Water-Cooled Roll With Coaxial Shaft Gap For Steel Slab Furnace

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Solution Overview

Problem

Water-cooled rolls in tunnel furnaces experience high thermal dispersion, leading to increased energy consumption and reduced lifespan, while dry rolls are costly and have limited versatility due to high operating temperature constraints.

Innovation Solution

A water-cooled handling roll design featuring a gap between two coaxial shafts, with centering rings acting as spacers to minimize thermal bridges and reduce thermal dispersion, and an insulating and refractory outer coating to maintain temperature and extend lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water-cooled rolls are used in tunnel furnaces, then the rolls can withstand high temperatures and maintain structural integrity, but thermal dispersion increases leading to higher energy consumption

Engineering Contradiction:
Improveroll lifespanVSAvoidthermal dispersion
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a nested structure where an inner shaft is positioned within the hollow cavity of an outer shaft. The inner shaft contains cooling water circulation means, while the outer shaft is coated with insulating and refractory materials. This nested configuration allows the cooling system to be protected by the insulating outer shaft, reducing thermal dispersion to the surrounding environment while maintaining the reliability of the roll structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The insulating and refractory coating on the outer shaft acts as an intermediary layer between the high-temperature furnace environment and the cooling water circulation system. This intermediary protects the cooling water from direct thermal exposure, reducing thermal dispersion while allowing the roll to withstand high temperatures, thus resolving the contradiction between reliability and energy loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If dry rolls without water cooling are used, then thermal dispersion is reduced and energy consumption decreases, but the rolls are costly and have limited versatility at high operating temperatures

Engineering Contradiction:
Improvethermal dispersionVSAvoidhandling varying temperatures
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic cooling system where water circulation can be activated or deactivated based on operating conditions. The cooling water circulation means are housed within the inner shaft, allowing operators to adjust cooling intensity or switch between water-cooled and dry operation modes, providing versatility in handling varying temperatures while maintaining lower thermal dispersion compared to traditional water-cooled rolls.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the outer shaft is coated with insulating and refractory material, then the roll can maintain temperature close to furnace temperature and extend lifespan, but the structural complexity increases

Engineering Contradiction:
Improveroll lifespanVSAvoidroll structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by coating the outer shaft with a combination of insulating and refractory materials. This composite coating provides both thermal insulation to maintain temperature close to furnace temperature and refractory properties to withstand high temperatures and extend roll lifespan. The dual-function coating reduces the need for additional protective structures, thereby limiting the increase in structural complexity.

Inventive Principle:
Principle #40Composite materials

4Loss of energy

If a gap is created between the inner and outer shafts, then thermal bridges are minimized and thermal dispersion is reduced, but the structural stability may be compromised

Engineering Contradiction:
Improvethermal dispersionVSAvoidshaft alignment
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent extracts the cooling water circulation means from direct contact with the outer shaft by positioning them within the inner shaft, creating a gap between the two shafts. This gap minimizes thermal bridges and reduces thermal dispersion. The inner shaft acts as a separate, enclosed cooling chamber that is thermally isolated from the outer shaft by the air gap, thereby reducing energy loss while maintaining structural stability through the coaxial arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

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 roll achieves reduced thermal dispersion and extended lifespan by minimizing thermal bridges and maintaining the outer shaft's temperature close to the furnace temperature, while being cost-effective and versatile in handling varying load sizes and temperatures.

Implementation Method 1

cooling water circulation means housed at least in part within the second shaft

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The inner shaft is positioned within the hollow cavity of the outer shaft with its axis coinciding substantially with that of the outer shaft

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

wherein said outermost surface is coated by an insulating and/or refractory material

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3148946B1Roll for handling a load in a furnace usable in a continuous casting and rolling process for thin carbon steel slabs
Publication Date: 2018.05.02 DANIELI CENT COMBUSTION
  • EP3148946B1 patent drawingFigure 1~2
  • EP3148946B1 patent drawingFigure 3
  • EP3148946B1 patent drawingFigure 4

AI summary

The present invention relates to a water-cooled handling roll (100) for handling a load (50), in particular a thin slab, in a furnace for temperature heating, maintaining and for buffering, arranged between casting and roughing, in a continuous casting and rolling process for thin carbon steel slabs. The roll (100) comprises a first internally hollow shaft (110), which is coated by an insulating and/or refractory material and a plurality of wheels (25) connected in stably fixed manner to an outermost surface (111) of the first shaft (110) to handle and support the load (50). According to the invention, the roll (100) also comprises a second shaft (120) arranged within an inner cavity of the first shaft (110) in position coaxial to the first shaft (110) and so as to define a gap (30) between the first shaft (110) and said second shaft (120). The roll (100) further comprises cooling water circulation means housed at least in part within said second shaft (120).