Burner Flame Guard Lamellae With Thermal Gap Sealing

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Solution Overview

Problem

Existing combustion processes in drying drums for asphalt production suffer from inefficiencies, high pollutant emissions, and the need for complex flame protection systems, which are not adequately addressed by prior technologies.

Innovation Solution

A flame protection device with circumferentially arranged lamellae that form a non-contact labyrinth seal with a curved gap, utilizing thermal expansion to enhance sealing and turbulence, made from heat-resistant materials, which reduces gas leakage and enhances combustion efficiency while integrating seamlessly with the drying drum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a flame protection device with lamellae is used to protect the burner flame, then combustion efficiency is improved and pollutant emissions are reduced, but the device complexity increases due to the need for precise gap sealing between adjacent lamellae

Engineering Contradiction:
Improvecombustion efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent utilizes thermal expansion of the lamellae to automatically seal the gaps between adjacent lamellae during operation. At operating temperatures (300°C to 700°C), the lamellae expand thermally, causing the gaps to close and form an effective seal without requiring additional sealing mechanisms. This resolves the contradiction by using a natural physical phenomenon to achieve sealing, thereby improving combustion efficiency while avoiding the need for complex sealing systems.

Inventive Principle:
Principle #37Thermal expansion

2Loss of energy

If the gap between adjacent lamellae is reduced to improve sealing effect, then gas leakage is reduced and combustion efficiency improves, but manufacturing precision requirements increase due to the need for tight gap control

Engineering Contradiction:
Improvegas leakageVSAvoidmanufacturing precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent specifies that the gap width at cold state should be at most 5 mm (particularly at most 4.5 mm or 4 mm), which is relatively large and easy to manufacture. During operation, thermal expansion of the lamellae reduces this gap to a minimum width of at most 1.0 mm (particularly at most 0.8 mm, 0.5 mm, or even 0.3 mm), achieving effective sealing. This approach resolves the contradiction by performing the sealing function during operation rather than requiring tight manufacturing tolerances.

Inventive Principle:
Principle #37Thermal expansion

Solution Approach 2:

The patent changes the physical state and dimensions of the lamellae through temperature variation. The gap width dynamically changes from a larger cold-state value (at most 5 mm) to a smaller operating-temperature value (at most 1.0 mm), utilizing parameter change (thermal expansion) to achieve sealing without stringent manufacturing precision requirements.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the lamellae are made thicker to reduce thermal expansion and maintain gap stability, then gap control improves, but the heat-resistant material requirements and weight increase

Engineering Contradiction:
Improvegap stabilityVSAvoidheat-resistant material requirements
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent explicitly utilizes thermal expansion rather than attempting to minimize it. By designing the gap dimensions to accommodate controlled thermal expansion, the system achieves effective sealing at operating temperature without requiring excessively thick lamellae or specialized heat-resistant materials with near-zero expansion coefficients.

Inventive Principle:
Principle #37Thermal expansion

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 improves combustion efficiency, reduces pollutant emissions, and allows for increased use of recycled materials, offering a cost-effective and sustainable combustion process with reduced heat loss and material contamination risks.

Implementation Method 1

a gap is provided between the adjacent lumellae, which decreases and, in particular, closes during operation of the flame guard device due to thermal expansion of the lumellae

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

Its sealing effect is based on the lengthening of the flow path through the gap to be sealed, which significantly increases flow resistance

Methodology Applied
Scientific EffectFlow resistance: Drag

Implementation Method 3

the shaped elements on the side of the gap can cause turbulence of a gas flow in the flame protection device

Methodology Applied
Scientific EffectTurbulence: Turbulence

Data Source

PatentEP4513119B1Flame protection device for a burner and drying drum with such a flame protection device
Publication Date: 2025.12.24 BENNINGHOVEN ZWEIGNEIDERLASSUNG DER WIRTGEN MINERAL TECH GMBH
  • EP4513119B1 patent drawingFigure 1
  • EP4513119B1 patent drawingFigure 2
  • EP4513119B1 patent drawingFigure 3

AI summary

A flame protection device for a burner (3), in particular in a drying drum (2), in particular in an asphalt plant, has a central longitudinal axis (7) and several lamellae (9, 31) which are arranged in a circumferential arrangement in the circumferential direction (10) with respect to the central longitudinal axis (7), wherein lamellae (9, 31) arranged adjacent in the circumferential direction (10) are sealed by means of a circumferential gap seal.