Density Measurement Accuracy in Storage Tanks

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Solution Overview

Problem

Current density measurement techniques in storage tanks based on the buoyancy principle face challenges in achieving high accuracy, with existing solutions often having an accuracy of 3 to 5 Kg/m3, which is insufficient to meet new standards requiring 0.5 Kg/m3 accuracy due to varying regional and country-specific regulations.

Innovation Solution

The proposed method involves performing both buoyancy and pressure measurements in storage tanks to improve density measurement accuracy. This includes using an electromechanical servo gauge for buoyancy measurements and a pressure sensor for pressure measurements, with the average density calculated from both measurements to enhance accuracy. Additionally, the method compensates for offset errors by using the average density determined at the highest product level in the tank.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If buoyancy measurement alone is used for density measurement, then the measurement method is simple and direct, but the measurement accuracy is insufficient (3 to 5 Kg/m3)

Engineering Contradiction:
Improvemeasurement method simplicityVSAvoiddensity measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent combines buoyancy measurement and pressure measurement into a unified density measurement system. The buoyancy measurement provides direct density information while the pressure measurement provides complementary data that compensates for errors in the buoyancy measurement, achieving high accuracy (0.5 Kg/m3) without significantly increasing system complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure measurement acts as an intermediary that indirectly compensates for errors in the direct buoyancy measurement. By measuring pressure at different heights and using it to calculate density, the system can correct offset errors in the buoyancy measurement, thereby improving overall measurement accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If additional pressure sensors are added to improve density measurement accuracy, then measurement accuracy improves (to 0.5 Kg/m3), but device complexity increases

Engineering Contradiction:
Improvedensity measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pressure sensors in the system serve multiple functions: they measure pressure for density calculation, compensate for offset errors in buoyancy measurement, and can potentially be used for other process monitoring purposes. This multi-functionality justifies the added complexity by providing multiple benefits from a single addition

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes the measurement parameters by introducing pressure measurements in addition to buoyancy measurements. By measuring pressure at different heights and using these parameter changes to calculate density, the system achieves higher accuracy while managing complexity through mathematical processing rather than hardware complexity

Inventive Principle:
Principle #35Parameter changes

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 significantly improves the accuracy of density measurements in storage tanks, enabling compliance with stricter standards by reducing measurement errors and providing more precise density readings.

Implementation Method 1

Density measurements in storage tanks can be carried out using the buoyancy principle. The buoyancy principle states that an object submerged in a fluid experiences an upward force equal to the weight of the fluid it displaces.

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

performing a pressure measurement of pressure in the tank and determining a second density based on the pressure measurement

Methodology Applied
Scientific EffectPressure measurement:

Data Source

PatentEP4495575A1Improving accuracy by adding additional sensors to a density measuring system
Publication Date: 2025.01.22 HONEYWELL INTERNATIONAL INC
  • EP4495575A1 patent drawingFigure 1A
  • EP4495575A1 patent drawingFigure 1B
  • EP4495575A1 patent drawingFigure 2~3

AI summary

Methods, systems and devices for measuring density can involve performing a buoyancy measurement with respect to a product in a tank and determining a first density based on the buoyancy measurement. A pressure measurement of pressure in the tank can be performed and a second density determined based on the pressure measurement. The average density in the tank can be calculated based on the first and second densities. The average densities measured in two or more positions in the tank can be then combined to increase accuracy in measuring density within the tank.