Electric Induction Impeder High-Temperature Cooling
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Solution Overview
Problem
Conventional impeders in electric induction welding face issues such as heat-related losses due to finite resistivity and coercivity, mechanical fragility, and cooling challenges, leading to reduced magnetic properties and potential overheating, especially in smaller diameter tubes.
Innovation Solution
The development of an impeder using high temperature magnetically conductive solid wires or ferrite enclosed in a ceramic composition, with optional internal cooling systems and a thermally designed texture to enhance heat transfer, eliminating the need for internal cooling and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferrite impeder is used in electric induction welding, then the magnetic field creates a low reluctance path inside the tube, but the ferrite heats up due to finite resistivity and coercivity losses, potentially exceeding Curie temperature or causing binder disintegration
Solution Approach 1:
The patent changes the material parameters by selecting ferrite compositions with higher Curie temperatures and optimized magnetic properties. It also modifies the operating parameters by adjusting the induction heating cycle to account for the impeder's thermal characteristics, thereby maintaining magnetic property stability while managing temperature rise.
Solution Approach 2:
The patent introduces a cooling medium as an intermediary substance that circulates through channels in the impeder structure. This cooling medium acts as a heat transfer mediator, absorbing excess heat from the ferrite and preventing it from reaching critical temperatures that would cause magnetic property loss or binder disintegration.
2Strength
If ferrite is enclosed in a fiberglass jacket for mechanical protection and cooling, then mechanical shock protection is improved, but cooling water contaminants can plug the coolant passage, causing immediate ferrite failure due to local overheating
Solution Approach 1:
The patent applies different material properties to different parts of the impeder structure. The fiberglass jacket provides mechanical protection where needed, while the cooling channels are designed with specific geometries and smooth surfaces to prevent contaminant accumulation. This localized optimization of material and structural properties addresses both mechanical strength and cooling reliability requirements.
Solution Approach 2:
The patent incorporates porous or filtered structures in the cooling system design. These porous elements act as filters to trap contaminants before they can plug the cooling passages, while still allowing efficient heat transfer from the ferrite to the cooling medium. This maintains cooling system reliability without compromising mechanical protection.
3Reliability
If the ferrite diameter is made as large as possible for smaller diameter tube fabrication, then magnetic saturation is avoided, but the clearance between ferrite and casing becomes tight, making the cooling system vulnerable to contaminant plugging
Solution Approach 1:
The patent transitions from a simple radial clearance design to a multi-dimensional cooling channel architecture. By creating dedicated cooling passages that extend axially and radially through the impeder structure, the design provides adequate cooling surface area and flow paths even when the radial clearance is minimal. This dimensional expansion of the cooling system resolves the conflict between maintaining tight ferrite-casing contact for magnetic performance and providing sufficient cooling capability.
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 effectively maintains magnetic properties at high temperatures, reduces mechanical shock, and prevents overheating, ensuring consistent and efficient welding processes without the need for internal cooling, thereby improving the reliability and efficiency of the welding process.
Implementation Method 1
A high frequency current is passed through a induction coil or contact points to induce eddy currents in the tube walls which heats the vee edges
Implementation Method 2
heats the vee edges through resistive heating to prepare for welding
Implementation Method 3
The magnetic field generated by the tube welder's induction coil or contacts passes through the weld vee
Data Source
AI summary
An impeder for use in an electric induction welding process is provided. A cooling medium is circulated centrally through the impeder's magnetic material and between the interior of the impeder's high temperature enclosure and the exterior of the magnetic material within the impeder with the impeder entry and exit passages for the cooling medium located on the same side of the impeder.