System and method for opto-acoustic liquid quantity measurement and transducer therefor
First Claim
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1. An optically controlled acoustic transmission and reception system, comprising:
- a tank,an electrically passive optically controlled acoustic transmitter,an electrically passive acoustic receiver,a first and a second source of electromagnetic radiation,a first and a second optical fiber,said transmitter being positioned to transmit acoustic waves into said tank,said first optical fiber being connected to said transmitter and to said first source of electromagnetic radiation, said receiver being connected to said second optical fiber, said transmitter being adapted to convert said electromagnetic radiation into acoustic pulses, said receiver being adapted to modulate electromagnetic radiation from said second source passing through said second optical fiber in response to said acoustic pulses, whereby said acoustic pulses from said transmitter are received by said receiver.
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Abstract
The system and method provide an electrically passive optically controlled acoustic transceiver system which measures the quantity of a liquid, such as aircraft fuel, in a tank. Pulsed electromagnetic radiation, such as light or infrared radiation, is guided through an optical fiber and impinged upon a flexible member adapted to flex when heated and transmit acoustic pulses. An optical fiber detector, is used to monitor the acoustic pulses reflected from the liquid level in a fuel tank. The system is electrically passive and does not require or use electrical power at the sensing location.
48 Citations
26 Claims
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1. An optically controlled acoustic transmission and reception system, comprising:
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a tank, an electrically passive optically controlled acoustic transmitter, an electrically passive acoustic receiver, a first and a second source of electromagnetic radiation, a first and a second optical fiber, said transmitter being positioned to transmit acoustic waves into said tank, said first optical fiber being connected to said transmitter and to said first source of electromagnetic radiation, said receiver being connected to said second optical fiber, said transmitter being adapted to convert said electromagnetic radiation into acoustic pulses, said receiver being adapted to modulate electromagnetic radiation from said second source passing through said second optical fiber in response to said acoustic pulses, whereby said acoustic pulses from said transmitter are received by said receiver. - View Dependent Claims (2, 3)
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4. An electrically passive optically activated transducer, comprising:
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a first and a second optical fiber, a flexible member adapted to vibrate and thereby provide acoustic waves in response to impingement thereon of pulsed electromagnetic radiation from said first optical fiber, said second optical fiber being adapted to modulate electromagnetic radiation passing through said second optical fiber in response to the impingement of said acoustic waves on said second optical fiber. - View Dependent Claims (5)
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- 6. An electrically passive optically activated system, comprising a first and a second optical fiber, a source of pulsed infrared radiation, a source of visible light and a flexible member adapted to vibrate and thereby provide acoustic pulses in response to impingement of pulsed infrared radiation thereon said source of infrared radiation being adapted to transmit pulses of infrared radiation into said first optical fiber, said acoustic pulses from said flexible member being reflected to said second optical fiber, said source of visible light being adapted to transmit visible light into said second optical fiber, said second optical fiber being adapted to modulate said visible light passing through said second optical fiber in response to said reflected acoustic pulses.
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8. An electrically passive method of optically controlling acoustic transmission comprising:
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(a) providing a tank enclosing a chamber, an electrically passive optically controlled acoustic transmitter, a first source of electromagnetic radiation, a first optical fiber, said transmitter being positioned to transmit acoustic waves into said tank, said optical fiber being connected to said transmitter and to said first source of electromagnetic radiation, said transmitter being adapted to convert said electromagnetic radiation into acoustic pulses, and (b) transmitting electromagnetic radiation from said first source through said first fiber whereby acoustic waves are transmitted from said acoustic transmitter. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. An electrically passive method of optically activating an acoustic transmitter for transmission of acoustic waves into a liquid enclosed by a tank comprising:
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(a) providing a tank, an optical fiber, a transducer comprising a flexible member adapted to vibrate in response to impingement of pulsed electromagnetic radiation thereon, said tank enclosing a liquid, said first optical fiber being adapted to pass electromagnetic radiation onto said flexible member, and (b) passing electromagnetic radiation from an electromagnetic radiation source through said optical fiber onto said flexible member whereby said transducer transmits acoustic waves into said liquid. - View Dependent Claims (18, 19, 20)
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21. An electrically passive method of fuel quantity measurement comprising (a) providing a tank enclosing liquid fuel said fuel having air-liquid interface,
(a) providing a first optical fiber, a flexible member adapted to vibrate in response to impingement of pulsed electromagnetic radiation thereon, said first optical fiber being adapted to pass electromagnetic radiation onto said flexible member, (b) passing electromagnetic radiation through said fiber optical fiber onto said flexible member whereby said transducer transmits acoustic waves, providing an electrically passive acoustic receiver, and a second source of electromagnetic radiation, said receiver comprising at least a portion of a second optical fiber, said receiver being positioned to receive acoustic waves from said tank, said receiver being connected to said second optical fiber, said receiver being adapted to modulate electromagnetic radiation from said second source passing through said second optical fiber in response to said acoustic waves whereby said acoustic waves are received by said receiver, measuring the time period required for said acoustic waves to travel to said air-liquid interface and back to said receiver, and determining the quantity of said liquid fuel from said time period and information relating liquid quantity in said tank to said time period.
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23. An electrically passive system for liquid quantity determination, comprising:
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a tank, an electrically passive optically controlled acoustic transmitter, said transmitter comprising an optical fiber, an optical source, an acoustic detector, microprocessor, said optical source and said acoustic detector being connected to said microprocessor, said optical source being connected to said optical fiber, said tank being adapted to enclose liquid and air, said liquid and air having a liquid-air interface, said transmitter being adapted to transmit initial acoustic waves through said liquid to said liquid-air interface, a portion of said initial acoustic waves being reflected from said liquid-air interface, said acoustic detector being adapted to detect said reflected acoustic waves, said microprocessor being adapted to determine the quantity of said liquid in said tank. - View Dependent Claims (24, 25, 26)
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Specification