Method and apparatus for radar-based level gauging

Abstract

A method for radar-based gauging of the level of a substance in a tank (13) having at least one interfering structure (16a-c), comprises the steps of: (i) transmitting a microwave signal in a plurality of radiation lobes (15a-b; 15a-d), each of which being individually directed towards the substance and at least one of which being directed towards the interfering structure; (ii) for each of the radiation lobes detecting temporally resolved the microwave signal as reflected against the substance, and for at least one of the lobes detecting the microwave signal as reflected against the interfering structure; (iii) based on signal strengths of the detected microwave signals, distinguishing the detected microwave signals, which have been reflected against the substance; and (iv) based on a propagation time of at least one of the microwave signals distinguished as those, which have been reflected against the substance, calculating the level of the substance.

Description

[0001] The invention relates generally to level gauging, and more specifically the invention relates to a method and an apparatus for radar-based level gauging.BACKGROUND OF THE INVENTION AND RELATED ART[0002] Radar-based methods are extensively used for level gauging, i.e. measuring a distance from the top of a tank to a surface of a liquid or some kind of granular solid stored in the tank, by means of transmitting a microwaves towards the surface of the liquid or the granular solid, receiving the microwaves as reflected against the surface of the liquid or solid, and calculating the level of the liquid or solid in the tank from the propagation time of the transmitted and reflected microwaves.[0003] One very general problem in this respect is that the tank typically includes various structures, such as support beams, pipes, agitators, tank walls, etc. Such structures may also reflect microwaves, which can interfere with the microwaves reflected from the surface of the liquid or sol...

AI Technical Summary

Benefits of technology

The invention is about a method and apparatus for radar-based level gauging in tanks with interfering structures, such as support beams, pipes, and tank walls. The method involves transmitting microwaves in multiple directions and detecting the reflected signals from the surface of the liquid or solid in the tank. By analyzing the signal strengths and propagation time of the reflected signals, the method can distinguish the signals reflected from the surface of the liquid or solid and use them to calculate the level of the substance in the tank. The invention provides a reliable, efficient, accurate, and precise method for level gauging in tanks with interfering structures.

Problems solved by technology

One very general problem in this respect is that the tank typically includes various structures, such as support beams, pipes, agitators, tank walls, etc.

Such structures may also reflect microwaves, which can interfere with the microwaves reflected from the surface of the liquid or solid, the level of which being gauged.

Furthermore when the echo from the surface is close to a disturbing echo there is a possibility for a large measuring error.

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