Fire-Triggered Pressure Relief Valve With SMA Latch Release
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Solution Overview
Problem
Existing pressure relief devices for high-pressure gas storage systems lack effective emergency countermeasures, particularly in detecting and responding to fire situations quickly and reliably.
Innovation Solution
The development of improved pressure relief valves with a vent passage, a moveable plug, a latch mechanism, and a trigger assembly that includes a fire detection portion and a latch control portion. These components work together to allow gas to vent from the tank when exposed to heat above a threshold, ensuring rapid and reliable pressure relief in emergency situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing pressure relief devices are used, then the basic venting function is provided, but the detection range and response speed to emergency situations are insufficient
Solution Approach 1:
The pressure relief valve is divided into functionally independent modules: a fire detection portion with elongate body, a trigger assembly with latch control, a vent passage with movable plug, and a tank. This segmentation allows each component to be optimized for its specific function while maintaining overall system reliability and enabling targeted replacement or maintenance of individual modules.
Solution Approach 2:
The fire detection portion replaces traditional mechanical pressure sensors with a thermal detection mechanism. The elongate body of the fire detection portion detects heat from fire conditions, automatically triggering the venting sequence without requiring complex electronic sensors or mechanical pressure switches, thus improving reliability while maintaining relatively simple structure.
2Speed
If the pressure relief valve is designed with simple structure, then manufacturing is easier, but the response speed to fire emergencies is slower
Solution Approach 1:
The latch is pre-positioned in the trigger assembly, ready to release immediately upon fire detection. The trigger assembly is designed so that when the fire detection portion detects heat, the latch automatically releases without requiring additional activation steps, enabling instantaneous plug movement and rapid venting response.
Solution Approach 2:
Instead of requiring active movement or power input to open the valve, the system is designed so that the default state is closed and held by the latch, and opening occurs automatically when the latch releases due to fire detection. This inversion of the control logic eliminates the need for complex actuation mechanisms while achieving fast response.
3Reliability
If the plug is designed to move freely in the vent passage, then venting is faster, but the valve cannot maintain sealed position under normal conditions
Solution Approach 1:
The latch mechanism is designed to automatically engage and hold the plug in the sealed position without requiring external power or control systems. The mechanical latch self-locks the plug under normal conditions and automatically releases when the fire detection portion detects heat, providing reliable sealing while enabling rapid automatic venting without complex control systems.
4Adaptability or versatility
If the fire detection portion has extended length for wider detection range, then detection coverage is improved, but the device dimensions and complexity increase
Solution Approach 1:
The elongate body of the fire detection portion serves multiple functions: it acts as the structural framework for the trigger assembly, provides the detection surface for fire heat, and serves as the mounting structure for the latch mechanism. This multi-functionality allows the single component to provide extended detection range without proportionally increasing overall device complexity.
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 proposed solution provides enhanced emergency countermeasures by offering a wider range of detection for emergency situations, such as fire, and enables faster response times, thereby improving safety in high-pressure gas storage systems.
Implementation Method 1
The pressure relief valve also includes a shape memory alloy wire that has a first length disposed in the body of the pressure relief valve and a second length disposed outside the body of the pressure relief valve. The shape memory alloy wire is configured to shorten when exposed to a temperature above a threshold temperature.
Implementation Method 2
The vent passage has a first end configured to be in fluid communication with the orifice and thereby with the internal volume of the tank to allow gas from the tank to flow out of the tank into the pressure relief valve... allowing gas in the tank to flow to a second end of the vent passage and out of the pressure relief valve
Data Source
AI summary
A pressure relief valve configured to vent a pressurized tank in the event of a fire is provided. The pressure relief valve includes a body, a vent passage, a plug and a latch. The vent passage is disposed through the body. The vent passage can be placed in fluid communication with an internal volume of a tank and with the atmosphere. The plug is moveably mounted in the vent passage. The latch has a blocking member disposed in contact with a control end of the plug in a first configuration and out of contact with the control end in a second configuration. The second configuration allows movement of the plug in the vent passage. One or both of a shape memory alloy wire and a trigger piston is configured to actuate the latch from the first to the second configuration. The shape memory alloy wire is configured to shorten when exposed to a temperature above a threshold temperature. The trigger piston moves, e.g., by a pressurized gas, in a trigger actuation passage to actuate the latch from the first configuration to the second configuration.