Ultrasonic instrument to measure the gas velocity and/or the solids loading in a flowing gas stream

An instrument for measuring the mass flow rate of solids suspended in a gas being transported through a conduit comprising:

• an ultrasound transmitter for generating a pulsed ultrasound beam and defining an aiming line,
• first coupling means for mounting said transmitter to said conduit and for enabling the angle of said transducer aiming line to be varied,
• an ultrasound receiver for detecting the strength of signals generated by said transmitter and defining an aiming line,
• second coupling means for mounting said receiver to said conduit such that said receiver and said transmitter are spaced whereby said beam travels across said conduit and said signal strength is influenced by the concentration of said solids in said conduit and for enabling the angle of said receiver aiming line to be varied,
• variable positioning means for positioning said aiming line angles such that, in a reference position, said aiming lines are coaxial, and in a displaced position, said transmitter aiming line is displaced upstream with respect to said fluid flow, and said receiver aiming line is displaced downstream with respect to said fluid flow enabling sensing of the downstream drift of said ultrasound beam whereby the velocity of said gas in said conduit may be determined,
• controlling and processing means for setting said transmitter and said receiver aiming lines at a first relationship, and causing said transmitter to generate said ultrasound beam, measuring the signal strength of said beam received by said receiver, storing a value representative of said first relationship and said received signal strength, setting said aiming lines of said transmitter and said receiver to a plurality of other angularly displaced positions, thereby generating signal strength data for each of said relationships, calculating the gas velocity by the relationship at which the received signal strength is at a maximum, and calculating the loading of said solids by the signal strength at said maximum.

An instrument for measuring the velocity of a fluid being transported through a conduit comprising:

• a linear array of discrete ultrasound generators,
• controller means for energizing said ultrasound generators with a transmitter phase difference to develop a steerable ultrasound wave front which passes through said fluid,
• a linear array of discrete ultrasound receivers,
• receiving means for receiving signal from each of said receivers and assembling them with a predetermined receiver phase difference to detect said ultrasound wave front emanating from said generators, and
• controller means for setting said transmitter phase difference and said receiver phase difference to maximize the signal strength of the received wave front, and for sweeping through a range of phase differences to direct said ultrasound wave front upstream relative to said ultrasound receivers to evaluate the downstream drift of said wave front caused by said velocity thereby enabling the evaluation of said fluid velocity.

An instrument for measuring the mass flow rate of solids suspended in a gas being transported through a conduit comprising:

• an ultrasound transmitter for generating a pulsed ultrasound beam and defining an aiming line,
• a first variable pitch mount for mounting said transmitter to said conduit and for enabling the angle of said transducer aiming line to be varied,
• an ultrasound receiver for detecting the strength of signals generated by said transmitter and defining an aiming line normal to said face,
• a second variable pitch mount for mounting said receiver to said conduit such that said receiver and said transmitter are spaced whereby said beam travels across said conduit and said signal strength is influenced by the concentration of said solids in said conduit and for enabling the angle of said receiver aiming line to be varied,
• variable positioning means coupled to said transmitter and receiver for positioning said aiming line angles such that, in an initial position, said aiming lines are coaxial, and in a displaced position, said transmitter aiming line is displaced upstream with respect to said fluid flow, and said receiver aiming line is displaced downstream with respect to said fluid flow enabling sensing of the downstream drift of said ultrasound beam whereby the velocity of said gas in said conduit may be determined,
• controlling and processing means for setting said transmitter and said receiver aiming lines at a first relationship, and causing said transmitter to generate said ultrasound beam, measuring the signal strength of said beam received by said receiver, storing a value representative of said first relationship and said received signal strength, setting said aiming lines of said transmitter and said receiver to a plurality of other angularly displaced positions, thereby generating signal strength data for each of said relationships, calculating the gas velocity by the relationship at which the received signal strength is at a maximum, and calculating the loading of said solids by the signal strength at said maximum.

A method of measuring the velocity of a fluid being transported through a conduit comprising the steps of:

• providing a first ultrasound transducer defining an aiming line,
• providing a second ultrasound transducer defining an aiming line,
• positioning said transducer aiming lines from an initial position wherein said lines are coaxial to displaced positions in which said first transducer aiming line is displaced upstream with respect to said fluid flow, and said second transducer aiming line is displaced downstream with respect to said fluid flow,
• energizing said first transducer to generate a packet of ultrasound energy,
• sensing the output from said second transducer generated by receiving of said packet of ultrasound energy after said packet has passed across said fluid flow,
• varying the angles of said first and second transducer aiming lines thereby evaluating the downstream drift of said packet, and
• computing fluid velocity from said drift.