Flux-Balanced Induction Heating Workcoils for Roll Bearing Protection
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Solution Overview
Problem
Conventional induction heating systems for paper production rolls often result in currents exiting the rolls through their bearings, leading to premature wear and damage, necessitating frequent replacements and increased downtime.
Innovation Solution
The use of flux-balanced induction heating workcoils, which generate magnetic fluxes that cancel each other out, reducing the flow of currents parallel to the roll axis and minimizing current exit through the bearings, thereby reducing wear and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional induction heating systems are used to heat roll surfaces, then the roll surface temperature is increased to control compression, but currents exit through the bearings causing premature wear and damage
Solution Approach 1:
The induction heating system is divided into multiple independent workcoils (first workcoil and second workcoil) that can be controlled separately. Each workcoil generates magnetic flux in a specific zone, allowing segmented control of heating regions and current paths to prevent current concentration through bearings
Solution Approach 2:
Different zones of the roll are heated with different characteristics using separate workcoils. The first workcoil heats a first zone while the second workcoil heats a second zone, creating localized thermal profiles that optimize both temperature control and current distribution to minimize bearing currents
2Manufacturing precision
If induction heating is applied to control roll compression, then the compression control precision is improved, but bearing wear increases due to current exit
Solution Approach 1:
Magnetic flux serves as an intermediary that transfers energy from the workcoils to the roll surface without direct electrical contact. By carefully designing the magnetic flux paths through the workcoils, energy is delivered to heat the roll surface while the flux paths are configured to prevent current leakage through bearings
Solution Approach 2:
The system controls heating parameters (current amplitude, frequency, duty cycle) of each workcoil independently to optimize the thermal profile. By adjusting these parameters, the system achieves precise compression control while modifying current distribution patterns to minimize harmful bearing currents
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
This approach minimizes bearing currents, extending the lifespan of the bearings, reducing maintenance costs, and maintaining system efficiency by ensuring that magnetic fluxes remain within the control zone of the roll.
Implementation Method 1
The one or more magnetic cores and the one or more conductive coils are configured to generate substantially balanced magnetic fluxes when the one or more conductive coils are energized
Implementation Method 2
heat created by currents induced in the roll by the magnetic fluxes produces a steady state thermal profile on a surface of the roll
Implementation Method 3
The one or more magnetic cores and the one or more conductive coils are configured to generate substantially balanced magnetic fluxes when the one or more conductive coils are energized
Data Source
AI summary
An apparatus includes one or more magnetic cores (206, 326, 336, 356, 386, 396a-396b) collectively having an inner leg located between two outer legs. The legs are coupled to one or more connecting portions. The apparatus also includes one or more conductive coils (204, 324, 334, 354, 384, 394) wound around the inner leg. The one or more magnetic cores and the one or more conductive coils are configured to generate substantially balanced magnetic fluxes within a roll (119, 212, 404) when the one or more conductive coils are energized. Also, the one or more magnetic cores and the one or more conductive coils are configured so that heat created by currents induced in the roll by the magnetic fluxes produces a steady state thermal profile on a surface of the roll. The steady state thermal profile has one peak that falls within a control zone associated with the roll. The one or more magnetic cores could include a single magnetic core or multiple magnetic cores.