Ultrasonic level measurement apparatus and method having variable transmit power
AssigneeMobrey Limited
InventorsJeffery Allan Sears, Luis Filipe Da Silva Ribeiro Coelho
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Abstract
The invention provides a method for improving the accuracy of level measurement by reducing or eliminating receive circuit saturation in ultrasound level measurement apparatus. The method involves adjusting the transmit power in order to control echo amplitude, in particular to avoid saturation, when the surface being monitored is within a pre-defined distance from the ultrasound transducer. The particular advantage of the invention is that it may be implemented without change to the electronic circuitry embodied in the apparatus.
Claims8
A method of determining the level of a material surface in a confined space, from a position above said surface, using an ultrasound transducer positioned above said surface, said method including the steps of:
- causing said transducer to transmit pulses of ultrasound toward said surface;
- receiving echo signals arising from said pulses being reflected from said surface;
- and
- processing said echo signals to determine the distance from said transducer to said surface,
- said method being characterized in that energy applied to the creation of said pulses is reduced by reducing the amplitudes of the transmitted pulses when the distance between said transducer and said surface is less than a defined distance and the amplitudes of said echo signals exceed a pre-defined amplitude.
Apparatus for determining the level of a material surface in a confined space, from a position above said surface, said apparatus including:
- an ultrasound transducer positionable above said surface,
- a transmit circuit operable to cause said transducer to transmit pulses of ultrasound toward said surface;
- a receive circuit operable to receive echo signals arising from said pulses being reflected from said surface;
- and
- a processing circuit operable to process said echo signals to determine the distance from said transducer to said surface,
- said apparatus being characterized in that said transmit circuit under the command of said processing circuit is configured to apply less energy to the creation of said pulses by reducing the amplitudes of the transmitted pulses when the distance between said transducer and said surface is less than a defined distance and the amplitudes of said echo signals exceed a pre-defined amplitude.
Dependencies are inferred from the claim text.