Method of measuring the temperature of water in a meter

A measurement method for measuring the temperature of water, the method being performed at least in part in a meter and comprising:

• causing an emitter transducer of the meter to emit an ultrasonic measurement signal, and acquiring an electrical measurement signal produced by a receiver transducer of the meter when it receives the ultrasonic measurement signal after the ultrasonic measurement signal has travelled along a path of defined length in the water;
• measuring a speed of the ultrasonic measurement signal in the water;
• measuring a level of the electrical measurement signal;
• using the level of the electrical measurement signal to determine whether the temperature of the water is less than or greater than an inflection temperature corresponding to a point of inflection in a curve plotting the speed of sound in water as a function of the temperature of the water;
• estimating the temperature of the water from the speed of the ultrasonic measurement signal by using a first formula if the temperature of the water is less than the inflection temperature, and by using a second formula if the temperature of the water is greater than the inflection temperature;
• and
• for determining whether the temperature of the water is less than or greater than the inflection temperature, comparing the level of the electrical measurement signal with a predefined threshold that is equal to a first reference level of the electrical measurement signal multiplied by a reference factor, the first reference level being previously measured during a stage of calibrating the meter while the temperature of the water is equal to a first reference temperature, and the reference factor corresponding to the variation in the level of the electrical measurement signal that is to be expected form the temperature difference between the first reference temperature and the inflection temperature.

A measurement method for measuring the temperature of water, the method being performed at least in part in a meter and comprising:

• causing an emitter transducer of the meter to emit an ultrasonic measurement signal, and acquiring an electrical measurement signal produced by a receiver transducer of the meter when it receives the ultrasonic measurement signal after the ultrasonic measurement signal has travelled along a path of defined length in the water;
• measuring a speed of the ultrasonic measurement signal in the water;
• measuring a level of the electrical measurement signal;
• using the level of the electrical measurement signal to determine whether the temperature of the water is less than or greater than an inflection temperature corresponding to a point of inflection in a curve plotting the speed of sound in water as a function of the temperature of the water;
• and
• estimating the temperature of the water from the speed of the ultrasonic measurement signal by using a first formula if the temperature of the water is less than the inflection temperature, and by using a second formula if the temperature of the water is greater than the inflection temperature,
• wherein the level of the electrical measurement signal is equal to the mean of the amplitudes of a plurality of lobes, said lobes being situated in the middle of a portion of the electrical measurement signal in which said electrical measurement signal presents an amplitude that is substantially constant.