Drain pan unit and air conditioner

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Solution Overview

Problem

Bacteria, such as mold and microorganisms, tend to propagate inside the drain pan of air conditioners, leading to contamination.

Innovation Solution

A drain pan unit with a light-transmissive member that emits ultraviolet light, combined with a photocatalyst and a reflector, is used to promote oxidative decomposition and sterilization, reducing bacterial propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional drain pan is used, then the structure is simple and easy to manufacture, but bacteria and mold propagate inside the drain pan causing contamination

Engineering Contradiction:
Improveanti-bacterial performanceVSAvoiddrain pan structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A light-transmissive member (quartz plate or resin plate) is introduced as an intermediary component between the ultraviolet light source and the drain pan interior. This mediator transmits ultraviolet light effectively while maintaining structural integrity, enabling sterilization without requiring the light source to be in direct contact with the water collection area

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The drain pan unit combines multiple materials with complementary properties: a light-transmissive member (quartz or resin) for UV transmission, a reflector (aluminum plate) for light direction, and a photocatalyst layer (titanium dioxide) for enhanced sterilization. This composite structure achieves superior anti-bacterial performance compared to conventional single-material drain pans

Inventive Principle:
Principle #40Composite materials

2Reliability

If a light-transmissive member is added to enable UV transmission, then sterilization is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvesterilization capabilityVSAvoiddrain pan assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The light-transmissive member performs multiple functions simultaneously: it transmits ultraviolet light for sterilization, serves as a structural component of the drain pan assembly, and acts as a protective barrier for the light source. This multi-functionality reduces the need for additional separate components

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

Solution Approach 2:

The invention offers parameter flexibility by allowing the light-transmissive member to be made from different materials (quartz plate or resin plate) depending on specific application requirements. This enables optimization of manufacturing ease, cost, and UV transmission properties based on the particular use case

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 ultraviolet light emitted from the light-transmissive member, in conjunction with the photocatalyst, effectively reduces bacterial growth and contamination within the drain pan, preventing clogging and unpleasant odors.

Implementation Method 1

a light-transmissive member forming at least part of the drain pan and configured for transmitting ultraviolet light emitted from the light source

Methodology Applied
Scientific EffectUltraviolet light transmission: Light

Implementation Method 2

the ultraviolet light applied to the inside of the drain pan (41) promotes the oxidative decomposition performance of the photocatalyst (70)

Methodology Applied
Scientific EffectPhotocatalysis: Photo-oxidation

Implementation Method 3

a reflector (50) placed over a surface (61a) of the light guide member (60) opposite to the light-emitting surface (61) to reflect ultraviolet light

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3896358B1Drain pan unit and air conditioner
Publication Date: 2023.06.14 DAIKIN INDUSTRIES LTD
  • EP3896358B1 patent drawingFigure 1~2
  • EP3896358B1 patent drawingFigure 3~4
  • EP3896358B1 patent drawingFigure 5~6

AI summary

A drain pan (41) includes a light-transmissive member (T) forming at least part of the drain pan (41) and is for transmitting ultraviolet light emitted from a light source (80). The light-transmissive member (T) has a light-emitting surface (61) that is exposed to the inside of the drain pan (41) and from which ultraviolet light that has been transmitted through the light-transmissive member (T) is emitted.