Laundry washing machine with improved level sensing device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laundry washing machines with level sensing devices using pressure sensors and air chambers suffer from inaccurate liquid level detection due to the cylindrical liquid flowing path, leading to intermittent detections and potential heater damage from incorrect liquid level management.
Innovation Solution
A laundry washing machine design featuring a level sensing device with a rectilinear (or flat) portion in the liquid flowing path between the washing tub and air chamber, allowing for more accurate and stable liquid level detection by ensuring the pressure sensor activates only when the liquid reaches the rectilinear portion, preventing rapid switching and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cylindrical liquid flowing path is used in the level sensing device, then the device structure is simple, but the liquid level detection accuracy deteriorates due to intermittent detections at the upper part of the circumference
Solution Approach 1:
The patent introduces an asymmetric rectilinear portion in the upper part of the liquid flowing path, replacing the symmetric cylindrical shape. This rectilinear portion has a flat upper surface that provides a stable, non-curved detection point, eliminating the intermittent detection problem caused by the cylindrical circumference while maintaining manufacturing simplicity.
2Speed
If the pressure sensor activates when liquid reaches the upper part of the cylindrical path, then the detection responds quickly, but the detection stability deteriorates due to rapid switching around the starting detection level
Solution Approach 1:
The rectilinear portion creates an asymmetric detection geometry where the flat upper surface provides a single, stable activation point. This prevents the rapid switching that occurs with cylindrical geometry, as the liquid level must reach a specific planar surface rather than a curved circumference, thereby improving detection stability while maintaining response speed.
3Reliability
If incorrect liquid level detection occurs, then the washing cycle management may be wrong, but the heater damage risk increases due to heater not being properly immersed in liquid
Solution Approach 1:
The rectilinear portion provides a more reliable detection point that accurately indicates when the liquid level is sufficient to immerse the heater. By eliminating intermittent detections, it ensures the heater is properly immersed before heating operations begin, preventing heater damage while maintaining reliable washing cycle management.
Solution Approach 2:
The level sensing device with the rectilinear portion detects the liquid level in advance before heating operations start. This preliminary detection ensures that the liquid level is sufficient to cover the heater before it is activated, preventing heater damage from improper immersion.
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
Enhances the accuracy and stability of liquid level detection, preventing incorrect washing cycle management and potential heater damage, thereby increasing the machine's reliability and longevity.
Implementation Method 1
The air volume enclosed above the liquid in the chamber is therefore subjected to a pressure which is sensed by the pressure sensor and then translated into a measure of the liquid level in the machine
Implementation Method 2
When the liquid rises in the tub, a corresponding liquid column is also created in the air chamber. The liquid column applies a pressure to the air volume enclosed thereabove in the air chamber
Data Source
AI summary
A laundry washing machine (1) has a washing tub (3) external to a rotatable washing drum (4) adapted to receive laundry. The machine further has a level sensing device (19) having a pressure sensor (50) suitable for determining the liquid level inside the washing tub (3). The level sensing device (19) further has an air chamber (51; 151) connectable to a detection outlet (60) associated to the washing tub (3). A liquid flowing path (61) is defined between the detection outlet (60) and the air chamber (51; 151), wherein the liquid may flow between the washing tub (3) and the air chamber (51;151). In a mounted configuration, the air chamber (51; 151) is associated to the washing tub (3) and the laundry washing machine (1) is positioned in its working position, and the path (61) is shaped such that at least a section of the path, in a plane perpendicular to a flowing direction (V) of the liquid, has the upper part comprising a rectilinear portion (64a; 64b; 164a).