Sensor Fusion for Bubble-Resistant Chemical Reservoir Level Detection
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Solution Overview
Problem
Existing ultrasonic level-sensors in semiconductor and related industries are unable to accurately detect liquid levels in chemical reservoirs due to the presence of bubbles and foam, leading to false overflow alarms and costly chemical wastage.
Innovation Solution
A system comprising a liquid-level sensor, a mass-detection device, and a processor that determines the actual volume of liquid by comparing measurements from the liquid-level sensor and the mass-detection device, and activates a showerhead to reduce or eliminate bubbles and foam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic level-sensors are used to detect liquid levels, then liquid level detection is enabled, but false overflow alarms occur due to bubbles and foam
Solution Approach 1:
A mass-detection device (intermediary) is introduced between the liquid level and the overflow detection system. This device measures the actual mass of the reservoir and liquid, providing a reliable reference that is not affected by bubbles or foam. The processor compares the mass-based volume calculation with the level sensor reading to determine if an actual overflow condition exists, thereby eliminating false alarms caused by air pockets.
2Productivity
If ultrasonic level-sensors are used, then liquid level monitoring is achieved, but chemical wastage occurs due to false alarms
Solution Approach 1:
The system implements feedback by continuously comparing the volume calculated from mass measurements with the volume indicated by the level sensor. When the level sensor indicates high volume but the mass-based calculation shows normal volume (indicating bubbles/foam), the system provides feedback to suppress the false overflow alarm and activates the showerhead to eliminate the bubbles, preventing unnecessary chemical dumping and maintaining process continuity.
3Measurement precision
If multiple sensors are combined for accurate detection, then detection accuracy improves, but system complexity increases
Solution Approach 1:
The system merges two different measurement approaches (level sensing and mass detection) into a unified overflow detection system. The processor integrates data from both the ultrasonic level sensor and the mass-detection device, using their complementary strengths: the level sensor provides continuous monitoring while the mass sensor provides absolute reference measurements, together achieving high accuracy without excessive complexity.
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
The system effectively prevents false overflow alarms, reduces chemical wastage, and ensures accurate liquid level detection, thereby minimizing production losses and maintaining process integrity.
Implementation Method 1
Contemporaneous types of ultrasonic level-sensors are unable to detect bubbles and/or foam
Implementation Method 2
a mass-detection device for determining a mass of the fluid reservoir and liquid contained therein
Implementation Method 3
a mechanism to reduce a volume of bubbles and foam within the chemical or liquid reservoir
Data Source
AI summary
In one embodiment, the disclosed apparatus is an in-situ, closed-loop bubble and foam detection and reduction system that includes a liquid-level sensor to determine a volume of a liquid in a fluid reservoir, a mass-detection device to determine a mass of the fluid reservoir and any liquid contained within the fluid reservoir, a processor electrically coupled to the liquid-level sensor and the mass-detection device to determine an actual volume of the liquid within the fluid reservoir, and a showerhead coupled to the processor and positioned above the fluid reservoir. The showerhead is activated by the processor when a volume of the liquid determined by the liquid-level sensor exceeds the actual volume of the liquid by a predetermined amount. Other apparatuses and methods are disclosed.