Process Water Tank Gas Sensing for Reuse Quality Control

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Solution Overview

Problem

Household appliances like dishwashers and washing machines face challenges in reliably storing process water for extended periods due to uncontrolled germ growth, affecting water quality, making it difficult to estimate permissible storage time.

Innovation Solution

Incorporating a gas sensor to detect gases indicating bacterial metabolism, coupled with a water treatment device that can be activated based on sensor signals to treat or discard the water, ensuring it remains clean and safe for reuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If process water is stored in the tank for longer periods to reduce water consumption, then water resource efficiency is improved, but uncontrolled germ growth occurs affecting water quality

Engineering Contradiction:

Improvewater consumptionVSAvoidwater quality

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The gas sensor continuously monitors the storage compartment for indicators of bacterial metabolism (such as ammonia, organic gases, methane, hydrogen sulfide). When specific gas concentrations are detected, the system provides feedback to the controller, which then activates the water treatment device or discards the contaminated water, creating a closed-loop quality control system that maintains water quality during extended storage

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The water treatment device changes the physical or chemical parameters of the stored water to eliminate pathogens and control bacterial growth. This may involve applying UV radiation, ozone treatment, or other treatment methods that alter water parameters such as oxidation-reduction potential, thereby maintaining water quality for extended storage periods

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a gas sensor and water treatment device are added to monitor and treat stored water, then water quality is maintained, but device complexity increases

Engineering Contradiction:

Improvewater qualityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs self-monitoring and self-treatment of the stored water. The gas sensor automatically detects contamination indicators, and the controller autonomously activates the water treatment device when needed, eliminating the need for manual water quality assessment and treatment by the user, thereby justifying the added complexity through automated self-maintenance

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The water treatment device serves multiple functions: it treats water during storage to prevent bacterial growth, prepares water before reuse in the washing machine, and can be activated based on various conditions (time-based scheduling, gas sensor signals, or controller decisions). This multi-functionality justifies the added complexity by consolidating multiple water management tasks into a single device

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This solution allows for reliable long-term storage of process water by monitoring bacterial activity and treating it only when necessary, preventing odor formation and killing pathogens, thereby extending storage time and maintaining water quality.

Implementation Method 1

The gas sensor is configured to detect at least one of the following gases: ammonia, at least one organic gas, in particular methane, hydrogen sulfide. Such gases are typical degradation products of the anaerobic bacterial metabolism.

Methodology Applied

Scientific EffectGas detection through bacterial metabolism indicators:

Implementation Method 2

A biological water treatment device is provided to purify the water in the tank. In order to render the microorganisms acting in this process ineffective again, it is further proposed to treat the process water with UV light, ozone or the like.

Methodology Applied

Scientific EffectUV light treatment:

Implementation Method 3

Methodology Applied

Scientific EffectOzone treatment: Ozone

Data Source

PatentEP2397062B1Domestic appliance with tank for storage of process water with gas sensor

Publication Date: 2013.07.31 V-ZUG AG

Figure 1~3

AI summary

A household appliance, in particular a dishwasher or washing machine, has a tank (2) for temporarily storing process water between cleaning cycles. A water treatment device (9), e.g., with an electrolysis cell with a diamond electrode, is provided to treat the water in the tank and thus suppress odor and microbial growth. A gas sensor (12) serves to detect gases escaping from the process water stored in the tank (2). The gas sensor (12) provides information about the condition of the stored process water, allowing it to be treated or discarded as needed.