Sandwich Electron Exit Window Foil for Corrosion and Heat Control
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Solution Overview
Problem
Existing electron exit window foils for electron beam emitters, particularly in the food industry, face challenges such as oxidation and corrosion due to the corrosive environment, leading to reduced lifetime and operational stability.
Innovation Solution
A sandwich-structured electron exit window foil comprising a protective noble metal layer, a titanium layer for structural support, and a thermally conductive aluminum layer to manage heat, is proposed to enhance durability and stability in corrosive environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plain Ti foil is used for the electron exit window, then electron permeability and structural support are provided, but the foil oxidizes and corrodes in the corrosive environment, reducing lifetime and operational stability
Solution Approach 1:
The patent applies a composite structure consisting of multiple layers: a Ti foil base layer providing structural support and electron permeability, an Al layer providing thermal conduction, and a protective noble metal layer (such as Rh, Pt, or Au) providing corrosion and oxidation resistance. This composite material approach allows each layer to contribute its specific properties, resolving the contradiction between structural requirements and environmental resistance.
2Productivity
If the electron beam emitter is designed for high performance sterilization, then high electron transmission is achieved, but temperatures exceed 250°C, causing the Ti foil to degrade
Solution Approach 1:
The composite structure includes a thermally conductive Al layer that efficiently conducts heat away from the electron exit window, preventing excessive temperature buildup. This allows the system to maintain high electron transmission for effective sterilization while keeping the Ti foil temperature below the critical 250°C threshold through improved thermal management.
Solution Approach 2:
Different layers of the composite structure are assigned different functional qualities: the Ti layer provides structural support and electron permeability, the Al layer provides thermal conduction, and the noble metal layer provides corrosion protection. This local differentiation of material properties allows the system to handle high temperatures and maintain high productivity without degrading the Ti foil.
3Object-affected harmful factors
If a protective layer is added to the Ti foil, then corrosion resistance is improved, but the structural support and electron permeability may be compromised
Solution Approach 1:
The composite structure is designed so that the Ti foil base layer maintains its structural support function and electron permeability, while the additional Al and noble metal layers provide thermal conduction and corrosion protection respectively. The protective noble metal layer is applied as a thin coating that provides corrosion resistance without significantly compromising the mechanical strength or electron transmission properties of the underlying Ti structure.
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 proposed solution significantly improves the durability and operational stability of the electron exit window foil, extending its lifetime by providing effective corrosive protection and efficient heat management.
Implementation Method 1
a thermally conductive layer made of Al (aluminum), for conveying heat from the sandwich structure
Implementation Method 2
the filament is emitting electrons. The filament is often referred to as an electron beam generator and is preferably arranged in high vacuum for increasing the mean free path of the emitted electrons
Implementation Method 3
arranged in high vacuum for increasing the mean free path of the emitted electrons
Implementation Method 4
a supporting layer made of Ti (titanium) for providing structural support for the sandwich structure
Implementation Method 5
A problem with a Ti film is that it may oxidize, leading to reduced lifetime and operational stability. Oxidation happens since the film faces the atmosphere surrounding the electron beam emitter, which is a corrosive environment
Data Source
AI summary
An electron exit window foil for an electron beam emitter having an electron beam generator and operating in a corrosive environment. The electron exit window foil has a sandwich structure with an outer side arranged to face the corrosive environment and an inner side arranged to face the electron beam generator. The sandwich structure comprises, as seen from the outer side to the inner side, a protective layer, for protecting the sandwich structure from the corrosive environment, a supporting layer made of Ti, for providing structural support for the sandwich structure, and a thermally conductive layer made of Al, for conveying heat from the sandwich structure.