Sprinkler Activation Using Shape Memory Alloy Fracture
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Solution Overview
Problem
Existing fire sprinkler systems have long response times due to the unfavorable heat-absorbing surface to volume ratio of traditional glass bulbs, which is costly and fragile, making them inefficient for fast fire suppression.
Innovation Solution
A sprinkler activation mechanism using a shape memory alloy (SMA) element that memorizes a shape and fractures a brittle tube, such as tempered glass or ceramic, to release the fire fighting fluid when the environmental temperature exceeds a predetermined threshold, providing a fast and robust response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional glass bulbs are used in sprinkler systems, then the sprinkler can detect heat and activate, but the response time is long due to unfavorable heat-absorbing surface to volume ratio
Solution Approach 1:
The patent changes the material parameter from traditional glass to shape memory alloy (SMA), which has superior thermal response characteristics. The SMA element undergoes a phase transformation at a predetermined temperature, causing a sudden shape change that fractures the brittle tube. This material parameter change enables significantly faster heat response and activation compared to conventional glass bulbs.
Solution Approach 2:
The invention uses a composite structure combining a shape memory alloy element with a brittle tube (tempered glass or ceramic). The SMA element provides fast thermal response and shape transformation, while the brittle tube provides structural containment and fracture-based activation. This composite approach leverages the complementary properties of both materials to achieve rapid, reliable sprinkler activation.
2Reliability
If traditional glass bulbs are used, then the sprinkler system can function, but the glass bulbs are fragile and costly
Solution Approach 1:
The patent replaces expensive, fragile glass bulbs with a more cost-effective assembly using tempered glass or ceramic brittle tubes combined with SMA elements. The brittle tube is designed to fracture reliably at the activation temperature, and can be replaced as a disposable component. This approach reduces manufacturing costs while improving reliability through the use of tempered materials that are more durable during installation and maintenance.
3Speed
If the SMA element expands to break the bulb, then fast response is achieved, but the bulb must be precisely designed to fracture
Solution Approach 1:
The SMA element is pre-formed with a specific shape and memory configuration during manufacturing. The brittle tube is also pre-designed with controlled weakness points or geometric features that facilitate fracture. When the SMA element undergoes phase transformation and expands, it applies force to predetermined locations on the brittle tube, ensuring reliable fracture without requiring complex real-time adjustments. This preliminary design of both components simplifies the manufacturing process while maintaining fast response characteristics.
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 SMA element enables a significantly faster response time comparable to or surpassing glass bulbs, while being more cost-effective and durable, ensuring efficient fire suppression without the fragility issues of traditional glass bulbs.
Implementation Method 1
a shape memory alloy (SMA) element associated with the frangible bulb having a first configuration that fits with the bulb and a second configuration at a predetermined temperature which breaks the frangible bulb
Data Source
AI summary
A sprinkler head including a sprinkler body with a passage for fluid and a seal mechanism sealing the passage, and a cage member. A frangible bulb extends between the cage member and the seal. A shape memory alloy element is associated with the frangible bulb and has a first configuration that fits within, about, or abutting the bulb and a second configuration at a predetermined temperature which breaks the frangible bulb releasing the fluid through the passage.