Thermal trip device for triggering the automatic closing of a fire damper in an air duct
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal tripping devices for fire dampers, such as those using thermal fuses, are inflexible, prone to premature activation during transport or storage, and cannot be reset, requiring multiple variants for different temperature settings and lacking compact design.
Innovation Solution
A thermal tripping device with a microcontroller-based electronic control unit and integrated temperature sensors on a single circuit board, allowing for adjustable temperature settings and compact, resettable operation, eliminating the need for separate wiring and multiple fuse variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If thermal fuses are used for temperature detection, then the device structure is simple, but the device cannot be reset and requires multiple variants for different temperature settings
Solution Approach 1:
The patent replaces mechanical thermal fuses with an electronic temperature detection system using temperature sensors (such as thermistors or integrated temperature sensors) connected to a microcontroller. This electronic system can be programmed to detect multiple temperature thresholds and can be reset by power cycling, eliminating the need for multiple physical fuse variants and providing programmable adaptability for different temperature settings.
Solution Approach 2:
The microcontroller-based temperature detection system serves multiple functions: it can detect various temperature thresholds through programming, provide resettable operation, enable visual indication through LEDs, and support different operating modes (normal mode and test mode). This single electronic system replaces what would otherwise require multiple specialized thermal fuse components for different applications.
2Ease of manufacture
If thermal fuses are used, then manufacturing is simple, but SMD production is not possible as the fuse would melt during soldering
Solution Approach 1:
The patent replaces heat-sensitive thermal fuses with electronic temperature sensors and a microcontroller that are insensitive to soldering temperatures. These electronic components can be manufactured using standard SMD (Surface Mount Device) techniques, allowing for automated pick-and-place assembly and reflow soldering processes that would melt traditional thermal fuses. The temperature detection function is implemented through electronic circuits rather than heat-sensitive mechanical components.
3Volume of moving object
If thermal fuses are used, then the device is compact, but the device may trip during transport or storage if limit temperature is reached
Solution Approach 1:
The patent implements a dynamic temperature detection system with a microcontroller that continuously monitors temperature and compares it against programmable thresholds. The system includes hysteresis logic and can distinguish between gradual temperature changes (such as those during transport) and rapid temperature rises (indicative of fire conditions). The visual indication system using LEDs provides feedback about the current state, and the system can be reset by power cycling, preventing permanent tripping during storage.
Solution Approach 2:
The system uses programmable temperature thresholds and detection parameters that can be adjusted based on application requirements. The microcontroller can be configured with different tripping temperatures and can implement detection algorithms that account for environmental conditions during transport and storage, reducing false activations while maintaining sensitivity to actual fire conditions.
4Measurement precision
If separate wiring for temperature sensors is used, then temperature detection is accurate, but the device complexity increases
Solution Approach 1:
The patent integrates the temperature sensor directly with the microcontroller, either as an integrated temperature sensor on the same chip or as a thermistor mounted directly on the circuit board near the microcontroller. This integration eliminates the need for separate wiring harnesses and external sensor mounting, reducing wiring complexity while maintaining temperature detection accuracy through direct thermal coupling between the sensor and the air duct environment.
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 a flexible, compact, and resettable thermal tripping device that can be easily configured for various applications, reducing the risk of premature activation and ensuring reliable operation across different temperature settings.
Implementation Method 1
a first temperature sensor connected to the control unit for the continuous detection of a duct air temperature value inside the air duct
Implementation Method 2
a second temperature sensor connected to the control unit for the continuous detection of an ambient air temperature value outside the air duct
Implementation Method 3
an electrically controllable switching element downstream of the control unit for interrupting the power supply to the actuator
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a thermal release device (10) for triggering the automatic closing of a fire damper (4) in an air duct (5) by means of an actuator (1). The release device is designed for mounting on the air duct. It is also configured to interrupt a release line (8) of the actuator that is looped through the release device.The triggering device comprises an electronic control unit (14), a first temperature sensor (16) connected thereto for detecting a duct air temperature value (θi) inside the air duct (5), a second temperature sensor (17) connected thereto for detecting an ambient air temperature value (θa) outside the air duct, and an electrically controllable switching element (S) downstream of the control unit for interrupting the power supply to the actuator (1) when the duct air temperature limit or a predefinable ambient air temperature limit (θGa) is exceeded. According to the invention, the triggering device has a housing (12) and a circuit carrier (11) at least partially enclosed therein. The first and second temperature sensors are arranged on a first (19-1) and second circuit carrier section (19-2), respectively.When installed correctly, the first temperature sensor is located inside and the second temperature sensor is located outside the air duct.