a predetermined rate at least equal to the amount lost through compartment leakage to ensure a predetermined average gas extinguishant concentration for a predetermined time in the compartment to adequately control or extinguish a fire in the compartment.