Universal Propulsion Company, Inc.

Goodrich Corporation

Jim Eskildsen

James J Baker

Christopher J Bock

A dual stage hybrid inflation device includes a first stage gas source having a pressurized gas stored in a first stage pressure vessel and a second stage gas source having a pyrotechnic gas generator having a gas output directed into the first stage pressure vessel. The first stage pressure vessel is in fluid communication with an inflatable device such as an aircraft emergency evacuation slide via an externally actuated valve upstream of a pressure actuated valve such as a rupturable diaphragm. A control circuit provides a signal to the externally actuated valve to begin a flow of gases from first stage pressure vessel to a chamber on the upstream side of the burst diaphragm. The control circuit also sends a signal to the squib that initiates the pyrotechnic second stage gas source. As the pyrotechnic gas generator of the second stage gas source burns, the hot gaseous products of the second stage gas source mix with the pressurized gas stored in the first stage pressure vessel a predetermined time after the externally actuated valve opens.

Overpressure limiting hybrid inflator

A system for deploying an aircraft emergency evacuation slide or other inflatable device utilizes an inflation gas that is stored in a partially liquified state. The inflation gas includes a gaseous compound, preferably nitrous oxide, that is capable of undergoing an exothermic thermal decomposition, which gives off heat and produces a greater number moles of inflation gas than the number of moles of gas stored. The increase in moles of gas allows a greater inflation volume for a given weight of stored gas, while the exothermic decomposition produces additional heat that offsets, to some extent, the endothermic boiling and expansion of the liquified stored gas.

Aircraft evacuation slide inflation system using a stored liquified gas capable of thermal decomposition

A dual stage hybrid inflation device includes a pressure switch that prevents the second stage pyrotechnic gas generator from being initiated when the additional heat and gas would overpressurize the first stage pressure vessel. As the pressurized gas stored in the first stage pressure vessel escapes the first stage pressure vessel, the pressure in the first stage pressure vessel drops. If the pressure in the first stage pressure vessel drops below the threshold pressure of the pressure switch, the pressure switch closes allowing the voltage signal to reach the pyrotechnic gas generator thereby initiating the second stage gas source. In an alternative embodiment, the pressure transducer is replaced by a pressure transducer or a temperature transducer and timing circuit. By delaying the initiation of the second stage gas source until after the pressure in the first stage pressure vessel has dropped below the threshold level, the appropriate augmentation of the compressed first stage gas can be realized without the necessity of designing the first stage pressure vessel to withstand initiation of the pyrotechnic gas generator under maximum inflation pressure conditions.

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Tempe, AZ, United States of America

Jim Eskildsen