Post-Tensioned Concrete Fermentation Tank Roof for Gas-Tight Access

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Solution Overview

Problem

Concrete fermentation tanks suffer from gas leaks due to crack formation in the roof structure, necessitating frequent repairs and complicating the installation of technical infrastructure, while the dome-shaped roof design complicates access and maintenance.

Innovation Solution

A self-supporting concrete roof structure is achieved through post-tensioning with metal tendons located in the lower half, eliminating the need for heavy crossbeams and allowing a flat or slightly sloped design, which minimizes cracks and maintains gas-tightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a dome-shaped concrete roof structure is used, then the structural strength is improved, but the installation of technical infrastructure becomes complex and requires additional walkways

Engineering Contradiction:
Improvestructural strengthVSAvoidinstallation of technical infrastructure
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent inverts the conventional dome-shaped roof design by using a flat or slightly sloped roof structure. This inversion maintains structural strength through post-tensioning while dramatically simplifying the installation of technical infrastructure, eliminating the need for complex walkways and providing easy access to equipment.

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

Solution Approach 2:

The patent changes the geometric parameters of the roof from a curved dome shape to a flat or slightly sloped configuration. This parameter change, combined with post-tensioning technology, maintains structural integrity while improving ease of operation for installing and maintaining technical infrastructure.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a heavy concrete roof structure is used, then the structural stability is improved, but the internal volume of the concrete tank is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoidinternal volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The patent replaces the conventional mechanical support system (heavy concrete crossbeams) with a post-tensioning system using metal tendons. This substitution maintains structural stability through tensile forces while eliminating the need for heavy supporting elements, thereby maximizing the internal volume of the fermentation tank.

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

Solution Approach 2:

The post-tensioning system applies counteracting tensile forces through metal tendons to compensate for the weight of the concrete roof structure. This anti-weight mechanism allows the use of lighter concrete sections while maintaining structural stability, thus increasing the available internal volume.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Volume of moving object

If the concrete roof structure is made lighter, then the internal volume is increased, but crack formation occurs due to sagging under own weight

Engineering Contradiction:
Improveinternal volumeVSAvoidgas-tightness
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies post-tensioning to the concrete roof structure after casting, creating preliminary compressive forces that counteract the tensile stresses from sagging. This preliminary action prevents crack formation before the structure is put into service, ensuring long-term gas-tightness while maintaining a lightweight design for maximum internal volume.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The post-tensioning system applies preliminary anti-action forces to counteract the harmful tensile stresses that would otherwise cause cracking. By pre-applying these counteracting forces, the structure remains crack-free and gas-tight despite being lightweight and having large internal volume.

Inventive Principle:
Principle #9Preliminary anti-action

4Strength

If reinforcement meshes are installed in the concrete roof structure, then the structural strength is improved, but small cracks still form allowing gas leaks

Engineering Contradiction:
Improvestructural strengthVSAvoidgas-tightness
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent supplements or replaces conventional reinforcement meshes with a post-tensioning system using metal tendons. This mechanical system applies continuous compressive forces that prevent crack formation at the source, providing superior gas-tightness compared to passive reinforcement meshes that only resist cracks after they form.

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

Solution Approach 2:

The patent changes the stress state parameters of the concrete roof by applying post-tensioning forces, transforming the concrete from a tensile-stressed state (prone to cracking) to a compressive-stressed state (crack-resistant). This parameter change ensures long-term gas-tightness while maintaining structural strength.

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 solution results in a longer lifespan of up to 50 years with reduced maintenance needs, simplified infrastructure placement, and enhanced gas retention, avoiding immediate leaks and facilitating easy access.

Implementation Method 1

The concrete roof structure is post-tensioned by means of multiple metal tendons in the concrete roof structure

Methodology Applied
Scientific EffectPost-tensioning: Tension

Implementation Method 2

The concrete roof structure will heat up and cool down due to environmental factors, causing the concrete to expand and contract

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4682329A1Concrete tank for fermentation with optimized roof construction, method for manufacturing and use of such concrete tank for fermentation
Publication Date: 2026.01.21 BIO-DYNAMICS NV
  • EP4682329A1 patent drawingFigure 1
  • EP4682329A1 patent drawingFigure 2
  • EP4682329A1 patent drawingFigure 3

AI summary

The present invention relates to a concrete tank for fermentation comprising a concrete floor slab, a cylindrical concrete side wall, and a concrete roof structure, wherein the concrete roof structure is a self-supporting concrete structure, wherein the concrete roof structure is post-tensioned by means of a plurality of metal tendons in the concrete roof structure, wherein the metal tendons form chords of a circle, wherein the circle is concentric with a circular cross-section of the cylindrical concrete side wall and wherein the metal tendons, as viewed in a height direction, are located in a lower half of the concrete roof structure. The invention also relates to a method for manufacturing a concrete tank for fermentation and to the use of such a concrete tank for fermentation of biomass.