Temperature compensating inflation device

• US 20040000617A1
• Filed: 06/26/2002
• Published: 01/01/2004
• Est. Priority Date: 06/26/2002
• Status: Active Grant

• Current Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Goodrich Corporation (Raytheon Technologies Corporation d/b/a RTX), Universal Propulsion Company Incorporated (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Baker, James J., Eskildsen, Jim
• Granted Patent: US 6,860,205 B2
• Time in Patent Office: Days
• US Class Current: 244/129.1
• CPC Class Codes: B64D 25/14 Inflatable escape chutes

Abstract

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.

Claims

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

a remotely 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 having a gas output directed into said first stage pressure vessel;

an initiator for initiating said second stage gas source, a sensor having an output signal indicative of one of the physical properties of the pressurized cold gas consisting of temperature and pressure; and

a electronic circuit having an input for receiving a signal from said sensor and an output for initiating said second stage gas source, said electronic circuit operating to delay initiation of said second stage gas source for a period of time after said remotely actuated valve opens, the length of said period of time being determined based upon said output signal from said sensor.

2. The apparatus of claim 1, wherein:

said remotely actuated valve is electrically actuated.

3. The apparatus of claim 1, wherein:

said second stage gas source comprises a pyrotechnic gas generator.

4. The apparatus of claim 1, wherein:

said sensor having an output signal indicative of one of the physical properties of the pressurized cold gas comprises a pressure transducer.

5. The apparatus of claim 4, wherein:

said electronic circuit comprises means for receiving a voltage signal indicative of the opening of said remotely actuated valve and wherein said pressure transducer is interposed between said signal indicative of the opening of said remotely actuate valve and said second stage gas source such that said signal is interrupted until the pressure of said pressurized cold gas drops below a predetermined level.

6. The apparatus of claim 5, further comprising:

means for generating a voltage signal indicative of the opening of an aircraft emergency evacuation exit door, said voltage signal operating to open said remotely actuated valve and to provide said voltage signal indicative of the opening of said remotely actuated valve.

7. The apparatus of claim 1, wherein:

said sensor having an output signal indicative of one of the physical properties of the pressurized cold gas comprises a temperature transducer.

8. The apparatus of claim 7, wherein:

said electronic circuit comprises an electronic timing circuit having a first input for receiving a signal indicative of the opening of said remotely actuated valve, a second input for receiving a signal from said temperature transducer and an output for providing a delayed signal for initiating said second stage gas source.

9. 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

a remotely 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 second stage pressure vessel having a gas exit aperture in fluid communication with said first stage pressure vessel;

a frangible seal disposed in said gas exit aperture, said frangible seal operable to open said gas exit aperture to permit gas to flow through said gas exit aperture when pressure in said second stage pressure vessel exceeds a predetermined level;

a compressed gas stored within said second stage pressure vessel; and

a pyrotechnic material contained within said second stage pressure vessel,

an initiator for initiating said second stage gas source,

a sensor having an output signal indicative of one of the physical properties of the pressurized cold gas consisting of temperature and pressure; and

a electronic circuit having an input for receiving a signal from said sensor and an output for initiating said second stage gas source, said electronic circuit operating to delay initiation of said second stage gas source for a period of time after said remotely actuated valve opens, the length of said period of time being determined based upon said output signal from said sensor.

10. The apparatus of claim 9, wherein:

said sensor having an output signal indicative of one of the physical properties of the pressurized cold gas comprises a pressure transducer.

11. The apparatus of claim 10, wherein:

said electronic circuit comprises means for receiving a voltage signal indicative of the opening of said remotely actuated valve, wherein said pressure transducer is interposed between said signal indicative of the opening of said remotely actuate valve and said second stage gas source such that said signal is interrupted until the pressure of said pressurized cold gas drops below a predetermined level.

12. The apparatus of claim 11, further comprising:

means for generating a voltage signal indicative of the opening of an aircraft emergency evacuation exit door, said voltage signal operating to open said remotely actuated valve and to provide said voltage signal indicative of the opening of said remotely actuated valve.

13. The apparatus of claim 9, wherein:

said sensor having an output signal indicative of one of the physical properties of the pressurized cold gas comprises a temperature transducer.

14. The apparatus of claim 13, wherein:

said electronic circuit comprises an electronic timing circuit having a first input for receiving a signal indicative of the opening of said remotely actuated valve, a second input for receiving a signal from said temperature transducer and an output for providing a delayed signal for initiating said second stage gas source.

15. 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,

a remotely 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; and

an aspirator disposed between said remotely actuated valve and said inflatable device,

a second stage gas source comprising a pyrotechnic material having a gas output directed into said first stage pressure vessel;

an initiator for initiating said second stage gas source,

a sensor for measuring the pressure of the pressurized cold gas; and

a electronic circuit having an input for receiving a signal from said sensor and an output for initiating said second stage gas source, said electronic circuit operating to delay initiation of said second stage gas source until after said remotely actuated valve has opened and the pressure of said pressurized cold gas drops below a predetermined level.

16. The apparatus of claim 15, wherein:

said sensor having an output signal indicative of one of the physical properties of the pressurized cold gas comprises a pressure transducer.

17. The apparatus of claim 16, wherein:

said electronic circuit comprises means for receiving a voltage signal indicative of the opening of said remotely actuated valve, wherein said pressure transducer is interposed between said signal indicative of the opening of said remotely actuate valve and said second stage gas source such that said signal is interrupted until the pressure of said pressurized cold gas drops below a predetermined level.

18. The apparatus of claim 17, further comprising:

means for generating a voltage signal indicative of the opening of an aircraft emergency evacuation exit door, said voltage signal operating to open said remotely actuated valve and to provide said voltage signal indicative of the opening of said remotely actuated valve.

19. The apparatus of claim 15, wherein:

said sensor having an output signal indicative of one of the physical properties of the pressurized cold gas comprises a temperature transducer.

20. The apparatus of claim 19, wherein:

said electronic circuit comprises an electronic timing circuit having a first input for receiving a signal indicative of the opening of said remotely actuated valve, a second input for receiving a signal from said temperature transducer and an output for providing a delayed signal for initiating said second stage gas source.

21. A method for inflating an inflatable device comprising:

storing a first stage gas in a first stage pressure vessel;

sensing one of the physical properties of said first stage gas consisting of temperature and pressure with a transducer and providing an output signal indicative said of one of the physical properties of said first stage gas;

opening a remotely operated valve in response to an external signal to release said first stage gas through said valve into said inflatable device; and

thereafter initiating a second stage gas source having a gas output directed into said first stage pressure vessel, said initiating of said second stage gas source occurring after a delay period, the length of said delay period being determined by said output signal indicative of said one of the physical properties of said first stage gas,

whereby said second stage gas source augments said first stage gas flowing through said valve into said inflatable device.

22. The method of claim 21, wherein:

said one of the physical properties of said first stage gas comprises the pressure of said first stage gas, wherein the length of said delay period comprises the length of time necessary for said pressure of said first stage gas to drop below a predetermined level.

23. The method of claim 22, wherein:

said one of the physical properties of said first stage gas comprises the temperature of said first stage gas.

24. The method of claim 21, wherein:

said second stage gas source comprises;

a second stage pressure vessel having a gas exit aperture in fluid communication with said first stage pressure vessel;

a frangible seal disposed in said gas exit aperture, said frangible seal operable to open said gas exit aperture to permit gas to flow through said gas exit aperture when pressure in said second stage pressure vessel exceeds a predetermined level;

a compressed gas stored within said second stage pressure vessel; and

a pyrotechnic material contained within said second stage pressure vessel,

wherein said means for initiating said second stage gas source comprises an electrically initiated squib operable to initiate said pyrotechnic material.

25. The method of claim 21, wherein:

said external signal comprises a signal indicative of the opening of an aircraft emergency exit door.

26. The method of claim 21, further comprising:

flowing said first stage gas through an aspirator to entrain ambient air prior to said first stage gas flowing into said inflatable device.

27. A method for inflating an inflatable device comprising:

storing a first stage gas in a first stage pressure vessel;

sensing the pressure of said first stage gas;

opening a remotely operated valve in response to an external signal to release said first stage gas through said valve into said inflatable device; and

thereafter initiating a second stage gas source having a gas output directed into said first stage pressure vessel, said initiating of said second stage gas source occurring after a delay period, the length of said delay period being equal to the time necessary for the sensed pressure of said first stage gas to drop below a predetermined level, whereby said second stage gas source augments said first stage gas flowing through said valve into said inflatable device.

28. The method of claim 27, wherein:

said external signal comprises a signal indicative of the opening of an aircraft emergency exit door.

29. The method of claim 27, further comprising:

flowing said first stage gas through an aspirator to entrain ambient air prior to said first stage gas flowing into said inflatable device.

30. A method for inflating an inflatable device comprising:

storing a first stage gas in a first stage pressure vessel;

sensing the temperature of said first stage gas;

opening a remotely operated valve in response to an external signal to release said first stage gas through said valve into said inflatable device; and

thereafter initiating a second stage gas source having a gas output directed into said first stage pressure vessel, said initiating of said second stage gas source occurring after a delay period, the length of said delay period being computed based on the sensed temperature of said first stage gas, whereby said second stage gas source augments said first stage gas flowing through said valve into said inflatable device.

31. The method of claim 30, wherein:

the length of said delay period increases with the absolute temperature of said first stage gas.

32. The method of claim 30, wherein:

said external signal comprises a signal indicative of the opening of an aircraft emergency exit door.

33. The method of claim 30, further comprising:

flowing said first stage gas through an aspirator to entrain ambient air prior to said first stage gas flowing into said inflatable device.

34. The method of claim 30, wherein:

said second stage gas source comprises;

a second stage pressure vessel having a gas exit aperture in fluid communication with said first stage pressure vessel;

a frangible seal disposed in said gas exit aperture, said frangible seal operable to open said gas exit aperture to permit gas to flow through said gas exit aperture when pressure in said second stage pressure vessel exceeds a predetermined level;

a compressed gas stored within said second stage pressure vessel; and

a pyrotechnic material contained within said second stage pressure vessel,

wherein said means for initiating said second stage gas source comprises an electrically initiated squib operable to initiate said pyrotechnic material.

35. A method for inflating an inflatable device comprising:

storing a first stage gas in a first stage pressure vessel;

sensing one of the physical properties of said first stage gas consisting of temperature and pressure and providing an output signal indicative of said one of the physical properties of said first stage gas;

opening a remotely operated valve in response to an external signal to release said first stage gas through said valve into said inflatable device; and

thereafter initiating a second stage gas source having a gas output directed into said first stage pressure vessel, said initiating of said second stage gas source occurring after a delay period, the length of said delay period being determined by said output signal indicative of said one of the physical properties of said first stage gas,

whereby said second stage gas source augments said first stage gas flowing through said valve into said inflatable device, wherein

said second stage gas source comprises;

a second stage pressure vessel having a gas exit aperture in fluid communication with said first stage pressure vessel;

a frangible seal disposed in said gas exit aperture, said frangible seal operable to open said gas exit aperture to permit gas to flow through said gas exit aperture when pressure in said second stage pressure vessel exceeds a predetermined level;

a compressed gas stored within said second stage pressure vessel; and

a pyrotechnic material contained within said second stage pressure vessel.

36. The method of claim 35, wherein:

said one of the physical properties of said first stage gas comprises the pressure of said first stage gas and wherein the length of said delay period comprises the length of time necessary for said pressure of said first stage gas to drop below a predetermined level.

37. The method of claim 36, wherein:

said one of the physical properties of said first stage gas comprises the temperature of said first stage gas.

38. Apparatus for inflating an inflatable device comprising:

means for storing a first stage gas in a first stage pressure vessel;

means for sensing one of the physical properties of said first stage gas consisting of temperature and pressure with a transducer and providing an output signal indicative said of one of the physical properties of said first stage gas;

means for opening a remotely operated valve in response to an external signal to release said first stage gas through said valve into said inflatable device; and

means for initiating a second stage gas source having a gas output directed into said first stage pressure vessel, said initiating of said second stage gas source occurring after a delay period, the length of said delay period being determined by said output signal indicative of said one of the physical properties of said first stage gas.

39. The apparatus of claim 38, wherein:

said second stage gas source comprises;

a second stage pressure vessel having a gas exit aperture in fluid communication with said first stage pressure vessel;

a frangible seal disposed in said gas exit aperture, said frangible seal operable to open said gas exit aperture to permit gas to flow through said gas exit aperture when pressure in said second stage pressure vessel exceeds a predetermined level;

a compressed gas stored within said second stage pressure vessel; and

a pyrotechnic material contained within said second stage pressure vessel,

wherein said means for initiating said second stage gas source comprises an electrically initiated squib operable to initiate said pyrotechnic material.

40. The apparatus of claim 39, wherein

said means for sensing one of the physical properties of said first stage gas comprises a pressure transducer.

41. The apparatus of claim 40, wherein:

said means for initiating said second stage gas source comprises said pressure transducer interposed between a signal for initiating said second stage gas source and said electrically initiated squib such that said signal for initiating said second stage gas source is interrupted until the pressure in said second stage pressure vessel falls below a predetermined level.

42. The apparatus of claim 38 wherein:

said means for sensing one of the physical properties of said first stage gas comprises a temperature transducer.

43. The apparatus of claim 42 wherein:

said means for initiating said second stage gas source comprises an electronic delay circuit having a first input for receiving a signal from said temperature transducer, a second input for receiving a signal for initiating said second stage gas source and an output to said electrically initiated squib, said electronic delay circuit receiving said signal for initiating said second stage gas source and providing a signal to said electrically initiated squib after a delay period, said delay period being determined by said signal from said temperature transducer.