Ribbed Shelf Heater Pin Support for Thermal Expansion
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Solution Overview
Problem
Conventional heat processing furnaces face issues with quick temperature changes, durability, and cost due to thermal expansion and contraction of helical heating wires, leading to potential short-circuits and disconnections, and the use of expensive high-load-resistant wires.
Innovation Solution
A heat processing furnace design featuring a cylindrical heater with ribbed shelf sections and pin members to hold helical heating resistance wires, allowing radial movement and preventing dropout, enabling quick temperature changes while maintaining durability without additional cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the heating wire is supported with a clearance to allow thermal expansion and contraction, then the heating wire can undergo thermal expansion without constraint, but the heating wire is likely to be deformed due to repeated temperature changes, generating short-circuits and disconnection
Solution Approach 1:
The support structure transitions from a static fixed support to a dynamic support that allows controlled movement. The heating wire is supported at multiple points along its length, enabling it to expand and contract axially while maintaining radial stability. This dynamic support system accommodates thermal deformation without causing wire failure or short-circuits.
Solution Approach 2:
Multiple support points act as intermediaries between the heating wire and the furnace structure. These support points distribute the mechanical stress and constrain the wire's movement in the radial direction while allowing axial expansion, preventing direct contact between adjacent wire turns and eliminating short-circuit risks.
2Reliability
If a fixing member is welded to the heating wire to prevent accumulation of elongation, then the heating wire position is stabilized, but the joined portion is exposed to high temperature causing stress concentration and deterioration in durability
Solution Approach 1:
The support function is segmented into multiple discrete support points distributed along the heating wire length. Each support point independently constrains radial movement while allowing axial expansion. This segmentation eliminates the need for welded fixing members, as the distributed supports collectively maintain wire position stability without creating stress concentration points.
3Stability of the object's composition
If the heating wire is moved downward due to gravitation during repeated thermal cycles, then the heating wire accommodates thermal expansion, but the moving amount accumulates at the lowermost turn increasing winding diameter and causing deformation
Solution Approach 1:
The support structure enables dynamic adjustment of wire position at multiple points along its length. As the wire expands and contracts, the support points allow controlled movement while maintaining the wire's helical geometry. This prevents accumulation of deformation at the lowermost turn by distributing the accommodation of thermal expansion across multiple support locations.
4Reliability
If expensive high-load-resistant heating wire is used to withstand large power during quick temperature changes, then the heating wire can handle high loads, but the cost increases
Solution Approach 1:
Multiple support points are installed beforehand to cushion and distribute the mechanical stress on the heating wire during thermal expansion and contraction. This pre-established support system protects the wire from excessive stress, allowing the use of less expensive standard heating wire that would otherwise be prone to failure under repeated thermal cycling and high power loads.
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 design allows for efficient quick temperature increases and decreases while enhancing the durability of heating wires, reducing the risk of disconnections and enabling the use of less expensive kanthal wire, thus improving the furnace's operational efficiency and longevity.
Implementation Method 1
a heating resistor disposed on an inner circumference of the heat insulating member via a supporting member... The heating wire can heat an inside of the furnace to a high temperature such as about 800° C. to 1000° C.
Implementation Method 2
The heat insulating member can reduce a heat quantity lost as radiant heat and conductive heat, so as to enhance efficiency in heating.
Implementation Method 3
the heating wire is thermally expanded during a heating operation... the heating wire undergoes a creep strain, and slowly increases in length over time
Implementation Method 4
the heating wire is moved in the supporting member because of the repeated heat expansion and heat shrinkage caused by the rinse and drop in temperature, and the heating wire is moved downward little by little because of gravitation
Data Source
AI summary
The present invention is a heat processing furnace comprising: a processing vessel for accommodating an object to be processed and performing thereto a heat process; and a cylindrical heater disposed to surround a circumference of the processing vessel, for heating the object to be processed; wherein: the heater includes a cylindrical heat insulating member, ribbed shelf sections that are axially formed in a tier-like manner on an inner circumference of the heat insulating member, and heating resistance wires of a helical pattern that are placed along the respective shelf sections; and pin members are arranged in the heat insulating member at suitable intervals therebetween, the pin members holding the heating resistance wires such that the heating resistance wires are movable in a radial direction of the heater, while preventing dropout of the heating resistance wires from the shelf sections.