Fluid Sterilization Device with Low Surface Roughness

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Solution Overview

Problem

Existing fluid sterilization devices using ultraviolet rays face reduced sterilization effectiveness due to foreign substance adhesion on the inner surfaces, which decreases reflectivity and requires time-consuming maintenance.

Innovation Solution

A fluid sterilization device made of stainless steel with 8 wt% or more nickel, featuring a surface roughness of 50 nanometers or less, and incorporating an antifouling film on the window to reduce adhesion and improve reflectivity, along with a scraper for easy removal of adhering substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the fluid sterilization device is used for sterilizing seawater or groundwater, then sterilization function is achieved, but foreign substances adhere to the inner surface of the tubular portion, reducing reflectivity and sterilization effect

Engineering Contradiction:
Improvesterilization effectVSAvoidforeign substance adhesion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the surface roughness parameter of the tubular portion inner surface to 50 nm or less, and specifies the material as stainless steel containing 8 wt% or more nickel. These parameter changes make the surface resistant to foreign substance adhesion while maintaining high reflectivity for ultraviolet rays, thereby resolving the contradiction between sterilization effect and foreign substance adhesion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material specification - stainless steel containing specific amounts of nickel (8 wt% or more) and other elements within defined ranges. This composite material composition provides both corrosion resistance against seawater/groundwater and low surface roughness to prevent foreign substance adhesion, while maintaining high ultraviolet reflectivity.

Inventive Principle:
Principle #40Composite materials

2Productivity

If foreign substances adhere to the inner surface of the tubular portion, then the reflectivity of ultraviolet rays decreases, but this requires disassembly and cleaning, reducing operating rate

Engineering Contradiction:
Improveoperating rateVSAvoidmaintenance time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

By controlling the surface roughness to 50 nm or less and specifying the stainless steel composition with 8 wt% or more nickel, the patent creates a surface that resists foreign substance adhesion. This prevents reflectivity degradation and eliminates the need for frequent disassembly and cleaning, thereby maintaining high operating rate and reducing maintenance time.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If foreign substances adhere to the window, then ultraviolet rays are blocked, but cleaning requires device disassembly and time

Engineering Contradiction:
Improvesterilization effectivenessVSAvoidmaintenance effort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies the same surface treatment principle to the window - controlling surface roughness to 50 nm or less and using stainless steel with 8 wt% or more nickel. This prevents foreign substance adhesion on the window surface, maintaining ultraviolet ray transmission and sterilization effectiveness while eliminating cleaning requirements.

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

Enhances the reflectivity of ultraviolet rays, maintains sterilization efficiency, and reduces maintenance efforts by preventing foreign substance adhesion and facilitating the removal of adhered substances.

Implementation Method 1

a light-emitting element provided on a surface on the tubular portion side of the substrate, and configured to emit an ultraviolet ray

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

the ultraviolet rays emitted from the light source and incident on an inner surface of the tubular portion propagate while being repeatedly reflected inside the tubular portion

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3992154B1Fluid sterilization device
Publication Date: 2024.10.30 TOSHIBA LIGHTING & TECHNOLOGY CORP
  • EP3992154B1 patent drawingFigure 1

AI summary

A fluid sterilization device according to an embodiment includes a tubular portion; a supply head provided in one end portion of the tubular portion; a discharge head provided in the other end portion of the tubular portion, and including a hole penetrating through the discharge head between an end face on a tubular portion side and an end face on a side opposite the tubular portion side; a substrate provided inside the hole of the discharge head; a light-emitting element provided on a surface on the tubular portion side of the substrate, and configured to emit an ultraviolet ray; and a window provided in the discharge head, and facing the light-emitting element. A surface roughness Ra of an inner surface of the tubular portion is 50 nanometers (nm) or less.