Piezoelectric apparatus for measuring bodily fluid pressure within a conduit
First Claim
1. In a system for measuring bodily fluid pressure, a transducer connectable to a dome containing fluid under pressure, said fluid under pressure being hydraulically coupled to the source of said bodily fluid, said dome having a first diaphragm which flexes in response to variations in fluid pressure, said transducer comprising:
- a housing connectable to said dome;
a plate having at least one natural resonant frequency which varies as mechanical stress applied to it varies;
means for connecting said plate between said housing and said first diaphragm to apply varying stress to said plate as said first diaphragm flexes;
a pair of piezoelectric sheet transceivers, each in intimate contact with a respective portion of said plate;
electronic means for energizing one of said piezoelectric transceivers to vibrate said plate at its resonant frequency; and
said other piezoelectric transducer producing a signal proportional to the frequency of vibrations of said plate, said signal thereby being indicative of said bodily fluid pressure.
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Accused Products
Abstract
An apparatus for measuring pressure within a conduit is disclosed preferably comprising a tube whose resonant frequency varies with the pressure of fluid within the tube; means for passing the fluid to be measured through the tube; two active piezoelectric films disposed in intimate contact with the tube on opposite sides thereof; first electronic means for energizing the first of the films to cause the tube to resonate at its natural frequency, and second electronic means connected to the other of the films to monitor the frequency of the tube.
214 Citations
20 Claims
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1. In a system for measuring bodily fluid pressure, a transducer connectable to a dome containing fluid under pressure, said fluid under pressure being hydraulically coupled to the source of said bodily fluid, said dome having a first diaphragm which flexes in response to variations in fluid pressure, said transducer comprising:
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a housing connectable to said dome; a plate having at least one natural resonant frequency which varies as mechanical stress applied to it varies; means for connecting said plate between said housing and said first diaphragm to apply varying stress to said plate as said first diaphragm flexes; a pair of piezoelectric sheet transceivers, each in intimate contact with a respective portion of said plate; electronic means for energizing one of said piezoelectric transceivers to vibrate said plate at its resonant frequency; and said other piezoelectric transducer producing a signal proportional to the frequency of vibrations of said plate, said signal thereby being indicative of said bodily fluid pressure. - View Dependent Claims (2, 3)
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4. A transducer for measuring bodily fluid by monitoring fluid pressure within a conduit, the conduit fluid being hydraulically coupled to the bodily fluid whereby the conduit fluid pressure is proportional to the bodily fluid pressure, the transducer comprising:
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a structural member having at least one natural resonant frequency which varies as mechanical stress applied to it varies; means for connecting said structural member to said conduit to apply a stress to said structural member proportional to the fluid pressure within said conduit thereby varying said member'"'"'s natural resonant frequency; a pair of piezoelectric sheet transceivers, each in intimate contact with a respective portion of said structural member; electronic means for energizing one of said piezoelectric transceivers to vibrate said structural member at its resonant frequency; and said other piezoelectric transceiver producing a signal proportional to the frequency of vibrations of said structural member, said signal thereby being indicative of said pressure within said conduit. - View Dependent Claims (5, 6, 7, 8, 9, 10, 14)
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11. In a system for measuring bodily fluid pressure, apparatus comprising:
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a tube whose resonant frequency varies with the pressure of fluid within the tube; means for passing fluid hydraulically coupled to the bodily fluid to be measured through the tube; two active piezoelectric films disposed in intimate contact with said tube on opposite sides thereof; first electronic means for energizing the first of said films to cause said tube to resonate at its natural frequency; and second electronic means connected to the other of said films to monitor said frequency. - View Dependent Claims (12, 13, 15, 16, 17, 18, 19, 20)
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Specification