Dishwasher Water Level Detection Using TRIAC Firing Angle

Solution Overview

Problem

Existing dishwashers consume excessive power and produce noise due to unnecessary operation of the drain pump, especially when the water sump is already empty or nearly empty, as they rely on pressure sensors to detect water levels.

Innovation Solution

The method utilizes the TRIAC firing angle condition to detect and derive the water level in the dishwasher, allowing for control of the circulation pump's speed and power consumption without additional sensors, and only starts the drain pump when a predefined minimum water level is reached, thereby reducing power consumption and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drain pump is started at the beginning of a washing cycle to ensure no water remains in the sump, then the water level detection reliability is improved, but the power consumption and noise emission increase due to unnecessary operation when the sump is already empty

Engineering Contradiction:

Improvewater level detection reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The circulation pump motor itself serves the dual function of both circulating water and indicating water level through its electrical characteristics. The motor's current consumption and power factor naturally vary with water level, eliminating the need for separate detection devices and allowing the system to self-diagnose water level conditions.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The motor of the circulation pump is made multi-functional by using its electrical parameters not only for driving the pump but also for detecting water level. This allows a single component to perform multiple functions: water circulation, power consumption, and level sensing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If additional pressure sensors are installed to accurately detect water level, then the measurement precision is improved, but the device complexity and cost increase

Engineering Contradiction:

Improvewater level measurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The motor of the circulation pump is made multi-functional by using its electrical parameters not only for driving the pump but also for detecting water level. This allows a single component to perform multiple functions: water circulation, power consumption, and level sensing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The circulation pump motor itself serves the dual function of both circulating water and indicating water level through its electrical characteristics. The motor's current consumption and power factor naturally vary with water level, eliminating the need for separate detection devices and allowing the system to self-diagnose water level conditions.

Inventive Principle:

Principle #25Self-service

3Reliability

If the drain pump is operated continuously to ensure empty sump, then the water level detection reliability is improved, but the noise emission increases due to unnecessary operation

Engineering Contradiction:

Improvewater level detection reliabilityVSAvoidnoise emission

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The circulation pump motor itself serves the dual function of both circulating water and indicating water level through its electrical characteristics. The motor's current consumption and power factor naturally vary with water level, eliminating the need for separate detection devices and allowing the system to self-diagnose water level conditions.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system performs a preliminary check of the water level condition before starting the drain pump operation by analyzing the motor's electrical parameters. This preliminary detection allows the control system to avoid unnecessary drain pump operation when the sump is already empty, thereby reducing noise emission.

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

This approach reduces power consumption and noise emission by eliminating unnecessary drain pump operations and eliminating the need for additional pressure sensors, while maintaining effective water circulation and pressure control.

Implementation Method 1

a firing angle condition of a TRIAC of the dishwasher, which is connected to a circulation pump for providing electrical power to a motor of the circulation pump, is detected and/ or used to derive the water level in the dishwasher

Methodology Applied

Scientific EffectTRIAC firing angle control:

Data Source

PatentEP2731259B1Dishwasher and method for detecting the water level within a dishwasher

Publication Date: 2018.04.25 ELECTROLUX HOME PROD CORP NV

Figure 1

AI summary

The invention relates to a method for detecting a water level in a dishwasher comprising a circulation pump and a TRIAC connected to the circulation pump for providing electrical power to a motor (20) of the circulation pump. According to the invention, a firing angle condition (18) of the TRIAC is used to derive the water level in the dishwasher. The invention further relates to a dishwasher comprising a circulation pump and a TRIAC connected to the circulation pump for providing electrical power to a motor of the circulation pump, a drain pump connected to a sump of the dishwasher, means for detecting a firing angle condition of the TRIAC. Control means are provided for starting the drain pump and / or supplying additional water when predefined conditions of the TRIAC firing angle are reached.