Fire Damper Blocking Apparatus Using Melting Thermocouple
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Solution Overview
Problem
Fire dampers require a mechanism to remain closed during a fire, even if the drive mechanism fails or is destroyed, to prevent smoke spread and ensure safety, which existing technologies do not adequately address.
Innovation Solution
A blocking apparatus for fire dampers using a thermocouple with a lower melting temperature than the wrap spring and holding apparatus, which prestresses the wrap spring to allow bidirectional rotation during normal conditions but locks in one direction when the thermocouple melts, ensuring the fire damper remains closed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a drive mechanism is used to activate the fire damper, then the fire damper can be opened and closed during normal operation, but the drive mechanism may fail or be destroyed in a fire, causing the fire damper to open unintentionally
Solution Approach 1:
The wrap spring is pre-tensioned before the fire event occurs, storing mechanical energy in advance. When the thermocouple melts during fire, the pre-tensioned spring automatically activates to block the drive shaft, preventing unintentional opening without requiring any additional action or power source during the emergency.
Solution Approach 2:
The high temperature of the fire, which destroys the drive mechanism, is converted into a beneficial trigger by using a thermocouple with a specific melting point. The heat that would normally be harmful causes the thermocouple to melt, which releases the wrap spring to activate the blocking function, turning the fire's thermal energy into a safety mechanism.
2Reliability
If a blocking mechanism is added to ensure the fire damper remains closed during fire, then reliability improves, but the device complexity increases
Solution Approach 1:
The thermocouple acts as a simple intermediary element between the fire heat and the wrap spring. Instead of using a complex thermal sensor, control system, and actuator, the patent uses a passive thermocouple that melts at a specific temperature to trigger the blocking mechanism, significantly simplifying the overall device structure while maintaining high reliability.
Solution Approach 2:
The wrap spring is self-activating and does not require any external power source, control system, or additional actuators. The spring automatically engages the blocking function when the thermocouple melts, using its own pre-stored mechanical energy to perform the blocking action, thereby minimizing device complexity.
3Strength
If the wrap spring is made of high-melting-point material to ensure structural integrity, then strength improves, but the thermocouple cannot be integrated to provide automatic blocking during fire
Solution Approach 1:
The patent divides the functional requirements into two separate components: the wrap spring made of high-strength steel for structural integrity and blocking force, and the thermocouple made of low-melting-point material for thermal triggering. This segmentation allows each component to be optimized for its specific function without compromise, enabling both high strength and thermocouple integration.
Solution Approach 2:
The blocking apparatus uses a composite material strategy by combining different materials with distinct properties: high-strength steel for the wrap spring to ensure mechanical strength, and low-melting-point alloy for the thermocouple to provide thermal sensitivity. This material differentiation enables the system to achieve both structural integrity and automatic fire-responsive blocking.
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 reliably keeps the fire damper closed during a fire by using a thermocouple that melts and relaxes the wrap spring, blocking one direction and allowing freewheeling in the other, ensuring smoke containment and safety.
Implementation Method 1
containing at least one thermocouple (140, 142), made of a material having a lower melting temperature than the material having the lowest melting temperature in the holding apparatus (150) and/or than the melting temperature of the material of the wrap spring (130, 130b)
Implementation Method 2
a wrap spring (130, 130b) of the blocking apparatus (10, 10b) which is held mechanically prestressed in the holding apparatus (150)
Data Source
AI summary
Various embodiments include a blocking apparatus comprising: a holding apparatus; a receiving element mounted in the holding apparatus about an axis of rotation, defining a through-opening with a through-axis parallel to the axis of rotation; a wrap spring mechanically prestressed in the holding apparatus, with a winding arranged around the receiving element; and a thermocouple made of a material having a lower melting temperature than the holding apparatus and/or the wrap spring. The thermocouple holds at least one end of the wrap spring with respect to the holding apparatus in the prestressed state in such a way that the receiving element can be freely rotated in both drive directions about the axis of rotation. The receiving element is blocked in one of the two drive directions in the relaxed state of the wrap spring and in the triggered state of a thermal fuse.