Magnetic Shielding for Electron Beam Irradiation Stability
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Solution Overview
Problem
The electron beam irradiation apparatus is affected by Earth's magnetism and peripheral device magnetism, causing unstable electron beam trajectories and reduced sterilization intensity due to curvature or collision of beams within the nozzle member.
Innovation Solution
Incorporation of magnetic shield members made of high permeability materials, such as Mumetal, within the vacuum chamber and nozzle member to block external magnetism, combined with a cooling system to prevent heat-induced permeability reduction, ensuring stable electron beam emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the nozzle member is made long to reach the bottom of tall containers, then the sterilization range is improved, but the electron beam trajectory becomes curved by Earth's magnetism causing unstable beam emission
Solution Approach 1:
A magnetic shield member made of high permeability material is introduced as an intermediary between the electron beam and Earth's magnetic field. This shield blocks the harmful magnetic influence while allowing the electron beam to pass through and reach the container bottom, resolving the contradiction between long trajectory and stable emission.
2Adaptability or versatility
If the nozzle member is made slender to fit into narrow container mouths, then the adaptability is improved, but the structural strength and magnetic shielding effectiveness are reduced
Solution Approach 1:
The magnetic shield member is nested within the nozzle member structure, with the shield positioned inside the nozzle's cylindrical wall. This nested configuration allows the slender nozzle to maintain both its ability to fit narrow container mouths and its magnetic shielding effectiveness, as the shield is contained within the existing structural envelope.
3Reliability
If the magnetic shield member is placed close to the electron beam trajectory to maximize shielding, then the beam stability is improved, but the heat from the beam reduces the material permeability
Solution Approach 1:
The magnetic shield member is designed with non-uniform thickness along its length, with greater thickness (and thus better thermal mass and shielding) at sections farther from the electron beam entry point, and reduced thickness near the beam entry where heat exposure is highest. This local quality variation optimizes both shielding effectiveness and thermal resistance.
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 stabilizes electron beam intensity and maintains effective sterilization within the container by shielding against Earth's and peripheral device magnetism, while preventing heat damage to the magnetic shield members.
Implementation Method 1
a magnetic shield member for a vacuum chamber and a magnetic shield member for the nozzle member, the magnetic shield members being respectively provided for the vacuum chamber and the nozzle member so as to block variable magnetism generated around an electron beam trajectory
Implementation Method 2
Incorporation of magnetic shield members made of high permeability materials, such as Mumetal, within the vacuum chamber and nozzle member
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
An electron beam irradiation apparatus that emits an electron beam into a container, the electron beam irradiation apparatus including: a vacuum housing constituting a vacuum chamber; an electron generator provided in the vacuum housing; a cylindrical nozzle member that is extended from the vacuum housing so as to be inserted into the container and has exit windows on the distal end of the nozzle member, the exit windows being provided for emission of an electron beam generated by the electron generator into the container; and a magnetic shield member for the vacuum chamber and a magnetic shield member for the nozzle member, the magnetic shield members being respectively provided for the vacuum housing and the nozzle member so as to block variable magnetism generated around an electron beam trajectory extended from the electron generator to the exit windows.