Segmented Roller Heat Loss Reduction in Thermal Furnaces

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Solution Overview

Problem

Conventional roller kilns experience significant heat losses due to the passage of rollers from the hot furnace interior to the cold environment, with existing insulation solutions only reducing losses by up to 40%, leading to high energy costs and inefficiency.

Innovation Solution

A roller kiln design featuring a central segment within the heating chamber and end segments with lower thermal conductivity, arranged outside the chamber, which minimizes heat conduction and allows for adjustable rigidity and reduced deformation, along with segmented rollers and thermally insulating caps to reduce heat loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional rollers are used to transport items through the heating chamber, then the rollers can perform their transport function, but significant heat losses occur as heat conducts from the hot furnace interior through the rollers to the cold environment

Engineering Contradiction:

Improveheat lossVSAvoidroller structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The roller is divided into multiple segments along its axial direction, with each segment having different thermal conductivity properties. The heating chamber-side segments are made of materials with higher thermal conductivity to maintain roller strength and transport function, while the outer segments extending beyond the heating chamber are made of materials with lower thermal conductivity to reduce heat loss to the environment. This segmentation allows the roller to simultaneously fulfill transport requirements while minimizing energy loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the roller are assigned different material properties tailored to their specific functional requirements. The inner segments within the heating chamber region use materials optimized for mechanical strength and heat resistance, while the outer segments use materials optimized for thermal insulation. This local differentiation of material quality enables the roller to address both transport functionality and heat loss reduction without compromising overall performance.

Inventive Principle:

Principle #3Local quality

2Strength

If the rollers are made of materials with high thermal conductivity to ensure structural integrity, then the roller strength is maintained, but heat losses increase significantly

Engineering Contradiction:

Improveroller strengthVSAvoidheat loss

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The roller structure is segmented into multiple sections along its axis, with each segment using materials optimized for its specific location. The inner segments within the heating chamber use high-strength, high-thermal-conductivity materials to maintain structural integrity under thermal and mechanical loads. The outer segments extending beyond the heating chamber use low-thermal-conductivity materials to minimize heat loss, while still providing sufficient structural support for their location.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different material properties are assigned to different portions of the roller based on local requirements. The heating chamber region uses materials with high strength and appropriate thermal conductivity to withstand the thermal environment and mechanical stresses. The outer regions use materials with lower thermal conductivity to reduce heat loss to the environment, while maintaining sufficient structural strength for their specific loading conditions.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If existing insulation solutions such as roll-end shielding scoops and tube-mounted radiation plugs are applied, then heat loss is reduced by up to 40%, but further reduction to minimize energy costs remains unachieved

Engineering Contradiction:

Improveheat lossVSAvoidinsulation structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The roller is segmented into multiple sections along its axial direction, with each segment having different thermal conductivity properties. The heating chamber-side segments are made of materials with higher thermal conductivity to maintain roller strength and transport function, while the outer segments extending beyond the heating chamber are made of materials with lower thermal conductivity to reduce heat loss to the environment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3321620B1Roller furnace for thermal treatment of an item, uses thereof and method for economical treatment of an object to be fired with heat

Publication Date: 2021.03.31 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

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Figure 2A~2B
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AI summary

A roller furnace for the thermal treatment of a material is provided, characterized in that it has at least one roller comprising at least one central segment located in the heating chamber and two end segments arranged at least partially outside the heating chamber at each end of the roller, wherein the first and second end segments each have a force-fit and/or form-fit connection with the central segment and the first and second end segments have a lower specific thermal conductivity than the central segment. This minimizes the heat losses of the roller furnace and enables very economical operation of the roller furnace. The use of the roller furnace according to the invention for the thermal treatment of a material is proposed, and a method for the economical heat treatment of a material is presented.