Radar Level Gauge Probe Open End Design
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Solution Overview
Problem
Current GWR-type radar level gauge systems face challenges in accurately determining filling levels close to the end of the probe due to reflections at the probe end, resulting in a lower dead zone or blind zone.
Innovation Solution
The method involves determining the level of the product surface based on the position along the probe where the echo signal strength reaches a predetermined threshold value, and an offset distance from that position towards the second probe end, without requiring a highly inductive probe termination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a highly inductive probe termination is used to reduce the lower dead zone, then the measurement precision is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the problematic probe termination section and replaces it with a simple open end. By removing the complex inductive termination structure and using a simple open end instead, the invention eliminates the source of measurement errors while maintaining the ability to measure filling levels accurately, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
Instead of adding complexity to the probe termination to reduce the lower dead zone, the invention inverts the approach by using a simple open end that naturally eliminates the dead zone effect. This inversion of the conventional wisdom leads to a simpler device that achieves the same or better measurement accuracy
2Measurement precision
If a highly inductive probe termination is used to reduce the lower dead zone, then the measurement precision is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent removes the complex inductive termination section from the probe, eliminating the need for high-precision manufacturing of specialized termination components. The simple open end design requires only basic manufacturing tolerances, thus resolving the contradiction between measurement precision and manufacturing precision requirements
Solution Approach 2:
The invention uses a simple, easily manufactured open end design that can be produced with standard manufacturing tolerances, replacing the need for expensive, precision-critical inductive termination components. This approach maintains measurement accuracy while significantly reducing manufacturing complexity and cost
3Measurement precision
If a highly inductive probe termination is used to reduce the lower dead zone, then the lower dead zone is reduced, but the robustness of the probe decreases
Solution Approach 1:
The patent removes the fragile inductive termination section from the probe structure. By eliminating this complex and vulnerable component, the probe becomes more robust and less sensitive to damage from mechanical stress, chemical exposure, and environmental factors, while still achieving accurate measurements through the simple open end design
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 approach reduces or eliminates the lower dead zone, making the radar level gauge system more robust, less sensitive to damage and disturbances, and suitable for a broader range of applications, while also simplifying manufacturing and installation.
Implementation Method 1
The electromagnetic signals are reflected at the surface of the product, and the reflected signals are received by a receiver or transceiver comprised in the radar level gauge system
Implementation Method 2
the distance to the surface of the product is generally determined based on the time between transmission of an electromagnetic signal and receipt of the reflection thereof
Implementation Method 3
EP 2 012 098 proposes to inductively connect the inner conductor and the outer conductor with a spiral spring at the end of the probe. The inductive connection between the inner conductor and the outer conductor delays the reflection (echo) from the probe end
Data Source
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AI summary
In summary, the present invention thus relates to a method of determining a level of a product in a tank, comprising generating and transmitting an electromagnetic transmit signal; guiding the transmit signal towards and into the product; returning an electromagnetic reflection signal resulting from reflection of the transmit signal; receiving, the reflection signal; determining, based on the reflection signal and a timing relation between the reflection signal and the transmit signal, an echo signal exhibiting an echo signal strength as a function of a propagation parameter indicative of position along the probe; and determining the level of the surface of the product based on a propagation parameter value indicative of a first threshold position along the probe for which the echo signal has reached a predetermined threshold signal strength, and an offset indicative of an offset distance along the probe from the first threshold position towards the second probe end.