Leak-Triggered Pump Control for Water-Conducting Appliances

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Solution Overview

Problem

Existing water-bearing household appliances, such as dishwashers and washing machines, face issues with water leakage and damage due to continuous operation of the drain pump after a leak is detected, leading to potential overheating and standby losses from constant power supply to logic circuits.

Innovation Solution

A water safety switch connected to a controller that initiates control steps to prevent water escape, including activating the drain pump, and features self-diagnosis and an electromagnetically controlled inlet valve to ensure safety without standby losses, allowing the drain pump to operate intermittently to avoid overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drain pump is activated directly by the water safety switch bypassing the main switch, then water safety is improved, but the drain pump overheats due to continuous operation

Engineering Contradiction:
Improvewater safetyVSAvoiddrain pump temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The controller monitors the water safety switch signal and regulates the drain pump operation accordingly, providing feedback control to prevent continuous operation and overheating while maintaining water safety

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The controller acts as an intermediary between the water safety switch and the drain pump, mediating the activation signal to ensure the pump operates only when necessary and not continuously, thus preventing overheating

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If the logic circuit is continuously fed by mains voltage, then the response time for leak detection is improved, but standby losses increase

Engineering Contradiction:
Improveleak detection response timeVSAvoidstandby losses
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

Instead of continuous power supply, the system uses periodic or event-triggered power supply to the controller, activating it only when the water safety switch signals a leak condition, thus reducing standby energy losses while maintaining rapid response capability

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The water safety switch is positioned to directly activate the controller when a leak is detected, preparing the system in advance so that no additional detection time is needed, enabling rapid response without requiring continuous high-power operation

Inventive Principle:
Principle #10Preliminary action

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

Ensures water safety and prevents damage by controlling the drain pump effectively, even when the appliance is switched off, while avoiding overheating and standby losses, through a self-diagnosing system that activates necessary safety measures and manages the drain pump's operation.

Implementation Method 1

The water safety switch is switchable by a float

Methodology Applied
Scientific EffectFloat switch mechanism: Archimedes' Principle (Buoyancy)

Implementation Method 2

it has an electromagnetically controlled inlet valve (40) which is connected to the controller (14)

Methodology Applied
Scientific EffectElectromagnetic control: Electromagnet

Data Source

PatentEP2188432B1Water-conducting domestic appliance
Publication Date: 2014.10.08 BSH HAUSGERATE GMBH
  • EP2188432B1 patent drawingFigure 1

AI summary

A safety device for improving the water safety of a water-conducting domestic appliance (1), especially a dishwasher or washing machine, comprises a control (14) for controlling an evacuation pump (8), a main switch (16), electrically connected to the control (14), and a water safety switch (22) which reacts to the unwanted leakage of water and which has at least one first switched position, the main switch (16) and the water safety switch (22) having respective connections to electrical mains (18), and the main switch (16), when switched on, connecting the control (14) to the electrical mains (18). The invention is characterized in that the water safety switch (22) has an electrical connection to the control (14) and switches to a first switched position when there is an unwanted leakage of water and connects the control (14) to the electrical mains (18).