Sintering Furnace Tray Stack Gas Flow

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Solution Overview

Problem

Sintering furnaces face challenges in achieving uniform temperature distribution, leading to inhomogeneous metallurgical parameters and shape distortion in sintered products, particularly in smaller furnaces, due to temperature gradients caused by non-uniform furnace atmosphere gas flow.

Innovation Solution

The design incorporates a retort with a stack of sintering trays and a peripheral wall with distributed holes for gas flow, along with heat exchangers at the inlet and outlet to preheat and recover heat, ensuring a more homogeneous temperature distribution by optimizing gas flow patterns and using graphite components to resist high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If furnace atmosphere gas is passed through the retort during sintering, then the sintering process can be performed with atmosphere treatment, but temperature gradients occur leading to inhomogeneous temperature distribution

Engineering Contradiction:
Improveatmosphere treatment capabilityVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The retort is divided into multiple zones with separate gas inlets and outlets, allowing independent control of atmosphere flow in different regions. This segmentation enables uniform temperature distribution while maintaining atmosphere treatment capability by balancing gas flow across all zones

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the retort are provided with tailored gas flow characteristics through localized inlet/outlet arrangements. The gas flow rate and direction are optimized for each specific zone to prevent temperature gradients while maintaining appropriate atmosphere conditions for sintering

Inventive Principle:
Principle #3Local quality

2Volume of stationary object

If the retort volume is reduced for smaller furnace size, then the furnace becomes more compact, but temperature inhomogeneity increases particularly in small furnaces

Engineering Contradiction:
Improvefurnace sizeVSAvoidmetallurgical parameter homogeneity
Core Design Contradiction:
Volume of stationary objectVSManufacturing precision

Solution Approach 1:

Even in compact retorts, multiple gas inlet and outlet points are strategically positioned to create balanced flow paths. This ensures that despite reduced volume, temperature distribution remains uniform by preventing localized overheating or cold spots that would otherwise occur in small furnaces

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Gas flow paths are designed to utilize three-dimensional space efficiently within the compact retort. By creating multiple flow dimensions and pathways, the system achieves uniform temperature distribution without increasing overall furnace volume

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If gas flow rate is increased to improve atmosphere treatment, then sintering efficiency increases, but temperature gradients become more pronounced

Engineering Contradiction:
Improvesintering efficiencyVSAvoidtemperature gradient
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The gas flow is divided into multiple streams through distributed inlets and outlets. This allows high total flow rates for efficient sintering while each individual stream maintains lower velocity to minimize temperature gradients, achieving both productivity and temperature uniformity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system optimizes gas flow parameters by adjusting pressure, temperature, and flow distribution across multiple pathways. This enables maintaining high overall productivity while controlling local flow velocities to prevent excessive temperature gradients

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 configuration enhances the homogeneity of metallurgical parameters such as coercivity and magnetic saturation, improving the quality of sintered products while maintaining a compact and energy-efficient sintering process.

Implementation Method 1

a heat exchanger for heating the furnace atmosphere gas entering the retort is arranged at the inlet in the interior of the retort

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a heat exchanger for recovering heat from the furnace atmosphere gas withdrawn from the retort is arranged at the outlet in the interior of the retort

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the interspace being enclosed by a peripheral wall provided with distributed holes for transfer of the furnace atmosphere gas between the interspace interior of the peripheral wall and the space exterior to the peripheral wall

Methodology Applied
Scientific EffectGas flow through pressure gradient: Pressure Gradient

Data Source

PatentEP4382841A1Sintering furnace
Publication Date: 2024.06.12 SECO TOOLS AB
  • EP4382841A1 patent drawingFigure 1
  • EP4382841A1 patent drawingFigure 2a
  • EP4382841A1 patent drawingFigure 2b

AI summary

The present invention relates to a sintering furnace (100) for sintering of green compacts comprising a retort (9); and i) an inlet for furnace atmosphere gas at one end of the retort (9); ii) a stack of sintering trays (1, 2, 3, 4, 5, 6) comprising central openings (11) arranged in the interior of the retort (9), said central openings (11) having an area A for transfer of the furnace atmosphere gas introduced through the inlet, wherein neighbouring sintering trays of said stack are spaced apart at a predetermined distance from one another whereby an interspace (16) is provided between said neighbouring sintering trays, said interspace (16) being enclosed by a peripheral wall (15) provided with distributed holes (10) for transfer of the furnace atmosphere gas between the interspace (16) interior of the peripheral wall (15) and the space exterior to the peripheral wall (15), wherein the ratio of the area A of each individual central opening (11) to the total area of the distributed holes (10) between each individual pair of neighbouring sintering trays ranges from 1:10 to 10:1; iii) an outlet for withdrawal of the furnace atmosphere gas at an end of the retort (9) opposite to the end of the inlet, said inlet and outlet being arranged at opposite ends of the stack of sintering trays (1, 2, 3, 4, 5, 6). The invention also relates to a method for sintering green compacts in the sintering furnace (100) and to sintered compacts obtainable by the method.