Flow Sensor Assembly for Corrosive Liquid Detection
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Solution Overview
Problem
Existing flow sensors for heating systems in swimming pools and spas, such as adjustable water pressure switches and other types, fail to accurately detect low water flow rates, leading to overheating and reduced compressor life due to corrosion and complexity issues, especially when exposed to high concentrations of chlorine and other corrosive chemicals.
Innovation Solution
A flow sensor assembly comprising an O-ring support, a printed circuit board with thermistors and a processor that compares resistance values to determine flow rates, using titanium sensor pins and an over-molding material for corrosion resistance and reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional flow sensors are used in corrosive environments, then they fail to accurately detect low water flow rates, but using corrosion-resistant materials and simplified design improves reliability and accuracy
Solution Approach 1:
The patent employs a composite construction combining titanium sensor pins (corrosion-resistant) with a plastic housing and over-molding material. This composite approach allows the sensor to withstand corrosive chlorine environments while maintaining accurate flow detection capabilities through the specialized titanium components.
Solution Approach 2:
The patent replaces traditional mechanical pressure switch mechanisms with an electronic sensor system using thermistors and a microprocessor. This substitution eliminates mechanical wear and corrosion issues while improving accuracy in detecting low flow rates in corrosive environments.
2Measurement precision
If complex sensor designs are used to improve detection accuracy, then manufacturing costs and device complexity increase, but simplified designs reduce costs while maintaining reliability
Solution Approach 1:
The patent extracts the essential flow detection function from complex mechanical assemblies and implements it through a simplified electronic circuit with thermistors and a microprocessor. This extraction maintains measurement precision while dramatically reducing device complexity and manufacturing costs.
Solution Approach 2:
The patent uses cost-effective materials such as plastic housing and over-molding material combined with inexpensive thermistor sensors, replacing expensive mechanical components. This approach maintains adequate precision for pool heating applications while significantly reducing manufacturing costs.
3Measurement precision
If traditional pressure switches are used, then the system cannot detect low flow rates accurately, but thermistor-based sensors provide accurate detection across all flow conditions
Solution Approach 1:
The patent replaces mechanical pressure switches with an electronic thermistor-based sensor system that provides accurate detection across all flow conditions including very low flow rates. The microprocessor analyzes resistance changes to determine flow status, eliminating the inability of mechanical switches to detect low flows.
Solution Approach 2:
The patent implements a feedback system where the microprocessor continuously monitors thermistor resistance values and adjusts its determination of flow status based on predefined thresholds. This feedback mechanism enables accurate detection across varying flow conditions while providing clear operational signals to the heating system.
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 provides accurate and reliable detection of flow rates, even in corrosive environments, preventing overheating and extending the life of heating system components while being cost-effective and simple in design.
Implementation Method 1
a self-heating thermistor that generates a known amount of heat
Implementation Method 2
The PCB includes a plurality of thermistors associated with the plurality of couplings, wherein each thermistor of the plurality of thermistors are positioned on the PCB and are adjacent to a respective coupling of the plurality of couplings
Data Source
AI summary
Provided are flow sensor assemblies for determining a flow rate of a liquid that include an O-ring support, a printed circuit board (PCB) positioned in the O-ring support, a plurality of couplings of a male sensor pin and a female sensor pin, a plurality of thermistors associated with the plurality of couplings, wherein each thermistor of the plurality of thermistors are positioned on the PCB and are adjacent to a respective coupling of the plurality of couplings, and an over-molding material that holds the PCB in place with regard to the O-ring support. Methods are also provided.