Toroidal Low-Energy Electron Sterilization for Full-Surface Coverage

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Solution Overview

Problem

Conventional sterilization methods such as steam, ethylene oxide, X-ray, Gamma irradiation, and high energy electron beam face challenges including damage to heat-sensitive materials, toxicity, high radiation risks, and logistical complexities, making them inefficient and costly for sterilizing objects in open environments.

Innovation Solution

A sterilization device using a toroidal housing with a thermionic cathode, anode grid, and anode wire generates a spray of accelerated electrons that sterilize objects from all sides and inside without requiring multiple beam emitters, utilizing low energy electron beams that are safer and more efficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sterilization methods (steam, ethylene oxide, X-ray, Gamma irradiation, high energy electron beam) are used, then sterilization effectiveness is achieved, but damage to heat-sensitive materials, toxicity, high radiation risks, and heavy protection barriers are required

Engineering Contradiction:
Improvesterilization effectivenessVSAvoiddamage to materials, toxicity, radiation risks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the energy parameter of the electron beam from high energy to low energy (accelerating voltage of 1-100 kV, preferably 5-50 kV). This parameter change allows the electrons to have sufficient sterilization capability while lacking the penetration power that causes damage to heat-sensitive materials and requires heavy protection barriers. The low energy electrons are absorbed within millimeters of the surface, eliminating radiation risks and toxicity associated with conventional methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional high energy electron beam system with a low energy electron beam system. This substitution eliminates the need for heavy protection barriers and complex safety infrastructure while maintaining sterilization effectiveness. The low energy electrons are generated by simple accelerating structures rather than complex high energy particle accelerators.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If multiple beam emitters are used to sterilize objects from all sides, then complete sterilization coverage is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvesterilization coverageVSAvoidnumber of beam emitters
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a toroidal (doughnut-shaped) housing with the cathode and anode arranged in a curved configuration. This spherical/curved geometry allows the electron beam to be emitted in multiple directions simultaneously, sterilizing the object from all sides including internal surfaces in a single pass. The curved electrode arrangement naturally directs electrons toward the central cavity where the object is placed, eliminating the need for multiple separate beam emitters.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The single toroidal electron beam generator performs multiple functions: it sterilizes external surfaces, internal surfaces, and cavities of the object simultaneously. The curved electrode design allows the beam to wrap around and treat all surfaces of the object in one operation, making the device universally applicable to various object shapes and sizes without requiring additional emitters.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If high energy electron beam is used, then sterilization speed is fast, but heavy protection barriers and complex safety measures are required

Engineering Contradiction:
Improvesterilization speedVSAvoidprotection barriers
Core Design Contradiction:
ProductivityVSWeight of stationary object

Solution Approach 1:

The patent reduces the accelerating voltage from high energy levels (MeV range) to low energy levels (1-100 kV). This parameter change maintains the fast sterilization speed because the low energy electrons still have sufficient kinetic energy to inactivate microorganisms upon impact, but they are absorbed within millimeters of the surface rather than penetrating deeply. This eliminates the need for heavy protection barriers while preserving productivity.

Inventive Principle:
Principle #35Parameter changes

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 device efficiently sterilizes objects from all sides and inside in a short time, reducing the need for heavy protection barriers, minimizing environmental impact, and lowering operational costs compared to conventional methods.

Implementation Method 1

a thermionic cathode to release one or more primary electrons

Methodology Applied
Scientific EffectThermionic emission: Thermionic Emission

Implementation Method 2

an anode grid to attract and accelerate the one or more primary electrons to obtain accelerated primary electrons

Methodology Applied
Scientific EffectElectrostatic attraction and acceleration: Electric Field

Implementation Method 3

electrons released from a gas plasma discharge within the toroidal housing

Methodology Applied
Scientific EffectGas plasma discharge: Plasma

Implementation Method 4

The anode wire is to accelerate the one or more additional electrons and the accelerated primary electrons to create a spray of accelerated electrons

Methodology Applied
Scientific EffectElectrostatic acceleration: Electric Field

Implementation Method 5

The spray of accelerated electrons is to collide with at least one surface of the object to sterilize the object

Methodology Applied
Scientific EffectElectron beam sterilization: Electron Beam

Data Source

PatentEP4529476B1Sterilization of an object using low energy electron beam
Publication Date: 2026.02.04 PHARMALAB INDIA PVT LTD
  • EP4529476B1 patent drawingFigure 1
  • EP4529476B1 patent drawingFigure 2
  • EP4529476B1 patent drawingFigure 3A

AI summary

A sterilization device (102) has been disclosed. The sterilization device (102) comprises a toroidal housing (104) having an outer wall (106), an inner wall (108), and a central cavity (302) to receive an object (306) to be sterilized. The toroidal housing (104) comprises a thermionic cathode (110) to release primary electrons, an anode grid (112) to attract and accelerate the primary electrons to obtain accelerated primary electrons, and an anode wire (114) to pull additional electrons released from a gas plasma discharge within the toroidal housing (104). The anode wire (114) accelerates the additional electrons and the accelerated primary electrons to create a spray of accelerated electrons (308) that is released through the inner wall (108). The spray of accelerated electrons (308) collides with the object (306) to sterilize the object (306).