Washer Foam Detection Using Stationary Drum Pressure Timing
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Solution Overview
Problem
Existing methods for detecting foam in laundry care appliances have reduced reliability due to pressure measurements being affected by a moving laundry drum, leading to potential damage and poor washing results from excess foam.
Innovation Solution
A detection device that records first and second liquid pressures when the laundry drum is stationary, using backflow time of wash water to determine foam presence, with a calibration device to adapt to different laundry amounts and surfactant conditions, allowing for direct comparison of pressure and time differences to assess foam generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure measurements are taken in a moving laundry drum to detect foam, then foam detection can be performed during washing, but the reliability of detection is reduced due to drum movement affecting pressure readings
Solution Approach 1:
The patent utilizes the periodic stopping phases of the laundry drum during the washing cycle to perform pressure measurements. By scheduling foam detection during these natural pause periods when the drum is stationary, the system achieves reliable measurements without requiring continuous drum operation, thus resolving the contradiction between maintaining washing productivity and ensuring detection reliability.
2Ease of operation
If average liquid pressure values are used to determine foam presence, then detection can be performed, but accuracy is reduced
Solution Approach 1:
The patent replaces the conventional method of using average pressure values with a method based on measuring the time duration of pressure increase (backflow time). This substitution of measurement approach maintains operational simplicity while significantly improving foam detection accuracy, as the time-based measurement is less susceptible to variations and provides more precise foam presence determination.
3Reliability
If the laundry drum is stopped to perform accurate pressure measurements, then detection reliability improves, but washing productivity decreases
Solution Approach 1:
The patent performs foam detection during pre-wash phases or at the beginning of washing cycles when the drum naturally stops before the main washing action begins. By conducting pressure measurements during these preliminary stationary phases, the system ensures reliable detection without interrupting the subsequent productive washing operation, thus maintaining overall washing 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
This method enhances the reliability of foam detection, preventing overflow and ensuring effective washing performance by accurately determining foam presence without relying on average liquid pressure values.
Implementation Method 1
a pressure detection device for detecting a first liquid pressure in the tub at a first point in time and a second liquid pressure at a second point in time
Data Source
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AI summary
The present invention relates to a laundry care appliance (100) having a detector device (130) for detecting foam in an outer tub (115), which comprises a pressure measuring device (110) for measuring a first liquid pressure in the outer tub (115) at a first instant and a second liquid pressure at a second instant while the inner tub (117) is at rest; and determining means (119) for determining the presence of foam on the basis of the first liquid pressure and the second liquid pressure. The invention also relates to a method for detecting foam in a laundry care appliance.