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US 5,488,953 AGranted
Diffracting doppler-transducer
AssigneeEcoCath, Inc.
InventorDavid Vilkomerson
Life of this patent
Estimating the term…
Abstract
An ultrasonic transducer apparatus of variable frequency including a diffracting structure adapted for emitting and receiving a plurality of diffracted ultrasonic beams of calculable different angles for determining the velocity of a fluid flowing through a lumen, and flow volume. Velocity and flow volume are determined from at least two equations in the two unknowns of the velocity, and the angle between the ultrasonic transducer apparatus and the direction of the fluid flow, and from a determination of the diameter of the lumen.
Claims20
A method of determining a velocity of a fluid flowing through a lumen, comprising the steps of:
- placing a piezoelectric ultrasonic transducer apparatus proximate to said lumen, said ultrasonic transducer apparatus including a diffracting structure comprising a linear array of alternately polarized vibrating elements fabricated from a piezoelectric material which emit and receive a plurality of diffracted ultrasonic beams;
- exciting said ultrasonic transducer apparatus to operate at a given frequency to enable said transducer apparatus to emit said plurality of diffracted ultrasonic beams;
- measuring the time changes of said plurality of diffracted ultrasonic beams as said plurality of diffracted ultrasonic beams are backscattered by said fluid back towards said diffracting structure to determine said velocity of said fluid.
A method of determining a diameter of a lumen having a first side and a second side through which a fluid under investigation flows, comprising the steps of:
- placing a piezoelectric ultrasonic transducer apparatus proximate to said lumen, said transducer apparatus including a diffracting structure comprising a linear array of alternately polarized vibrating elements fabricated from a piezoelectric material which emit and receive a non-diffracted ultrasonic beam;
- exciting said ultrasonic transducer apparatus to operate at a given frequency to enable said diffracting structure to emit said non-diffracted ultrasonic beam from said first side of said lumen to said second side of said lumen;
- and
- determining said diameter of said lumen as said non-diffracted beam is reflected by said second side of said lumen back towards said first side of said lumen.
1 more element
A method of determining the absolute flow volume of a fluid flowing through a lumen of a given diameter from the product of a velocity of said fluid and an area of said lumen, comprising the steps of:
- placing a piezoelectric ultrasonic transducer apparatus proximate to said lumen, said transducer apparatus including a diffracting structure comprising a linear array of alternately polarized vibrating elements fabricated from a piezoelectric material which emit and receive a plurality of diffracted ultrasonic beams, said diffracting structure being further adapted for emitting and receiving a non-diffracted ultrasonic beam;
- exciting said ultrasonic transducer apparatus to operate at a first frequency to enable said diffracting structure to emit said plurality of diffracted ultrasonic beams towards said fluid, said ultrasonic transducer apparatus measuring the frequency shift of said plurality of diffracted ultrasonic beams as said plurality of diffracted ultrasonic beams are reflected by said fluid back towards said diffracting structure, thereby determining said velocity of said fluid;
- and
- exciting said ultrasonic transducer apparatus at a second frequency to enable said diffracting structure to emit said non-diffracted ultrasonic beam from a first side of said lumen to a second side of said lumen, said ultrasonic transducer apparatus determining said area as said non-diffracted ultrasonic beam is reflected by said second side of said lumen back towards said first side of said lumen;
- determining said diameter of said lumen as said non-diffracted beam is reflected by said second side of said lumen back towards said first side of said lumen.
2 more elements
An apparatus for determining the velocity of a fluid flowing through a lumen, comprising:
- a transducer having a planar substrate member fabricated from a piezoelectric material and a linear array of alternately polarized vibrating elements fabricated from a piezoelectric material formed upon a surface of said planar substrate member, said alternately polarized vibrating elements forming a diffracting structure for emitting a plurality of diffracted ultrasonic beams of at least one given frequency and receiving a plurality of diffracted ultrasonic beams of at least one given frequency;
- pulse generation means coupled to said diffracting structure of said transducer, for generating a signal which causes said alternately polarized vibrating elements of said diffracting structure to vibrate and emit said plurality of diffracted ultrasonic beams of said at least one given frequency, so that when said emitted diffracted ultrasonic beams of said at least one given frequency impinge upon the fluid flowing through the lumen at a given velocity, the fluid reflects back said plurality of diffracted ultrasonic beams as a plurality of backscattered diffracted beams of a shifted frequency, said backscattered diffracted beams being received by said alternately polarized vibrating elements of said diffracting structure of said transducer, whereby said backscattered beams cause said alternately polarized vibrating elements to vibrate at said shifted frequency, thereby producing a signal which is indicative of said shifted frequency;
- and
- signal processing means associated with said pulse generation means and said transducer for receiving said signal which is indicative of said shifted frequency and comparing it with said at least one given frequency of said emitted diffracted ultrasonic beams to determine the given velocity of the fluid.
1 more element
An ultrasonic transducer comprising:
- a planar substrate member fabricated from a piezoelectric material;
- a linear array of alternately polarized vibrating elements fabricated from a piezoelectric material, said linear array of alternately polarized vibrating elements being disposed upon a surface of said planar substrate member, said alternately polarized vibrating elements forming a diffracting structure.
Dependencies are inferred from the claim text.