Liquid Storage Venting with Inert Gas and Pressure Control

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Solution Overview

Problem

Existing liquid storage systems face challenges in maintaining a gas space above the liquid level with low oxygen concentration and appropriate pressure to prevent metal corrosion and flammable liquid fires, while ensuring efficient liquid pumping.

Innovation Solution

A liquid storage system with a vent pipe and pressure control apparatus that introduces nonflammable gases, such as argon, and uses check valves to regulate pressure within a predetermined range, combined with an oxygen filter to minimize oxygen concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a non-valve vent pipe is used to provide constant communication between the gas space and atmosphere, then the pressure in the gas space is maintained close to ambient atmospheric pressure, but oxygen enters the gas space causing metal corrosion and potential fire hazards

Engineering Contradiction:
Improvepressure in gas spaceVSAvoidoxygen concentration in gas space
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a valve as an intermediary component in the vent pipe system. This valve selectively controls the communication between the gas space and atmosphere, allowing pressure equalization while preventing oxygen ingress. The valve acts as a mediator that permits beneficial pressure regulation while blocking harmful oxygen entry.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs inert gas (such as nitrogen or carbon dioxide) to replace air in the gas space. By creating an inert atmosphere, the system maintains pressure control while eliminating oxygen that causes corrosion and fire hazards. The inert gas fills the gas space without reacting with the stored liquid or tank materials.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Object-affected harmful factors

If a vent pipe with atmospheric valve is used to prevent oxygen entry, then metal corrosion and fire hazards are reduced, but the pressure control in the gas space becomes insufficient for efficient liquid pumping

Engineering Contradiction:
Improvemetal corrosion and fire preventionVSAvoidpressure regulation in gas space
Core Design Contradiction:
Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The patent combines multiple functions into a single integrated vent system. The valve component simultaneously performs pressure regulation and oxygen exclusion, while the inert gas supply system provides both atmosphere control and pressure maintenance. This multi-functional design ensures both protection from corrosion/fire and adequate pressure for pumping.

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

Solution Approach 2:

The patent changes the composition parameter of the gas space from air (oxygen-containing) to inert gas (oxygen-free). This parameter change fundamentally alters the chemical properties of the gas space, preventing oxidation and combustion while allowing physical pressure regulation to function effectively for pumping operations.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the gas space is completely sealed to prevent oxygen entry, then corrosion and fire hazards are eliminated, but pressure reduction becomes excessive making liquid pumping difficult

Engineering Contradiction:
Improveoxygen exclusionVSAvoidpressure in gas space
Core Design Contradiction:
Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The patent uses a controllable valve as an intermediary to manage the sealed environment. The valve selectively opens to allow inert gas entry or pressure equalization when needed, and closes to maintain the oxygen-free sealed environment. This intermediary control mechanism prevents excessive pressure reduction while maintaining oxygen exclusion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state parameter of the gas space from completely sealed (fixed volume) to controllably sealed with pressure regulation. By introducing controlled pressure changes through the valve system, the maintain inert atmosphere while preventing excessive vacuum conditions that would hinder pumping operations.

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

The system effectively maintains a gas space with near-zero oxygen concentration and stable pressure, preventing corrosion and fires, while facilitating efficient liquid pumping by regulating pressure and oxygen levels.

Implementation Method 1

supplying an inert gas (for example, carbon dioxide) having a specific gravity larger than that of air into the tank and forming a layer of an inert gas vertically above the liquid level

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

a pressure control apparatus installed in the vent pipe to operate responsive to the pressure difference between the gas space and ambient atmosphere so as to limit the pressure in the gas space to a predetermined range including ambient atmospheric pressure

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 3

the pressure control apparatus is configured to discharge the gas from the gas space out of the tank through the vent pipe when the pressure in the gas space is higher than or equal to a predetermined upper limit by gauge pressure

Methodology Applied
Scientific EffectPressure relief: Pressure Gradient

Implementation Method 4

a pressure relief valve that is a check valve for allowing a flow of gas from the gas space to outside of the tank and for stopping a flow of air from outside of the tank to the gas space in the vent pipe

Methodology Applied
Scientific EffectCheck valve mechanism: Valve

Data Source

PatentEP3453644B1Liquid storage system and method of supplying nonflammable gases in the same
Publication Date: 2020.04.15 KK TOSHIBA
  • EP3453644B1 patent drawingFigure 1
  • EP3453644B1 patent drawingFigure 2
  • EP3453644B1 patent drawingFigure 3

AI summary

According an embodiment, a liquid storage system comprises a tank (10) for storing liquid fuel (20), a vent pipe (40) for providing communication between outside of the tank (10) and a gas space (22) above a level (21) of liquid fuel (20) in the tank (10), a nonflammable gas supplying apparatus (30) for supplying the gas space (22) with nonflammable gases, a pressure control apparatus (50) installed in the vent pipe (40) to operate responsively to the pressure difference between the gas space (22) and atmospheric pressure so as to limit a pressure in the gas space (22) to a predetermined range. The pressure control apparatus (50) introduces ambient air outside the tank (10) into the gas space (22) through the vent pipe(40) when the pressure in the gas space (22) is lower than a predetermined lower limit, and discharge the gas from the gas space (22) out of the tank (10) through the vent pipe (40) when the pressure in the gas space (22) is higher than a predetermined upper limit.