Washer Foam Detection During Pumping With a Moving Drum
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Solution Overview
Problem
Existing methods for detecting and treating foam in laundry treatment machines require the drum to be stationary during pumping, which is impractical and can lead to foaming issues such as poor cleaning performance and increased load on heating elements due to foam impeding the washing process.
Innovation Solution
A program-controlled laundry treatment machine with a pressure sensor that measures and smooths the pressure signal while the drum is moving, allowing for the detection of foam and implementation of measures to treat it during the pumping phase, including adjusting drum speed and heating energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the drum is kept stationary during pumping to detect foam using pressure gradient methods, then foam detection can be performed, but cleaning performance deteriorates and washing time is lost
Solution Approach 1:
The patent applies the dynamics principle by enabling the drum to rotate during pumping operations while foam detection is performed. The control unit continuously monitors pressure gradient data even when the drum is in motion, transforming the system from a static detection mode to a dynamic operation mode. This resolves the contradiction by allowing both foam detection and cleaning performance to coexist, as the drum no longer needs to stop to enable detection.
2Device complexity
If the drum is stopped during pumping for foam detection, then pressure signal measurement is simplified, but washing process time increases
Solution Approach 1:
The patent implements continuity of useful action by performing foam detection continuously during the pumping phase without interrupting the washing process. The control unit processes pressure gradient data in real-time while the drum rotates, eliminating the need for separate detection cycles. This maintains the washing process time efficiency while achieving accurate foam detection through continuous monitoring.
3Productivity
If foam is not detected early, then the washing process continues normally, but excessive foam develops causing poor cleaning and increased heating load
Solution Approach 1:
The patent applies feedback by continuously monitoring pressure gradient data during pumping and using this information to detect foam presence. When foam is detected through analysis of the pressure signal characteristics, the control unit can trigger appropriate responses such as adjusting pumping parameters or notifying the user. This early detection feedback mechanism prevents excessive foam from developing and causing harmful effects on cleaning performance and heating efficiency.
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 precise and early detection of foam, preventing unwanted foam formation and improving cleaning efficiency by allowing the drum to move during pumping, reducing washing performance losses and avoiding foam-related issues.
Implementation Method 1
determining a pressure gradient in a measurement interval with a defined length from the pressure curve obtained
Implementation Method 2
Foam and fluff residues can settle in areas of the laundry treatment machine where the flow is calmer and can be concentrated there
Implementation Method 3
excess foam leads to an increased load on the heating elements and to strong local temperature differences in the washing suds. The reason for this is that the temperature sensors react sluggishly, since the heat transfer from the foam to the temperature sensor is much less than from a liquid to the temperature sensor
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a program-controlled laundry treatment machine, having a rotatable drum, which is arranged in the washing tub, for accommodating laundry which is to be treated, having a washing liquor discharge system which is arranged at the bottom of the washing tub and has a washing liquor pump and a pressure sensor for determining the pressure of a liquid which is located in the washing tub, and having a control device which is programmed such that the laundry treatment machine can carry out the following process: (i) measure and record the pressure signal; (ii) smooth the pressure signal in order to obtain a smoothed pressure curve; (iii) determine a pressure gradient at a measurement interval of defined length from the pressure curve obtained; and (iv) carry out a measure, which is dependent on the pressure gradient and is matched to the pressure gradient, for treating foam, wherein the method is intended to be carried out during a program step which serves to remove water from the washing tub and is characterized in that step (i) is carried out during operation of the washing liquor pump with the drum moving at the same time.