Washing Machine Foam Level Sensing for Overflow Prevention
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Solution Overview
Problem
Existing washing machines face issues with excessive foam formation during the washing process, which reduces rinsing performance, leaves detergent residues on clothes, and can cause overflow, necessitating the use of less foaming detergents, decreased drum rotation speed, increased temperature, or additional equipment to manage foam.
Innovation Solution
A washing machine equipped with a foam level sensor that interrupts the spinning process and operates the drum at a lower speed and runtime ratio to mix and drain the foam, preventing excessive foam formation without additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the drum rotation speed is decreased to prevent excessive foam formation, then foam overflow is prevented, but washing productivity and cycle time are reduced
Solution Approach 1:
The patent applies periodic action by implementing intermittent drum rotation during the washing cycle. When excessive foam is detected, the drum rotation is temporarily stopped or reversed, creating periodic motion patterns that collapse foam bubbles and reduce foam volume without requiring continuous low-speed operation, thus maintaining productivity while preventing foam overflow.
Solution Approach 2:
The patent changes operational parameters dynamically by adjusting drum rotation speed and direction based on foam detection. The control unit monitors foam levels and modifies the drum's rotational parameters in real-time, switching between normal washing speeds and foam-reducing speeds or reverse rotation, thereby preventing foam overflow while minimizing impact on washing efficiency.
2Object-affected harmful factors
If additional equipment is added to manage foam (hot air generator, water spray system), then foam control effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies self-service by utilizing the washing machine's existing drum rotation mechanism to control and eliminate foam. The control unit leverages the normal washing operations and drum motion to collapse foam bubbles through intermittent stopping or reversal, eliminating the need for separate foam management equipment while maintaining effective foam control.
Solution Approach 2:
The patent makes the drum rotation mechanism multi-functional by using it for both normal washing operations and foam control. The same drum that performs the primary washing function is also utilized to collapse foam through periodic stopping or reverse rotation, thereby avoiding additional equipment while achieving effective foam management.
3Quantity of substance
If the drum is stopped and restarted frequently to mix and drain foam, then foam level is reduced, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by implementing intermittent drum rotation during the washing cycle. When excessive foam is detected, the drum rotation is temporarily stopped or reversed, creating periodic motion patterns that collapse foam bubbles and reduce foam volume without requiring continuous low-speed operation, thus maintaining productivity while preventing foam overflow.
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
Effectively prevents foam overflow and enhances washing performance by reducing foam levels during spinning, ensuring detergent residues are minimized and the machine operates efficiently without additional equipment.
Implementation Method 1
a foam level sensor which detects the foam level inside the drum
Implementation Method 2
the drum starts operating bi-directionally or unidirectionally preferably with starts and stops as in main washing step with a pre-determined low speed and/or runtime rate so as not to increase the foaming and the foam mixes with water
Implementation Method 3
The draining pump is operated as the drum starts operating to drain the foamed water
Data Source
Figure 1
AI summary
This invention relates to a washing machine (1) and a control method thereof wherein the main washing, the rinsing and the spinning steps are executed, a foam level sensor (6) is used to detect the excessive foaming that may occur inside the drum (2) after the main washing and the rinsing, and a foam decreasing algorithm is executed to decrease the foam.