Method for measuring a speed of a fluid
AssigneeSagemcom Energy & Telecom SAS
InventorHenri Teboulle
Life of this patent
Estimating the term…
Abstract
A method of measuring the speed of a fluid comprising the following steps: generating a plurality of pseudorandom frequencies (fus_n); for each pseudorandom frequency (fus_n), emitting ultrasound signals into the fluid to travel along a path of defined length; receiving the ultrasound signals; for each received ultrasound signal, producing a travel time measurement, so as to generate for each pseudorandom frequency (fus_n) a predefined number of travel time measurements; for each pseudorandom frequency (fus_n), evaluating the accuracy of the measurements; for evaluating the speed of the fluid, making use of the measurements produced for the pseudorandom frequency that presents the greatest accuracy.
Claims26
A method of measuring the speed of a fluid, the method comprising:
- measurement stages, each comprising the following steps:
- generating a plurality of pseudorandom emission frequencies (fus_n);
- for each pseudorandom emission frequency (fus_n), producing travel time measurements representative of times taken by ultrasound measurement signals emitted at said pseudorandom emission frequency to travel along a path of defined length;
- for each pseudorandom emission frequency (fus_n), evaluating the accuracy of the travel time measurements;
- and
- for evaluating the speed of the fluid, making use of the travel time measurements produced for the pseudorandom emission frequency (fus_k) that presents the greatest accuracy;
- and
- detection stages, each performed between two measurement stages, each detection stage comprising the following steps:
- measuring an interfering ultrasound signal level present in the fluid;
- comparing the interfering ultrasound signal level with a current value of a detection threshold, the detection threshold being capable of taking a plurality of predefined values lying between a maximum detection threshold and a minimum detection threshold;
- if the measured interfering ultrasound signal level is less than the current value of the detection threshold, reducing the current value of the detection threshold, and reiterating the measurement step and the comparison step;
- and
- when the measured interfering ultrasound signal level becomes greater than or equal to a limit current value of the detection threshold, detecting a disturbance and, as a function of the limit current value of the detection threshold, determining whether the disturbance comes from an anomaly or from an attempted fraud.
A method of measuring the speed of a fluid, the method comprising measurement stages, each comprising the following steps:
- generating a plurality of pseudorandom emission frequencies (fus_n);
- for each pseudorandom emission frequency (fus_n), producing travel time measurements representative of times taken by ultrasound measurement signals emitted at said pseudorandom emission frequency to travel along a path of defined length;
- for each pseudorandom emission frequency (fus_n), evaluating the accuracy of the travel time measurements;
- for evaluating the speed of the fluid, making use of the travel time measurements produced for the pseudorandom emission frequency (fus_k) that presents the greatest accuracy;
- the measurement method being such that, for each pseudorandom emission frequency (fus_n), evaluating the accuracy of the travel time measurements comprises a step of calculating a mean M′fus_n of the travel time measurements, and a step of determining a number of inaccurate travel time measurements lying outside a range [M′fus_n−X, M′fus_n+X], the emission frequency that presents the greatest accuracy being the frequency for which the number of inaccurate travel time measurements is the lowest,
- wherein the measurement method further comprises detection stages, each performed between two measurement stages, each detection stage comprising the following steps:
- measuring an interfering ultrasound signal level present in the fluid;
- comparing the interfering ultrasound signal level with a current value of a detection threshold, the detection threshold being capable of taking a plurality of predefined values lying between a maximum detection threshold and a minimum detection threshold;
- if the measured interfering ultrasound signal level is less than the current value of the detection threshold, reducing the current value of the detection threshold, and reiterating the measurement step and the comparison step;
- when the measured interfering ultrasound signal level becomes greater than or equal to a limit current value of the detection threshold, detecting a disturbance and, as a function of the limit current value of the detection threshold, determining whether the disturbance comes from an anomaly or from an attempted fraud.
Dependencies are inferred from the claim text.