Apparatus and method for measuring a fluid flow parameter within an internal passage of an elongated body

Abstract

A method and apparatus for measuring at least one parameter of a fluid flowing through an internal passage of an elongated body is provided. The internal passage is disposed between a first wall and a second wall, and the first wall and the second wall each include an interior surface and an exterior surface. The method includes the steps of providing an array of at least two ultrasonic sensor units, operating the sensor units to transmit ultrasonic signals at one or more frequencies substantially coincident with at least one frequency at which the transmitted ultrasonic signals resonate within the first wall, receiving the ultrasonic signals with the sensor units, and processing the received ultrasonic signals to measure the at least one parameter of fluid flow within the internal passage.

1 . A method for measuring at least one parameter of a fluid flowing through an internal passage of an elongated body, which internal passage is disposed between a first wall and a second wall, and the first wall and the second wall each include an interior surface and an exterior surface, the method comprising:
 providing an array of at least two ultrasonic sensor units, each sensor unit including an ultrasonic transmitter mounted on the exterior surface of the first wall and an ultrasonic receiver located on the exterior surface of the second wall and substantially aligned with the transmitter;   operating the ultrasonic transmitters to transmit ultrasonic signals through the first wall and in a direction normal to the first wall, at one or more frequencies substantially coincident with at least one frequency at which the transmitted ultrasonic signals resonate within the first wall, in a manner that maintains or increases the amplitude of the ultrasonic signals traveling through the first wall, and thereby increases the signal-to-noise ratio of the ultrasonic signals;   receiving the ultrasonic signals with the ultrasonic receivers; and   processing the received ultrasonic signals to measure the at least one parameter of fluid flow within the internal passage.   
     
     
         2 . The method of  claim 1 , further comprising the steps of:
 comparing a frequency of the transmitted ultrasonic signals to a fundamental resonance frequency of the elongated body, and determining a delta between the two; and   selectively tuning the frequency of the transmitted ultrasonic signals to substantially coincide with the fundamental resonance frequency if the delta is outside an acceptable range.   
     
     
         3 . The method of  claim 2 , wherein the steps of comparing and selectively tuning are performed prior to measuring the at least one parameter of fluid flow within the internal passage of the elongated body. 
     
     
         4 . The method of  claim 2 , wherein the steps of comparing and selectively tuning are performed periodically. 
     
     
         5 . The method of  claim 2 , wherein the steps of comparing and selectively tuning are performed continuously. 
     
     
         6 . A method for sensing flow within an internal passage of a pipe, which passage is disposed between a first wall of the pipe and a second wall of the pipe, the method comprising:
 providing a flow meter having an array of at least two ultrasonic sensor units, each sensor unit including an ultrasonic transmitter mounted on an exterior surface of the first wall and an ultrasonic receiver located on an exterior surface of the second wall and substantially aligned with the transmitter;   operating the ultrasonic transmitters to transmit ultrasonic signals through the first wall and in a direction normal to the first wall, at one or more frequencies substantially coincident with at least one frequency at which the transmitted ultrasonic signals resonate within the first wall, in a manner that maintains or increases the amplitude of the ultrasonic signals traveling through the first wall, and thereby increases the signal-to-noise ratio of the ultrasonic signals transmitted into the internal passage; and   receiving the ultrasonic signals with the ultrasonic receivers.   
     
     
         7 . The method of  claim 6 , further comprising the steps of:
 comparing a frequency of the transmitted ultrasonic signals to a fundamental resonance frequency of the elongated body, and determining a delta between the two; and   selectively tuning the frequency of the transmitted ultrasonic signals to substantially coincide with the fundamental resonance frequency if the delta is outside an acceptable range.   
     
     
         8 . The method of  claim 7 , wherein the steps of comparing and selectively tuning are performed prior to measuring the at least one parameter of fluid flow within the internal passage of the elongated body. 
     
     
         9 . The method of  claim 7 , wherein the steps of comparing and selectively tuning are performed periodically. 
     
     
         10 . The method of  claim 7 , wherein the steps of comparing and selectively tuning are performed continuously. 
     
     
         11 . An apparatus for sensing flow within an internal passage of a pipe, which passage is disposed between a first wall of the pipe and a second wall of the pipe, the apparatus comprising:
 an array of at least two ultrasonic sensor units, each sensor unit including an ultrasonic transmitter mounted on an exterior surface of the first wall and an ultrasonic receiver located on an exterior surface of the second wall and substantially aligned with the transmitter to receive ultrasonic signals transmitted therefrom; and   a processor adapted to operate the ultrasonic transmitters to transmit ultrasonic signals through the first wall and in a direction normal to the first wall, at one or more frequencies substantially coincident with at least one frequency at which the transmitted ultrasonic signals resonate within the first wall of the pipe, in a manner that maintains or increases the amplitude of the ultrasonic signals traveling through the first wall, and thereby increases the signal-to-noise ratio of the ultrasonic signals transmitted into the internal passage, and adapted to receive signals from the ultrasonic receivers.   
     
     
         12 . The apparatus of  claim 11 , wherein the processor is further adapted to compare a frequency of the transmitted ultrasonic signals to a fundamental resonance frequency of the elongated body, and determine a delta between the two; and selectively tune the frequency of the transmitted ultrasonic signals to substantially coincide with the fundamental resonance frequency if the delta is outside an acceptable range. 
     
     
         13 . The apparatus of  claim 12 , wherein the processor is further adapted to compare and selectively tune the frequency of the transmitted ultrasonic signals prior to measuring the at least one parameter of fluid flow within the internal passage of the elongated body. 
     
     
         14 . The method of  claim 12 , wherein the processor is further adapted to compare and selectively tune the frequency of the transmitted ultrasonic signals periodically. 
     
     
         15 . The method of  claim 12 , wherein the processor is further adapted to compare and selectively tune the frequency of the transmitted ultrasonic signals continuously.