Radar Level Gauge Spacer Arrangement
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Solution Overview
Problem
Conventional radar level gauge systems experience measurement disturbances due to spacer reflections, especially in high-frequency applications and high-temperature, high-pressure environments, where ceramic spacers are preferred but cause stronger reflections, and low-reflection materials like PTFE may not adequately minimize interference.
Innovation Solution
A guided wave radar level gauge system with a multi-conductor probe featuring a first and second probe conductor, where spacers are configured to allow fluid flow and have extensions corresponding to a quarter of the transmit signal's wavelength, creating impedance variations to minimize combined spacer reflections, allowing for the use of a variety of materials including ceramics and facilitating FMCW techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic spacers are used in high-temperature high-pressure applications, then the spacers can withstand the harsh environment, but the spacer reflections become stronger and detrimental to measurement quality
Solution Approach 1:
The patent converts the harmful strong reflection property of ceramic spacers into a beneficial effect by precisely controlling the spacer extension length to correspond to a quarter wavelength of the transmit signal. This creates an impedance transformation effect where the spacer reflection is transformed into a useful impedance matching mechanism, reducing measurement disturbances while maintaining the mechanical durability of ceramic materials in harsh environments.
Solution Approach 2:
The patent changes the critical parameter of spacer extension length to specifically match a quarter wavelength of the transmit signal at the center frequency. This parameter optimization transforms the spacer from a harmful reflective element into a beneficial impedance transformation element, enabling the use of durable ceramic materials without compromising measurement quality.
2Measurement precision
If higher frequencies (1-2 GHz) are used for the transmit signal, then measurement sensitivity is improved, but the measurements become significantly more sensitive to spacer reflections
Solution Approach 1:
The patent optimizes the spacer extension length parameter to correspond to a quarter wavelength of the higher frequency transmit signal. This parameter adjustment ensures that even at higher frequencies where measurements are more sensitive to spacer reflections, the spacers create a beneficial impedance transformation effect rather than harmful reflections, enabling improved measurement sensitivity without the usual penalty of increased spacer interference.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces measurement disturbances by controlling spacer reflections, enabling accurate filling level determination in various environments and allowing for the use of a broader range of spacer materials, including ceramics, while maintaining measurement quality.
Implementation Method 1
an electromagnetic surface echo signal resulting from reflection of the transmit signal at a surface of the product
Implementation Method 2
each spacer in the plurality of spacers is configured in such a way that said multi-conductor probe, within said spacer extension, exhibits a first probe portion with a first impedance, a second probe portion with a second impedance, and a third probe portion, between said first probe portion and said second probe portion, with a third impedance lower than said first impedance and said second impedance
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A radar level gauge system comprising a transceiver; a multi-conductor probe comprising a first probe conductor and a second probe conductor extending together from an upper probe end to a lower probe end; a plurality of spacer arrangements distributed along the multi-conductor probe; and processing circuitry for determining the filling level. Each spacer arrangement in the plurality of spacer arrangements comprises a first spacer member configured to reflect a transmit signal as a first spacer reflection signal having a first amplitude; and a second spacer member configured to reflect the transmit signal as a second spacer reflection signal having a second amplitude. The first spacer member and the second spacer member are arranged along the multi-conductor probe so that the first and second spacer reflection signals interact to provide a combined spacer reflection signal having an amplitude lower than each of the first amplitude and the second amplitude.