Method for the detection of foam in a laundry washing machine, and washing machine
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laundry washing machines face challenges in detecting foam early in the washing cycle, leading to inefficient washing, potential detergent residue on laundry, and pump malfunction due to excessive foam, which complicates the design and increases costs.
Innovation Solution
A method that determines foam presence by measuring the liquid level difference between recirculation pump activation and deactivation phases using a liquid level sensor, allowing for early detection and reduction of foam through various actions such as adjusting washing time, heating, and rinsing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If foam detection is performed during initial phases using water level measurement, then foam detection capability is improved, but measurement precision deteriorates due to inability to distinguish foam from liquid
Solution Approach 1:
The recirculation pump is activated before foam detection to create a recirculation phase, allowing the system to establish a baseline liquid level measurement before foam interference occurs. This preliminary action enables subsequent foam detection by comparing levels during different operational phases.
Solution Approach 2:
The system performs periodic measurements of liquid level during different phases (steady phase and recirculation phase) to detect changes indicative of foam presence. By measuring at multiple time points and comparing variations, the system can distinguish foam from liquid despite using a single water level sensor.
2Measurement precision
If a dedicated foam sensor is integrated with temperature sensor, then foam detection precision is improved, but device complexity increases
Solution Approach 1:
The water level sensor performs multiple functions: it measures both liquid level and detects foam presence by analyzing level variations during recirculation. This multi-functionality eliminates the need for a dedicated foam sensor, maintaining measurement precision while reducing device complexity.
Solution Approach 2:
The system uses its existing water level sensor and recirculation pump to perform foam detection, rather than requiring additional specialized sensors. The recirculation pump's normal operation serves the dual purpose of liquid circulation and foam detection, simplifying the overall device architecture.
3Object-generated harmful factors
If recirculation pump is activated continuously, then foam reduction is improved, but energy consumption increases
Solution Approach 1:
The recirculation pump is activated periodically in phases rather than continuously. It operates during recirculation phases to reduce foam and remains deactivated during steady phases, thereby maintaining effective foam control while significantly reducing energy consumption compared to continuous operation.
Solution Approach 2:
The system uses feedback from water level sensor measurements to control recirculation pump operation. When foam is detected through level variations, the pump is activated to reduce foam; when no foam is present, the pump remains deactivated, optimizing energy usage based on actual foam conditions.
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 enables effective foam detection and reduction at an early stage of the washing cycle, improving washing efficiency, reducing detergent residue, and ensuring proper pump operation, while simplifying the machine design and enhancing reliability.
Implementation Method 1
a liquid level sensor for detecting the liquid level in said washing tub
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a method for determining the presence of foam in a laundry washing machine (1) comprising a washing tub (3) containing a washing drum (4) and a recirculation pump (21). The method comprises the steps of: performing a steady phase wherein the recirculation pump (21) is deactivated and a recirculation phase wherein the recirculation pump (21) is activated; detecting a first level (L1) of the washing liquid in the washing tub (3) during the steady phase; detecting a second level (L2) of the washing liquid in the washing tub (3) during the recirculation phase; determining the level difference (LD) between the second level (L2) and the first level (L1); comparing the determined level difference (LD) with a threshold value (TV) and if the determined level difference (LD) is below the threshold value (TV) establishing the presence of foam.