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Closed loop pressure determination system and method for fiber optic pressure transducer system

  • US 5,517,998 A
  • Filed: 01/24/1994
  • Issued: 05/21/1996
  • Est. Priority Date: 01/24/1994
  • Status: Expired due to Term
First Claim
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1. A closed loop pressure determination system incorporating a pressure transducer comprising:

  • a lumen enclosing an optical pathway having proximal and distal ends for sending and receiving light signals, said lumen including a sealed internal passage;

    said pressure transducer comprising a pressure responsive member disposed at said distal end of said optical pathway, said member having first and second surfaces wherein said first surface is exposed to a first variable pressure p1 sought to be repeatedly determined, said member second surface being pressure coupled to said passage at a second variable pressure p2, said pressure responsive member being provided for modulating a light signal traveling along said optical pathway in response to changes in said first variable pressure p1 ;

    a reference pressure sensor, said reference pressure sensor being pressure coupled to said lumen passage, said reference pressure sensor providing an output signal indicative of said pressure p2 ;

    a comparator in signal receiving communication with said pressure transducer for receiving said modulated light signal and in communication with a signal source indicative of a pre-established reference pressure pref, and for providing a comparator output signal indicative of the pressure difference Δ

    p wherein
    
    
    space="preserve" listing-type="equation">Δ

    p=p.sub.ref -(p.sub.1 -p.sub.2);

    anda pressure variation means connected to said comparator for receiving said output signal, said lumen passage being sealingly connected in fluid flow communication with said pressure variation means, said means being provided for varying the pressure p2 within the passage and on the second surface in response to the comparator output signal so as to make p2 =p1 +c, where c equals a predetermined constant.

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