Single conductor probe gwr system with reduced end of nozzle reflection

Abstract

A radar level gauge system (1), for determining a filling level of a product (6) contained in a tank (5), comprising a transceiver (10) arranged outside the tank for generating, transmitting and receiving electromagnetic signals; a single conductor probe (3) arranged inside the tank and electrically connected to the transceiver via a feed-through (15; 19) arranged at the top of a nozzle (16) of the tank. The single conductor probe (3) extends through the nozzle (16) towards and into the product contained in the tank, for guiding a transmitted signal (S T ) from the transceiver towards a surface of the product, and for returning a surface echo signal (S R ) resulting from reflection of the transmitted signal at the surface back towards the transceiver. An impedance matching arrangement (35; 40; 44; 48) is provided to the probe (3) and extends along a portion of the probe. An extension of the impedance matching arrangement (35; 40; 44; 48), in a direction perpendicular to the probe (3), is constant or changes with increasing distance from the feed-through (15; 19) with a first rate of change inside the nozzle (16), and changes with increasing distance from the feed-through (15; 19) with a second, negative rate of change below the nozzle (16) over a distance corresponding to at least a quarter of a wavelength of the transmitted signal (S T ). The second rate of change is more negative than the first rate of change.

Description

technical field [0001] The invention relates to a GWR (Guided Wave Radar) type radar level gauge system for determining the fill level of a product contained in a tank. Background technique [0002] Radar level gauge (RLG) systems are widely used to determine the fill level of product contained in tanks. Radar level gauging is generally performed by means of non-contact measurement, which emits an electromagnetic signal towards the product contained in the tank, or contact measurement, commonly known as Guided Wave Radar (GWR), which relies on Probes guide and guide electromagnetic signals into the product. The probes are generally arranged to extend vertically from the top of the tank to the bottom of the tank. The probe can also be arranged in a measuring tube, the so-called cavity, which is connected to the outer wall of the tank and fluidly connected to the inside of the tank. [0003] The transmitted electromagnetic signal is reflected at the surface of the product a...

AI Technical Summary

Problems solved by technology

There will therefore only be a large impedance step, but since this impedance step is positioned below the spout end, the area of ​​the tank top where reliable fill height measurements cannot be made (the so-called "dead zone") will start at the end of the mouthpiece and will still be evident

Additionally, there will still be significant signal loss, which limits the maximum measurable distance

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