Overpressure limiting hybrid inflator
First Claim
1. Apparatus for inflating an inflatable device comprising:
- a first stage gas source comprising;
a first stage pressure vessel having a gas exit opening, a pressurized cold gas stored within said first stage pressure vessel, and an externally actuated valve in fluid communication with said gas exit opening and responsive to an external signal for opening to provide a gas flow path between said first stage pressure vessel and said inflatable device;
a second stage gas source comprising a pyrotechnic gas generator having a gas output directed into said first stage pressure vessel;
an initiator for initiating said second stage gas source such that the gas output of said second stage gas source is directed into said first stage pressure vessel a predetermined period after actuation of said externally actuated valve; and
, a pressure actuated valve having an inlet and an outlet, said pressure actuated valve being interposed in said gas flow path between said first stage pressure vessel and said inflatable device, said pressure actuated valve being operable to open a gas flow path between said externally actuated valve and said inflatable device when a pressure at said inlet of said pressure actuated valve exceeds a predetermined threshold pressure.
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Accused Products
Abstract
A dual stage hybrid inflation device includes a first stage gas source comprising a pressurized gas stored in a first stage pressure vessel and a second stage gas source comprising 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. At low temperatures, the pressure actuated valve prevents the flow of gas from the first stage. This allows the hot combustion products from the second stage gas source to mix with the pressurized gas in the first stage pressure vessel, thereby heating the pressurized gas until sufficient pressure is developed in the first stage pressure vessel to open the pressure actuated valve. At high temperatures, however, pressure in the first stage pressure vessel is above the threshold pressure of the pressure actuated valve. Accordingly, when the externally actuated valve is opened, the pressure actuated valve opens immediately, thereby allowing the pressure in the first stage pressure vessel to drop to a safe level before the pyrotechnic gas generator is initiated.
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Citations
17 Claims
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1. Apparatus for inflating an inflatable device comprising:
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a first stage gas source comprising;
a first stage pressure vessel having a gas exit opening, a pressurized cold gas stored within said first stage pressure vessel, and an externally actuated valve in fluid communication with said gas exit opening and responsive to an external signal for opening to provide a gas flow path between said first stage pressure vessel and said inflatable device;
a second stage gas source comprising a pyrotechnic gas generator having a gas output directed into said first stage pressure vessel;
an initiator for initiating said second stage gas source such that the gas output of said second stage gas source is directed into said first stage pressure vessel a predetermined period after actuation of said externally actuated valve; and
,a pressure actuated valve having an inlet and an outlet, said pressure actuated valve being interposed in said gas flow path between said first stage pressure vessel and said inflatable device, said pressure actuated valve being operable to open a gas flow path between said externally actuated valve and said inflatable device when a pressure at said inlet of said pressure actuated valve exceeds a predetermined threshold pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of inflating an inflatable device comprising:
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opening an externally actuated valve to begin a flow of gases from a first stage gas source to a pressure actuated valve interposed in a gas flow path between said externally actuated valve and said inflatable device;
initiating a second stage gas source comprising a pyrotechnic gas generator having a heated gas output;
directing said heated gas output from said second stage gas source into said first stage gas source a predetermined period of time after the step of opening said externally actuated valve such that said heated gas output enters said first stage gas source adding heat and gaseous products to said first stage gas source and thereby raising the gas pressure within said first stage gas source; and
opening a pressure actuated valve interposed in a gas flow path between said externally actuated valve and said inflatable device to establish a flow of gas from said first stage gas source to said inflatable device said pressure actuated valve opening when the gas pressure within said first stage gas source exceeds a predetermined threshold. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification