Timed window ultrasonic gas meter with nose cone
First Claim
1. A method of detecting the arrival at a transducer of an acoustic wave packet within a series of acoustic wave packets, said method comprising the steps of:
- (a) determining a nominal time of propagation of a single acoustic wave packet by;
(i) simultaneously starting a timer and transmitting said single acoustic wave packet to said transducer;
(ii) receiving said single acoustic wave packet at said transducer; and
(iii) identifying a predetermined part of said received wave packet and stopping said timer to thereby determine said nominal time of propagation;
(b) transmitting said series of acoustic wave packets to said transducer wherein the transmission of any one said wave packet within said series, excepting a first wave packet, is initiated upon detection of arrival at said transducer of an immediately preceding one of said wave packets in said series;
(c) upon each transmission of said wave packet in step (b) starting a timer; and
(d) determining when said timer is within a predetermined time of said nominal time of propagation to then enable identification at said transducer of said predetermined part of the corresponding wave packet to thereby detect the arrival of said corresponding wave packet.
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Accused Products
Abstract
There is disclosed an ultrasonic fluid flow meter (50) which measures the flow speed of a fluid by measuring the time, in each direction, for a sequence of ultrasonic pulses (55) to pass between two transducers (54A, 54B) positioned in a measuring tube (52) in the fluid flow path. The second and subsequent transmit pulses of each sequence are caused to start by the arrival of its predecessor at the detector end of the measuring tube. A first transmit pulse calculates a delay (110) to a zero crossing which is used to identify a particular zero crossing at which the arrival of each pulse in the sequence is determined.
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Citations
13 Claims
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1. A method of detecting the arrival at a transducer of an acoustic wave packet within a series of acoustic wave packets, said method comprising the steps of:
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(a) determining a nominal time of propagation of a single acoustic wave packet by;
(i) simultaneously starting a timer and transmitting said single acoustic wave packet to said transducer;
(ii) receiving said single acoustic wave packet at said transducer; and
(iii) identifying a predetermined part of said received wave packet and stopping said timer to thereby determine said nominal time of propagation;
(b) transmitting said series of acoustic wave packets to said transducer wherein the transmission of any one said wave packet within said series, excepting a first wave packet, is initiated upon detection of arrival at said transducer of an immediately preceding one of said wave packets in said series;
(c) upon each transmission of said wave packet in step (b) starting a timer; and
(d) determining when said timer is within a predetermined time of said nominal time of propagation to then enable identification at said transducer of said predetermined part of the corresponding wave packet to thereby detect the arrival of said corresponding wave packet. - View Dependent Claims (2, 3)
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4. A method of detecting the arrival at a transducer of an acoustic wave packet within a series of acoustic wave packets, where the transmission of any one wave packet in said series, excepting a first wave packet, is initiated upon detection of arrival at said transducer of an immediately preceding wave packet in said series, and the detection comprises identifying a particular part of a waveform received at said transducer after arming a receiving arrangement that detection is imminent, characterised in that said method includes, prior to transmission of said series, transmitting a single acoustic wave packet to said transducer and determining a nominal propagation time of said single wave packet by identifying a corresponding particular part of a corresponding waveform received without arming said receiving arrangement, whereby said nominal propagation time is used to arm said receiving arrangement for the detection of each said wave packet within said series.
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5. An electronic fluid meter comprising:
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a duct through which a fluid can flow;
at least two acoustic transducers arranged within said duct to transmit acoustic energy therebetween, said transducers being separated by a predetermined distance defining a measurement portion;
a control system for causing transmission and monitoring reception of acoustic wave packets between said transducers, said control system comprising;
first means for determining a nominal time of propagation of a single acoustic wave packet, said first means comprising;
(i) second means for simultaneously starting a timer and transmitting said single acoustic wave packet to said transducer;
(ii) third means for receiving said single acoustic wave packet at said transducer; and
(iii) fourth means for identifying a predetermined part of said wave packet and stopping said timer to thereby determine said nominal time of propagation;
fifth means for transmitting said series of acoustic wave packets to said transducer wherein the transmission of any one wave packet within said series, excepting a first wave packet, is initiated upon detection of arrival of an immediately preceding wave packet in said series;
sixth means for, upon each transmission of said wave packet, starting a timer; and
seventh means for determining when said timer is within a predetermined time of said nominal time of propagation to then enable identification of said predetermined part of the corresponding wave packet to thereby detect the arrival of said corresponding wave packet. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A method of measuring a fluid flow parameter, said method comprising the steps of:
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transmitting an ultrasonic test pulse from a first location within a fluid flow path, receiving said ultrasonic test pulse at a second location within the fluid flow path to determine a time delay value between a start of transmission of said test pulse and a zero amplitude crossing of said received ultrasonic test pulse, thereafter transmitting from said first location, a plurality of successive ultrasonic measurement pulses for reception at said second location, said reception being detected by crossing said zero amplitude after expiration of said time delay value, said transmission being started simultaneously with reception of the preceding ultrasonic measurement pulses. - View Dependent Claims (12, 13)
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Specification