Dishwasher Pump Current Monitoring for Heater Overheating Prevention

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Solution Overview

Problem

Dishwashers with low water levels risk pump failure and heater overheating, leading to potential fire hazards, and existing solutions rely on level sensors or complex current monitoring systems.

Innovation Solution

A control unit that monitors the current drawn by the circulation pump to detect low water levels without additional sensors, delaying heater operation and providing extra water intake to prevent overheating and ensure safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If water usage is reduced to save energy and water resources, then water consumption decreases, but the water level drops below the pump and heater operation levels causing pump failure and heater overheating

Engineering Contradiction:
Improvewater consumptionVSAvoidpump and heater operation reliability
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The control unit proactively monitors pump current to detect low water levels before they cause pump failure or heater overheating. By taking preliminary action to detect and respond to declining water levels, the system prevents harmful conditions while maintaining reduced water usage cycles.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the current drawn by the circulation pump as feedback on water level conditions. This feedback mechanism allows the control unit to detect low water levels and adjust heater operation accordingly, enabling safe operation with reduced water consumption.

Inventive Principle:
Principle #23Feedback

2Device complexity

If current monitoring is used to detect low water levels, then level sensor requirements are eliminated, but the control system complexity increases

Engineering Contradiction:
Improvesensor system complexityVSAvoidwater level detection accuracy
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The pump current serves as an intermediary indicator of water level conditions. Instead of directly measuring water level with sensors, the system uses the easily measurable electrical current as a proxy that correlates with water level, simplifying the detection system while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The circulation pump's own electrical characteristics (current draw) are used to provide information about water level conditions. The pump essentially reports its operational status through its current consumption, eliminating the need for separate sensing systems.

Inventive Principle:
Principle #25Self-service

3Productivity

If the heater operates immediately in low water level conditions, then washing efficiency is maintained, but the heater overheats and creates fire hazards

Engineering Contradiction:
Improvewashing efficiencyVSAvoidheater overheating and fire hazard
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control unit applies preliminary anti-action by delaying heater operation when low water levels are detected through pump current monitoring. This prevents the harmful effect of overheating before it can occur, while still allowing the washing process to continue with adjusted timing.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The heater operation timing is made dynamic rather than fixed. The control unit adjusts heater activation based on real-time water level conditions inferred from pump current, allowing flexible operation that maintains washing efficiency while preventing overheating hazards.

Inventive Principle:
Principle #15Dynamics

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 solution effectively prevents heater overheating and pump failure by monitoring current values to detect low water levels, eliminating the need for level sensors and ensuring the dishwasher operates safely and efficiently, even with reduced water usage.

Implementation Method 1

a control unit that monitors the current value drawn by the circulation pump, thus that detects whether the pump is out of water

Methodology Applied
Scientific EffectElectrical current measurement: Ohmmeter

Implementation Method 2

the heater that provides the heating of the washing water

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3138460B1A dishwasher with increased security and the control method thereof
Publication Date: 2019.11.13 ARCELIK AS
  • EP3138460B1 patent drawingFigure 1
  • EP3138460B1 patent drawingFigure 2
  • EP3138460B1 patent drawingFigure 3

AI summary

The present invention relates to a dishwasher (1) comprising a body (2); a washing area (3) that is arranged in the body (2) and wherein the dishes are placed and washed; a heater (4) that is disposed at the floor/base of the washing area (3) and that enables the wash water to be heated; a pump (5) that realizes the cycle of the wash water in the washing area (3); and a control unit (6) that controls the heater (4) and monitors the current (I) drawn by the pump (5) and that decides that the pump (5) is out of water if the drawn amount of the current (I) is less than a predetermined limit current value (Ilim) during a predetermined first limit time period (t1).