Liquid level sensor
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Solution Overview
Problem
Existing condensate pumps in air-conditioning systems face issues with inaccurate liquid level measurement, noise generation, and mechanical failures due to reliance on magnetic floats and capacitance sensors, which require time-consuming calibration and are prone to human error and physical damage.
Innovation Solution
A liquid level sensor module with multiple sensing elements and a microprocessor that dynamically calculates and adjusts the condensate pump speed based on real-time liquid level data, eliminating the need for manual calibration and providing accurate flow control without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic float switches are used to control condensate pump operation, then pump operation can be controlled based on liquid level, but the system generates noise and mechanical failures due to vibration and physical damage
Solution Approach 1:
The patent replaces mechanical float switches with a capacitive sensing system that uses electrical fields to detect liquid levels. The capacitive sensor measures changes in capacitance caused by the dielectric properties of liquid versus air, enabling contactless detection of liquid levels and elimination of mechanical moving parts that cause noise and vibration.
Solution Approach 2:
The patent introduces a microprocessor as an intermediary between the capacitive sensor and pump control. The microprocessor processes capacitive measurements, applies calibration data, and makes intelligent control decisions, replacing direct mechanical switch actuation and enabling smoother, quieter pump operation through electronic control.
2Measurement precision
If capacitance-based liquid level sensors are used, then liquid level information can be obtained, but manual calibration is required which is time-consuming and prone to human error
Solution Approach 1:
The patent implements self-calibration functionality where the system automatically performs calibration during installation or operation. The microprocessor guides the calibration process, automatically measures capacitance at known liquid levels, and stores calibration parameters without requiring manual intervention, eliminating time-consuming manual calibration procedures.
Solution Approach 2:
The patent performs calibration automatically during the installation phase or initial operation before normal use begins. By completing the calibration process in advance during a controlled setup period, the system eliminates the need for time-consuming calibration during ongoing operation, and the microprocessor stores calibration data for future use.
3Productivity
If condensate pump is mounted within or adjacent to AC unit housing, then travel distance between reservoir and pump is minimized, but pump vibration causes rattling noise within housing
Solution Approach 1:
The patent replaces mechanical float switch actuation with capacitive sensing and electronic control, eliminating the need for mechanical components that rattle within the housing. The contactless capacitive detection and electronic pump control eliminate mechanical impacts and vibrations that cause rattling noise while maintaining efficient condensate removal.
Solution Approach 2:
The patent implements continuous feedback from capacitive sensors to the microprocessor, which monitors liquid levels and adjusts pump operation in real-time. This feedback control enables smooth, progressive pump activation and shutdown, preventing sudden mechanical movements and vibrations that would cause rattling noise within the housing.
4Ease of operation
If floats are used for level indication, then pump operation control is simple, but floats can become stuck during prolonged shutdown periods
Solution Approach 1:
The patent replaces mechanical floats with capacitive sensors that detect liquid levels through electrical field changes. This substitution eliminates mechanical components that can become stuck or fail during prolonged shutdown periods, while maintaining simple automated pump control through electronic sensing and microprocessor management.
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 solution enhances the reliability and accuracy of condensate pump operation, reduces noise, and extends the lifespan of the pump by continuously monitoring and correcting for calibration drift, ensuring efficient and safe condensate management.
Implementation Method 1
capacitance measurements may be used, but only to provide level information
Implementation Method 2
capacitance-based liquid level sensors
Data Source
AI summary
The present invention provides a liquid level sensor and an automatic calibration process which removes the need for prior manual calibration of the liquid level sensor, as this happens dynamically during installation and use of the pump. Further, by frequently monitoring the calibration of the sensor and correcting for long term drift or contamination on the sensing surface, the reliability of the liquid level sensor is considerably better than those of the prior art. By operating a solid state sensor, there are no moving parts in the liquid level sensor described above.