Pallet Conveyor Rails for Hot Coil Thermal Deformation
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Solution Overview
Problem
Conventional pallet-type conveyor systems deform and ride unevenly when carrying hot metal-strip coils, leading to damage and difficulties in handling due to thermal expansion, causing the coils to be ovalized and the rollers to be subjected to excessive stress.
Innovation Solution
The conveyor system features longitudinally extending rails with angled end regions and a planar center, allowing for thermal deformation compensation, ensuring continuous contact with rollers and preventing damage, along with radiant-heat shields and flexible web structures to maintain smooth rolling, and pivot joints for accommodating thermal expansion without stressing the frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional pallets are used to carry hot metal-strip coils, then the pallets can transport the heavy loads, but the pallets deform substantially due to thermal expansion causing uneven riding on rollers
Solution Approach 1:
The rail cross-section is changed from a conventional shape to an asymmetric shape with a higher portion and a lower portion. This parameter change in the geometric configuration allows the rail to compensate for thermal expansion deformations, maintaining planarity of the running surface despite temperature increases up to 800°C.
Solution Approach 2:
The invention explicitly accounts for thermal expansion effects by designing the rail cross-section with asymmetric geometry. The higher and lower portions are positioned to compensate for the differential expansion that occurs when the rail is exposed to radiant heat from hot coils, ensuring the running face remains planar.
2Strength
If pallets are made of metal to withstand heavy loads, then they can carry 30-40 ton coils, but they experience considerable differential expansion when exposed to radiant heat
Solution Approach 1:
Different portions of the rail cross-section are given different heights to create local quality variations. The higher portion and lower portion are strategically positioned to compensate for differential thermal expansion in different regions of the rail, maintaining overall dimensional stability while preserving load-bearing capacity.
3Ease of operation
If pallets ride on rollers with a planar running surface, then they can move smoothly when cold, but thermal deformation causes them to sit on only one or two rollers and bump down the line
Solution Approach 1:
The cross-sectional geometry of the rail is modified with asymmetric higher and lower portions to maintain contact with multiple rollers during thermal expansion. This parameter change ensures the running surface remains effectively planar relative to the roller array, preventing bumping and maintaining reliable contact.
4Ease of manufacture
If conventional rails with uniform cross-section are used, then they are simple to manufacture, but they deform non-uniformly when exposed to radiant heat from hot coils
Solution Approach 1:
The rail cross-section is designed with local quality variations through the higher and lower portions. While this increases manufacturing complexity compared to uniform sections, the asymmetric geometry is designed to counteract the non-uniform thermal expansion patterns that occur when rails are exposed to radiant heat from hot coils.
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 enables the conveyor system to handle hot coils without deformation, maintaining smooth rolling and preventing damage to both the pallets and the coils, ensuring efficient and stable transportation without compromising the rollers or the coils' shape.
Implementation Method 1
the considerable heat of the loads being transported causes the pallets to deform substantially... there is considerable differential expansion
Implementation Method 2
the considerable heat of the loads being transported causes the pallets to deform substantially... more directly exposed to the radiant heat emitted by it
Data Source
AI summary
A conveyor having an array of rollers defining a transport plane is used with pallets each having supports forming an upwardly open saddle adapted to hold a coil of metal strip, and a pair of generally parallel and longitudinally extending rails underneath and fixed to the supports. Each rail has a downwardly directed face adapted to ride directly on the rollers and having a generally planar center region and a pair of upwardly angled end regions each forming a small acute angle with the respective center region.