Method of determining whether process water is present in a circulation pump of an appliance for washing and rinsing goods, and appliance and computer program therewith
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Solution Overview
Problem
Existing washing appliances, such as dishwashers, require complex and costly sensors to determine if process water is present in the circulation pump, which increases complexity and cost.
Innovation Solution
A method and appliance that measure the minimum and maximum load of the circulation pump at different speeds to determine if process water is present, using the difference or quotient of operating current measurements to indicate the presence of water without traditional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensors (flow sensors, pressure sensors, pressure switches, float switches) are used to determine process water presence in the circulation pump, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the water detection function from separate physical sensors and integrates it into the existing pump motor control system. By measuring the electrical load (current) of the pump motor at different speeds, the system infers water presence without requiring additional flow, pressure, or float sensors. This removes the need for complex sensor assemblies while maintaining detection capability.
Solution Approach 2:
The pump motor serves multiple functions: it pumps water during operation and simultaneously acts as a sensor for detecting water presence through its electrical load characteristics. The existing motor infrastructure is utilized for dual purposes - water circulation and water detection - eliminating the need for dedicated detection sensors and reducing overall device complexity.
2Measurement precision
If traditional sensors (flow sensors, pressure sensors, pressure switches, float switches) are used to determine process water presence in the circulation pump, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent replaces expensive, complex sensor assemblies with a low-cost electrical measurement approach. By utilizing the existing pump motor's electrical characteristics and measuring current load with standard electrical sensors already present in the appliance, the system achieves water detection at minimal additional cost, effectively using inexpensive measurement methods instead of costly specialized sensors.
Solution Approach 2:
The pump motor itself provides the detection function through its inherent electrical load characteristics when operating with water versus without water. The system uses the motor's own operational parameters (current draw at different speeds) to determine water presence, making the motor self-diagnostic and eliminating the need for separate detection components that would increase manufacturing cost.
3Productivity
If the circulation pump speed is increased to improve water circulation, then productivity is improved, but energy consumption increases
Solution Approach 1:
The patent implements variable speed operation of the circulation pump, allowing the motor speed to be dynamically adjusted based on operational requirements. The pump operates at different speeds (first speed and second speed) depending on the washing phase and water presence conditions, optimizing both circulation efficiency and energy consumption rather than running at constant high speed.
Solution Approach 2:
The system changes the operational parameters (speed) of the pump motor based on detected conditions. By measuring electrical load at different predetermined speeds and comparing the relationship between minimum and maximum load values, the system adapts the pump's operating characteristics to match actual water presence and circulation needs, achieving optimal productivity-energy balance.
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
Enables the determination of process water presence in the circulation pump without the need for flow, pressure, or float sensors, reducing complexity and cost while effectively monitoring water levels.
Implementation Method 1
measuring a minimum load of the circulation pump at a predetermined first speed, measuring a maximum load of the circulation pump at a predetermined second speed
Data Source
AI summary
Provided herein is a method of determining whether process water is present in a circulation pump of an appliance for washing and rinsing goods, and an appliance performing the method. The method of determining whether process water is present in a circulation pump of an appliance for washing and rinsing goods may include measuring a minimum value of a property representing load of the circulation pump at a predetermined first speed, measuring a maximum value of a property representing load of the circulation pump at a predetermined second speed, the second speed being higher than the first speed, determining a relation between said minimum value and said maximum value, and determining, from said relation, whether process water is present in the circulation pump.