This invention relates to emergency evacuation equipment for aircraft, in particular, to inflators for inflatable aircraft emergency evacuation slides.
The requirement for reliably evacuating airline passengers in the event of an emergency is well-known. Emergencies at take-off and landing often demand swift removal of passengers from the aircraft because of the potential for injuries from fire, explosion, or sinking in water. A conventional method of quickly evacuating a large number of passengers from an aircraft is to provide multiple emergency exits, each of which is equipped with an inflatable evacuation slide. The inflatable evacuation slides are normally stored in an uninflated condition in a compartment requiring a minimum amount of space within the airframe. Door exit inflatable slides are typically either mounted on the interior of the aircraft door or immediate adjacent thereto. Overwing exits are normally stored in an uninflated condition in a special compartment that opens to the exterior of the aircraft adjacent to the overwing exit.
Modern evacuation slide inflation systems typically comprise a pressure vessel containing a stored pressurized gas, either alone or in combination with a pyrotechnic gas generator, used to supply the source gas for inflating the emergency evacuation slide. The pressure vessel is sealed by a control valve that opens in response to the emergency exit door being opened in the “armed” condition to inflate the inflatable evacuation slide. Regulations require inflation systems that use stored gas to have an overpressure relief valve to release gas in the event of over pressurization of the inflation system pressure vessel. Regulations do not require, and the prior art control valves to not have provisions to vent leakage through the control valve itself. Accordingly, it is possible for modest leakage past the control valve to result in an unintentional pressurization and accidental deployment of the emergency evacuation slide from a slow build-up of leakage pressure. Accordingly, what is needed is an inflation system control valve having a valve leakage trap and safety vent that safely vents valve leakage gas away from the inflatable evacuation slide without compromising the reliability of the control valve to fully inflate the inflatable evacuation slide in the event of an emergency.