Method and apparatus for controlling the supply of a level of a liquid contained in a vessel
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Solution Overview
Problem
Current methods and apparatuses for controlling the liquid level in vessels, such as in washing machines, are not reliable and economical, as they fail to accurately adjust for variations in liquid viscosity, leading to incomplete or uneven liquid supply during washing and rinsing processes.
Innovation Solution
A method and apparatus that utilize a digital sensor to detect the presence of air bubbles in the liquid flow, generating a digital signal that compares to a reference signal to adjust the pump's actuation duration based on viscosity changes, ensuring complete liquid supply by modifying the pump's operation according to differences in signal frequency and duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pump operates at constant nominal flow-rate to induce liquid flow, then the liquid supply process is simple, but the vessel cannot be completely emptied when liquid viscosity varies
Solution Approach 1:
The system uses a digital sensor to detect air bubbles in the liquid flow and generates a digital signal that is compared to a reference signal. Based on the comparison results, the control unit adjusts the pump actuation duration to compensate for viscosity variations, ensuring complete vessel emptying while maintaining simple constant flow-rate operation
Solution Approach 2:
The invention changes the pump actuation duration parameter dynamically based on detected liquid viscosity. By comparing the digital sensor signal frequency and duration to reference values, the system adjusts the pump operation time to adapt to different liquid viscosities, ensuring reliable complete emptying
2Reliability
If the pump actuation duration is extended to ensure complete liquid supply, then all liquid can be supplied, but the washing and rinsing processes take longer
Solution Approach 1:
The control unit receives feedback from the digital sensor comparing detected signal characteristics to reference values, and adjusts the pump actuation duration precisely to the minimum required time for complete liquid supply, avoiding unnecessary time extension
Solution Approach 2:
The system dynamically adjusts the pump actuation duration based on real-time detection of liquid viscosity through air bubble analysis. The actuation time is optimized for each specific liquid type, providing just enough time for complete supply without excessive delay
3Reliability
If a digital sensor and signal comparison system is implemented to adjust pump duration, then liquid supply reliability improves, but device complexity increases
Solution Approach 1:
The system uses air bubbles as an intermediary to indirectly measure liquid viscosity. Instead of directly measuring viscosity, the digital sensor detects air bubbles in the liquid flow, and the presence/absence pattern serves as a proxy for viscosity determination, simplifying the control system
Solution Approach 2:
The invention replaces complex mechanical viscosity measurement devices with an optical/electronic digital sensor system that detects air bubbles. This substitution uses light or electromagnetic field-based detection instead of mechanical measurement, reducing device complexity while improving measurement accuracy
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 provides a reliable and economical solution for controlling the liquid supply, ensuring complete emptying of the vessel by adjusting the pump's actuation time based on viscosity changes, thereby maintaining optimal washing and rinsing processes.
Implementation Method 1
a digital sensor (18) which detects the flow of liquid in a detection section (16) of the outlet duct (14)
Data Source
Figure 1~2
Figure 2a
Figure 3
AI summary
The method comprises the operating step of actuating a pump at a constant nominal flow-rate in order to induce a flow of liquid out of a vessel (12) through an outlet duct (14). Said outlet duct (14) communicates with the vessel (12) with an upper aperture (22a), situated at a height that defines an intermediate level (12), and a lower aperture (22b), situated at a height that defines a reduced level (13). The method provides for detecting the flow of liquid in a detection section (16) of the outlet duct (14). A digital signal (S) is supplied, which assumes an alternate sequence of states when the level of the liquid is between the intermediate level (12) and the reduced level (13). Each one of such states is either an air-indicating state (s0) or, respectively, a liquid- indicating state (s1) each time, in the detection section (16), the presence or, respectively, the absence of air bubbles is detected in the flow of liquid. The method provides for comparing the digital signal (S) with a reference signal (S') having a predetermined sequence of air-indicating states and liquid-indicating states; and modifying the duration of actuation of the pump as a function of a difference existing in the comparison between the digital signal (S) and the reference signal (S'). In addition to the method, an apparatus (10) is also provided for controlling the supply of a level of liquid contained in a vessel (12).