Radar Level Measurement Using Guided Wave Probe

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Solution Overview

Problem

Conventional methods for detecting the level of liquid in a vessel, especially when a supercritical fluid is present above the liquid, are ineffective due to difficulties in discriminating between the liquid and supercritical phases, particularly in corrosive environments like the urea synthesis from ammonia and carbon dioxide, where the liquid is boiling, and existing radar-based solutions face unfavorable signal-to-noise ratios and maintenance challenges.

Innovation Solution

A radar method utilizing a tube to guide radar waves to the liquid surface within the vessel, incorporating a reflective bottom surface and strategically positioned holes to reduce liquid movement and enhance interface detection, while using corrosion-resistant materials and heating to prevent condensation, allowing for accurate level measurement in corrosive and dynamic conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional radar methods are used to measure liquid level in a vessel with supercritical fluid, then the measurement can be performed non-contact, but the signal-to-noise ratio is highly unfavorable making detection impossible

Engineering Contradiction:
Improveliquid level detection accuracyVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A probe rod acts as an intermediary element between the radar transmitter and the liquid surface. The rod guides electromagnetic waves along its surface, enabling the radar signal to reach the liquid interface effectively even in the presence of supercritical fluid, thereby improving signal-to-noise ratio and measurement reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state or configuration of the measurement system by introducing a solid probe rod that modifies how electromagnetic waves propagate through the medium, allowing effective signal transmission where direct radar fails

Inventive Principle:
Principle #35Parameter changes

2Reliability

If radioactive measurement methods are used for liquid level detection, then measurement can be performed in corrosive environments, but safety hazards and maintenance requirements increase significantly

Engineering Contradiction:
Improvemeasurement capability in corrosive environmentVSAvoidsafety hazards and maintenance intensity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention replaces radioactive measurement methods with electromagnetic radar measurement using a probe rod. This substitution eliminates all safety hazards associated with radioactive materials while maintaining the capability to measure liquid levels in corrosive environments, as the non-contact radar method requires no direct interaction with the corrosive medium

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The probe rod can be made from inexpensive, easily replaceable materials. If corrosion or damage occurs, the entire rod can be quickly replaced without complex maintenance procedures, reducing both maintenance intensity and operational downtime

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If standard radar waves are transmitted directly into the vessel, then the system is simple, but the boiling liquid creates excessive noise and movement making interface detection impossible

Engineering Contradiction:
Improveradar system structureVSAvoidinterface detection capability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The probe rod serves as a mediator that channels electromagnetic waves along its length to the liquid interface. This guided wave approach isolates the measurement signal from the noisy environment of boiling liquid, enabling precise interface detection without requiring complex noise filtering systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The measurement function is segmented into two parts: the probe rod handles signal transmission to the interface, while the radar electronics remain outside the harsh environment. This segmentation allows simple overall system design while achieving precise measurements

Inventive Principle:
Principle #1Segmentation

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

The method effectively measures the level of liquid in vessels with supercritical fluids above, even when the liquid is boiling, by improving signal clarity and reducing maintenance needs, suitable for corrosive environments like urea synthesis reactors.

Implementation Method 1

A radar dish, or antenna, transmits pulses of radio waves or microwaves which bounce off any object in their path. The object returns a tiny part of the wave's energy to a dish or antenna which is usually located at the same site as the transmitter.

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

transmits pulses of radio waves or microwaves which bounce off any object in their path

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

In order to avoid condensation of water vapor on the radar antenna, it is heated by means of an electric heater or similar device

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2753902B1Radar level measurement
Publication Date: 2019.06.26 STAMICARBON BV
  • EP2753902B1 patent drawingFigure 1~3
  • EP2753902B1 patent drawingFigure 4

AI summary

Disclosed is a method of measuring the level of a liquid in a vessel, such as a chemical reactor, by radar. The method particularly pertains to situations wherein a supercritical fluid is present above the liquid. More particularly, the method serves to cope with the typical vigorous circumstances of a chemical reaction, such as urea synthesis. The invention foresees the use of a tube extending into the liquid, so as to guide the radar waves to the surface level of the liquid.