Horizontal Tank Leak Detection via External Pressure

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Solution Overview

Problem

Current storage tank leak detection systems are imprecise and unable to effectively detect small leaks in large, horizontally disposed cylindrical tanks, particularly due to issues with fluid expansion, temperature changes, and external factors, leading to environmental and economic consequences.

Innovation Solution

A precise mass measurement system combined with real-time density measurement of storage tank contents using a quartz crystal differential pressure transducer and data correction techniques to account for temperature and tank shell variations, allowing for direct and quantitative leak detection without internal pressure or vacuum application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If typical leak detection methods using internal pressure or vacuum are applied, then leak detection capability is improved, but tank safety is worsened due to exposure to failure

Engineering Contradiction:
Improveleak detection capabilityVSAvoidtank safety
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

Instead of applying pressure or vacuum inside the tank to detect leaks, the patent applies pressure from outside the tank (using a flexible membrane against the tank exterior) to create a pressure differential that causes inward deformation. This reverses the conventional approach, eliminating the need to pressurize the tank contents while still enabling leak detection through measurement of tank wall deformation and fluid level changes.

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If mass measurement based leak detection is used in horizontal cylindrical tanks, then leak detection is simplified, but measurement accuracy is worsened due to fluid expansion and temperature changes

Engineering Contradiction:
Improvedetection system simplicityVSAvoidleak determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a flexible membrane as an intermediary element placed against the tank exterior. This membrane transmits external pressure to the tank wall and simultaneously serves as a reference for measuring tank deformation. By using this intermediary, the system can distinguish between mass changes caused by leaks versus those caused by thermal expansion or contraction, thereby maintaining measurement simplicity while improving accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical leak detection methods (pressure testing, visual inspection) with a system based on measuring mechanical deformation of the tank wall and correlating it with fluid level changes. Instead of directly measuring leak flow, the system measures the mechanical response of the tank structure to controlled external pressure, substituting direct mechanical leak detection with indirect structural response measurement.

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

3Reliability

If multiple detection probes are used for leak detection, then detection thoroughness is improved, but system complexity is worsened

Engineering Contradiction:
Improvedetection thoroughnessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple detection functions into a single integrated system. Instead of using separate probes for pressure measurement, fluid level detection, and temperature monitoring, the invention uses a unified approach where external pressure application and tank deformation measurement are combined with fluid level monitoring to collectively detect leaks. This merging reduces the number of separate components while maintaining comprehensive detection capability.

Inventive Principle:
Principle #5Merging (Combining)

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 system provides a low detection threshold for leaks, minimizing production downtime and environmental impact, with the ability to detect leaks as small as 0.1 gallons per hour in 50,000 gallon tanks with high accuracy, surpassing existing systems.

Implementation Method 1

A precise mass measurement system combined with real-time density measurement of storage tank contents using a quartz crystal differential pressure transducer

Methodology Applied
Scientific EffectDifferential pressure measurement:

Implementation Method 2

the fluid product level in the tank rises due to the warming (expansion) of the tank's liquid contents

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2399111B1Method and apparatus for leak detection in horizontal cylindrical storage tanks
Publication Date: 2020.06.17 MASS TECHNOLOGY CORP
  • EP2399111B1 patent drawingFigure 1
  • EP2399111B1 patent drawingFigure 2
  • EP2399111B1 patent drawing

AI summary

A safe, precise, and cost effective storage tank leak detection system. Embodiments include two highly precise quartz crystal type pressure transducers held at a constant temperature. A bubbler to achieve access to the hydrostatic pressure at the tank bottom and just below the liquid surface. First transducer and bubbler are used to measure fluid mass while second transducer and bubbler are used to measure fluid density then used in combination with data correction and regression techniques to yield a storage tank leak detection system for use in horizontal cylindrically shaped tanks with an extremely low leak detection threshold. The storage tank leak detection system is thought to be most useful for detecting and measuring very small leaks in large horizontal cylindrical storage tanks.