Corner-Mounted Surface Thermistors for Compact Point Heat Detection
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Solution Overview
Problem
Current point heat detectors based on lead type temperature sensors require manual mounting above the PCB surface, leading to increased costs, space consumption, and design limitations due to their tall profile, and are prone to human error and complexity in manufacturing.
Innovation Solution
Implementing surface mounted thermistors on the corners of a PCB, with angular spacing and apertures to reduce thermal inertia, and using a proportional integral observer process to estimate airflow temperature, along with dedicated software to compensate for thermal inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lead type temperature sensors are mounted above the PCB surface to reduce thermal inertia influence, then temperature measurement accuracy is improved, but manufacturing complexity and cost increase due to manual mounting requirements
Solution Approach 1:
The patent merges the temperature sensor mounting process with the PCB manufacturing process itself. Surface mounted thermistors are integrated directly onto the PCB surface during automated PCB fabrication, eliminating the need for separate manual mounting operations. This combining of operations reduces manufacturing complexity while maintaining measurement accuracy through proper thermal isolation design.
Solution Approach 2:
The patent replaces manual mechanical mounting operations with automated PCB surface mount technology. The thermistors are positioned and secured using automated pick-and-place machines and reflow soldering processes, substituting human labor with automated manufacturing systems. This substitution maintains precise positioning for thermal isolation while dramatically reducing manufacturing complexity and cost.
2Speed
If lead type temperature sensors are spaced above the PCB surface to minimize PCB thermal inertia, then response time to air temperature changes is improved, but device height profile increases
Solution Approach 1:
The patent transitions from vertical spacing (elevating sensors above PCB surface) to horizontal integration (mounting sensors directly on PCB surface with thermal isolation). By changing the dimension of thermal isolation from vertical separation to horizontal patterning on the PCB surface, the device achieves fast response times while maintaining a low height profile suitable for compact installations.
Solution Approach 2:
The patent applies local thermal isolation properties at the sensor-PCB interface rather than requiring uniform vertical spacing. By creating localized thermal isolation features (such as thermal barriers, air gaps, or insulating structures) only at the critical sensor mounting locations, the design achieves fast thermal response where needed while keeping the overall device profile compact.
3Manufacturing precision
If manual mounting processes are used for lead type temperature sensors, then sensor positioning accuracy is improved, but production cost and human error increase
Solution Approach 1:
The patent replaces manual mechanical positioning and mounting with automated PCB surface mount processes. Automated pick-and-place machines position thermistors with high precision, and reflow soldering secures them accurately. This substitution eliminates human error while maintaining positioning accuracy through programmable automation, significantly reducing labor costs and improving consistency.
Solution Approach 2:
The patent changes the manufacturing parameters from manual operations to automated process parameters. By defining precise positioning coordinates, solder paste patterns, and reflow temperature profiles, the manufacturing process achieves high precision through controlled parameters rather than human skill. This parameter-based approach reduces variability and cost while maintaining 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
The solution results in a more compact, cost-effective, and accurate fire detection system with improved design flexibility, reduced manufacturing complexity, and enhanced directionality in detecting heat sources.
Implementation Method 1
point heat detectors based on surface mounted thermistors
Implementation Method 2
apertures to reduce thermal inertia
Data Source
AI summary
Devices, systems, and methods for providing point heat detectors based on surface mounted thermistors are described herein. One circuit board for a point heat detector of a fire sensing system includes a circuit board body having number of corners, at least one hole provided in the circuit board body proximate to one of the corners, and a surface mounted thermistor mounted on at least one corner.